// One-time asset/codegen fetcher for Star Control Super Melee.
//
//   node tools/fetchStarControlAssets.js --ships     # download + build ship rotation sheets
//   node tools/fetchStarControlAssets.js --stats     # print UQM stat blocks for manual review
//
// Downloads ship art and stats from the Ur-Quan Masters GitHub mirror
// (juj/sc2-uqm). UQM content is CC BY-NC-SA 2.5 — an attribution line ships in
// data/star-control-ships.json and on the game's setup screen. This script is
// never run by the site; it needs network access plus ImageMagick (`magick`).
//
// --ships: for each ship, the GitHub contents API lists
// sc2/content/base/ships/<dir>/, the 16 `<base>-big-000..015.png` rotation
// frames are downloaded and composed into a 16x1 spritesheet at
// assets/images/starcontrol/sc-ship-<slug>.png. UQM frames are tightly
// cropped per frame (different sizes within one rotation) and aligned by
// per-frame hotspots in `<base>-big.ani`, so each frame is composited onto a
// uniform transparent cell with its hotspot at the cell centre; the cell
// dimensions are written into that ship's `sprite` block in
// data/star-control-ships.json (only the sprite block is touched).

import { readFileSync, writeFileSync, mkdirSync, rmSync } from 'node:fs';
import { execFileSync } from 'node:child_process';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';
import { tmpdir } from 'node:os';

const root = join(dirname(fileURLToPath(import.meta.url)), '..');
const REPO = 'juj/sc2-uqm';
const CONTENT = 'sc2/content/base/ships';
const SRC = 'sc2/src/uqm/ships';
const OUT_DIR = join(root, 'assets/images/starcontrol');
const JSON_PATH = join(root, 'data/star-control-ships.json');

// slug (our JSON key) -> UQM content directory. Frame prefixes are discovered,
// not guessed (e.g. human/cruiser-big-000.png).
const CONTENT_DIRS = {
  androsynth: 'androsynth', arilou: 'arilou', chenjesu: 'chenjesu', chmmr: 'chmmr',
  druuge: 'druuge', earthling: 'human', ilwrath: 'ilwrath', kohrah: 'kohrah',
  melnorme: 'melnorme', mmrnmhrm: 'mmrnmhrm', mycon: 'mycon', orz: 'orz',
  pkunk: 'pkunk', shofixti: 'shofixti', slylandro: 'slylandro', spathi: 'spathi',
  supox: 'supox', syreen: 'syreen', thraddash: 'thraddash', umgah: 'umgah',
  urquan: 'urquan', utwig: 'utwig', vux: 'vux', yehat: 'yehat', zoqfot: 'zoqfotpik',
};

// slug -> the rotation-frame prefix that is the SHIP (several directories
// also hold 16-frame weapon animations like spathi's "butt-big-000..015").
const SHIP_BASE = {
  androsynth: 'guardian', arilou: 'skiff', chenjesu: 'broodhome', chmmr: 'avatar',
  druuge: 'mauler', earthling: 'cruiser', ilwrath: 'avenger', kohrah: 'marauder',
  melnorme: 'trader', mmrnmhrm: 'xform', mycon: 'podship', orz: 'nemesis',
  pkunk: 'fury', shofixti: 'scout', slylandro: 'probe', spathi: 'eluder',
  supox: 'blade', syreen: 'penetrator', thraddash: 'torch', umgah: 'drone',
  urquan: 'dreadnought', utwig: 'jugger', vux: 'intruder', yehat: 'terminator',
  zoqfot: 'stinger',
};

// slug -> UQM source directory for --stats.
const SRC_DIRS = {
  androsynth: 'androsyn', arilou: 'arilou', chenjesu: 'chenjesu', chmmr: 'chmmr',
  druuge: 'druuge', earthling: 'human', ilwrath: 'ilwrath', kohrah: 'blackurq',
  melnorme: 'melnorme', mmrnmhrm: 'mmrnmhrm', mycon: 'mycon', orz: 'orz',
  pkunk: 'pkunk', shofixti: 'shofixti', slylandro: 'slylandr', spathi: 'spathi',
  supox: 'supox', syreen: 'syreen', thraddash: 'thradd', umgah: 'umgah',
  urquan: 'urquan', utwig: 'utwig', vux: 'vux', yehat: 'yehat', zoqfot: 'zoqfot',
};

async function ghJson(path) {
  const res = await fetch(`https://api.github.com/repos/${REPO}/contents/${path}`, {
    headers: { 'User-Agent': 'fertig-classic-games-asset-fetch' },
  });
  if (!res.ok) throw new Error(`GitHub API ${res.status} for ${path}`);
  return res.json();
}

async function download(url, dest) {
  const res = await fetch(url);
  if (!res.ok) throw new Error(`download ${res.status} for ${url}`);
  writeFileSync(dest, Buffer.from(await res.arrayBuffer()));
}

