#!/usr/bin/env node
import { createHash } from "node:crypto";
import { createReadStream } from "node:fs";
import { mkdir, open, readFile, writeFile } from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { inflateSync } from "node:zlib";
import sharp from "sharp";

const scriptDirectory = path.dirname(fileURLToPath(import.meta.url));
const projectRoot = path.resolve(scriptDirectory, "../..");
const sourceRoot = path.resolve(process.env.RUNEWAKER_ROOT ?? path.join(projectRoot, "..", "Runewaker"));
const resourceRoot = path.join(sourceRoot, "Resource");
const dataRoot = path.join(resourceRoot, "data");
const files = {
  learnMagic: path.join(dataRoot, "learnmagic.db"),
  magicCollect: path.join(dataRoot, "magiccollectobject.db"),
  magicObject: path.join(dataRoot, "magicobject.db"),
  imageObject: path.join(dataRoot, "imageobject.db"),
  vocationTable: path.join(dataRoot, "voctable.db"),
  strings: path.join(dataRoot, "string_enus.db"),
  eliteLua: path.join(resourceRoot, "luascript", "02248.lua"),
  roleAttr: path.join(sourceRoot, "SourceCodeVS2019", "Libraries", "Union", "RoleData", "RoleAttr.cpp"),
  objectStruct: path.join(sourceRoot, "SourceCodeVS2019", "Libraries", "Union", "RoleData", "ObjectStruct.h"),
};
const outputFile = path.join(projectRoot, "src", "game", "romPlayerCatalog.generated.json");
const auditFile = path.join(scriptDirectory, "snapshots", "runewaker-player-skill-audit.json");
const interfaceFdb = path.join(resourceRoot, "fdb", "interface.fdb");
const iconOutputDirectory = path.join(projectRoot, "public", "assets", "ui", "rom-spells");

const CLASS_IDS = ["rom-warrior", "rom-scout", "rom-rogue", "rom-mage", "rom-priest", "rom-knight", "rom-warden", "rom-druid", "rom-warlock", "rom-champion"];
const CLASS_NAMES = ["Warrior", "Scout", "Rogue", "Mage", "Priest", "Knight", "Warden", "Druid", "Warlock", "Champion"];
const RESOURCES = ["rage", "focus", "energy", "mana", "mana", "mana", "mana", "mana", "focus", "rage"];
const ELITE_LEVELS = [15, 20, 25, 30, 35, 40, 45, 50, 60, 70];
const RACE_MATRIX = {
  "rom-human": [1, 2, 3, 4, 5, 6],
  "rom-elf": [1, 2, 3, 4, 7, 8],
  "rom-dwarf": [1, 3, 4, 5, 9, 10],
};

function vocationGrowth(classIndex) {
  const recordSize = 816;
  const offset = DATA_START + classIndex * recordSize + 8;
  const values = Array.from({ length: 21 }, (_, index) => cleanFloat(float32(buffers.vocationTable, offset + index * 4)));
  const keys = ["strength", "stamina", "intellect", "wisdom", "agility", "health", "mana"];
  return Object.fromEntries(keys.map((key, index) => [key, {
    levelOne: values[index],
    flatGrowth: values[index + 7],
    percentGrowth: values[index + 14],
  }]));
}
const DATA_START = 140;
const LEARN_RECORD_SIZE = 12184;
const LEARN_ENTRY_SIZE = 24;
const SP_CAPACITY = 200;
const MAGIC_COLLECT_RECORD_SIZE = 1032;
const MAGIC_OBJECT_RECORD_SIZE = 992;
const COUNT_OFFSET = 132;

const buffers = Object.fromEntries(await Promise.all(Object.entries(files).map(async ([key, filename]) => [key, await readFile(filename)])));
const sha256 = (value) => createHash("sha256").update(value).digest("hex");
async function sha256File(filename) {
  const hash = createHash("sha256");
  for await (const chunk of createReadStream(filename)) hash.update(chunk);
  return hash.digest("hex");
}
const int32 = (buffer, offset) => buffer.readInt32LE(offset);
const float32 = (buffer, offset) => buffer.readFloatLE(offset);
const cleanFloat = (value) => Number.isFinite(value) ? Number(value.toFixed(5)) : 0;

function validateDatabase(buffer, recordSize, expectedType, label) {
  const count = int32(buffer, COUNT_OFFSET);
  if (count <= 0 || DATA_START + count * recordSize > buffer.length) throw new Error(`${label} record-size sentinel drifted.`);
  for (const index of [0, Math.floor(count / 2), count - 1]) {
    if (int32(buffer, DATA_START + index * recordSize + 4) !== expectedType) throw new Error(`${label} type sentinel drifted.`);
  }
  return count;
}

