// Pull the vehicle models out of a GTA:SA install.
//
//   node tools/extract-vehicles.js --game "D:/.../Grand Theft Auto San Andreas"
//
// data/vehicles.ide gives the id -> model/txd mapping and data/carcols.dat the
// paint palette. Upgrade parts come from data/maps/veh_mods/veh_mods.ide, and
// data/carmods.dat says which ones each vehicle accepts. models/gta3.img holds
// every file. Everything lands in models/vehicles/ as <id>.dff / <id>.txd -
// vehicles are 400-611 and upgrades 1000-1193, so one flat folder does - next
// to the shared vehicle.txd and a vehicles.json describing the lot.

const fs = require('fs');
const path = require('path');
const { Img } = require('./img.js');

const USUAL_PLACES = [
  'C:/Program Files (x86)/Rockstar Games/GTA San Andreas',
  'C:/Program Files/Rockstar Games/GTA San Andreas',
  'C:/Program Files (x86)/Steam/steamapps/common/Grand Theft Auto San Andreas',
  'D:/SteamLibrary/steamapps/common/Grand Theft Auto San Andreas',
  'D:/Games/GTA San Andreas',
];

function parseArgs(argv) {
  const args = { game: '', out: path.join(__dirname, '..', 'models', 'vehicles') };
  for (let i = 0; i < argv.length; i++) {
    if (argv[i] === '--game') args.game = argv[++i];
    else if (argv[i] === '--out') args.out = argv[++i];
  }
  return args;
}

function findGame(given) {
  const candidates = given ? [given] : USUAL_PLACES;
  for (const dir of candidates) {
    if (fs.existsSync(path.join(dir, 'data', 'vehicles.ide'))) return dir;
  }
  throw new Error(
    given
      ? `no data/vehicles.ide under ${given}`
      : 'could not find a GTA:SA install - pass --game "<path>"'
  );
}

// Both ide and dat files are comma or whitespace separated, with # comments and
// named sections closed by 'end'.
function readSections(file) {
  const sections = new Map();
  let current = null;
  for (let line of fs.readFileSync(file, 'latin1').split(/\r?\n/)) {
    line = line.replace(/#.*$/, '').trim();
    if (!line) continue;
    if (!current) {
      current = { name: line.toLowerCase(), lines: [] };
      sections.set(current.name, current.lines);
      continue;
    }
    if (line.toLowerCase() === 'end') { current = null; continue; }
    current.lines.push(line);
  }
  return sections;
}

// Three retail vehicles.ide lines (emperor, wayfarer, dodo) drop the comma
// between the model and txd names, so whitespace separates fields too - which
// is what the game's own parser does. No field we read contains a space.
function fields(line) {
  return line.split(/[,\s]+/).map((f) => f.trim()).filter((f) => f !== '');
}

function parseVehicles(gameDir) {
  const cars = readSections(path.join(gameDir, 'data', 'vehicles.ide')).get('cars') || [];
  return cars.map((line) => {
    const f = fields(line);
    // Field 12 is the wheel scale for every vehicle type: cars append the wheel
    // model id and two scales, planes append a LOD model id after them.
    const wheelScale = Number(f[12]);
    return {
      id: Number(f[0]),
      model: f[1],
      txd: f[2],
      type: f[3],
      gameName: f[5] || f[1],
      wheelScale: Number.isFinite(wheelScale) ? wheelScale : 1,
    };
  }).filter((v) => Number.isFinite(v.id) && v.model);
}

// carcols has a 'col' palette, a 'car' section of primary/secondary pairs and a
// 'car4' section for the handful of vehicles that use four slots.
function parseCarcols(gameDir) {
  const sections = readSections(path.join(gameDir, 'data', 'carcols.dat'));

  const palette = (sections.get('col') || []).map((line) => fields(line).map(Number).slice(0, 3));

  const combos = new Map();
  const collect = (name, width) => {
    for (const line of sections.get(name) || []) {
      const f = fields(line);
      const model = f[0].toLowerCase();
      const ids = f.slice(1).map(Number).filter(Number.isFinite);
      const out = [];
      for (let i = 0; i + width <= ids.length; i += width) out.push(ids.slice(i, i + width));
      if (out.length) combos.set(model, out);
    }
  };
  collect('car', 2);
  collect('car4', 4); // wins where a model appears in both

  return { palette, combos };
}

// The upgrade parts are ordinary objects in their own ide, ids 1000-1193, all
// of them pointing at the shared vehicle txd.
function parseUpgrades(gameDir) {
  const file = path.join(gameDir, 'data', 'maps', 'veh_mods', 'veh_mods.ide');
  const objs = readSections(file).get('objs') || [];
  return objs.map((line) => {
    const f = fields(line);
    return { id: Number(f[0]), model: f[1] };
  }).filter((u) => Number.isFinite(u.id) && u.model);
}