// Finds the rotation-frame prefix: a group of exactly 16 files named
// `<base>-big-000.png` .. `<base>-big-015.png` (weapon/captain art doesn't
// match this shape; e.g. human's saturn-big has 23 frames and is skipped).
function findRotationGroup(listing, preferredBase) {
  const groups = {};
  for (const f of listing) {
    const m = /^(.+)-big-(\d{3})\.png$/.exec(f.name);
    if (!m) continue;
    (groups[m[1]] ??= []).push({ n: Number(m[2]), url: f.download_url });
  }
  const candidates = Object.entries(groups)
    .filter(([, frames]) => frames.length === 16
      && Math.min(...frames.map((fr) => fr.n)) === 0
      && Math.max(...frames.map((fr) => fr.n)) === 15);
  if (candidates.length === 0) return null;
  let picked = candidates.find(([base]) => base === preferredBase);
  if (!picked) {
    console.warn(`  preferred base "${preferredBase}" not found; candidates: ${candidates.map(([k]) => k).join(', ')}`);
    [picked] = candidates;
  }
  const [base, frames] = picked;
  frames.sort((a, b) => a.n - b.n);
  return { base, frames };
}

// Parses a UQM .ani file: `<frame>.png <transparent> <colormap> <hotX> <hotY>`
// per line. Returns { frameNumber: {x, y} } for the rotation frames.
function parseAni(text) {
  const hot = {};
  for (const line of text.split('\n')) {
    const parts = line.trim().split(/\s+/);
    if (parts.length < 5) continue;
    const m = /-(\d{3})\.png$/i.exec(parts[0]);
    if (!m) continue;
    const x = Number(parts[parts.length - 2]);
    const y = Number(parts[parts.length - 1]);
    if (Number.isFinite(x) && Number.isFinite(y)) hot[Number(m[1])] = { x, y };
  }
  return hot;
}

async function buildSheet(slug, group, aniUrl, suffix = '') {
  const tmp = join(tmpdir(), `sc-fetch-${slug}${suffix}`);
  rmSync(tmp, { recursive: true, force: true });
  mkdirSync(tmp, { recursive: true });
  const files = [];
  for (const fr of group.frames) {
    const dest = join(tmp, `f-${String(fr.n).padStart(3, '0')}.png`);
    await download(fr.url, dest);
    files.push(dest);
  }

  // Per-frame dims (UQM crops each rotation frame individually).
  const dimLines = execFileSync('magick', ['identify', '-format', '%w %h\n', ...files])
    .toString().trim().split('\n');
  const dims = dimLines.map((l) => l.split(' ').map(Number));

  // Per-frame hotspots from the .ani; fall back to frame centres if absent.
  let hotspots = null;
  if (aniUrl) {
    try {
      const res = await fetch(aniUrl);
      if (res.ok) {
        const parsed = parseAni(await res.text());
        if (group.frames.every((fr) => parsed[fr.n])) hotspots = parsed;
      }
    } catch { /* fall through to centre alignment */ }
  }
  if (!hotspots) {
    console.warn(`  no usable .ani for ${slug}${suffix}; centring frames`);
    hotspots = {};
    group.frames.forEach((fr, i) => {
      hotspots[fr.n] = { x: Math.floor(dims[i][0] / 2), y: Math.floor(dims[i][1] / 2) };
    });
  }