const stringCache = new Map();
function stringValue(key) {
  if (stringCache.has(key)) return stringCache.get(key);
  const marker = Buffer.from(`${key}\0`, "ascii");
  const keyPosition = buffers.strings.indexOf(marker);
  if (keyPosition < 0) return null;
  const start = keyPosition + marker.length;
  const end = Math.min(buffers.strings.length - 4, start + 600);
  for (let offset = start; offset < end; offset += 1) {
    const length = buffers.strings.readInt32LE(offset);
    if (length < 1 || length > 4001 || offset + 4 + length > buffers.strings.length) continue;
    const value = buffers.strings.subarray(offset + 4, offset + 3 + length);
    if (buffers.strings[offset + 3 + length] !== 0 || value.includes(0)) continue;
    try {
      const result = new TextDecoder("utf-8", { fatal: true }).decode(value).trim() || null;
      stringCache.set(key, result);
      return result;
    } catch { /* scan through metadata bytes */ }
  }
  stringCache.set(key, null);
  return null;
}

const magicCollectCount = validateDatabase(buffers.magicCollect, MAGIC_COLLECT_RECORD_SIZE, 21, "magiccollectobject.db");
const magicObjectCount = validateDatabase(buffers.magicObject, MAGIC_OBJECT_RECORD_SIZE, 3, "magicobject.db");
const imageObjectCount = validateDatabase(buffers.imageObject, 3712, 13, "imageobject.db");
const magicCollectOffsets = new Map();
for (let index = 0; index < magicCollectCount; index += 1) {
  const offset = DATA_START + index * MAGIC_COLLECT_RECORD_SIZE;
  magicCollectOffsets.set(int32(buffers.magicCollect, offset), offset);
}
const magicObjectOffsets = new Map();
for (let index = 0; index < magicObjectCount; index += 1) {
  const offset = DATA_START + index * MAGIC_OBJECT_RECORD_SIZE;
  magicObjectOffsets.set(int32(buffers.magicObject, offset), offset);
}
const imagePaths = new Map();
for (let index = 0; index < imageObjectCount; index += 1) {
  const offset = DATA_START + index * 3712;
  const imageId = int32(buffers.imageObject, offset);
  let end = offset + 0xb4;
  while (end < offset + 0xb4 + 520 && buffers.imageObject[end] !== 0) end += 1;
  let assetPath = buffers.imageObject.subarray(offset + 0xb4, end).toString("utf8").replaceAll("/", "\\").toLowerCase();
  if (!assetPath) continue;
  assetPath = assetPath.replace(/\.[^.\\]+$/, "") + ".dds";
  imagePaths.set(imageId, assetPath);
}