// carmods lists which parts each vehicle accepts ('mods'), which left/right
// parts are fitted as a pair ('link'), and the wheel shop line-ups ('wheel').
function parseCarmods(gameDir) {
  const sections = readSections(path.join(gameDir, 'data', 'carmods.dat'));

  const mods = new Map();
  for (const line of sections.get('mods') || []) {
    const f = fields(line);
    // Retail comments the bike lines out, so they never reach here.
    if (f.length > 1) mods.set(f[0].toLowerCase(), f.slice(1).map((n) => n.toLowerCase()));
  }

  const links = new Map();
  for (const line of sections.get('link') || []) {
    const f = fields(line);
    if (f.length === 2) links.set(f[0].toLowerCase(), f[1].toLowerCase());
  }

  return { mods, links };
}

function main() {
  const args = parseArgs(process.argv.slice(2));
  const gameDir = findGame(args.game);
  console.log(`game    -> ${gameDir}`);

  const vehicles = parseVehicles(gameDir);
  const { palette, combos } = parseCarcols(gameDir);
  const upgrades = parseUpgrades(gameDir);
  const { mods, links } = parseCarmods(gameDir);
  console.log(
    `data    -> ${vehicles.length} vehicles, ${upgrades.length} upgrades, ` +
      `${palette.length} palette colours`
  );

  fs.mkdirSync(args.out, { recursive: true });

  // The five textures every vehicle shares - grunge, glass, lights, tyres -
  // live here rather than in the per-vehicle txd, so without it most of a car
  // renders untextured. The upgrade parts use it as their only dictionary.
  const sharedTxd = path.join(gameDir, 'models', 'generic', 'vehicle.txd');
  if (!fs.existsSync(sharedTxd)) throw new Error(`missing ${sharedTxd}`);
  fs.copyFileSync(sharedTxd, path.join(args.out, 'vehicle.txd'));

  const img = new Img(path.join(gameDir, 'models', 'gta3.img'));
  const missing = [];

  const byModel = new Map();
  const upgradeMeta = {};
  let upgradesWritten = 0;
  for (const upgrade of upgrades) {
    const dff = img.read(`${upgrade.model}.dff`);
    if (!dff) { missing.push(`${upgrade.id} ${upgrade.model}.dff`); continue; }
    fs.writeFileSync(path.join(args.out, `${upgrade.id}.dff`), dff);
    upgradeMeta[upgrade.id] = { name: upgrade.model };
    byModel.set(upgrade.model.toLowerCase(), upgrade.id);
    upgradesWritten++;
  }

  const meta = {};
  let written = 0;
  for (const vehicle of vehicles) {
    const dff = img.read(`${vehicle.model}.dff`);
    if (!dff) { missing.push(`${vehicle.id} ${vehicle.model}.dff`); continue; }
    fs.writeFileSync(path.join(args.out, `${vehicle.id}.dff`), dff);

    const txd = img.read(`${vehicle.txd}.txd`);
    if (txd) fs.writeFileSync(path.join(args.out, `${vehicle.id}.txd`), txd);

    // A paintjob is a one texture dictionary sitting next to the vehicle in the
    // archive as <model>1.txd upwards. Written out zero based, because that is
    // what ChangeVehiclePaintjob counts from. Thirteen vehicles have any.
    let paintjobs = 0;
    for (let n = 1; ; n++) {
      const job = img.read(`${vehicle.model}${n}.txd`);
      if (!job) break;
      fs.writeFileSync(path.join(args.out, `${vehicle.id}_pj${n - 1}.txd`), job);
      paintjobs++;
    }

    meta[vehicle.id] = {
      name: vehicle.model,
      gameName: vehicle.gameName,
      type: vehicle.type,
      wheelScale: vehicle.wheelScale,
      paintjobs,
      colors: combos.get(vehicle.model.toLowerCase()) || [],
      mods: (mods.get(vehicle.model.toLowerCase()) || [])
        .map((name) => byModel.get(name))
        .filter((id) => id !== undefined),
    };
    written++;
  }
  img.close();

  // Wheels are not in any vehicle's mods list because any wheel fits anything.
  const wheels = upgrades
    .filter((u) => /^wheel_/.test(u.model) && upgradeMeta[u.id])
    .map((u) => u.id);

  const linkIds = {};
  for (const [left, right] of links) {
    if (byModel.has(left) && byModel.has(right)) linkIds[byModel.get(left)] = byModel.get(right);
  }

  fs.writeFileSync(
    path.join(args.out, 'vehicles.json'),
    JSON.stringify({ palette, vehicles: meta, upgrades: upgradeMeta, wheels, links: linkIds }, null, 1)
  );

  console.log(`written -> ${written} vehicles, ${upgradesWritten} upgrades into ${args.out}`);
  if (missing.length) console.log(`missing -> ${missing.length}: ${missing.join(', ')}`);
}

main();