import { createHash, randomBytes, scryptSync, timingSafeEqual } from "node:crypto";
import { mkdirSync, readFileSync } from "node:fs";
import { resolve } from "node:path";
import { DatabaseSync } from "node:sqlite";

const SESSION_LIFETIME_MS = 30 * 24 * 60 * 60 * 1000;
const MAX_JSON_BYTES = 1024 * 1024;
const AUTH_WINDOW_MS = 15 * 60 * 1000;
const AUTH_ATTEMPTS_PER_WINDOW = 20;
const HOCKEY_PVP_COUNTDOWN_MS = 5_000;
const ROGUELIKE_PVP_MODE = "roguelike-pvp";
const ROGUELIKE_PVP_COUNTDOWN_MS = 5_000;
const ROGUELIKE_PVP_DRAFT_MS = 15_000;
const ROGUELIKE_PVP_DISCONNECT_GRACE_MS = 15_000;
const ROGUELIKE_PVP_CONNECTED_WINDOW_MS = 3_000;
const ROGUELIKE_PVP_QUEUE_TTL_MS = 30_000;
const ROGUELIKE_PVP_MATCH_TTL_MS = 10 * 60_000;
const ROGUELIKE_PVP_MAX_SNAPSHOT_BYTES = 2_048;
const HEALER_CLASS_IDS = new Set(["priest", "druid", "shaman", "paladin", "chronomancer"]);
const ROGUELIKE_PVP_PHASES = new Set(["countdown", "combat", "draft", "won", "lost"]);
const ROGUELIKE_PVP_BUFF_IDS = [
  "mend-echo",
  "mend-efficiency",
  "mend-cast-speed",
  "renew-spread",
  "renew-duration",
  "renew-potency",
  "shield-echo",
  "shield-potency",
  "shield-guard",
  "purify-renew",
  "purify-shield",
  "purify-chain",
  "radiance-cooldown",
  "radiance-renew",
  "radiance-shield",
  "barrier-cooldown",
  "barrier-duration",
  "barrier-regen",
];
const ROGUELIKE_PVP_BUFF_ID_SET = new Set(ROGUELIKE_PVP_BUFF_IDS);
const ROGUELIKE_PVP_SINGLE_RANK_BUFF_IDS = new Set([
  "purify-renew",
  "purify-shield",
  "purify-chain",
  "radiance-renew",
]);
const ROGUELIKE_PVP_CURSE_IDS = ["ability1", "ability2", "ability3", "ability4", "ability5", "ability6"]
  .flatMap((abilityId) => [`${abilityId}-mana-cost`, `${abilityId}-cooldown`]);
const ROGUELIKE_PVP_CURSE_ID_SET = new Set(ROGUELIKE_PVP_CURSE_IDS);
const ROGUELIKE_PVP_SUPPORTED_BUFF_IDS = {
  priest: new Set(ROGUELIKE_PVP_BUFF_IDS),
  druid: new Set(ROGUELIKE_PVP_BUFF_IDS),
  shaman: new Set(ROGUELIKE_PVP_BUFF_IDS),
  paladin: new Set([
    "mend-echo", "mend-efficiency", "mend-cast-speed",
    "purify-renew", "purify-shield", "purify-chain",
    "barrier-cooldown", "barrier-duration",
  ]),
  chronomancer: new Set([
    "mend-echo", "mend-efficiency", "mend-cast-speed",
    "purify-renew", "purify-shield", "purify-chain",
    "radiance-cooldown", "barrier-cooldown",
  ]),
};
const authAttempts = new Map();

function apiError(message, status = 400) {
  const error = new Error(message);
  error.status = status;
  return error;
}

function sendJson(response, status, body) {
  response.statusCode = status;
  response.setHeader("Content-Type", "application/json; charset=utf-8");
  response.setHeader("Cache-Control", "no-store");
  response.setHeader("X-Content-Type-Options", "nosniff");
  response.end(JSON.stringify(body));
}

function configuredCorsOrigins() {
  return String(process.env.CORS_ORIGINS ?? "")
    .split(",")
    .map((origin) => origin.trim())
    .filter(Boolean);
}

function setCorsHeaders(request, response) {
  const origin = request.headers.origin;
  if (!origin) return;
  const configured = configuredCorsOrigins();
  if (!configured.includes("*") && !configured.includes(origin)) return;
  response.setHeader("Access-Control-Allow-Origin", origin);
  response.setHeader("Access-Control-Allow-Headers", "Authorization,Content-Type");
  response.setHeader("Access-Control-Allow-Methods", "GET,POST,PUT,DELETE,OPTIONS");
  response.setHeader("Access-Control-Max-Age", "86400");
  response.setHeader("Vary", "Origin");
}

async function readJson(request) {
  const chunks = [];
  let size = 0;
  for await (const chunk of request) {
    size += chunk.length;
    if (size > MAX_JSON_BYTES) throw apiError("Request body is too large.", 413);
    chunks.push(chunk);
  }
  try {
    return JSON.parse(Buffer.concat(chunks).toString("utf8"));
  } catch {
    throw apiError("Request body must be valid JSON.");
  }
}

function canonicalUsername(value) {
  return String(value ?? "").trim().toLocaleLowerCase();
}

function validateUsername(value) {
  const username = String(value ?? "").trim();
  if (!/^[A-Za-z0-9_]{3,20}$/.test(username)) {
    throw apiError("Username must be 3–20 letters, numbers, or underscores.");
  }
  return username;
}

function validatePassword(value) {
  const password = String(value ?? "");
  if (password.length < 10 || password.length > 128) {
    throw apiError("Password must be 10–128 characters.");
  }
  return password;
}

function passwordDigest(password, salt) {
  return scryptSync(password, salt, 64).toString("hex");
}

function verifyPassword(password, account) {
  const actual = Buffer.from(passwordDigest(password, account.passwordSalt), "hex");
  const expected = Buffer.from(account.passwordHash, "hex");
  return actual.length === expected.length && timingSafeEqual(actual, expected);
}

function tokenHash(token) {
  return createHash("sha256").update(token).digest("hex");
}

function bearerToken(request) {
  const authorization = String(request.headers.authorization ?? "");
  return authorization.startsWith("Bearer ") ? authorization.slice(7).trim() : "";
}

function createSession(database, accountId) {
  const token = randomBytes(32).toString("base64url");
  const expiresAt = new Date(Date.now() + SESSION_LIFETIME_MS).toISOString();
  database.prepare(`
    INSERT INTO sessions (account_id, token_hash, expires_at)
    VALUES (?, ?, ?)
  `).run(accountId, tokenHash(token), expiresAt);
  return token;
}

function currentSession(database, request) {
  const token = bearerToken(request);
  if (!token) return null;
  return database.prepare(`
    SELECT accounts.id AS accountId, accounts.username
    FROM sessions
    JOIN accounts ON accounts.id = sessions.account_id
    WHERE sessions.token_hash = ? AND sessions.expires_at > CURRENT_TIMESTAMP
  `).get(tokenHash(token)) ?? null;
}

function requireSession(database, request) {
  const session = currentSession(database, request);
  if (!session) throw apiError("Sign in required.", 401);
  return session;
}

function clientAddress(request) {
  return request.socket?.remoteAddress ?? "unknown";
}

function enforceAuthRateLimit(request) {
  const now = Date.now();
  const key = clientAddress(request);
  const existing = authAttempts.get(key);
  const bucket = existing && now - existing.startedAt < AUTH_WINDOW_MS
    ? existing
    : { startedAt: now, count: 0 };
  bucket.count += 1;
  authAttempts.set(key, bucket);
  if (bucket.count > AUTH_ATTEMPTS_PER_WINDOW) {
    throw apiError("Too many authentication attempts. Try again later.", 429);
  }
}

function register(database, payload) {
  const username = validateUsername(payload?.username);
  const password = validatePassword(payload?.password);
  const canonical = canonicalUsername(username);
  if (database.prepare("SELECT id FROM accounts WHERE canonical_username = ?").get(canonical)) {
    throw apiError("Account already exists.", 409);
  }
  const salt = randomBytes(16).toString("hex");
  const result = database.prepare(`
    INSERT INTO accounts (username, canonical_username, password_hash, password_salt)
    VALUES (?, ?, ?, ?)
  `).run(username, canonical, passwordDigest(password, salt), salt);
  const accountId = Number(result.lastInsertRowid);
  return { account: { id: accountId, username }, token: createSession(database, accountId) };
}

function login(database, payload) {
  const canonical = canonicalUsername(payload?.username);
  const password = String(payload?.password ?? "");
  const account = database.prepare(`
    SELECT id, username, password_hash AS passwordHash, password_salt AS passwordSalt
    FROM accounts WHERE canonical_username = ?
  `).get(canonical);
  if (!account || !verifyPassword(password, account)) {
    throw apiError("Username or password is incorrect.", 401);
  }
  return {
    account: { id: account.id, username: account.username },
    token: createSession(database, account.id),
  };
}

function validateSlotId(value) {
  const slotId = Number(value);
  if (!Number.isInteger(slotId) || slotId < 1 || slotId > 3) throw apiError("Invalid save slot.");
  return slotId;
}

