#!/usr/bin/env node
/**
 * download-textures.js — Bulk-download item/block textures for all supported
 * mods into the local texture cache.
 *
 * Supported mods (Prominence Hasturian Era II modpack):
 *   Minecraft, Create, CC:Tweaked, Mythic Metals, Farmer's Delight,
 *   Ad Astra, BetterEnd, Applied Energistics 2, Twilight Forest
 *
 * Run once (or on container start) to pre-populate the cache so the proxy
 * never needs to hit upstream for known textures.
 *
 * Usage:   node download-textures.js [cacheDir]
 * Default: /data/texture-cache  (matches server.js)
 */

import fs from 'fs';
import path from 'path';

const CACHE_DIR = process.argv[2] || process.env.TEXTURE_CACHE_DIR || '/data/texture-cache';

// ── Upstream repos (same namespaces as TEXTURE_UPSTREAMS in server.js) ─────

const REPOS = {
  minecraft: {
    api: 'https://api.github.com/repos/InventivetalentDev/minecraft-assets/git/trees/1.21.4?recursive=1',
    raw: 'https://cdn.jsdelivr.net/gh/InventivetalentDev/minecraft-assets@1.21.4',
    prefix: 'assets/minecraft/textures/',
    folders: ['item/', 'block/'],
  },
  create: {
    api: 'https://api.github.com/repos/Creators-of-Create/Create/git/trees/mc1.20.1/dev?recursive=1',
    raw: 'https://raw.githubusercontent.com/Creators-of-Create/Create/mc1.20.1/dev',
    prefix: 'src/main/resources/assets/create/textures/',
    folders: ['item/', 'block/'],
  },
  computercraft: {
    api: 'https://api.github.com/repos/cc-tweaked/CC-Tweaked/git/trees/mc-1.20.x?recursive=1',
    raw: 'https://raw.githubusercontent.com/cc-tweaked/CC-Tweaked/mc-1.20.x',
    prefix: 'projects/common/src/main/resources/assets/computercraft/textures/',
    folders: ['item/', 'block/'],
  },
  mythicmetals: {
    api: 'https://api.github.com/repos/Noaaan/MythicMetals/git/trees/1.20?recursive=1',
    raw: 'https://raw.githubusercontent.com/Noaaan/MythicMetals/1.20',
    prefix: 'src/main/resources/assets/mythicmetals/textures/',
    folders: ['item/', 'block/'],
  },
  farmersdelight: {
    api: 'https://api.github.com/repos/vectorwing/FarmersDelight/git/trees/1.20?recursive=1',
    raw: 'https://raw.githubusercontent.com/vectorwing/FarmersDelight/1.20',
    prefix: 'src/main/resources/assets/farmersdelight/textures/',
    folders: ['item/', 'block/'],
  },
  ad_astra: {
    api: 'https://api.github.com/repos/terrarium-earth/Ad-Astra/git/trees/1.20.1?recursive=1',
    raw: 'https://raw.githubusercontent.com/terrarium-earth/Ad-Astra/1.20.1',
    prefix: 'common/src/main/resources/assets/ad_astra/textures/',
    folders: ['item/', 'block/'],
  },
  betterend: {
    api: 'https://api.github.com/repos/quiqueck/BetterEnd/git/trees/1.20?recursive=1',
    raw: 'https://raw.githubusercontent.com/quiqueck/BetterEnd/1.20',
    prefix: 'src/main/resources/assets/betterend/textures/',
    folders: ['item/', 'block/'],
  },
  ae2: {
    api: 'https://api.github.com/repos/AppliedEnergistics/Applied-Energistics-2/git/trees/fabric/1.20.1?recursive=1',
    raw: 'https://raw.githubusercontent.com/AppliedEnergistics/Applied-Energistics-2/fabric/1.20.1',
    prefix: 'src/main/resources/assets/ae2/textures/',
    folders: ['item/', 'block/'],
  },
  twilightforest: {
    api: 'https://api.github.com/repos/TeamTwilight/twilightforest/git/trees/1.20.1?recursive=1',
    raw: 'https://raw.githubusercontent.com/TeamTwilight/twilightforest/1.20.1',
    prefix: 'src/main/resources/assets/twilightforest/textures/',
    folders: ['item/', 'block/'],
  },
};

