#!/usr/bin/env python3
import os
import sys
import json
import hashlib
import argparse

CHUNK_SIZE = 1024 * 1024  # 1 MB


def compute_sha1(path):
    """Spočítá SHA1 hash souboru."""
    h = hashlib.sha1()
    with open(path, "rb") as f:
        while True:
            chunk = f.read(CHUNK_SIZE)
            if not chunk:
                break
            h.update(chunk)
    return h.hexdigest()


def generate_manifest(root_dir, base_url, version, output_path):
    root_dir = os.path.abspath(root_dir)
    files = []

    for dirpath, dirnames, filenames in os.walk(root_dir):
        # ignoruj klasické bordely
        dirnames[:] = [
            d for d in dirnames
            if d not in (".git", ".svn", "__pycache__", ".idea", ".vs")
        ]

        for filename in filenames:
            full_path = os.path.join(dirpath, filename)
            rel_path = os.path.relpath(full_path, root_dir)

            # relativní cesty v manifestu vždy s '/'
            rel_path = rel_path.replace(os.sep, "/")

            # manifest.json sám sebe přeskoč
            if rel_path == "manifest.json":
                continue

            size = os.path.getsize(full_path)
            sha1 = compute_sha1(full_path)

            files.append({
                "path": rel_path,
                "size": size,
                "sha1": sha1,
            })

    manifest = {
        "version": version,
        "base_url": base_url.rstrip("/") + "/",  # vždy zakončit '/'
        "files": files,
    }

    with open(output_path, "w", encoding="utf-8") as f:
        json.dump(manifest, f, indent=2, ensure_ascii=False)

    print(f"Manifest hotový: {output_path}")
    print(f"Počet souborů: {len(files)}")


def main():
    parser = argparse.ArgumentParser(
        description="Vygeneruje manifest.json pro WoW klienta."
    )
    parser.add_argument(
        "root_dir",
        help="Kořenový adresář hry (tam kde je Data/, Wow.exe, atd.)"
    )
    parser.add_argument(
        "--base-url",
        required=True,
        help="Base URL, odkud to bude klient stahovat, např. https://ftp.chochrun.eu/wow/"
    )
    parser.add_argument(
        "--version",
        default="0.1",
        help="Verze manifestu (string, jen info). Default: 0.1"
    )
    parser.add_argument(
        "-o", "--output",
        help="Kam zapsat manifest.json (default: root_dir/manifest.json)"
    )

    args = parser.parse_args()

    root_dir = args.root_dir
    output_path = args.output or os.path.join(root_dir, "manifest.json")

    if not os.path.isdir(root_dir):
        print(f"Chyba: '{root_dir}' není adresář.", file=sys.stderr)
        sys.exit(1)

    generate_manifest(root_dir, args.base_url, args.version, output_path)


if __name__ == "__main__":
    main()