function validateHealerClassId(value) {
  const healerClassId = String(value ?? "");
  if (!HEALER_CLASS_IDS.has(healerClassId)) throw apiError("Healer class is invalid.");
  return healerClassId;
}

function validateRoguelikePvpMode(value) {
  if (value !== ROGUELIKE_PVP_MODE) throw apiError("PVP queue mode is invalid.");
  return ROGUELIKE_PVP_MODE;
}

function validateRoguelikePvpGeneration(value) {
  const generation = Number(value);
  if (!Number.isSafeInteger(generation) || generation < 1) {
    throw apiError("Roguelike PVP match generation is invalid.");
  }
  return generation;
}

function validateRoguelikePvpRound(value) {
  const round = Number(value);
  if (!Number.isSafeInteger(round) || round < 1 || round > 100_000) {
    throw apiError("Roguelike PVP round is invalid.");
  }
  return round;
}

function validateRoguelikePvpSnapshot(value) {
  if (!value || typeof value !== "object" || Array.isArray(value)) {
    throw apiError("Roguelike PVP snapshot is invalid.");
  }
  if (Buffer.byteLength(JSON.stringify(value), "utf8") > ROGUELIKE_PVP_MAX_SNAPSHOT_BYTES) {
    throw apiError("Roguelike PVP snapshot is too large.", 413);
  }
  const allowedKeys = new Set([
    "sequence",
    "round",
    "phase",
    "partyHp",
    "bossHp",
    "bossMaxHp",
    "defeatedBosses",
  ]);
  if (Object.keys(value).some((key) => !allowedKeys.has(key))) {
    throw apiError("Roguelike PVP snapshot contains unsupported data.");
  }
  const sequence = value.sequence;
  if (typeof value.round !== "number") throw apiError("Roguelike PVP round is invalid.");
  const round = validateRoguelikePvpRound(value.round);
  const phase = String(value.phase ?? "");
  const partyHp = value.partyHp;
  const bossHp = value.bossHp;
  const bossMaxHp = value.bossMaxHp;
  const defeatedBosses = value.defeatedBosses;
  if (!Number.isSafeInteger(sequence) || sequence < 1) {
    throw apiError("Roguelike PVP snapshot sequence is invalid.");
  }
  if (!ROGUELIKE_PVP_PHASES.has(phase)) throw apiError("Roguelike PVP snapshot phase is invalid.");
  if (!Array.isArray(partyHp) || partyHp.length !== 5
      || partyHp.some((hp) => typeof hp !== "number" || !Number.isFinite(hp) || hp < 0 || hp > 1)) {
    throw apiError("Roguelike PVP party health is invalid.");
  }
  if (!Number.isFinite(bossHp) || !Number.isFinite(bossMaxHp)
      || bossHp < 0 || bossMaxHp < 0 || bossHp > bossMaxHp) {
    throw apiError("Roguelike PVP boss health is invalid.");
  }
  if (!Number.isSafeInteger(defeatedBosses) || defeatedBosses < 0) {
    throw apiError("Roguelike PVP defeated boss count is invalid.");
  }
  if (phase === "won") {
    throw apiError("Roguelike PVP wins are adjudicated by the match server.");
  }
  if (phase === "lost" && partyHp.some((hp) => hp !== 0)) {
    throw apiError("Roguelike PVP loss requires all five party members at zero health.");
  }
  return {
    sequence,
    round,
    phase,
    partyHp: [...partyHp],
    bossHp,
    bossMaxHp,
    defeatedBosses,
  };
}

function validateRoguelikePvpDraftSelection(value) {
  if (!value || typeof value !== "object" || Array.isArray(value)) {
    throw apiError("Roguelike PVP draft selection is invalid.");
  }
  const buffId = value.buffId === null ? null : String(value.buffId ?? "");
  const curseId = value.curseId === null ? null : String(value.curseId ?? "");
  if (buffId !== null && !ROGUELIKE_PVP_BUFF_ID_SET.has(buffId)
      || curseId !== null && !ROGUELIKE_PVP_CURSE_ID_SET.has(curseId)) {
    throw apiError("Roguelike PVP draft selection is invalid.");
  }
  if (value.autoPicked !== undefined && typeof value.autoPicked !== "boolean") {
    throw apiError("Roguelike PVP auto-pick marker is invalid.");
  }
  return { buffId, curseId, autoPicked: value.autoPicked === true };
}

function createRoguelikePvpSeededRandom(seed) {
  let state = seed >>> 0;
  return () => {
    state = (state + 0x6d2b79f5) >>> 0;
    let value = state;
    value = Math.imul(value ^ (value >>> 15), value | 1);
    value ^= value + Math.imul(value ^ (value >>> 7), value | 61);
    return ((value ^ (value >>> 14)) >>> 0) / 0x100000000;
  };
}

function selectRoguelikePvpPool(pool, random, count) {
  const available = [...pool];
  const selected = [];
  while (selected.length < count && available.length > 0) {
    const index = Math.floor(random() * available.length);
    selected.push(available[index]);
    available.splice(index, 1);
  }
  return selected;
}

function roguelikePvpDraftOffers(match, side, round) {
  const progress = match.draftProgress;
  const buffRanks = progress.buffRanks[side];
  const curseRanks = progress.curseRanks[side];
  const random = createRoguelikePvpSeededRandom(
    (match.seed ^ Math.imul(round, 0x7f4a7c15)) >>> 0,
  );
  const availableBuffs = ROGUELIKE_PVP_BUFF_IDS.filter((buffId) => {
    const maxRank = ROGUELIKE_PVP_SINGLE_RANK_BUFF_IDS.has(buffId) ? 1 : 3;
    return Math.max(0, Math.floor(buffRanks[buffId] ?? 0)) < maxRank;
  });
  // Client draft generation shuffles the complete uncapped catalog before
  // filtering class-specific no-op buffs. Mirror that order exactly.
  const shuffledBuffs = selectRoguelikePvpPool(availableBuffs, random, availableBuffs.length);
  const supportedBuffs = ROGUELIKE_PVP_SUPPORTED_BUFF_IDS[match.players[side].healerClassId];
  const buffChoices = shuffledBuffs.filter((buffId) => supportedBuffs.has(buffId)).slice(0, 3);
  const availableCurses = ROGUELIKE_PVP_CURSE_IDS.filter(
    (curseId) => Math.max(0, Math.floor(curseRanks[curseId] ?? 0)) < 3,
  );
  const curseChoices = selectRoguelikePvpPool(availableCurses, random, 3);
  return { buffChoices, curseChoices };
}

function roguelikePvpBossCountForRound(round) {
  return round % 5 === 0 ? 3 : 2;
}

function validateSave(value, slotId) {
  const schemaVersion = Number(value?.schemaVersion);
  if (!value || typeof value !== "object" || schemaVersion !== 5 && schemaVersion !== 6 && schemaVersion !== 7) {
    throw apiError("Save snapshot is invalid.");
  }
  if (Number(value.slotId) !== slotId) throw apiError("Save slot does not match request.");
  if (typeof value.hunterName !== "string" || !value.hunterName.trim()) {
    throw apiError("Save snapshot has no hunter name.");
  }
  return { ...value, schemaVersion: 7 };
}

function normalizeNonNegativeInteger(value) {
  const number = Math.floor(Number(value));
  return Number.isFinite(number) ? Math.max(0, number) : 0;
}

function normalizeNonNegativeNumber(value) {
  const number = Number(value);
  return Number.isFinite(number) ? Math.max(0, number) : 0;
}

function mergeLeaderboardHighWater(database, accountId, slotId, save) {
  const blockbreaker = database.prepare(`
    SELECT highest_bricks AS highestBricks, longest_seconds AS longestSeconds, highest_score AS highestScore
    FROM blockbreaker_records WHERE account_id = ? AND slot_id = ?
  `).get(accountId, slotId);
  const aether = database.prepare(`
    SELECT highest_score AS highestScore, wave_at_best AS waveAtBest, duration_at_best AS durationAtBest
    FROM aether_assault_records WHERE account_id = ? AND slot_id = ?
  `).get(accountId, slotId);
  const stats = save.stats && typeof save.stats === "object" ? save.stats : {};
  const candidateAether = {
    score: normalizeNonNegativeInteger(stats.highestAetherAssaultScore),
    wave: normalizeNonNegativeInteger(stats.highestAetherAssaultWaveAtBest),
    duration: normalizeNonNegativeNumber(stats.longestAetherAssaultSecondsAtBest),
  };
  const storedAether = {
    score: normalizeNonNegativeInteger(aether?.highestScore),
    wave: normalizeNonNegativeInteger(aether?.waveAtBest),
    duration: normalizeNonNegativeNumber(aether?.durationAtBest),
  };
  const aetherRecord = candidateAether.score > storedAether.score
    || candidateAether.score === storedAether.score && candidateAether.wave > storedAether.wave
    || candidateAether.score === storedAether.score && candidateAether.wave === storedAether.wave && candidateAether.duration > storedAether.duration
    ? candidateAether
    : storedAether;
  return {
    ...save,
    schemaVersion: 7,
    stats: {
      ...stats,
      roguelikePvpWins: normalizeNonNegativeInteger(stats.roguelikePvpWins),
      roguelikePvpLosses: normalizeNonNegativeInteger(stats.roguelikePvpLosses),
      highestRoguelikePvpRound: normalizeNonNegativeInteger(stats.highestRoguelikePvpRound),
      highestBlockbreakerBricks: Math.max(
        normalizeNonNegativeInteger(stats.highestBlockbreakerBricks),
        normalizeNonNegativeInteger(blockbreaker?.highestBricks),
      ),
      longestBlockbreakerSeconds: Math.max(
        normalizeNonNegativeNumber(stats.longestBlockbreakerSeconds),
        normalizeNonNegativeNumber(blockbreaker?.longestSeconds),
      ),
      highestBlockbreakerScore: Math.max(
        normalizeNonNegativeInteger(stats.highestBlockbreakerScore),
        normalizeNonNegativeInteger(blockbreaker?.highestScore),
      ),
      highestAetherAssaultScore: aetherRecord.score,
      highestAetherAssaultWaveAtBest: aetherRecord.wave,
      longestAetherAssaultSecondsAtBest: aetherRecord.duration,
    },
  };
}