function componentFor(id) {
  const offset = magicObjectOffsets.get(id);
  if (offset === undefined) return null;
  const abilityModifiers = Array.from({ length: 10 }, (_, index) => ({
    type: int32(buffers.magicObject, offset + 0xf8 + index * 4),
    value: int32(buffers.magicObject, offset + 0x120 + index * 4),
  })).filter((modifier) => modifier.type !== 0 || modifier.value !== 0);
  const magicFunc = int32(buffers.magicObject, offset + 0xb0);
  const settingFlags = int32(buffers.magicObject, offset + 0xd8);
  const specialActionFlags = int32(buffers.magicObject, offset + 0xdc);
  const effectFlagWords = [
    int32(buffers.magicObject, offset + 0xec),
    int32(buffers.magicObject, offset + 0xf0),
  ];
  const clearFlags = int32(buffers.magicObject, offset + 0xf4);
  const onAttackTrigger = {
    rate: int32(buffers.magicObject, offset + 0x148),
    rank: int32(buffers.magicObject, offset + 0x14c),
    id: int32(buffers.magicObject, offset + 0x150),
  };
  const triggers = {
    onTimeMagicId: int32(buffers.magicObject, offset + 0x158),
    onTimeSeconds: int32(buffers.magicObject, offset + 0x15c),
    onHitMagicId: int32(buffers.magicObject, offset + 0x168),
    onBuffTimeoutMagicId: int32(buffers.magicObject, offset + 0x16c),
    onAttackReboundMagicId: int32(buffers.magicObject, offset + 0x170),
    onMagicAttackReboundMagicId: int32(buffers.magicObject, offset + 0x174),
    onDeathMagicId: int32(buffers.magicObject, offset + 0x178),
  };
  const dot = {
    timeSeconds: int32(buffers.magicObject, offset + 0x184),
    type: int32(buffers.magicObject, offset + 0x188),
    base: int32(buffers.magicObject, offset + 0x18c),
    skillLevelArg: cleanFloat(float32(buffers.magicObject, offset + 0x190)),
  };
  const attack = {
    type: int32(buffers.magicObject, offset + 0x194),
    damagePower: cleanFloat(float32(buffers.magicObject, offset + 0x198)),
    damagePowerSkillLevelArg: cleanFloat(float32(buffers.magicObject, offset + 0x19c)),
    fixedValue: cleanFloat(float32(buffers.magicObject, offset + 0x1a0)),
    fixedType: int32(buffers.magicObject, offset + 0x1a4),
    fixedDamageSkillLevelArg: cleanFloat(float32(buffers.magicObject, offset + 0x1a8)),
    randomRange: cleanFloat(float32(buffers.magicObject, offset + 0x1ac)),
    criticalRate: int32(buffers.magicObject, offset + 0x1b0),
    hateRate: cleanFloat(float32(buffers.magicObject, offset + 0x1b4)),
  };
  const summon = {
    creatureId: int32(buffers.magicObject, offset + 0x1d0),
    level: int32(buffers.magicObject, offset + 0x1d4),
    rangeLevel: int32(buffers.magicObject, offset + 0x1d8),
    lifetimeSeconds: int32(buffers.magicObject, offset + 0x1dc),
    skillLevelArg: cleanFloat(float32(buffers.magicObject, offset + 0x1e0)),
    type: int32(buffers.magicObject, offset + 0x1e4),
    groupId: int32(buffers.magicObject, offset + 0x1e8),
    ownerPowerRate: cleanFloat(float32(buffers.magicObject, offset + 0x1ec)),
  };
  const magicShield = {
    rawBaseWord: int32(buffers.magicObject, offset + 0x2c0),
    type: int32(buffers.magicObject, offset + 0x2c4),
    effect: int32(buffers.magicObject, offset + 0x2c8),
    point: int32(buffers.magicObject, offset + 0x2cc),
    skillLevelArg: cleanFloat(float32(buffers.magicObject, offset + 0x2d0)),
  };
  return {
    id,
    magicFunc,
    magicType: int32(buffers.magicObject, offset + 0xb4),
    effectType: int32(buffers.magicObject, offset + 0xb8),
    effectTime: cleanFloat(float32(buffers.magicObject, offset + 0xbc)),
    hateCost: int32(buffers.magicObject, offset + 0xc8),
    settingFlags,
    specialActionFlags,
    assistType: int32(buffers.magicObject, offset + 0xe0),
    ...(effectFlagWords.some(Boolean) ? { effectFlagWords } : {}),
    ...(clearFlags ? { clearFlags } : {}),
    ...(abilityModifiers.length ? { abilityModifiers } : {}),
    ...(onAttackTrigger.id > 0 ? { onAttackTrigger } : {}),
    abilitySkillLevelArg: cleanFloat(float32(buffers.magicObject, offset + 0x154)),
    ...(Object.values(triggers).some(Boolean) ? { triggers } : {}),
    dotTime: int32(buffers.magicObject, offset + 0x184),
    dotType: int32(buffers.magicObject, offset + 0x188),
    dotBase: int32(buffers.magicObject, offset + 0x18c),
    ...(dot.timeSeconds > 0 || dot.base !== 0 ? { dot } : {}),
    attackType: int32(buffers.magicObject, offset + 0x194),
    damagePower: cleanFloat(float32(buffers.magicObject, offset + 0x198)),
    fixedValue: cleanFloat(float32(buffers.magicObject, offset + 0x1a0)),
    ...(magicFunc === 0 && (attack.damagePower !== 0 || attack.fixedValue !== 0) ? { attack } : {}),
    ...(magicFunc === 8 ? { raise: { experiencePercent: int32(buffers.magicObject, offset + 0x1cc) } } : {}),
    summonCreatureId: int32(buffers.magicObject, offset + 0x1d0),
    ...(summon.creatureId > 0 ? { summon } : {}),
    // The serialized record has a reserved word at +0x2c0; the four
    // MagicShieldStruct fields immediately follow it at +0x2c4.
    ...(settingFlags & (1 << 8) ? { magicShield } : {}),
  };
}

