"""Package verified generated mail overrides; never copy stale build directories."""

import argparse
import hashlib
import io
import json
from pathlib import Path, PurePosixPath
import re
import tarfile
import zipfile


def read_file(path):
    path = Path(path)
    if path.is_symlink() or not path.is_file():
        raise ValueError(f"Expected regular file: {path}")
    return path.read_bytes()


def checked_path(base, name):
    parts = PurePosixPath(name)
    if parts.is_absolute() or ".." in parts.parts or "\\" in name or ":" in name:
        raise ValueError(f"Unsafe package path: {name}")
    path = base.joinpath(*parts.parts)
    if not path.resolve().is_relative_to(base.resolve()):
        raise ValueError(f"Path escapes package root: {name}")
    return path


def digest(data):
    return hashlib.sha256(data).hexdigest()


def collect(root, version):
    root = Path(root)
    if not re.fullmatch(r"v[0-9]+\.[0-9]+\.[0-9]+", version):
        raise ValueError("Expected a stable vX.Y.Z package version")
    lock = json.loads(read_file(root / "gitea.lock.json"))
    if version != lock["tag"]:
        raise ValueError("Package version must match the locked Gitea tag")
    files = {}
    names = sorted(p.name for p in (root / "themes").iterdir() if p.is_dir() and not p.is_symlink())
    if not names:
        raise ValueError("No source theme manifests")
    for name in names:
        if not re.fullmatch(r"[a-z][a-z0-9-]*", name):
            raise ValueError(f"Invalid theme name: {name}")
        source = root / "themes" / name
        theme = json.loads(read_file(source / "theme.json"))
        if theme["name"] != name or theme["mode"] not in ("shared", "framed"):
            raise ValueError(f"Invalid theme metadata: {name}")
        built = root / "build" / "themes" / name
        meta = json.loads(read_file(built / "build.json"))
        if (meta["theme"], meta["mode"], meta["gitea_tag"], meta["gitea_commit"]) != (name, theme["mode"], version, lock["commit"]):
            raise ValueError(f"Stale build identity: {name}")
        if not {"theme.json", "theme.css"}.issubset(meta.get("sources") or {}) or not meta.get("files"):
            raise ValueError(f"Missing source/file provenance: {name}")
        expected_files = {"mail/base/head.tmpl", "mail/base/footer.tmpl"}
        if theme["mode"] == "framed":
            expected_files.update(path.removeprefix("templates/") for path in lock["files"] if path.startswith("templates/mail/") and path.endswith(".tmpl"))
            expected_files.update(path.relative_to(root / "framework").as_posix() for path in (root / "framework" / "mail").rglob("*.tmpl"))
        if set(meta["files"]) != expected_files:
            raise ValueError(f"Incomplete generated install package: {name}")
        for path, expected in meta["sources"].items():
            base = root if path.startswith(("framework/", "tools/")) else source
            if digest(read_file(checked_path(base, path))) != expected:
                raise ValueError(f"Source changed since build: {name}/{path}")
        for path, expected in meta["files"].items():
            if not path.startswith("mail/") or not path.endswith(".tmpl"):
                raise ValueError(f"Unexpected generated file: {path}")
            data = read_file(checked_path(built, path))
            if digest(data) != expected:
                raise ValueError(f"Generated checksum mismatch: {name}/{path}")
            files[f"themes/{name}/{path}"] = data
        files[f"themes/{name}/build.json"] = read_file(built / "build.json")
    manifest_data = read_file(root / "preview" / "rendered.js")
    prefix = b"window.__MAIL_PREVIEW__ = "
    manifest = json.loads(manifest_data.split(prefix, 1)[1].strip().removesuffix(b";"))
    languages = sorted(path.removeprefix("options/locale/locale_").removesuffix(".json") for path in lock["files"] if path.startswith("options/locale/locale_") and path.endswith(".json"))
    if manifest["upstream"] != version or manifest.get("upstream_commit") != lock["commit"] or sorted(manifest["themes"]) != names or sorted(manifest["languages"]) != languages:
        raise ValueError("Preview does not match lock/all source themes and languages; run preview all")
    files["preview/rendered.js"] = manifest_data
    for lang in languages:
        data = read_file(root / "preview" / "rendered" / (lang + ".js"))
        marker = ('window.__MAIL_PREVIEW_DATA__[' + json.dumps(lang) + '] = ').encode()
        payload = json.loads(data.split(marker, 1)[1].strip().removesuffix(b";"))
        if sorted(payload) != names or any(set(payload[name]) != set(manifest["registry"]) for name in names):
            raise ValueError(f"Incomplete preview language bundle: {lang}")
        files[f"preview/rendered/{lang}.js"] = data
    for name in ["LICENSE", "README.md", "CONTRIBUTING.md", "COMPATIBILITY.md", "docs/README.zh-CN.md", "docs/CONTRIBUTING.zh-CN.md", "preview/index.html"]:
        files[name] = read_file(root / name)
    for name in ["AGENTS.md", "THIRD_PARTY_NOTICES.md"]:
        if (root / name).exists():
            files[name] = read_file(root / name)
    for directory in [root / "docs", root / ".github" / "release-notes"]:
        for path in sorted(directory.rglob("*.md")):
            name = path.relative_to(root).as_posix()
            files[name] = read_file(checked_path(root, name))
    for path in sorted((root / "docs" / "images").iterdir()):
        if path.is_file() and (path.suffix == ".png" or path.name == "README.md"):
            files["docs/images/" + path.name] = read_file(path)
    license_data = read_file(root / "build" / "upstream" / "LICENSE")
    if digest(license_data) != lock["files"]["LICENSE"]:
        raise ValueError("Upstream license checksum mismatch")
    files["GITEA-LICENSE"] = license_data
    files["upstream-lock.json"] = read_file(root / "gitea.lock.json")
    return files


def package(root, version, output):
    files = collect(root, version)
    archive = f"gitea-mail-templates-{version}"
    output = Path(output)
    targets = [output / (archive + ext) for ext in (".zip", ".tar.gz")]
    if any(path.exists() for path in targets):
        raise ValueError("Refusing to overwrite existing release archives; use a new output directory")
    output.mkdir(parents=True, exist_ok=True)
    with zipfile.ZipFile(targets[0], "w", zipfile.ZIP_DEFLATED, compresslevel=9) as zipped, tarfile.open(targets[1], "w:gz") as tar:
        for name, data in sorted(files.items()):
            path = archive + "/" + name
            zipped.writestr(path, data)
            info = tarfile.TarInfo(path)
            info.size, info.mode = len(data), 0o644
            tar.addfile(info, io.BytesIO(data))
    print(f"[PASS] Packaged {len(files)} verified files: {targets[0]}, {targets[1]}")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--version", required=True)
    parser.add_argument("--root", type=Path, default=Path(__file__).resolve().parents[2])
    parser.add_argument("--output", type=Path, default=Path("dist"))
    args = parser.parse_args()
    try:
        package(args.root, args.version, args.output)
    except (ValueError, KeyError, IndexError, OSError) as error:
        parser.exit(1, f"[FAIL] {error}\n")