function syncLeaderboardStats(database, accountId, slotId, save) {
  database.prepare("DELETE FROM boss_kill_records WHERE account_id = ? AND slot_id = ?").run(accountId, slotId);
  const insertBoss = database.prepare(`
    INSERT INTO boss_kill_records (account_id, slot_id, boss_id, kills, updated_at)
    VALUES (?, ?, ?, ?, CURRENT_TIMESTAMP)
  `);
  const bossKills = save.stats?.bossKills && typeof save.stats.bossKills === "object"
    ? save.stats.bossKills
    : {};
  for (const [bossId, rawKills] of Object.entries(bossKills)) {
    if (!/^[a-z0-9-]{1,64}$/.test(bossId)) continue;
    const kills = normalizeNonNegativeInteger(rawKills);
    if (kills > 0) insertBoss.run(accountId, slotId, bossId, kills);
  }
  const highestRound = normalizeNonNegativeInteger(save.stats?.highestRoguelikeRound);
  database.prepare(`
    INSERT INTO roguelike_records (account_id, slot_id, highest_round, updated_at)
    VALUES (?, ?, ?, CURRENT_TIMESTAMP)
    ON CONFLICT(account_id, slot_id) DO UPDATE SET
      highest_round = excluded.highest_round,
      updated_at = CURRENT_TIMESTAMP
  `).run(accountId, slotId, highestRound);
  const highestEndlessKills = normalizeNonNegativeInteger(save.stats?.highestRogueTrialsEndlessKills);
  database.prepare(`
    INSERT INTO rogue_trials_endless_records (account_id, slot_id, highest_boss_kills, updated_at)
    VALUES (?, ?, ?, CURRENT_TIMESTAMP)
    ON CONFLICT(account_id, slot_id) DO UPDATE SET
      highest_boss_kills = excluded.highest_boss_kills,
      updated_at = CURRENT_TIMESTAMP
  `).run(accountId, slotId, highestEndlessKills);
  const highestHockeyReturns = normalizeNonNegativeInteger(save.stats?.highestHockeyHealingReturns);
  const hockeyDurationSeconds = normalizeNonNegativeNumber(save.stats?.longestHockeyHealingSecondsAtBest);
  database.prepare(`
    INSERT INTO hockey_healing_records (account_id, slot_id, highest_returns, duration_seconds, updated_at)
    VALUES (?, ?, ?, ?, CURRENT_TIMESTAMP)
    ON CONFLICT(account_id, slot_id) DO UPDATE SET
      highest_returns = excluded.highest_returns,
      duration_seconds = excluded.duration_seconds,
    updated_at = CURRENT_TIMESTAMP
  `).run(accountId, slotId, highestHockeyReturns, hockeyDurationSeconds);

  const hockeyPvpWins = normalizeNonNegativeInteger(save.stats?.hockeyHealingPvpWins);
  const hockeyPvpLosses = normalizeNonNegativeInteger(save.stats?.hockeyHealingPvpLosses);
  const hockeyPvpBossKills = normalizeNonNegativeInteger(save.stats?.hockeyHealingPvpBossKills);
  database.prepare(`
    INSERT INTO hockey_pvp_records (account_id, slot_id, wins, losses, boss_kills, updated_at)
    VALUES (?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
    ON CONFLICT(account_id, slot_id) DO UPDATE SET
      wins = excluded.wins,
      losses = excluded.losses,
      boss_kills = excluded.boss_kills,
      updated_at = CURRENT_TIMESTAMP
  `).run(accountId, slotId, hockeyPvpWins, hockeyPvpLosses, hockeyPvpBossKills);

  const highestBlockbreakerBricks = normalizeNonNegativeInteger(save.stats?.highestBlockbreakerBricks);
  const longestBlockbreakerSeconds = normalizeNonNegativeNumber(save.stats?.longestBlockbreakerSeconds);
  const highestBlockbreakerScore = normalizeNonNegativeInteger(save.stats?.highestBlockbreakerScore);
  database.prepare(`
    INSERT INTO blockbreaker_records (
      account_id, slot_id,
      highest_bricks, bricks_achieved_at,
      longest_seconds, time_achieved_at,
      highest_score, score_achieved_at,
      updated_at
    ) VALUES (?, ?, ?, CURRENT_TIMESTAMP, ?, CURRENT_TIMESTAMP, ?, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
    ON CONFLICT(account_id, slot_id) DO UPDATE SET
      bricks_achieved_at = CASE
        WHEN excluded.highest_bricks > blockbreaker_records.highest_bricks THEN CURRENT_TIMESTAMP
        ELSE blockbreaker_records.bricks_achieved_at
      END,
      highest_bricks = MAX(blockbreaker_records.highest_bricks, excluded.highest_bricks),
      time_achieved_at = CASE
        WHEN excluded.longest_seconds > blockbreaker_records.longest_seconds THEN CURRENT_TIMESTAMP
        ELSE blockbreaker_records.time_achieved_at
      END,
      longest_seconds = MAX(blockbreaker_records.longest_seconds, excluded.longest_seconds),
      score_achieved_at = CASE
        WHEN excluded.highest_score > blockbreaker_records.highest_score THEN CURRENT_TIMESTAMP
        ELSE blockbreaker_records.score_achieved_at
      END,
      highest_score = MAX(blockbreaker_records.highest_score, excluded.highest_score),
      updated_at = CURRENT_TIMESTAMP
  `).run(accountId, slotId, highestBlockbreakerBricks, longestBlockbreakerSeconds, highestBlockbreakerScore);

  const highestAetherScore = normalizeNonNegativeInteger(save.stats?.highestAetherAssaultScore);
  const aetherWaveAtBest = normalizeNonNegativeInteger(save.stats?.highestAetherAssaultWaveAtBest);
  const aetherDurationAtBest = normalizeNonNegativeNumber(save.stats?.longestAetherAssaultSecondsAtBest);
  database.prepare(`
    INSERT INTO aether_assault_records (
      account_id, slot_id, highest_score, wave_at_best, duration_at_best, score_achieved_at, updated_at
    ) VALUES (?, ?, ?, ?, ?, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
    ON CONFLICT(account_id, slot_id) DO UPDATE SET
      highest_score = excluded.highest_score,
      wave_at_best = excluded.wave_at_best,
      duration_at_best = excluded.duration_at_best,
      score_achieved_at = CASE
        WHEN excluded.highest_score > aether_assault_records.highest_score
          OR excluded.highest_score = aether_assault_records.highest_score
            AND excluded.wave_at_best > aether_assault_records.wave_at_best
        THEN CURRENT_TIMESTAMP
        ELSE aether_assault_records.score_achieved_at
      END,
      updated_at = CURRENT_TIMESTAMP
    WHERE excluded.highest_score > aether_assault_records.highest_score
      OR excluded.highest_score = aether_assault_records.highest_score
        AND excluded.wave_at_best > aether_assault_records.wave_at_best
      OR excluded.highest_score = aether_assault_records.highest_score
        AND excluded.wave_at_best = aether_assault_records.wave_at_best
        AND excluded.duration_at_best > aether_assault_records.duration_at_best
  `).run(accountId, slotId, highestAetherScore, aetherWaveAtBest, aetherDurationAtBest);
}