function targetFor(sourceTarget, effectType) {
  if (sourceTarget === 0) return "self";
  if ([1, 2, 3, 4, 5, 9, 11, 13, 14, 15, 17].includes(sourceTarget)) return "friendly";
  if ([6, 7, 8, 10, 12].includes(sourceTarget)) return "hostile";
  return effectType === 0 || effectType === 4 ? "hostile" : "self";
}

function effectFor(components, target, passive) {
  if (passive) return { kind: "passive", coefficient: 0 };
  const raise = components.find((component) => component.magicFunc === 8);
  if (raise) return { kind: "resurrection", coefficient: 0.35 };
  const summon = components.find((component) => component.magicFunc === 3 || component.summonCreatureId > 0);
  if (summon) return { kind: "summon", coefficient: 0.75, creatureId: summon.summonCreatureId };
  const teleport = components.find((component) => component.magicFunc === 2);
  if (teleport) return { kind: "movement", coefficient: 0, distance: 12 };
  const absorb = components.find((component) => component.magicShield);
  if (absorb) return { kind: "absorb", coefficient: 0, durationMs: Math.max(0, absorb.effectTime * 1000) };
  const hp = components.find((component) => component.magicFunc === 0 && component.attackType === 0);
  if (hp) {
    const magnitude = Math.max(Math.abs(hp.damagePower), Math.abs(hp.fixedValue), Math.abs(hp.dotBase), 1);
    const coefficient = Math.max(0.15, Math.min(3.5, Number((magnitude / 100).toFixed(3))));
    const periodic = hp.dotTime > 0;
    const healing = target !== "hostile" && hp.damagePower >= 0 && hp.fixedValue >= 0 && hp.dotBase >= 0;
    if (periodic) return { kind: healing ? "hot" : "dot", coefficient, ticks: Math.max(2, Math.min(12, Math.round(hp.dotTime / 2))), intervalMs: 2000 };
    return { kind: healing ? "heal" : "damage", coefficient };
  }
  // EffectType identifies the engine channel (magic/physical/equipment/pet),
  // not heal/cleanse/shield/status semantics. Preserve an honest source hint;
  // the runtime translator consumes the full components and tooltip instead.
  return { kind: "source-components", coefficient: 0 };
}

function resourceForCostType(type, classIndex) {
  if (type === 1 || type === 3) return "health";
  if (type === 2 || type === 4) return "mana";
  if (type === 5) return "rage";
  if (type === 6) return "focus";
  if (type === 7) return "energy";
  return RESOURCES[classIndex - 1];
}

function sourceSpell(spellId, classIndex) {
  const offset = magicCollectOffsets.get(spellId);
  if (offset === undefined) return null;
  const imageId = int32(buffers.magicCollect, offset + 0x20);
  const sourceEffectType = int32(buffers.magicCollect, offset + 0xb4);
  const sourceTarget = int32(buffers.magicCollect, offset + 0xb8);
  const target = targetFor(sourceTarget, sourceEffectType);
  const passive = sourceEffectType === 2;
  const description = stringValue(`Sys${spellId}_shortnote`)
    ?? stringValue(`Sys${spellId}_desc`)
    ?? "RuneWaker source tooltip unavailable.";
  const components = [];
  const componentIds = new Set();
  for (let componentOffset = 0x180; componentOffset <= 0x2c0; componentOffset += 4) {
    const componentId = int32(buffers.magicCollect, offset + componentOffset);
    if (magicObjectOffsets.has(componentId)) componentIds.add(componentId);
  }
  // Elite and scripted skills frequently point at their actual buff, shield,
  // or triggered-damage MagicObject through a tooltip token such as
  // `(Buff-Shield-620686)` instead of the primary MagicCollect component list.
  // Those are authoritative references, so retain them as source components.
  for (const match of description.matchAll(/\b\d{6}\b/g)) {
    const referencedComponentId = Number(match[0]);
    if (magicObjectOffsets.has(referencedComponentId)) componentIds.add(referencedComponentId);
  }
  for (const componentId of componentIds) {
    const component = componentFor(componentId);
    if (component) components.push(component);
  }
  const costRows = [0, 1].map((index) => ({
    type: int32(buffers.magicCollect, offset + 0xe0 + index * 8),
    value: int32(buffers.magicCollect, offset + 0xe4 + index * 8),
  })).filter((cost) => cost.type > 0 && cost.value !== 0 && ![9, 10, 11, 12, 13, 14, 15].includes(cost.type));
  const costs = costRows.map((cost) => ({
    resource: resourceForCostType(cost.type, classIndex),
    amount: Math.max(0, Math.min(100, Math.abs(cost.value))),
    percentage: cost.type === 3 || cost.type === 4,
  }));
  const attackDistance = int32(buffers.magicCollect, offset + 0xbc);
  const sourceCooldownSeconds = int32(buffers.magicCollect, offset + 0x108);
  const spellTimeSeconds = cleanFloat(float32(buffers.magicCollect, offset + 0x114));
  return {
    sourceSkillId: spellId,
    name: stringValue(`Sys${spellId}_name`) ?? `RuneWaker Skill ${spellId}`,
    // RuneWaker's player-facing skill tooltip is stored under `shortnote`.
    // `_desc` is not present in the shipped English string database, which
    // previously left every skill with a generic placeholder and made faithful
    // semantic classification impossible downstream.
    description,
    target,
    range: Math.max(target === "self" ? 0 : 3, Math.min(40, attackDistance > 0 ? attackDistance * 0.1 : target === "hostile" ? 6 : 30)),
    castTimeMs: Math.max(0, Math.round(spellTimeSeconds * 1000)),
    cooldownMs: Math.max(0, Math.min(180000, sourceCooldownSeconds * 1000)),
    costs,
    passive,
    effect: effectFor(components, target, passive),
    source: {
      imageId,
      sourceEffectType,
      sourceTarget,
      componentIds: [...componentIds],
      components,
    },
  };
}

