"""provision —— 把一个 MC 版本的客户端文件装进 store 目录，供渲染用。

只装渲染必需的内容（用户口径：只用渲染能力，不 gameplay）：
  versions/<id>/<id>.jar   客户端本体
  versions/<id>/<id>.json  版本信息（协议/主类的依据）
  libraries/**             依赖库
  assets/indexes/*.json    资源索引
  assets/objects/**        资源对象（**跳过音频**，我们不输出声音）

为什么自己做而不用 MCLC：
  MCLC 会顺带写 options.txt / usercache.json / logs，污染实例隔离；
  而我们要的只是「文件到位」。另外跳过音频能把下载量砍掉一大截。

★ 与版本无关：所有 URL 都从官方 version_manifest / version json 读，
  所以加新版本不需要改代码（这正是「按世代分派」想要的性质）。
"""
from __future__ import annotations

import json
import os
import sys
import time
import urllib.request
from concurrent.futures import ThreadPoolExecutor, as_completed
from pathlib import Path

MANIFEST = "https://piston-meta.mojang.com/mc/game/version_manifest_v2.json"

# 不下载的资源（渲染用不到，体积却大）
SKIP_ASSET_PREFIXES = (
    "minecraft/sounds/",
    "minecraft/sounds.json",
    "realms/",
)


def _get(url: str, timeout: int = 60) -> bytes:
    req = urllib.request.Request(url, headers={"User-Agent": "mcfold-provision/1.0"})
    with urllib.request.urlopen(req, timeout=timeout) as r:
        return r.read()


def _download(url: str, dest: Path, retries: int = 3) -> tuple[Path, int]:
    """下载到 dest（已存在且非空则跳过）。返回 (路径, 字节数)。"""
    if dest.is_file() and dest.stat().st_size > 0:
        return dest, dest.stat().st_size
    dest.parent.mkdir(parents=True, exist_ok=True)
    last = None
    for i in range(retries):
        try:
            data = _get(url)
            tmp = dest.with_suffix(dest.suffix + ".part")
            tmp.write_bytes(data)
            os.replace(tmp, dest)
            return dest, len(data)
        except Exception as e:      # noqa: BLE001
            last = e
            time.sleep(1.5 * (i + 1))
    raise RuntimeError(f"下载失败 {url}: {last}")


def resolve_version(version: str) -> dict:
    """从官方 manifest 拿版本 json（支持 '1.21.1' 或 'latest'）。"""
    manifest = json.loads(_get(MANIFEST))
    if version in ("latest", "latest-release"):
        version = manifest["latest"]["release"]
    for v in manifest["versions"]:
        if v["id"] == version:
            return json.loads(_get(v["url"]))
    raise SystemExit(f"未知版本: {version}")


def maven_url(lib: dict) -> str | None:
    """库的下载地址：优先用 version json 里给的 artifact.url。"""
    dl = (lib.get("downloads") or {}).get("artifact")
    if dl and dl.get("url"):
        return dl["url"]
    # 回退：按 maven 坐标拼（有些库不给 downloads）
    name = lib.get("name", "")
    parts = name.split(":")
    if len(parts) != 3:
        return None
    g, a, v = parts
    base = lib.get("url") or "https://libraries.minecraft.net/"
    if not base.endswith("/"):
        base += "/"
    return f"{base}{g.replace('.', '/')}/{a}/{v}/{a}-{v}.jar"


def natives_artifacts(version_json: dict) -> list[tuple[str, str]]:
    """linux 平台的原生库（LWJGL .so）。

    ★ 实测（1.21.1）：natives 是**独立的库条目**
      （name 形如 `org.lwjgl:lwjgl-freetype:3.3.3:natives-linux`），
      不走老版的 `downloads.classifiers` 结构。
      所以这里按 name 后缀 `:natives-linux` 识别 —— 对两代都成立。
    """
    out = []
    for lib in version_json.get("libraries", []):
        rules = lib.get("rules")
        if rules and not _rules_allow_linux(rules, lib):
            continue
        art = (lib.get("downloads") or {}).get("artifact") or {}
        name = lib.get("name", "")
        path = art.get("path") or ""
        is_native = (":natives-linux" in name) or ("natives-linux" in path)
        if is_native and art.get("url"):
            out.append((art["url"], art["path"]))
    # 兼容老结构（classifiers）
    for lib in version_json.get("libraries", []):
        rules = lib.get("rules")
        if rules and not _rules_allow_linux(rules, lib):
            continue
        for cname, c in ((lib.get("downloads") or {}).get("classifiers") or {}).items():
            if "linux" in cname and c.get("url"):
                out.append((c["url"], c["path"]))
    return out


def _rules_allow_linux(rules: list, lib: dict) -> bool:
    """MC 的 rules 语义：从默认 allow 出发，按序应用 allow/disallow。"""
    allowed = True
    for r in rules:
        action = r.get("action")
        os_name = (r.get("os") or {}).get("name")
        if os_name is None or os_name == "linux":
            allowed = action == "allow"
    return allowed