function writeSave(database, accountId, slotId, rawSave) {
  const validatedSave = validateSave(rawSave, slotId);
  database.exec("BEGIN IMMEDIATE");
  try {
    const save = mergeLeaderboardHighWater(database, accountId, slotId, validatedSave);
    const serialized = JSON.stringify(save);
    if (Buffer.byteLength(serialized) > MAX_JSON_BYTES) throw apiError("Save snapshot is too large.", 413);
    database.prepare(`
      INSERT INTO hunter_saves (account_id, slot_id, hunter_name, save_json, updated_at)
      VALUES (?, ?, ?, ?, CURRENT_TIMESTAMP)
      ON CONFLICT(account_id, slot_id) DO UPDATE SET
        hunter_name = excluded.hunter_name,
        save_json = excluded.save_json,
        updated_at = CURRENT_TIMESTAMP
    `).run(accountId, slotId, save.hunterName.trim().slice(0, 20), serialized);
    syncLeaderboardStats(database, accountId, slotId, save);
    database.exec("COMMIT");
    return save;
  } catch (error) {
    database.exec("ROLLBACK");
    throw error;
  }
}

function readSave(database, accountId, slotId) {
  const row = database.prepare(`
    SELECT save_json AS saveJson FROM hunter_saves WHERE account_id = ? AND slot_id = ?
  `).get(accountId, slotId);
  if (!row) return null;
  try {
    const save = JSON.parse(row.saveJson);
    return mergeLeaderboardHighWater(database, accountId, slotId, save);
  } catch {
    return null;
  }
}

function listSaves(database, accountId) {
  return database.prepare(`
    SELECT slot_id AS slotId, save_json AS saveJson, updated_at AS updatedAt
    FROM hunter_saves WHERE account_id = ? ORDER BY slot_id
  `).all(accountId).flatMap((row) => {
    try {
      const save = mergeLeaderboardHighWater(database, accountId, row.slotId, JSON.parse(row.saveJson));
      return [{ slotId: row.slotId, save, updatedAt: row.updatedAt }];
    }
    catch { return []; }
  });
}

function leaderboardEntry(row, valueKey, secondaryValueKey) {
  return {
    rank: row.rank,
    username: row.username,
    hunterName: row.hunterName,
    slotId: row.slotId,
    value: row[valueKey],
    ...(secondaryValueKey ? { secondaryValue: row[secondaryValueKey] } : {}),
  };
}

function bossLeaderboard(database, accountId, slotId, bossId) {
  if (!/^[a-z0-9-]{1,64}$/.test(bossId)) throw apiError("Invalid boss.");
  const rows = database.prepare(`
    WITH ranked AS (
      SELECT
        RANK() OVER (ORDER BY records.kills DESC) AS rank,
        records.account_id AS accountId,
        records.slot_id AS slotId,
        records.kills,
        accounts.username,
        saves.hunter_name AS hunterName,
        records.updated_at AS updatedAt
      FROM boss_kill_records records
      JOIN accounts ON accounts.id = records.account_id
      JOIN hunter_saves saves ON saves.account_id = records.account_id AND saves.slot_id = records.slot_id
      WHERE records.boss_id = ?
    )
    SELECT * FROM ranked ORDER BY kills DESC, updatedAt ASC, accountId ASC, slotId ASC
  `).all(bossId);
  const current = rows.find((row) => row.accountId === accountId && row.slotId === slotId) ?? null;
  return {
    kind: "boss",
    bossId,
    top: rows.slice(0, 5).map((row) => leaderboardEntry(row, "kills")),
    current: current ? leaderboardEntry(current, "kills") : null,
  };
}

function roguelikeLeaderboard(database, accountId, slotId) {
  const rows = database.prepare(`
    WITH ranked AS (
      SELECT
        RANK() OVER (ORDER BY records.highest_round DESC) AS rank,
        records.account_id AS accountId,
        records.slot_id AS slotId,
        records.highest_round AS highestRound,
        accounts.username,
        saves.hunter_name AS hunterName,
        records.updated_at AS updatedAt
      FROM roguelike_records records
      JOIN accounts ON accounts.id = records.account_id
      JOIN hunter_saves saves ON saves.account_id = records.account_id AND saves.slot_id = records.slot_id
      WHERE records.highest_round > 0
    )
    SELECT * FROM ranked ORDER BY highestRound DESC, updatedAt ASC, accountId ASC, slotId ASC
  `).all();
  const current = rows.find((row) => row.accountId === accountId && row.slotId === slotId) ?? null;
  return {
    kind: "roguelike",
    top: rows.slice(0, 5).map((row) => leaderboardEntry(row, "highestRound")),
    current: current ? leaderboardEntry(current, "highestRound") : null,
  };
}

function rogueTrialsEndlessLeaderboard(database, accountId, slotId) {
  const rows = database.prepare(`
    WITH ranked AS (
      SELECT
        RANK() OVER (ORDER BY records.highest_boss_kills DESC) AS rank,
        records.account_id AS accountId,
        records.slot_id AS slotId,
        records.highest_boss_kills AS highestBossKills,
        accounts.username,
        saves.hunter_name AS hunterName,
        records.updated_at AS updatedAt
      FROM rogue_trials_endless_records records
      JOIN accounts ON accounts.id = records.account_id
      JOIN hunter_saves saves ON saves.account_id = records.account_id AND saves.slot_id = records.slot_id
      WHERE records.highest_boss_kills > 0
    )
    SELECT * FROM ranked ORDER BY highestBossKills DESC, updatedAt ASC, accountId ASC, slotId ASC
  `).all();
  const current = rows.find((row) => row.accountId === accountId && row.slotId === slotId) ?? null;
  return {
    kind: "rogue-trials-endless",
    top: rows.slice(0, 5).map((row) => leaderboardEntry(row, "highestBossKills")),
    current: current ? leaderboardEntry(current, "highestBossKills") : null,
  };
}

function hockeyHealingLeaderboard(database, accountId, slotId) {
  const rows = database.prepare(`
    WITH ranked AS (
      SELECT
        RANK() OVER (ORDER BY records.highest_returns DESC, records.duration_seconds DESC) AS rank,
        records.account_id AS accountId,
        records.slot_id AS slotId,
        records.highest_returns AS highestReturns,
        records.duration_seconds AS durationSeconds,
        accounts.username,
        saves.hunter_name AS hunterName,
        records.updated_at AS updatedAt
      FROM hockey_healing_records records
      JOIN accounts ON accounts.id = records.account_id
      JOIN hunter_saves saves ON saves.account_id = records.account_id AND saves.slot_id = records.slot_id
      WHERE records.highest_returns > 0 OR records.duration_seconds > 0
    )
    SELECT * FROM ranked
    ORDER BY highestReturns DESC, durationSeconds DESC, updatedAt ASC, accountId ASC, slotId ASC
  `).all();
  const current = rows.find((row) => row.accountId === accountId && row.slotId === slotId) ?? null;
  return {
    kind: "hockey-healing",
    top: rows.slice(0, 5).map((row) => leaderboardEntry(row, "highestReturns", "durationSeconds")),
    current: current ? leaderboardEntry(current, "highestReturns", "durationSeconds") : null,
  };
}

function hockeyPvpLeaderboard(database, accountId, slotId, kind) {
  const winsBoard = kind === "hockey-pvp-wins";
  const order = winsBoard
    ? "records.wins DESC, records.losses ASC"
    : "records.boss_kills DESC, records.wins DESC";
  const rows = database.prepare(`
    WITH ranked AS (
      SELECT
        RANK() OVER (ORDER BY ${order}) AS rank,
        records.account_id AS accountId,
        records.slot_id AS slotId,
        records.wins,
        records.losses,
        records.boss_kills AS bossKills,
        accounts.username,
        saves.hunter_name AS hunterName,
        records.updated_at AS updatedAt
      FROM hockey_pvp_records records
      JOIN accounts ON accounts.id = records.account_id
      JOIN hunter_saves saves ON saves.account_id = records.account_id AND saves.slot_id = records.slot_id
      WHERE ${winsBoard ? "records.wins > 0 OR records.losses > 0" : "records.boss_kills > 0"}
    )
    SELECT * FROM ranked
    ORDER BY ${winsBoard ? "wins DESC, losses ASC" : "bossKills DESC, wins DESC"}, updatedAt ASC, accountId ASC, slotId ASC
  `).all();
  const current = rows.find((row) => row.accountId === accountId && row.slotId === slotId) ?? null;
  const valueKey = winsBoard ? "wins" : "bossKills";
  const secondaryKey = winsBoard ? "losses" : undefined;
  return {
    kind,
    top: rows.slice(0, 5).map((row) => leaderboardEntry(row, valueKey, secondaryKey)),
    current: current ? leaderboardEntry(current, valueKey, secondaryKey) : null,
  };
}