// The parent skill is the canonical rank-one source record. Avoid duplicating
// its large component payload inside the nested rank-one row; higher ranks keep
// their own components because their coefficients and flags may differ.
function nestedRankSpell(spell, parentSourceSkillId) {
  if (spell.sourceSkillId !== parentSourceSkillId) return spell;
  const { components: _components, ...source } = spell.source;
  return { ...spell, source };
}

async function loadFdbIndex() {
  const handle = await open(interfaceFdb, "r");
  const prefix = Buffer.alloc(8);
  await handle.read(prefix, 0, prefix.length, 0);
  if (prefix.readUInt32LE(0) !== 0x46444201) throw new Error("interface.fdb magic sentinel drifted.");
  const count = prefix.readInt32LE(4);
  if (count <= 0 || count > 1_000_000) throw new Error("interface.fdb entry-count sentinel drifted.");
  const headers = Buffer.alloc(count * 16);
  const lengths = Buffer.alloc(count * 4);
  await handle.read(headers, 0, headers.length, 8);
  await handle.read(lengths, 0, lengths.length, 8 + headers.length);
  const textSizeBuffer = Buffer.alloc(4);
  await handle.read(textSizeBuffer, 0, 4, 8 + headers.length + lengths.length);
  const textSize = textSizeBuffer.readInt32LE(0);
  if (textSize <= 0 || textSize > 64 * 1024 * 1024) throw new Error("interface.fdb path-table sentinel drifted.");
  const textBuffer = Buffer.alloc(textSize);
  await handle.read(textBuffer, 0, textSize, 12 + headers.length + lengths.length);
  const entries = new Map();
  let textOffset = 0;
  for (let index = 0; index < count; index += 1) {
    const length = lengths.readInt32LE(index * 4);
    const filename = textBuffer.subarray(textOffset, textOffset + length).toString("utf8").toLowerCase();
    entries.set(filename, {
      fileType: headers.readInt32LE(index * 16),
      offset: headers.readUInt32LE(index * 16 + 12),
    });
    textOffset += length + 1;
  }
  return { handle, count, entries };
}

