#!/usr/bin/env node
import { createHash } from "node:crypto";
import { spawn } from "node:child_process";
import { access, mkdir, readFile, readdir, writeFile } from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { DEFAULT_AZEROTHCORE_COMMIT } from "./import-azerothcore-world.mjs";

const projectRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "../..");
const sourceRoot = path.resolve(
  process.env.AZEROTHCORE_SCRIPT_ROOT
    ?? path.join(projectRoot, "..", "HealerMan-Storage", "pipeline-work", "dungeons", "azerothcore-scripts"),
);
const scriptsRoot = path.join(sourceRoot, "src", "server", "scripts");
const outputFile = path.join(
  projectRoot,
  "src",
  "game",
  "generated",
  "azerothCoreScriptSpells.json",
);
const epochSourceFile = path.join(
  projectRoot,
  "dungeon-pipeline",
  "epoch-five-player-instances.json",
);
const repository = "https://github.com/azerothcore/azerothcore-wotlk";
const sourceRoots = [
  "src/server/scripts/Kalimdor/CavernsOfTime",
  "src/server/scripts/Northrend",
  "src/server/scripts/Outland",
  "src/server/scripts/World",
];

const exists = async (file) => {
  try {
    await access(file);
    return true;
  } catch {
    return false;
  }
};
const readJson = async (file) => JSON.parse(await readFile(file, "utf8"));
const sha256 = (value) => createHash("sha256").update(value).digest("hex");

function runGit(argumentsList, cwd = projectRoot) {
  return new Promise((resolve, reject) => {
    const child = spawn("git", argumentsList, {
      cwd,
      stdio: "inherit",
      windowsHide: true,
    });
    child.once("error", reject);
    child.once("exit", (code) => (
      code === 0
        ? resolve()
        : reject(new Error(`git ${argumentsList.join(" ")} exited ${code}.`))
    ));
  });
}

function readGit(argumentsList, cwd = projectRoot) {
  return new Promise((resolve, reject) => {
    const child = spawn("git", argumentsList, {
      cwd,
      stdio: ["ignore", "pipe", "pipe"],
      windowsHide: true,
    });
    let output = "";
    let errorOutput = "";
    child.stdout.setEncoding("utf8");
    child.stderr.setEncoding("utf8");
    child.stdout.on("data", (chunk) => { output += chunk; });
    child.stderr.on("data", (chunk) => { errorOutput += chunk; });
    child.once("error", reject);
    child.once("exit", (code) => (
      code === 0
        ? resolve(output.trim())
        : reject(new Error(
          `git ${argumentsList.join(" ")} exited ${code}: ${errorOutput.trim()}`,
        ))
    ));
  });
}

async function fetchPinnedSources() {
  const gitDirectory = path.join(sourceRoot, ".git");
  if (!await exists(gitDirectory)) {
    await mkdir(path.dirname(sourceRoot), { recursive: true });
    await runGit([
      "clone",
      "--filter=blob:none",
      "--no-checkout",
      "--no-tags",
      repository,
      sourceRoot,
    ]);
  }
  await runGit(["fetch", "--depth=1", "origin", DEFAULT_AZEROTHCORE_COMMIT], sourceRoot);
  await runGit(["sparse-checkout", "init", "--cone"], sourceRoot);
  await runGit(["sparse-checkout", "set", ...sourceRoots], sourceRoot);
  await runGit(["checkout", "--detach", DEFAULT_AZEROTHCORE_COMMIT], sourceRoot);
}

async function sourceFiles(root) {
  const output = [];
  for (const entry of await readdir(root, { withFileTypes: true })) {
    const file = path.join(root, entry.name);
    if (entry.isDirectory()) output.push(...await sourceFiles(file));
    else if (/\.(?:cpp|h)$/i.test(entry.name)) output.push(file);
  }
  return output.sort();
}

function balancedBlock(source, start) {
  const opening = source.indexOf("{", start);
  if (opening < 0) return "";
  let depth = 0;
  let quoted = null;
  let escaped = false;
  for (let index = opening; index < source.length; index += 1) {
    const character = source[index];
    if (quoted) {
      if (escaped) escaped = false;
      else if (character === "\\") escaped = true;
      else if (character === quoted) quoted = null;
      continue;
    }
    if (character === "\"" || character === "'") {
      quoted = character;
      continue;
    }
    if (character === "{") depth += 1;
    if (character === "}") {
      depth -= 1;
      if (depth === 0) return source.slice(opening + 1, index);
    }
  }
  return source.slice(opening + 1);
}

function spellDefinitions(source) {
  return new Map([...source.matchAll(/\b(SPELL_[A-Z0-9_]+)\s*=\s*(\d+)\b/g)]
    .map((match) => [match[1], Number(match[2])]));
}

function secondsToMs(value, unit) {
  const number = Number(value);
  if (!Number.isFinite(number)) return null;
  return Math.round(number * (unit.toLowerCase() === "min" ? 60_000 : 1_000));
}