function blockbreakerLeaderboard(database, accountId, slotId, kind) {
  const boards = {
    "blockbreaker-bricks": { column: "highest_bricks", valueKey: "highestBricks", achieved: "bricks_achieved_at" },
    "blockbreaker-time": { column: "longest_seconds", valueKey: "longestSeconds", achieved: "time_achieved_at" },
    "blockbreaker-score": { column: "highest_score", valueKey: "highestScore", achieved: "score_achieved_at" },
  };
  const board = boards[kind];
  if (!board) throw apiError("Invalid Blockbreaker leaderboard.");
  const rows = database.prepare(`
    WITH ranked AS (
      SELECT
        RANK() OVER (ORDER BY records.${board.column} DESC) AS rank,
        records.account_id AS accountId,
        records.slot_id AS slotId,
        records.${board.column} AS ${board.valueKey},
        records.${board.achieved} AS achievedAt,
        accounts.username,
        saves.hunter_name AS hunterName
      FROM blockbreaker_records records
      JOIN accounts ON accounts.id = records.account_id
      JOIN hunter_saves saves ON saves.account_id = records.account_id AND saves.slot_id = records.slot_id
      WHERE records.${board.column} > 0
    )
    SELECT * FROM ranked
    ORDER BY ${board.valueKey} DESC, achievedAt ASC, accountId ASC, slotId ASC
  `).all();
  const current = rows.find((row) => row.accountId === accountId && row.slotId === slotId) ?? null;
  return {
    kind,
    top: rows.slice(0, 5).map((row) => leaderboardEntry(row, board.valueKey)),
    current: current ? leaderboardEntry(current, board.valueKey) : null,
  };
}

function aetherAssaultLeaderboard(database, accountId, slotId) {
  const rows = database.prepare(`
    WITH ranked AS (
      SELECT
        RANK() OVER (
          ORDER BY records.highest_score DESC, records.wave_at_best DESC,
            records.score_achieved_at ASC, records.account_id ASC, records.slot_id ASC
        ) AS rank,
        records.account_id AS accountId,
        records.slot_id AS slotId,
        records.highest_score AS highestScore,
        records.wave_at_best AS waveAtBest,
        records.score_achieved_at AS achievedAt,
        accounts.username,
        saves.hunter_name AS hunterName
      FROM aether_assault_records records
      JOIN accounts ON accounts.id = records.account_id
      JOIN hunter_saves saves ON saves.account_id = records.account_id AND saves.slot_id = records.slot_id
      WHERE records.highest_score > 0
    )
    SELECT * FROM ranked
    ORDER BY highestScore DESC, waveAtBest DESC, achievedAt ASC, accountId ASC, slotId ASC
  `).all();
  const current = rows.find((row) => row.accountId === accountId && row.slotId === slotId) ?? null;
  return {
    kind: "aether-assault",
    top: rows.slice(0, 5).map((row) => leaderboardEntry(row, "highestScore", "waveAtBest")),
    current: current ? leaderboardEntry(current, "highestScore", "waveAtBest") : null,
  };
}

export function createGameApiHandler(options = {}) {
  const dataDirectory = resolve(options.dataDirectory ?? process.env.DATA_DIR ?? "data");
  mkdirSync(dataDirectory, { recursive: true });
  const database = new DatabaseSync(resolve(dataDirectory, "game.db"));
  database.exec(readFileSync(new URL("../db/schema.sql", import.meta.url), "utf8"));
  const hockeyPvpTickets = new Map();
  const hockeyPvpMatches = new Map();
  const roguelikePvpTickets = new Map();
  const roguelikePvpMatches = new Map();
  const roguelikePvpNow = typeof options.roguelikePvpNow === "function"
    ? options.roguelikePvpNow
    : Date.now;

  function cleanupRoguelikePvp(now = roguelikePvpNow()) {
    for (const [matchId, match] of roguelikePvpMatches) {
      if (now - match.lastActivityAtMs <= ROGUELIKE_PVP_MATCH_TTL_MS) continue;
      roguelikePvpMatches.delete(matchId);
      roguelikePvpTickets.delete(match.players.host.id);
      roguelikePvpTickets.delete(match.players.guest.id);
    }
    for (const [ticketId, ticket] of roguelikePvpTickets) {
      const expiredWaitingTicket = !ticket.matchId && now - ticket.createdAtMs > ROGUELIKE_PVP_QUEUE_TTL_MS;
      const missingMatch = ticket.matchId && !roguelikePvpMatches.has(ticket.matchId);
      if (ticket.cancelled || expiredWaitingTicket || missingMatch) roguelikePvpTickets.delete(ticketId);
    }
  }

  function roguelikePvpQueueResult(ticket) {
    const match = ticket.matchId ? roguelikePvpMatches.get(ticket.matchId) : null;
    if (!match) return { ticketId: ticket.id, status: "waiting" };
    const opponentSide = ticket.side === "host" ? "guest" : "host";
    const opponent = match.players[opponentSide];
    return {
      ticketId: ticket.id,
      status: "matched",
      match: {
        id: match.id,
        mode: match.mode,
        seed: match.seed,
        generation: match.generation,
        countdownEndsAtMs: match.countdownEndsAtMs,
        opponentName: opponent.hunterName,
        opponentHealerClassId: opponent.healerClassId,
        role: ticket.side,
      },
    };
  }

  function joinRoguelikePvpQueue(session, payload) {
    const mode = validateRoguelikePvpMode(payload?.mode);
    const slotId = validateSlotId(payload?.slotId);
    const hunterName = String(payload?.hunterName ?? "").trim().slice(0, 20);
    const healerClassId = validateHealerClassId(payload?.healerClassId);
    if (!hunterName) throw apiError("Hunter name is required.");
    const now = roguelikePvpNow();
    cleanupRoguelikePvp(now);
    const existing = [...roguelikePvpTickets.values()].find((ticket) =>
      ticket.accountId === session.accountId && ticket.mode === mode && !ticket.cancelled);
    if (existing) return roguelikePvpQueueResult(existing);

    const opponent = [...roguelikePvpTickets.values()].find((ticket) =>
      ticket.mode === mode && !ticket.matchId && !ticket.cancelled && ticket.accountId !== session.accountId);
    const ticket = {
      id: randomBytes(18).toString("base64url"),
      mode,
      accountId: session.accountId,
      username: session.username,
      slotId,
      hunterName,
      healerClassId,
      createdAtMs: now,
      matchId: null,
      side: null,
      cancelled: false,
    };
    roguelikePvpTickets.set(ticket.id, ticket);
    if (!opponent) return roguelikePvpQueueResult(ticket);

    const matchId = randomBytes(18).toString("base64url");
    const match = {
      id: matchId,
      mode,
      seed: randomBytes(4).readUInt32BE(0) || 1,
      generation: 1,
      countdownEndsAtMs: now + ROGUELIKE_PVP_COUNTDOWN_MS,
      createdAtMs: now,
      lastActivityAtMs: now,
      players: { host: opponent, guest: ticket },
      snapshots: { host: null, guest: null },
      lastSeenAtMs: { host: now, guest: now },
      drafts: new Map(),
      draftProgress: {
        completedRound: 0,
        buffRanks: { host: {}, guest: {} },
        curseRanks: { host: {}, guest: {} },
      },
      outcome: null,
      rematch: null,
    };
    opponent.matchId = matchId;
    opponent.side = "host";
    ticket.matchId = matchId;
    ticket.side = "guest";
    roguelikePvpMatches.set(matchId, match);
    return roguelikePvpQueueResult(ticket);
  }

  function requireRoguelikePvpTicket(session, ticketId) {
    cleanupRoguelikePvp();
    const ticket = roguelikePvpTickets.get(ticketId);
    if (!ticket || ticket.accountId !== session.accountId || ticket.cancelled) {
      throw apiError("Roguelike PVP queue ticket not found.", 404);
    }
    return ticket;
  }

  function requireRoguelikePvpMatch(session, matchId) {
    cleanupRoguelikePvp();
    const match = roguelikePvpMatches.get(matchId);
    if (!match) throw apiError("Roguelike PVP match not found.", 404);
    const side = match.players.host.accountId === session.accountId
      ? "host"
      : match.players.guest.accountId === session.accountId
        ? "guest"
        : null;
    if (!side) throw apiError("Roguelike PVP match access denied.", 403);
    return { match, side };
  }

  function touchRoguelikePvpMatch(match, side, now) {
    match.lastActivityAtMs = now;
    match.lastSeenAtMs[side] = now;
  }

  function freezeRoguelikePvpOutcome(match, winner, loser, reason, now) {
    if (!match.outcome) match.outcome = { winner, loser, reason, atMs: now };
    return match.outcome;
  }

  function roguelikePvpMatchStatus(match, side, now) {
    const opponentSide = side === "host" ? "guest" : "host";
    const opponentLastSeenAtMs = match.lastSeenAtMs[opponentSide];
    const disconnectDeadlineAtMs = opponentLastSeenAtMs + ROGUELIKE_PVP_DISCONNECT_GRACE_MS;
    if (!match.outcome && now >= disconnectDeadlineAtMs) {
      freezeRoguelikePvpOutcome(match, side, opponentSide, "disconnect", now);
    }
    // Keep the original response union so existing clients resolve any
    // authoritative terminal result without a protocol migration.
    const status = !match.outcome
      ? "active"
      : match.outcome.winner === side
        ? "won-by-forfeit"
        : "lost-by-forfeit";
    const opponentConnection = match.outcome?.reason === "disconnect" && match.outcome.loser === opponentSide
      ? "forfeited"
      : now - opponentLastSeenAtMs > ROGUELIKE_PVP_CONNECTED_WINDOW_MS
        ? "grace"
        : "connected";
    return {
      status,
      opponentConnection,
      opponentLastSeenAtMs,
      disconnectDeadlineAtMs,
      outcomeReason: match.outcome?.reason ?? null,
    };
  }