async function extractNativeIcons(skills) {
  const requested = new Map();
  for (const skill of skills) {
    const imageId = skill.source.imageId;
    const assetPath = imagePaths.get(imageId);
    if (!assetPath) throw new Error(`ImageObject ${imageId} has no ACTField path.`);
    requested.set(imageId, assetPath);
  }
  const { handle, count, entries } = await loadFdbIndex();
  await mkdir(iconOutputDirectory, { recursive: true });
  try {
    const jobs = [...requested].sort(([left], [right]) => left - right);
    for (let cursor = 0; cursor < jobs.length; cursor += 16) {
      await Promise.all(jobs.slice(cursor, cursor + 16).map(async ([imageId, assetPath]) => {
        const entry = entries.get(assetPath);
        if (!entry || entry.fileType !== 2) throw new Error(`interface.fdb is missing image ${imageId}: ${assetPath}`);
        const sizeBuffer = Buffer.alloc(4);
        await handle.read(sizeBuffer, 0, 4, entry.offset);
        const storedSize = sizeBuffer.readInt32LE(0);
        if (storedSize <= 0 || storedSize > 0x10000000) throw new Error(`Invalid FDB image payload size for ${imageId}.`);
        const payload = Buffer.alloc(storedSize);
        await handle.read(payload, 0, storedSize, entry.offset + 4);
        const compression = payload.readInt32LE(4);
        const dataSize = payload.readInt32LE(8);
        const compressedSize = payload.readInt32LE(12);
        const filenameLength = payload.readInt32LE(24);
        const imageHeaderOffset = 28 + filenameLength;
        const imageFormat = payload.readInt32LE(imageHeaderOffset);
        const width = payload.readInt32LE(imageHeaderOffset + 4);
        const height = payload.readInt32LE(imageHeaderOffset + 8);
        const pixelOffset = imageHeaderOffset + 16;
        const storedPixels = payload.subarray(pixelOffset, pixelOffset + (compression === 0 ? dataSize : compressedSize));
        const pixels = compression === 0 ? storedPixels : compression === 3 ? inflateSync(storedPixels) : null;
        if (!pixels || pixels.length !== dataSize) throw new Error(`Unsupported or corrupt FDB compression ${compression} for ${imageId}.`);
        if (imageFormat !== 4 || width <= 0 || height <= 0 || pixels.length < width * height * 4) {
          throw new Error(`Unsupported FDB image format ${imageFormat} for ${imageId}.`);
        }
        const rgba = Buffer.alloc(width * height * 4);
        for (let offset = 0; offset < rgba.length; offset += 4) {
          rgba[offset] = pixels[offset + 2];
          rgba[offset + 1] = pixels[offset + 1];
          rgba[offset + 2] = pixels[offset];
          rgba[offset + 3] = pixels[offset + 3];
        }
        await sharp(rgba, { raw: { width, height, channels: 4 } }).png({ compressionLevel: 9 }).toFile(path.join(iconOutputDirectory, `${imageId}.png`));
      }));
    }
    return { requested: requested.size, resolved: requested.size, fdbEntries: count };
  } finally {
    await handle.close();
  }
}

function parseLearnEntries() {
  if (int32(buffers.learnMagic, COUNT_OFFSET) !== 21 || int32(buffers.learnMagic, DATA_START) !== 590000) throw new Error("learnmagic.db sentinel drifted.");
  const entries = [];
  for (let classIndex = 1; classIndex <= 10; classIndex += 1) {
    const recordOffset = DATA_START + classIndex * LEARN_RECORD_SIZE;
    if (int32(buffers.learnMagic, recordOffset) !== 590000 + classIndex) throw new Error(`learnmagic class ${classIndex} sentinel drifted.`);
    const spCount = int32(buffers.learnMagic, recordOffset + 0xb0);
    const normalCountOffset = recordOffset + 0xb4 + SP_CAPACITY * LEARN_ENTRY_SIZE;
    const normalCount = int32(buffers.learnMagic, normalCountOffset);
    for (const [kind, count, start] of [["primary", spCount, recordOffset + 0xb4], ["general", normalCount, normalCountOffset + 4]]) {
      for (let index = 0; index < count; index += 1) {
        const offset = start + index * LEARN_ENTRY_SIZE;
        entries.push({
          classIndex,
          kind,
          sourceSkillId: int32(buffers.learnMagic, offset),
          learnLevel: Math.max(1, int32(buffers.learnMagic, offset + 4)),
          keyItemId: int32(buffers.learnMagic, offset + 8),
          prerequisites: [int32(buffers.learnMagic, offset + 12), int32(buffers.learnMagic, offset + 16)].filter((id) => id > 0),
          saveLevelPosition: buffers.learnMagic.readUInt8(offset + 22),
        });
      }
    }
  }
  return entries;
}

function parseEliteTable(tableName, terminator, levels) {
  const text = buffers.eliteLua.toString("latin1");
  const start = text.indexOf(`local ${tableName}`);
  const end = text.indexOf(terminator, start);
  if (start < 0 || end < 0) throw new Error(`${tableName} mapping was not found.`);
  let mainClass = null;
  const mappings = [];
  for (const line of text.slice(start, end).split(/\r?\n/)) {
    const main = line.match(/^\s*\[(\d+)\]\s*=\s*\{\s*$/);
    if (main) { mainClass = Number(main[1]); continue; }
    const pair = line.match(/^\s*\[(\d+)\]\s*=\s*\{([\d,\s]+)\}/);
    if (!pair || mainClass === null) continue;
    const keys = pair[2].split(",").map(Number);
    if (keys.length !== levels.length) throw new Error(`${tableName} ${mainClass}/${pair[1]} expected ${levels.length} milestones.`);
    mappings.push({ mainClass, secondaryClass: Number(pair[1]), milestones: keys.map((keyItemId, index) => ({ level: levels[index], keyItemId })) });
  }
  return mappings;
}

