#!/usr/bin/env nix-shell
#!nix-shell -i python3 -p python3 python3Packages.requests python3Packages.beautifulsoup4 gh
import json
import os
import shlex
import subprocess
import sys
import time
import urllib.parse
from dataclasses import dataclass
from pathlib import Path
from tempfile import TemporaryDirectory
from typing import IO

import requests
from bs4 import BeautifulSoup


def get_latest_url(
    extension_name: str, mediawiki_version: str
) -> urllib.parse.ParseResult:
    # <dl><dd><a rel="nofollow" class="external free" href="https://extdist.wmflabs.org/dist/extensions/QuickInstantCommons-REL1_41-2a29b3e.tar.gz">https://extdist.wmflabs.org/dist/extensions/QuickInstantCommons-REL1_41-2a29b3e.tar.gz</a></dd></dl>
    extension_url = f"https://www.mediawiki.org/wiki/Special:ExtensionDistributor?extdistname={extension_name}&extdistversion=REL{mediawiki_version}"
    body = requests.get(extension_url)
    soup = BeautifulSoup(body.text, "html.parser")
    url = soup.find_all("a", class_="external free")[0].get("href")
    return urllib.parse.urlparse(url)


def run(
    cmd: list[str],
    check: bool = True,
    stdout: int | None = None,
    stdin: int | None = subprocess.DEVNULL,
) -> subprocess.CompletedProcess[str]:
    print("$ " + shlex.join(cmd))
    return subprocess.run(cmd, check=check, stdout=stdout, stdin=stdin, text=True)


@dataclass
class Extension:
    name: str
    hash: str
    url: str


def download_file(url: str, local_filename: str):
    with requests.get(url, stream=True) as r:
        r.raise_for_status()
        with open(local_filename, "wb") as f:
            for chunk in r.iter_content(chunk_size=8192):
                # If you have chunk encoded response uncomment if
                # and set chunk_size parameter to None.
                # if chunk:
                f.write(chunk)
    return local_filename


def mirror_extension(extension_name: str, mediawiki_version: str) -> Extension:
    download_url = get_latest_url(extension_name, mediawiki_version)
    base_name = Path(download_url.path).name
    print(f"{base_name}: {download_url.geturl()}")

    if run(["gh", "release", "view", base_name], check=False).returncode != 0:
        run(["gh", "release", "create", "--title", base_name, base_name])
    mirror_url = f"https://github.com/NixOS/nixos-wiki-infra/releases/download/{base_name}/{base_name}"
    if requests.head(mirror_url).status_code == 404:
        with TemporaryDirectory() as tmpdir:
            download_file(download_url.geturl(), f"{tmpdir}/{base_name}")
            run(["gh", "release", "upload", base_name, f"{tmpdir}/{base_name}"])
    for i in range(30):
        try:
            data = run(
                ["nix", "store", "prefetch-file", "--unpack", mirror_url, "--json"],
                stdout=subprocess.PIPE,
            ).stdout.strip()
            hash = json.loads(data)["hash"]
        except subprocess.CalledProcessError:
            # sometimes github takes a while to make releases available
            print("nix-prefetch-url failed, retrying")
            time.sleep(i * 5)
            continue
        else:
            return Extension(name=extension_name, hash=hash, url=mirror_url)
    raise Exception("Failed to fetch extension, see above")


def write_nix_file(file: IO[str], mirrored_extensions: list[Extension]) -> None:
    file.write("{ fetchzip }: {\n")
    for extension in mirrored_extensions:
        file.write(
            f'  "{extension.name}" = fetchzip {{ url = "{extension.url}"; hash = "{extension.hash}"; }};\n'
        )
    file.write("}\n")


def get_mediawiki_version(mediawiki_version: str | None = None) -> str:
    if mediawiki_version is None:
        mediawiki_version = run(
            [
                "nix",
                "eval",
                "--inputs-from",
                ".#",
                "--raw",
                "nixpkgs#mediawiki.version",
            ],
            stdout=subprocess.PIPE,
        ).stdout.strip()
    mediawiki_version = mediawiki_version.replace(".", "_")
    version_parts = mediawiki_version.split("_")
    return version_parts[0] + "_" + version_parts[1]


def main():
    if len(sys.argv) < 2:
        print("Usage: update-extensions.py extensions.json [mediawiki_version]")
        sys.exit(1)

    extensions = json.loads(Path(sys.argv[1]).read_text())
    mediawiki_version = get_mediawiki_version(
        sys.argv[2] if len(sys.argv) > 2 else None
    )

    # so that gh picks up the correct repository
    os.chdir(Path(__file__).parent)

    mirrored_extensions = []
    for name in extensions.keys():
        extension = mirror_extension(name, mediawiki_version)
        mirrored_extensions.append(extension)

    with open("extensions.nix", "w") as file:
        write_nix_file(file, mirrored_extensions)


if __name__ == "__main__":
    main()