  function validateRoguelikePvpSnapshotProgress(match, previous, snapshot) {
    const completedRound = match.draftProgress.completedRound;
    const lowestRound = Math.max(1, completedRound);
    const highestRound = completedRound + 1;
    if (snapshot.round < lowestRound || snapshot.round > highestRound
        || previous && snapshot.round < previous.round) {
      throw apiError("Roguelike PVP snapshot round is ahead of match progress.", 409);
    }
  }

  function exchangeRoguelikePvpState(session, matchId, payload) {
    const { match, side } = requireRoguelikePvpMatch(session, matchId);
    const generation = validateRoguelikePvpGeneration(payload?.generation);
    if (generation !== match.generation) throw apiError("Roguelike PVP match generation is stale.", 409);
    const snapshot = validateRoguelikePvpSnapshot(payload?.snapshot);
    const previous = match.snapshots[side];
    if (previous && snapshot.sequence <= previous.sequence) {
      throw apiError("Roguelike PVP snapshot sequence is stale.", 409);
    }
    validateRoguelikePvpSnapshotProgress(match, previous, snapshot);
    const now = roguelikePvpNow();
    // A grace deadline is an earlier terminal event than a snapshot arriving
    // after it, preserving disconnect-forfeit behavior at the boundary.
    roguelikePvpMatchStatus(match, side, now);
    match.snapshots[side] = snapshot;
    if (!match.outcome && snapshot.phase === "lost") {
      const opponentSide = side === "host" ? "guest" : "host";
      // First accepted valid terminal report is final. If both parties wipe
      // between exchanges, request acceptance order is the stable tie-break.
      freezeRoguelikePvpOutcome(match, opponentSide, side, "party-wipe", now);
    }
    const matchStatus = roguelikePvpMatchStatus(match, side, now);
    touchRoguelikePvpMatch(match, side, now);
    const opponentSide = side === "host" ? "guest" : "host";
    return {
      ...matchStatus,
      serverTimeMs: now,
      opponentSnapshot: match.snapshots[opponentSide],
      hostSnapshot: match.snapshots.host,
    };
  }

  function createRoguelikePvpDraft(match, round, now) {
    const existing = match.drafts.get(round);
    if (existing) return existing;
    if (match.outcome) throw apiError("Roguelike PVP match is already complete.", 409);
    if (round !== match.draftProgress.completedRound + 1) {
      throw apiError("Roguelike PVP draft round is ahead of match progress.", 409);
    }
    const draft = {
      round,
      deadlineAtMs: now + ROGUELIKE_PVP_DRAFT_MS,
      submissions: { host: null, guest: null },
      offers: {
        host: roguelikePvpDraftOffers(match, "host", round),
        guest: roguelikePvpDraftOffers(match, "guest", round),
      },
    };
    match.drafts.set(round, draft);
    return draft;
  }

  function resolveExpiredRoguelikePvpDraft(match, draft, now) {
    if (now < draft.deadlineAtMs) return;
    for (const side of ["host", "guest"]) {
      if (draft.submissions[side]) continue;
      const offers = draft.offers[side];
      const selection = {
        buffId: offers.buffChoices[0] ?? null,
        curseId: offers.curseChoices[0] ?? null,
        autoPicked: true,
      };
      validateRoguelikePvpDraftOffer(draft, side, selection);
      draft.submissions[side] = selection;
      applyRoguelikePvpDraftRanks(match, side, selection);
    }
    if (draft.submissions.host && draft.submissions.guest) {
      match.draftProgress.completedRound = Math.max(match.draftProgress.completedRound, draft.round);
    }
  }

  function roguelikePvpDraftResult(match, draft, side, now) {
    resolveExpiredRoguelikePvpDraft(match, draft, now);
    const opponentSide = side === "host" ? "guest" : "host";
    const localSelection = draft.submissions[side];
    const opponentSelection = draft.submissions[opponentSide];
    const revealed = Boolean(localSelection && opponentSelection);
    return {
      status: revealed ? "revealed" : "waiting",
      round: draft.round,
      deadlineAtMs: draft.deadlineAtMs,
      deadlineExpired: now >= draft.deadlineAtMs,
      submitted: Boolean(localSelection),
      opponentSubmitted: Boolean(opponentSelection),
      buffChoices: [...draft.offers[side].buffChoices],
      curseChoices: [...draft.offers[side].curseChoices],
      ...(revealed ? { selection: localSelection, opponentSelection } : {}),
    };
  }

  function requireRoguelikePvpDraftIntermission(match, side, round) {
    if (match.outcome) throw apiError("Roguelike PVP match is already complete.", 409);
    const snapshot = match.snapshots[side];
    if (!snapshot || snapshot.round !== round || snapshot.phase !== "draft"
        || snapshot.bossHp !== 0
        || snapshot.defeatedBosses < roguelikePvpBossCountForRound(round)) {
      throw apiError("Roguelike PVP draft requires the current cleared-round intermission.", 409);
    }
  }

  function validateRoguelikePvpDraftOffer(draft, side, selection) {
    const offers = draft.offers[side];
    const validBuff = offers.buffChoices.length === 0
      ? selection.buffId === null
      : selection.buffId !== null && offers.buffChoices.includes(selection.buffId);
    const validCurse = offers.curseChoices.length === 0
      ? selection.curseId === null
      : selection.curseId !== null && offers.curseChoices.includes(selection.curseId);
    if (!validBuff || !validCurse) {
      throw apiError("Roguelike PVP draft selection was not offered.");
    }
  }

  function applyRoguelikePvpDraftRanks(match, side, selection) {
    if (selection.buffId) {
      const ranks = match.draftProgress.buffRanks[side];
      ranks[selection.buffId] = (ranks[selection.buffId] ?? 0) + 1;
    }
    if (selection.curseId) {
      const ranks = match.draftProgress.curseRanks[side];
      ranks[selection.curseId] = (ranks[selection.curseId] ?? 0) + 1;
    }
  }

  function openRoguelikePvpDraft(session, matchId, roundValue, payload) {
    const { match, side } = requireRoguelikePvpMatch(session, matchId);
    const generation = validateRoguelikePvpGeneration(payload?.generation);
    if (generation !== match.generation) throw apiError("Roguelike PVP match generation is stale.", 409);
    const round = validateRoguelikePvpRound(roundValue);
    const now = roguelikePvpNow();
    requireRoguelikePvpDraftIntermission(match, side, round);
    const draft = createRoguelikePvpDraft(match, round, now);
    touchRoguelikePvpMatch(match, side, now);
    return roguelikePvpDraftResult(match, draft, side, now);
  }

  function pollRoguelikePvpDraft(session, matchId, roundValue, generationValue) {
    const { match, side } = requireRoguelikePvpMatch(session, matchId);
    const generation = validateRoguelikePvpGeneration(generationValue);
    if (generation !== match.generation) throw apiError("Roguelike PVP match generation is stale.", 409);
    const round = validateRoguelikePvpRound(roundValue);
    requireRoguelikePvpDraftIntermission(match, side, round);
    const draft = match.drafts.get(round);
    if (!draft) throw apiError("Roguelike PVP draft is not open.", 404);
    const now = roguelikePvpNow();
    touchRoguelikePvpMatch(match, side, now);
    return roguelikePvpDraftResult(match, draft, side, now);
  }

  function submitRoguelikePvpDraft(session, matchId, roundValue, payload) {
    const { match, side } = requireRoguelikePvpMatch(session, matchId);
    const generation = validateRoguelikePvpGeneration(payload?.generation);
    if (generation !== match.generation) throw apiError("Roguelike PVP match generation is stale.", 409);
    const round = validateRoguelikePvpRound(roundValue);
    const selection = validateRoguelikePvpDraftSelection(payload?.selection);
    const now = roguelikePvpNow();
    requireRoguelikePvpDraftIntermission(match, side, round);
    const draft = createRoguelikePvpDraft(match, round, now);
    resolveExpiredRoguelikePvpDraft(match, draft, now);
    const existing = draft.submissions[side];
    if (existing) {
      if (existing.buffId !== selection.buffId || existing.curseId !== selection.curseId
          || existing.autoPicked !== selection.autoPicked) {
        throw apiError("Roguelike PVP draft selection is already locked.", 409);
      }
    } else {
      if (now >= draft.deadlineAtMs && !selection.autoPicked) {
        throw apiError("Roguelike PVP draft deadline has passed; an auto-pick is required.", 409);
      }
      validateRoguelikePvpDraftOffer(draft, side, selection);
      draft.submissions[side] = selection;
      applyRoguelikePvpDraftRanks(match, side, selection);
      if (draft.submissions.host && draft.submissions.guest) {
        match.draftProgress.completedRound = Math.max(match.draftProgress.completedRound, round);
      }
    }
    touchRoguelikePvpMatch(match, side, now);
    return roguelikePvpDraftResult(match, draft, side, now);
  }