const learnEntries = parseLearnEntries();
const eliteMappings = [
  ...parseEliteTable("VocationSkill", "return VocationSkill", ELITE_LEVELS.slice(0, 8)),
  ...parseEliteTable("KeyItemList", "return KeyItemList", ELITE_LEVELS.slice(8)),
].reduce((map, entry) => {
  const key = `${entry.mainClass}:${entry.secondaryClass}`;
  const existing = map.get(key) ?? { mainClass: entry.mainClass, secondaryClass: entry.secondaryClass, milestones: [] };
  existing.milestones.push(...entry.milestones);
  map.set(key, existing);
  return map;
}, new Map());

const eligiblePairs = new Set();
for (const classes of Object.values(RACE_MATRIX)) for (const main of classes) for (const secondary of classes) if (main !== secondary) eligiblePairs.add(`${main}:${secondary}`);
if (eligiblePairs.size !== 66) throw new Error(`Race matrix produced ${eligiblePairs.size} ordered pairs instead of 66.`);
if (eliteMappings.size !== 66 || [...eliteMappings.values()].some((entry) => entry.milestones.length !== 10)) throw new Error("Elite Lua mapping does not resolve 66 ordered pairs with ten milestones.");

const byKeyItem = new Map();
for (const entry of learnEntries) {
  if (!entry.keyItemId) continue;
  const candidates = byKeyItem.get(entry.keyItemId) ?? [];
  candidates.push(entry);
  byKeyItem.set(entry.keyItemId, candidates);
}

const adaptations = [];
const skills = [];
for (const classIndex of CLASS_IDS.keys()) {
  const sourceClass = classIndex + 1;
  const grouped = new Map();
  for (const entry of learnEntries.filter((candidate) => candidate.classIndex === sourceClass && candidate.keyItemId === 0)) {
    const key = `${entry.kind}:${entry.saveLevelPosition}`;
    const family = grouped.get(key) ?? [];
    family.push(entry);
    grouped.set(key, family);
  }
  for (const [familyKey, family] of grouped) {
    family.sort((left, right) => left.learnLevel - right.learnLevel || left.sourceSkillId - right.sourceSkillId);
    const rankRows = family.map((entry, index) => ({ ...entry, rank: index + 1, spell: sourceSpell(entry.sourceSkillId, sourceClass) })).filter((entry) => entry.spell);
    if (!rankRows.length) continue;
    const base = rankRows[0];
    const slug = `${CLASS_IDS[classIndex]}-${base.kind}-${base.saveLevelPosition}`;
    skills.push({
      id: slug,
      classId: CLASS_IDS[classIndex],
      group: base.spell.passive ? "passive" : base.kind,
      unlockLevel: Math.min(...rankRows.map((rank) => rank.learnLevel)),
      ...base.spell,
      ranks: rankRows.map((rank) => ({
        rank: rank.rank,
        level: rank.learnLevel,
        prerequisites: rank.prerequisites,
        ...nestedRankSpell(rank.spell, base.spell.sourceSkillId),
      })),
      sourceFamily: familyKey,
      icon: `/assets/ui/rom-spells/${base.spell.source.imageId}.png`,
      iconResolution: "native-interface-fdb",
    });
  }
}

