#!/usr/bin/env python3

import argparse
import json
import os
import shlex
import subprocess
import sys
import urllib.request
from dataclasses import dataclass
from pathlib import Path
from typing import Dict, List


@dataclass(frozen=True)
class Repo:
    name: str
    html_url: str
    description: str = ""

    @classmethod
    def from_response(cls, data: Dict[str, str]) -> "Repo":
        return cls(
            **{
                k: v
                for k, v in data.items()
                if k in cls.__dataclass_fields__.keys() and v is not None
            }
        )


def get_soft_repos() -> List[str]:
    return (
        subprocess.check_output(
            shlex.split("ssh -p 23231 localhost repos list"), text=True
        )
        .strip()
        .splitlines()
    )


def get_link_url(links: str) -> str:
    """parse a link from a github api header response

    will look like this:
    '<https://api.github.com/user/47667941/repos?per_page=100&page=2>; rel="next" <https://api.github.com/user/47667941/repos?per_page=100&page=2>; rel="last"'
    """
    return links.split(",")[0].split(";")[0].strip("<>")


def get_gh_repos() -> List[Repo]:
    """get a list of all repos on GH with pagination"""
    token = os.getenv("GITHUB_TOKEN")
    headers = {
        "Accept": "application/vnd.github+json",
        "X-GitHub-Api-Version": "2022-11-28",
    }
    if token != "":
        headers["Authorization"] = f"Bearer {token}"
    url = "https://api.github.com/user/47667941/repos?per_page=100"
    pages_left = True
    data = []
    while pages_left:
        req = urllib.request.Request(url, headers=headers)
        response = urllib.request.urlopen(req)
        data.extend(json.loads(response.read()))
        pages_left = 'rel="next"' in (link_header := response.getheader("link"))
        if pages_left:
            url = get_link_url(link_header)

    return [Repo.from_response(repo_data) for repo_data in data]


def mirror_repo(repo: Repo, dry_run=False) -> None:
    print(f"mirroring: {repo.name}")
    cmd = [
        *shlex.split("ssh -p 23231 localhost repos import --mirror"),

        repo.name,
        repo.html_url,
    ]
    if repo.description != "":
        cmd.append("-d")
        cmd.append(f"'{repo.description}'")
    if dry_run:
        print(" ".join(str(s) for s in cmd))
    else:
        subprocess.check_output(cmd)


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "-n",
        "--dry-run",
        help="set dry-run (don't actually mirror with soft-serve yet)",
        action="store_true",
    )
    args = parser.parse_args()
    dry_run = False
    repos = (Path(__file__).parent / "repos.txt").read_text().splitlines()
    gh_repos = get_gh_repos()
    soft_repos = get_soft_repos()

    non_existent = {
        repo for repo in repos if repo not in (repo.name for repo in gh_repos)
    }
    if non_existent:
        sys.exit("some repos don't exist on github: " + ";".join(non_existent))

    to_mirror = {
        repo for repo in gh_repos if repo.name in repos and repo.name not in soft_repos
    }
    if not to_mirror:
        sys.exit("no repos need to be mirrored")

    print(f"mirroring {len(to_mirror)} repo(s)")
    for repo in to_mirror:
        mirror_repo(repo, dry_run=args.dry_run)