  function roguelikePvpRematchResult(match, side, requestedGeneration) {
    const rematch = match.rematch;
    if (!rematch || rematch.fromGeneration !== requestedGeneration || !rematch.ready) {
      return { status: "waiting" };
    }
    const opponentSide = side === "host" ? "guest" : "host";
    return {
      status: "matched",
      match: {
        id: match.id,
        mode: match.mode,
        seed: rematch.seed,
        generation: rematch.toGeneration,
        countdownEndsAtMs: rematch.countdownEndsAtMs,
        opponentName: match.players[opponentSide].hunterName,
        opponentHealerClassId: match.players[opponentSide].healerClassId,
        role: side,
      },
    };
  }

  function requestRoguelikePvpRematch(session, matchId, payload) {
    const { match, side } = requireRoguelikePvpMatch(session, matchId);
    const generation = validateRoguelikePvpGeneration(payload?.generation);
    const now = roguelikePvpNow();
    touchRoguelikePvpMatch(match, side, now);
    if (generation < match.generation) {
      if (match.rematch?.fromGeneration !== generation || !match.rematch.ready) {
        throw apiError("Roguelike PVP match generation is stale.", 409);
      }
      return roguelikePvpRematchResult(match, side, generation);
    }
    if (generation > match.generation) throw apiError("Roguelike PVP match generation is invalid.", 409);
    if (!match.rematch || match.rematch.fromGeneration !== generation) {
      match.rematch = {
        fromGeneration: generation,
        toGeneration: generation + 1,
        requested: { host: false, guest: false },
        ready: false,
        seed: 0,
        countdownEndsAtMs: 0,
      };
    }
    match.rematch.requested[side] = true;
    if (!match.rematch.ready && match.rematch.requested.host && match.rematch.requested.guest) {
      match.rematch.ready = true;
      match.rematch.seed = randomBytes(4).readUInt32BE(0) || 1;
      match.rematch.countdownEndsAtMs = now + ROGUELIKE_PVP_COUNTDOWN_MS;
      match.seed = match.rematch.seed;
      match.generation = match.rematch.toGeneration;
      match.countdownEndsAtMs = match.rematch.countdownEndsAtMs;
      match.snapshots = { host: null, guest: null };
      match.lastSeenAtMs = { host: now, guest: now };
      match.drafts = new Map();
      match.draftProgress = {
        completedRound: 0,
        buffRanks: { host: {}, guest: {} },
        curseRanks: { host: {}, guest: {} },
      };
      match.outcome = null;
    }
    return roguelikePvpRematchResult(match, side, generation);
  }

  function cancelRoguelikePvpRematch(session, matchId, payload) {
    const { match, side } = requireRoguelikePvpMatch(session, matchId);
    const generation = validateRoguelikePvpGeneration(payload?.generation);
    const now = roguelikePvpNow();
    touchRoguelikePvpMatch(match, side, now);
    if (match.rematch?.fromGeneration === generation && !match.rematch.ready) {
      match.rematch.requested[side] = false;
    }
    return { ok: true };
  }

  function queueResult(ticket) {
    const match = ticket.matchId ? hockeyPvpMatches.get(ticket.matchId) : null;
    if (!match) return { ticketId: ticket.id, status: "waiting" };
    const opponentSide = ticket.side === "host" ? "guest" : "host";
    const opponent = match.players[opponentSide];
    return {
      ticketId: ticket.id,
      status: "matched",
      match: {
        id: match.id,
        seed: match.seed,
        generation: match.generation,
        countdownEndsAtMs: match.countdownEndsAtMs,
        opponentName: opponent.hunterName,
        role: ticket.side,
      },
    };
  }

  function joinHockeyPvpQueue(session, payload) {
    const slotId = validateSlotId(payload?.slotId);
    const hunterName = String(payload?.hunterName ?? "").trim().slice(0, 20);
    if (!hunterName) throw apiError("Hunter name is required.");
    const existing = [...hockeyPvpTickets.values()].find((ticket) =>
      ticket.accountId === session.accountId && !ticket.matchId && !ticket.cancelled && !ticket.completed);
    if (existing) return queueResult(existing);

    const now = Date.now();
    for (const ticket of hockeyPvpTickets.values()) {
      if (!ticket.matchId && now - ticket.createdAt > 30_000) {
        ticket.cancelled = true;
        ticket.completed = true;
      }
    }
    const opponent = [...hockeyPvpTickets.values()].find((ticket) =>
      !ticket.matchId && !ticket.cancelled && !ticket.completed && ticket.accountId !== session.accountId);
    const ticket = {
      id: randomBytes(18).toString("base64url"),
      accountId: session.accountId,
      username: session.username,
      slotId,
      hunterName,
      createdAt: now,
      matchId: null,
      side: null,
      cancelled: false,
      completed: false,
    };
    hockeyPvpTickets.set(ticket.id, ticket);
    if (!opponent) return queueResult(ticket);

    const matchId = randomBytes(18).toString("base64url");
    const match = {
      id: matchId,
      seed: randomBytes(4).readUInt32BE(0) || 1,
      generation: 1,
      createdAt: now,
      countdownEndsAtMs: now + HOCKEY_PVP_COUNTDOWN_MS,
      players: { host: opponent, guest: ticket },
      snapshots: { host: null, guest: null },
      rematch: null,
    };
    opponent.matchId = matchId;
    opponent.side = "host";
    ticket.matchId = matchId;
    ticket.side = "guest";
    hockeyPvpMatches.set(matchId, match);
    return queueResult(ticket);
  }

  function requireHockeyPvpTicket(session, ticketId) {
    const ticket = hockeyPvpTickets.get(ticketId);
    if (!ticket || ticket.accountId !== session.accountId || ticket.cancelled) throw apiError("Queue ticket not found.", 404);
    return ticket;
  }

  function requireHockeyPvpMatch(session, matchId) {
    const match = hockeyPvpMatches.get(matchId);
    if (!match) throw apiError("PVP match not found.", 404);
    const side = match.players.host.accountId === session.accountId
      ? "host"
      : match.players.guest.accountId === session.accountId
        ? "guest"
        : null;
    if (!side) throw apiError("PVP match access denied.", 403);
    return { match, side };
  }

  function hockeyPvpRematchResult(match, side, requestedGeneration) {
    const rematch = match.rematch;
    if (!rematch || rematch.fromGeneration !== requestedGeneration || !rematch.ready) {
      return { status: "waiting" };
    }
    const opponentSide = side === "host" ? "guest" : "host";
    return {
      status: "matched",
      match: {
        id: match.id,
        seed: rematch.seed,
        generation: rematch.toGeneration,
        countdownEndsAtMs: rematch.countdownEndsAtMs,
        opponentName: match.players[opponentSide].hunterName,
        role: side,
      },
    };
  }

  function requestHockeyPvpRematch(session, matchId, payload) {
    const { match, side } = requireHockeyPvpMatch(session, matchId);
    const generation = Number(payload?.generation);
    if (!Number.isSafeInteger(generation) || generation < 1) throw apiError("PVP match generation is invalid.");

    if (generation < match.generation) {
      if (match.rematch?.fromGeneration !== generation || !match.rematch.ready) {
        throw apiError("PVP match generation is stale.", 409);
      }
      return hockeyPvpRematchResult(match, side, generation);
    }
    if (generation > match.generation) throw apiError("PVP match generation is invalid.", 409);

    if (!match.rematch || match.rematch.fromGeneration !== generation) {
      match.rematch = {
        fromGeneration: generation,
        toGeneration: generation + 1,
        requested: { host: false, guest: false },
        ready: false,
        seed: 0,
        countdownEndsAtMs: 0,
      };
    }
    match.rematch.requested[side] = true;
    if (!match.rematch.ready && match.rematch.requested.host && match.rematch.requested.guest) {
      const now = Date.now();
      match.rematch.ready = true;
      match.rematch.seed = randomBytes(4).readUInt32BE(0) || 1;
      match.rematch.countdownEndsAtMs = now + HOCKEY_PVP_COUNTDOWN_MS;
      match.seed = match.rematch.seed;
      match.generation = match.rematch.toGeneration;
      match.countdownEndsAtMs = match.rematch.countdownEndsAtMs;
      match.snapshots = { host: null, guest: null };
    }
    return hockeyPvpRematchResult(match, side, generation);
  }

  function cancelHockeyPvpRematch(session, matchId, payload) {
    const { match, side } = requireHockeyPvpMatch(session, matchId);
    const generation = Number(payload?.generation);
    if (!Number.isSafeInteger(generation) || generation < 1) throw apiError("PVP match generation is invalid.");
    if (match.rematch?.fromGeneration === generation && !match.rematch.ready) {
      match.rematch.requested[side] = false;
    }
    return { ok: true };
  }

  async function handle(request, response, next) {
    if (!request.url?.startsWith("/api/")) return next();
    setCorsHeaders(request, response);
    if (request.method === "OPTIONS") {
      response.statusCode = 204;
      return response.end();
    }
    try {
      database.prepare("DELETE FROM sessions WHERE expires_at <= CURRENT_TIMESTAMP").run();
      const url = new URL(request.url, "http://localhost");
      const path = url.pathname;