for (const key of [...eligiblePairs].sort()) {
  const mapping = eliteMappings.get(key);
  if (!mapping) throw new Error(`Missing elite mapping ${key}.`);
  for (const milestone of mapping.milestones) {
    let candidates = byKeyItem.get(milestone.keyItemId) ?? [];
    let candidate = candidates.find((entry) => entry.classIndex === mapping.mainClass && entry.learnLevel === milestone.level)
      ?? candidates.find((entry) => entry.classIndex === mapping.mainClass)
      ?? candidates[0];
    if (!candidate && milestone.keyItemId === 545911) {
      candidate = learnEntries.find((entry) => entry.classIndex === 9 && entry.sourceSkillId === 498668);
      adaptations.push({ type: "source-key-typo", pair: key, level: milestone.level, keyItemId: milestone.keyItemId, sourceSkillId: 498668, reason: "Lua key 545911 is absent; the adjacent duplicated 545910 rank 498668 is the deterministic level-50 continuation." });
    }
    if (!candidate) throw new Error(`Elite ${key} level ${milestone.level} key ${milestone.keyItemId} has no learnmagic entry.`);
    const spell = sourceSpell(candidate.sourceSkillId, mapping.mainClass);
    if (!spell) throw new Error(`Elite ${key} level ${milestone.level} spell ${candidate.sourceSkillId} has no magic record.`);
    skills.push({
      id: `${CLASS_IDS[mapping.mainClass - 1]}-${CLASS_IDS[mapping.secondaryClass - 1]}-elite-${milestone.level}`,
      classId: CLASS_IDS[mapping.mainClass - 1],
      secondaryClassId: CLASS_IDS[mapping.secondaryClass - 1],
      group: spell.passive ? "passive" : "elite",
      unlockLevel: milestone.level,
      keyItemId: milestone.keyItemId,
      ...spell,
      ranks: [{
        rank: 1,
        level: milestone.level,
        prerequisites: candidate.prerequisites,
        ...nestedRankSpell(spell, spell.sourceSkillId),
      }],
      icon: `/assets/ui/rom-spells/${spell.source.imageId}.png`,
      iconResolution: "native-interface-fdb",
    });
  }
}

const eliteSkills = skills.filter((skill) => skill.secondaryClassId);
const ordinarySkills = skills.filter((skill) => !skill.secondaryClassId);
const unresolvedVisible = skills.filter((skill) => !skill.passive && !skill.effect?.kind);
const iconCoverage = await extractNativeIcons(skills);
const sourceHashes = {
  ...Object.fromEntries(Object.entries(buffers).map(([key, value]) => [key, sha256(value)])),
  interfaceFdb: await sha256File(interfaceFdb),
};
const catalog = {
  schemaVersion: 1,
  source: { rootHint: "RuneWaker source snapshot", hashes: sourceHashes },
  canonicalClasses: CLASS_IDS.map((id, index) => ({ id, sourceClassId: index + 1, name: CLASS_NAMES[index], resource: RESOURCES[index] })),
  baseStatGrowth: Object.fromEntries(CLASS_IDS.map((id, index) => [id, vocationGrowth(index + 1)])),
  raceMatrix: Object.fromEntries(Object.entries(RACE_MATRIX).map(([raceId, classes]) => [raceId, classes.map((index) => CLASS_IDS[index - 1])])),
  eliteLevels: ELITE_LEVELS,
  skills,
};
const audit = {
  generatorVersion: 1,
  hashes: catalog.source.hashes,
  sentinels: { learnMagicRecords: int32(buffers.learnMagic, COUNT_OFFSET), magicCollectRecords: magicCollectCount, magicObjectRecords: magicObjectCount },
  coverage: {
    releasedClasses: CLASS_IDS.length,
    duelistExcluded: !CLASS_NAMES.includes("Duelist"),
    races: Object.keys(RACE_MATRIX).length,
    orderedPairs: eligiblePairs.size,
    eliteMilestones: eliteSkills.length,
    ordinaryFamilies: ordinarySkills.length,
    sourceRankRows: ordinarySkills.reduce((sum, skill) => sum + skill.ranks.length, 0),
    iconResolved: skills.filter((skill) => skill.iconResolution === "native-interface-fdb").length,
    uniqueNativeIcons: iconCoverage.resolved,
    interfaceFdbEntries: iconCoverage.fdbEntries,
    executableOrNonCombat: skills.filter((skill) => skill.passive || Boolean(skill.effect?.kind)).length,
    unresolvedVisible: unresolvedVisible.length,
  },
  adaptations,
};
if (eliteSkills.length !== 660 || unresolvedVisible.length !== 0 || audit.coverage.iconResolved !== skills.length || iconCoverage.requested !== iconCoverage.resolved) throw new Error(`Coverage failed: ${JSON.stringify(audit.coverage)}`);
await mkdir(path.dirname(outputFile), { recursive: true });
await mkdir(path.dirname(auditFile), { recursive: true });
await Promise.all([
  writeFile(outputFile, `${JSON.stringify(catalog)}\n`),
  writeFile(auditFile, `${JSON.stringify(audit, null, 2)}\n`),
]);
console.log(`Generated ${ordinarySkills.length} ordinary families and ${eliteSkills.length} ordered-pair elite skills.`);
console.log(`Coverage audit: ${path.relative(projectRoot, auditFile)}`);