  // Uniform cell sized so every frame fits with its hotspot at the centre.
  let halfW = 0;
  let halfH = 0;
  group.frames.forEach((fr, i) => {
    const [w, h] = dims[i];
    const { x, y } = hotspots[fr.n];
    halfW = Math.max(halfW, x, w - x);
    halfH = Math.max(halfH, y, h - y);
  });
  const cellW = halfW * 2;
  const cellH = halfH * 2;

  const cells = [];
  group.frames.forEach((fr, i) => {
    const { x, y } = hotspots[fr.n];
    const cell = join(tmp, `c-${String(fr.n).padStart(3, '0')}.png`);
    execFileSync('magick', [
      '-size', `${cellW}x${cellH}`, 'xc:none',
      files[i], '-geometry', `+${halfW - x}+${halfH - y}`, '-composite', cell,
    ]);
    cells.push(cell);
  });

  const sheetName = `sc-ship-${slug}${suffix}`;
  const out = join(OUT_DIR, `${sheetName}.png`);
  execFileSync('magick', [...cells, '+append', '-background', 'none', out]);
  rmSync(tmp, { recursive: true, force: true });
  return { sheet: sheetName, frames: 16, frameWidth: cellW, frameHeight: cellH };
}

async function fetchShips() {
  mkdirSync(OUT_DIR, { recursive: true });
  const json = JSON.parse(readFileSync(JSON_PATH, 'utf8'));
  const results = [];
  for (const [slug, dir] of Object.entries(CONTENT_DIRS)) {
    if (!json.ships[slug]) { console.warn(`skip ${slug}: not in ships JSON`); continue; }
    process.stdout.write(`${slug} (${dir}) ... `);
    try {
      const listing = await ghJson(`${CONTENT}/${dir}`);
      const group = findRotationGroup(listing, SHIP_BASE[slug]);
      if (!group) { console.log('NO 16-frame rotation group found'); continue; }
      const aniUrl = listing.find((f) => f.name === `${group.base}-big.ani`)?.download_url;
      json.ships[slug].sprite = await buildSheet(slug, group, aniUrl);
      console.log(`ok (${group.base}, ${json.ships[slug].sprite.frameWidth}x${json.ships[slug].sprite.frameHeight})`);
      // Mmrnmhrm's alternate Y-Wing form has its own rotation frames.
      if (slug === 'mmrnmhrm' && json.ships[slug].forms?.[0]) {
        const yGroup = findRotationGroup(listing, 'ywing');
        if (yGroup?.base === 'ywing') {
          const yAni = listing.find((f) => f.name === 'ywing-big.ani')?.download_url;
          json.ships[slug].forms[0].sprite = await buildSheet(slug, yGroup, yAni, '-y');
          console.log(`  + y-form sheet (${json.ships[slug].forms[0].sprite.frameWidth}x${json.ships[slug].forms[0].sprite.frameHeight})`);
        }
      }
      results.push(slug);
    } catch (e) {
      console.log(`FAILED: ${e.message}`);
    }
  }
  writeFileSync(JSON_PATH, `${JSON.stringify(json, null, 2)}\n`);
  console.log(`\n${results.length}/${Object.keys(CONTENT_DIRS).length} sheets built; sprite blocks written to data/star-control-ships.json`);
}

const STAT_DEFINES = [
  'MAX_CREW', 'MAX_ENERGY', 'ENERGY_REGENERATION', 'ENERGY_WAIT', 'MAX_THRUST',
  'THRUST_INCREMENT', 'THRUST_WAIT', 'TURN_WAIT', 'SHIP_MASS',
  'WEAPON_ENERGY_COST', 'WEAPON_WAIT', 'SPECIAL_ENERGY_COST', 'SPECIAL_WAIT',
  'MISSILE_SPEED', 'MISSILE_LIFE', 'MISSILE_HITS', 'MISSILE_DAMAGE',
];

// Prints raw #define blocks for manual review/merge — NOT written to the JSON
// (several ships encode stats in code: Chmmr zapsats, Slylandro drive,
// Mmrnmhrm forms).
async function fetchStats() {
  for (const [slug, dir] of Object.entries(SRC_DIRS)) {
    const url = `https://raw.githubusercontent.com/${REPO}/master/${SRC}/${dir}/${dir}.c`;
    const res = await fetch(url);
    if (!res.ok) { console.log(`${slug}: fetch failed ${res.status}`); continue; }
    const text = await res.text();
    const out = {};
    for (const name of STAT_DEFINES) {
      const m = new RegExp(`^#define\\s+${name}\\s+(.+)$`, 'm').exec(text);
      if (m) out[name] = m[1].replace(/\/\*.*?\*\//g, '').trim();
    }
    console.log(`\n=== ${slug} (${dir}.c)`);
    console.log(JSON.stringify(out, null, 2));
  }
}

const args = process.argv.slice(2);
if (args.includes('--stats')) await fetchStats();
else if (args.includes('--ships')) await fetchShips();
else console.log('usage: node tools/fetchStarControlAssets.js --ships | --stats');