      if (path === "/api/health" && request.method === "GET") {
        return sendJson(response, 200, { ok: true, database: "ready" });
      }
      if (path === "/api/auth/register" && request.method === "POST") {
        enforceAuthRateLimit(request);
        return sendJson(response, 201, register(database, await readJson(request)));
      }
      if (path === "/api/auth/login" && request.method === "POST") {
        enforceAuthRateLimit(request);
        return sendJson(response, 200, login(database, await readJson(request)));
      }
      if (path === "/api/auth/session" && request.method === "GET") {
        const session = currentSession(database, request);
        return sendJson(response, session ? 200 : 401, session
          ? { account: { id: session.accountId, username: session.username } }
          : { error: "Sign in required." });
      }
      if (path === "/api/auth/logout" && request.method === "POST") {
        const token = bearerToken(request);
        if (token) database.prepare("DELETE FROM sessions WHERE token_hash = ?").run(tokenHash(token));
        return sendJson(response, 200, { ok: true });
      }

      const session = requireSession(database, request);
      if (path === "/api/roguelike-pvp/queue" && request.method === "POST") {
        return sendJson(response, 200, joinRoguelikePvpQueue(session, await readJson(request)));
      }
      const roguelikeQueueMatch = path.match(/^\/api\/roguelike-pvp\/queue\/([A-Za-z0-9_-]+)$/);
      if (roguelikeQueueMatch && request.method === "GET") {
        return sendJson(response, 200, roguelikePvpQueueResult(requireRoguelikePvpTicket(session, roguelikeQueueMatch[1])));
      }
      if (roguelikeQueueMatch && request.method === "DELETE") {
        const ticket = requireRoguelikePvpTicket(session, roguelikeQueueMatch[1]);
        if (ticket.matchId) throw apiError("Matched queue cannot be cancelled.", 409);
        ticket.cancelled = true;
        roguelikePvpTickets.delete(ticket.id);
        return sendJson(response, 200, { ok: true });
      }
      const roguelikeStateMatch = path.match(/^\/api\/roguelike-pvp\/matches\/([A-Za-z0-9_-]+)\/state$/);
      if (roguelikeStateMatch && request.method === "PUT") {
        return sendJson(response, 200, exchangeRoguelikePvpState(
          session,
          roguelikeStateMatch[1],
          await readJson(request),
        ));
      }
      const roguelikeDraftOpenMatch = path.match(/^\/api\/roguelike-pvp\/matches\/([A-Za-z0-9_-]+)\/drafts\/([1-9][0-9]*)\/open$/);
      if (roguelikeDraftOpenMatch && request.method === "POST") {
        return sendJson(response, 200, openRoguelikePvpDraft(
          session,
          roguelikeDraftOpenMatch[1],
          roguelikeDraftOpenMatch[2],
          await readJson(request),
        ));
      }
      const roguelikeDraftMatch = path.match(/^\/api\/roguelike-pvp\/matches\/([A-Za-z0-9_-]+)\/drafts\/([1-9][0-9]*)$/);
      if (roguelikeDraftMatch && request.method === "GET") {
        return sendJson(response, 200, pollRoguelikePvpDraft(
          session,
          roguelikeDraftMatch[1],
          roguelikeDraftMatch[2],
          url.searchParams.get("generation"),
        ));
      }
      if (roguelikeDraftMatch && request.method === "PUT") {
        return sendJson(response, 200, submitRoguelikePvpDraft(
          session,
          roguelikeDraftMatch[1],
          roguelikeDraftMatch[2],
          await readJson(request),
        ));
      }
      const roguelikeRematchMatch = path.match(/^\/api\/roguelike-pvp\/matches\/([A-Za-z0-9_-]+)\/rematch$/);
      if (roguelikeRematchMatch && request.method === "POST") {
        return sendJson(response, 200, requestRoguelikePvpRematch(
          session,
          roguelikeRematchMatch[1],
          await readJson(request),
        ));
      }
      if (roguelikeRematchMatch && request.method === "DELETE") {
        return sendJson(response, 200, cancelRoguelikePvpRematch(
          session,
          roguelikeRematchMatch[1],
          await readJson(request),
        ));
      }
      if (path === "/api/hockey-pvp/queue" && request.method === "POST") {
        return sendJson(response, 200, joinHockeyPvpQueue(session, await readJson(request)));
      }
      const queueMatch = path.match(/^\/api\/hockey-pvp\/queue\/([A-Za-z0-9_-]+)$/);
      if (queueMatch && request.method === "GET") {
        return sendJson(response, 200, queueResult(requireHockeyPvpTicket(session, queueMatch[1])));
      }
      if (queueMatch && request.method === "DELETE") {
        const ticket = requireHockeyPvpTicket(session, queueMatch[1]);
        if (ticket.matchId) throw apiError("Matched queue cannot be cancelled.", 409);
        ticket.cancelled = true;
        ticket.completed = true;
        return sendJson(response, 200, { ok: true });
      }
      const pvpStateMatch = path.match(/^\/api\/hockey-pvp\/matches\/([A-Za-z0-9_-]+)\/state$/);
      if (pvpStateMatch && request.method === "PUT") {
        const { match, side } = requireHockeyPvpMatch(session, pvpStateMatch[1]);
        const payload = await readJson(request);
        if (payload?.generation !== match.generation) throw apiError("PVP match generation is stale.", 409);
        if (!payload?.snapshot || typeof payload.snapshot !== "object") throw apiError("PVP snapshot is invalid.");
        match.snapshots[side] = payload.snapshot;
        return sendJson(response, 200, {
          opponentSnapshot: match.snapshots[side === "host" ? "guest" : "host"],
          hostSnapshot: match.snapshots.host,
        });
      }
      const pvpRematchMatch = path.match(/^\/api\/hockey-pvp\/matches\/([A-Za-z0-9_-]+)\/rematch$/);
      if (pvpRematchMatch && request.method === "POST") {
        return sendJson(response, 200, requestHockeyPvpRematch(session, pvpRematchMatch[1], await readJson(request)));
      }
      if (pvpRematchMatch && request.method === "DELETE") {
        return sendJson(response, 200, cancelHockeyPvpRematch(session, pvpRematchMatch[1], await readJson(request)));
      }
      if (path === "/api/saves" && request.method === "GET") {
        return sendJson(response, 200, { slots: listSaves(database, session.accountId) });
      }
      const saveMatch = path.match(/^\/api\/saves\/([1-3])$/);
      if (saveMatch && request.method === "GET") {
        return sendJson(response, 200, { save: readSave(database, session.accountId, validateSlotId(saveMatch[1])) });
      }
      if (saveMatch && request.method === "PUT") {
        const slotId = validateSlotId(saveMatch[1]);
        const payload = await readJson(request);
        return sendJson(response, 200, { save: writeSave(database, session.accountId, slotId, payload?.save) });
      }
      const bossMatch = path.match(/^\/api\/leaderboards\/boss\/([a-z0-9-]+)$/);
      if (bossMatch && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, bossLeaderboard(database, session.accountId, slotId, bossMatch[1]));
      }
      if (path === "/api/leaderboards/roguelike" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, roguelikeLeaderboard(database, session.accountId, slotId));
      }
      if (path === "/api/leaderboards/rogue-trials-endless" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, rogueTrialsEndlessLeaderboard(database, session.accountId, slotId));
      }
      if (path === "/api/leaderboards/hockey-healing" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, hockeyHealingLeaderboard(database, session.accountId, slotId));
      }
      if (path === "/api/leaderboards/hockey-pvp-wins" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, hockeyPvpLeaderboard(database, session.accountId, slotId, "hockey-pvp-wins"));
      }
      if (path === "/api/leaderboards/hockey-pvp-boss-kills" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, hockeyPvpLeaderboard(database, session.accountId, slotId, "hockey-pvp-boss-kills"));
      }
      if (path === "/api/leaderboards/blockbreaker-bricks" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, blockbreakerLeaderboard(database, session.accountId, slotId, "blockbreaker-bricks"));
      }
      if (path === "/api/leaderboards/blockbreaker-time" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, blockbreakerLeaderboard(database, session.accountId, slotId, "blockbreaker-time"));
      }
      if (path === "/api/leaderboards/blockbreaker-score" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, blockbreakerLeaderboard(database, session.accountId, slotId, "blockbreaker-score"));
      }
      if (path === "/api/leaderboards/aether-assault" && request.method === "GET") {
        const slotId = validateSlotId(url.searchParams.get("slot"));
        return sendJson(response, 200, aetherAssaultLeaderboard(database, session.accountId, slotId));
      }
      return sendJson(response, 404, { error: "API route not found." });
    } catch (error) {
      const status = Number(error?.status) || 500;
      const message = status >= 500 ? "Server error." : error.message;
      if (status >= 500) console.error(error);
      return sendJson(response, status, { error: message });
    }
  }

  return {
    handle,
    close: () => {
      hockeyPvpTickets.clear();
      hockeyPvpMatches.clear();
      roguelikePvpTickets.clear();
      roguelikePvpMatches.clear();
      database.close();
    },
  };
}