function cooldownFor(block, spellSymbol) {
  const stem = spellSymbol.replace(/^SPELL_/, "");
  const eventNames = [...new Set([
    `EVENT_${stem}`,
    `EVENT_SPELL_${stem}`,
  ])];
  const values = [];
  for (const eventName of eventNames) {
    for (const match of block.matchAll(new RegExp(
      `(?:RescheduleEvent|ScheduleEvent|Repeat)\\s*\\(\\s*${eventName}\\s*,?([^;]*)`,
      "g",
    ))) {
      for (const duration of match[1].matchAll(/(\d+(?:\.\d+)?)\s*(ms|s|min)\b/gi)) {
        const milliseconds = duration[2].toLowerCase() === "ms"
          ? Number(duration[1])
          : secondsToMs(duration[1], duration[2]);
        if (milliseconds && milliseconds >= 500) values.push(milliseconds);
      }
    }
    const caseStart = block.indexOf(`case ${eventName}:`);
    if (caseStart >= 0) {
      const caseEnd = block.indexOf("break;", caseStart);
      const caseBlock = block.slice(caseStart, caseEnd < 0 ? undefined : caseEnd);
      for (const duration of caseBlock.matchAll(/(\d+(?:\.\d+)?)\s*(ms|s|min)\b/gi)) {
        const milliseconds = duration[2].toLowerCase() === "ms"
          ? Number(duration[1])
          : secondsToMs(duration[1], duration[2]);
        if (milliseconds && milliseconds >= 500) values.push(milliseconds);
      }
    }
  }
  return values.length ? Math.min(...values) : undefined;
}

function isCombatSpell(symbol) {
  return !/(?:VISUAL|TELEPORT|CHANNEL_OOC|DUMMY|SCRIPT|TRIGGER|TARGETING|SUMMON|EMOTE|INTRO|OUTRO|ACHIEVEMENT|TRANSFORM|DESPAWN|KILL_CREDIT)/.test(symbol);
}

if (process.argv.includes("--fetch")) await fetchPinnedSources();
if (!await exists(scriptsRoot)) {
  throw new Error(
    `AzerothCore scripts are missing at ${scriptsRoot}; rerun with --fetch to check out commit ${DEFAULT_AZEROTHCORE_COMMIT}.`,
  );
}
if (!await exists(path.join(sourceRoot, ".git"))) {
  throw new Error(`AzerothCore script source at ${sourceRoot} is not a verifiable Git checkout.`);
}
const checkedOutCommit = await readGit(["rev-parse", "HEAD"], sourceRoot);
if (checkedOutCommit !== DEFAULT_AZEROTHCORE_COMMIT) {
  throw new Error(
    `AzerothCore script checkout is ${checkedOutCommit}; rerun with --fetch to restore ${DEFAULT_AZEROTHCORE_COMMIT}.`,
  );
}
const epochSource = await readJson(epochSourceFile);
const wantedSlugs = new Set(epochSource.dungeons.map((dungeon) => dungeon.slug));
const scriptNames = new Set();
for (const slug of wantedSlugs) {
    const draftFile = path.join(projectRoot, "..", "HealerMan-Storage", "pipeline-work", "dungeons", slug, "runtime-draft.json");
  if (!await exists(draftFile)) continue;
  const draft = await readJson(draftFile);
  for (const entity of draft.entities ?? []) {
    if (entity.scriptName) scriptNames.add(entity.scriptName);
  }
}

const files = await sourceFiles(scriptsRoot);
const documents = await Promise.all(files.map(async (file) => ({
  file,
  source: await readFile(file, "utf8"),
})));
const scripts = {};
const unresolved = [];
for (const scriptName of [...scriptNames].sort()) {
  const declaration = new RegExp(`\\b(?:struct|class)\\s+${scriptName}\\b`);
  const document = documents.find((candidate) => declaration.test(candidate.source))
    ?? documents.find((candidate) => new RegExp(`\\b${scriptName}\\b`).test(candidate.source));
  if (!document) {
    unresolved.push(scriptName);
    continue;
  }
  const declarationIndex = document.source.search(declaration);
  const block = balancedBlock(document.source, declarationIndex >= 0 ? declarationIndex : 0);
  const directoryDocuments = documents.filter(
    (candidate) => path.dirname(candidate.file) === path.dirname(document.file),
  );
  const definitions = new Map(
    directoryDocuments.flatMap((candidate) => [...spellDefinitions(candidate.source)]),
  );
  const usedSymbols = [...new Set([...block.matchAll(/\bSPELL_[A-Z0-9_]+\b/g)]
    .map((match) => match[0]))];
  const spells = usedSymbols
    .filter((symbol) => definitions.has(symbol))
    .map((symbol) => ({
      symbol,
      spellId: definitions.get(symbol),
      combat: isCombatSpell(symbol),
      ...(cooldownFor(block, symbol)
        ? { cooldownMs: cooldownFor(block, symbol) }
        : {}),
    }));
  scripts[scriptName] = {
    sourceFile: path.relative(projectRoot, document.file).replace(/\\/g, "/"),
    sourceHash: sha256(document.source),
    spells,
  };
}

const output = {
  schemaVersion: 1,
  source: {
    repository,
    commit: DEFAULT_AZEROTHCORE_COMMIT,
    roots: sourceRoots,
  },
  counts: {
    requestedScripts: scriptNames.size,
    resolvedScripts: Object.keys(scripts).length,
    unresolvedScripts: unresolved.length,
    combatSpells: Object.values(scripts)
      .flatMap((script) => script.spells)
      .filter((spell) => spell.combat).length,
  },
  unresolved,
  scripts,
};
await writeFile(outputFile, `${JSON.stringify(output, null, 2)}\n`, "utf8");
console.log(JSON.stringify({
  status: unresolved.length ? "review-required" : "green",
  output: path.relative(projectRoot, outputFile).replace(/\\/g, "/"),
  ...output.counts,
}, null, 2));