// ── Rate-limit-friendly parallel downloader ────────────────────────────────

const CONCURRENCY = 10;
const RETRY_DELAY = 1000;
const MAX_RETRIES = 3;

async function downloadFile(url, dest, retries = 0) {
  try {
    const res = await fetch(url);
    if (res.status === 404) return false;          // genuinely missing
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    const buffer = Buffer.from(await res.arrayBuffer());
    fs.mkdirSync(path.dirname(dest), { recursive: true });
    fs.writeFileSync(dest, buffer);
    return true;
  } catch (err) {
    if (retries < MAX_RETRIES) {
      await new Promise(r => setTimeout(r, RETRY_DELAY * (retries + 1)));
      return downloadFile(url, dest, retries + 1);
    }
    console.error(`  ✗ ${url}: ${err.message}`);
    return false;
  }
}

async function runPool(tasks) {
  let idx = 0;
  let ok = 0;
  let fail = 0;
  async function worker() {
    while (idx < tasks.length) {
      const task = tasks[idx++];
      const success = await downloadFile(task.url, task.dest);
      if (success) ok++;
      else fail++;
    }
  }
  const workers = Array.from({ length: Math.min(CONCURRENCY, tasks.length) }, () => worker());
  await Promise.all(workers);
  return { ok, fail };
}

// ── Main ───────────────────────────────────────────────────────────────────

async function downloadNamespace(name, repo) {
  console.log(`\n⬇  ${name}: fetching file list…`);

  const res = await fetch(repo.api, {
    headers: { 'User-Agent': 'inventory-manager-texture-dl' },
  });
  if (!res.ok) {
    console.error(`  ✗ GitHub API ${res.status}: ${await res.text()}`);
    return;
  }
  const data = await res.json();

  // Filter to only PNG files in the target folders under the prefix
  const tasks = [];
  for (const entry of data.tree || []) {
    if (entry.type !== 'blob') continue;
    if (!entry.path.startsWith(repo.prefix)) continue;
    if (!entry.path.endsWith('.png')) continue;

    const relPath = entry.path.slice(repo.prefix.length);   // e.g. "item/diamond.png"
    const inFolder = repo.folders.some(f => relPath.startsWith(f));
    if (!inFolder) continue;

    const dest = path.join(CACHE_DIR, name, relPath);
    if (fs.existsSync(dest)) continue;                      // already cached

    tasks.push({
      url: `${repo.raw}/${entry.path}`,
      dest,
    });
  }

  if (tasks.length === 0) {
    console.log(`  ✓ ${name}: all textures already cached`);
    return;
  }

  console.log(`  ↓ downloading ${tasks.length} textures…`);
  const { ok, fail } = await runPool(tasks);
  console.log(`  ✓ ${name}: ${ok} downloaded, ${fail} failed`);
}

async function main() {
  console.log(`Texture cache dir: ${CACHE_DIR}`);
  fs.mkdirSync(CACHE_DIR, { recursive: true });

  for (const [name, repo] of Object.entries(REPOS)) {
    await downloadNamespace(name, repo);
  }

  // Clean up any .miss files so newly-downloaded textures take effect
  let cleared = 0;
  function cleanMiss(dir) {
    try {
      for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
        const full = path.join(dir, entry.name);
        if (entry.isDirectory()) cleanMiss(full);
        else if (entry.name.endsWith('.miss')) { fs.unlinkSync(full); cleared++; }
      }
    } catch (_) { /* ignore */ }
  }
  cleanMiss(CACHE_DIR);
  if (cleared) console.log(`\n🗑  Cleared ${cleared} negative-cache entries`);

  // Build and print index stats
  const stats = {};
  function countPngs(dir, ns) {
    try {
      for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
        const full = path.join(dir, entry.name);
        if (entry.isDirectory()) countPngs(full, ns);
        else if (entry.name.endsWith('.png')) stats[ns] = (stats[ns] || 0) + 1;
      }
    } catch (_) { /* ignore */ }
  }
  for (const ns of Object.keys(REPOS)) {
    countPngs(path.join(CACHE_DIR, ns), ns);
  }
  console.log('\n📊 Cache totals:');
  for (const [ns, count] of Object.entries(stats)) {
    console.log(`   ${ns}: ${count} textures`);
  }
  console.log('\n✅ Done');
}

main().catch(err => {
  console.error('Fatal:', err);
  process.exit(1);
});