def library_path(lib: dict) -> str | None:
    """库在 libraries/ 下的相对路径。"""
    dl = (lib.get("downloads") or {}).get("artifact")
    if dl and dl.get("path"):
        return dl["path"]
    name = lib.get("name", "")
    parts = name.split(":")
    if len(parts) != 3:
        return None
    g, a, v = parts
    return f"{g.replace('.', '/')}/{a}/{v}/{a}-{v}.jar"


def provision(version: str, dest: Path, workers: int = 8,
              skip_assets: bool = False, verbose: bool = True) -> dict:
    """装一个版本的渲染所需文件。返回统计。"""
    dest = Path(dest)
    dest.mkdir(parents=True, exist_ok=True)
    vj = resolve_version(version)
    vid = vj["id"]

    jobs: list[tuple[str, Path]] = []

    # 1) 客户端 jar + version json
    client = vj["downloads"]["client"]
    vdir = dest / "versions" / vid
    jobs.append((client["url"], vdir / f"{vid}.jar"))
    (vdir).mkdir(parents=True, exist_ok=True)
    (vdir / f"{vid}.json").write_text(json.dumps(vj, indent=2))
    # mappings 也存一份（重映射用；不下载则反混淆得自己拉）
    cm = vj["downloads"].get("client_mappings")
    if cm:
        jobs.append((cm["url"], vdir / "client_mappings.txt"))

    # 2) libraries
    for lib in vj.get("libraries", []):
        rules = lib.get("rules")
        if rules and not _rules_allow_linux(rules, lib):
            continue
        url = maven_url(lib)
        rel = library_path(lib)
        if url and rel:
            jobs.append((url, dest / "libraries" / rel))
    for url, rel in natives_artifacts(vj):
        jobs.append((url, dest / "libraries" / rel))

    if verbose:
        print(f"[provision] {vid}: {len(jobs)} 个文件待检查/下载")

    # 3) assets（可跳过音频）
    asset_idx_id = vj.get("assetIndex", {}).get("id")
    if asset_idx_id and not skip_assets:
        idx_url = vj["assetIndex"]["url"]
        idx_dir = dest / "assets" / "indexes"
        idx_dir.mkdir(parents=True, exist_ok=True)
        # ★ 索引落盘名用 version id：MCLC 也这么做，而 MC 实际按
        #   options/启动参数里的 assetIndex 名去找（见 scaffold/README 坑 3）
        idx_file = idx_dir / f"{vid}.json"
        if not idx_file.is_file():
            idx_file.write_bytes(_get(idx_url))
        index = json.loads(idx_file.read_text())
        objects = index.get("objects", {})
        n_before = len(jobs)
        skipped = 0
        for name, o in objects.items():
            if any(name.startswith(p) for p in SKIP_ASSET_PREFIXES):
                skipped += 1
                continue
            h = o["hash"]
            jobs.append((
                f"https://resources.download.minecraft.net/{h[:2]}/{h}",
                dest / "assets" / "objects" / h[:2] / h,
            ))
        if verbose:
            print(f"[provision] assets: {len(objects)} 条，跳过 {skipped} 条（音频等），"
                  f"需下载 {len(jobs) - n_before}")

    # 4) 并行下载
    done = failed = 0
    bytes_total = 0
    errors: list[str] = []
    t0 = time.time()
    with ThreadPoolExecutor(max_workers=workers) as pool:
        futs = {pool.submit(_download, u, p): (u, p) for u, p in jobs}
        for i, fut in enumerate(as_completed(futs), 1):
            url, path = futs[fut]
            try:
                _, n = fut.result()
                done += 1
                bytes_total += n
            except Exception as e:      # noqa: BLE001
                failed += 1
                if len(errors) < 5:
                    errors.append(f"{path.name}: {e}")
            if verbose and i % 500 == 0:
                print(f"[provision]   {i}/{len(jobs)} ...")

    el = time.time() - t0
    if verbose:
        print(f"[provision] {vid} 完成：{done} 文件，{bytes_total / 1048576:.0f} MB，"
              f"{el:.0f}s，失败 {failed}")
        for e in errors:
            print(f"[provision]   ✗ {e}")
    return {"version": vid, "files": done, "failed": failed,
            "bytes": bytes_total, "seconds": el, "errors": errors,
            "dest": str(dest)}


def main(argv: list[str]) -> int:
    if len(argv) < 2:
        print("用法: python -m mcfold.provision <版本> [目标目录] [--no-assets]")
        return 2
    version = argv[1]
    dest = Path(argv[2]) if len(argv) > 2 and not argv[2].startswith("--") \
        else Path(f"/home/newqqagent/mcview/store/vanilla-{version}")
    stats = provision(version, dest, skip_assets="--no-assets" in argv)
    return 0 if stats["failed"] == 0 else 1


if __name__ == "__main__":
    sys.exit(main(sys.argv))