#!/usr/bin/env -S uv run --script --frozen --only-group release-tools  # -*-python-*-

import re
import subprocess
import time
from typing import Annotated

import typer
from github import Auth, Github
from github.PullRequest import PullRequest
from github.Repository import Repository
from rich.console import Console
from rich.progress import track


def prs_to_backport(repo: Repository, console: Console, skip: set[int]) -> list[int]:
    backport_prs = []
    with console.status("Getting list of closed backport candidate PRs..."):
        issues = list(repo.get_issues(labels=["backport candidate"], state="closed"))
    for issue in track(issues, console=console, description="Fetching PR metadata..."):
        if issue.number in skip:
            continue
        if issue.pull_request is None:
            continue
        pr = repo.get_pull(issue.number)

        if pr.merged_at is None:
            print(f"PR {pr.number} does not have a merged_at time!")
            continue

        backport_prs.append((pr.number, pr.merged_at))

    backport_prs.sort(key=lambda x: x[1])
    return [pr[0] for pr in backport_prs]


def wait_for_complete(repo: Repository, pr: PullRequest, console: Console) -> None:
    commit = repo.get_commit(pr.head.sha)
    with console.status("Waiting for tests to pass..."):
        while True:
            time.sleep(10)
            check_runs = commit.get_check_runs()
            if check_runs.totalCount == 0:
                continue
            all_completed = True
            for check in check_runs:
                if check.status != "completed":
                    all_completed = False
                    break
                elif check.conclusion not in ["success", "neutral", "skipped"]:
                    raise Exception(f"{check.name} failed!")
            if all_completed:
                break
    pr.merge(merge_method="rebase")


def mark_as_backported(repo: Repository, backport_pr: int, pr_number: int, commit: str) -> None:
    pr = repo.get_pull(pr_number)
    pr.create_issue_comment(f"Backported in #{backport_pr} ({commit})")
    pr.remove_from_labels("backport candidate")


def validate_github_token(value: str) -> str:
    # https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/about-authentication-to-github#githubs-token-formats
    if value.startswith("github_"):
        return value
    if re.match(r"gh[pousr]_", value):
        return value
    raise typer.BadParameter("Github access tokens start with `github_`, or `gh`")


def main(
    token: Annotated[
        str,
        typer.Option(
            metavar="TOKEN",
            envvar="GITHUB_TOKEN",
            show_envvar=True,
            callback=validate_github_token,
            help="Github access token",
        ),
    ],
    skip: Annotated[list[int], typer.Option(default_factory=list)],
) -> int:
    """Make a backport PR"""

    console = Console(stderr=True, log_path=False)

    latest_tag = subprocess.check_output(
        ["git", "tag", "-l", "--sort=-committerdate", "--no-merged", "upstream/main"],
        text=True,
    ).splitlines()[0]
    target_branch = latest_tag.split(".")[0] + ".x"

    gh = Github(auth=Auth.Token(token))
    repo = gh.get_repo("zulip/zulip")
    pr_ids = prs_to_backport(repo, console, set(skip))

    branchname = f"backports-{target_branch}"
    subprocess.check_call(["git", "fetch", "upstream"])
    subprocess.check_call(
        [
            "git",
            "checkout",
            "-b",
            branchname,
            "--track",
            f"upstream/{target_branch}",
        ]
    )
    successful_pr_id_commits = []
    for pr_number in track(pr_ids, console=console, description="Backporting..."):
        try:
            subprocess.check_call(
                ["./tools/backport-pull-request", str(pr_number)],
                stderr=subprocess.DEVNULL,
                stdout=subprocess.DEVNULL,
            )
            current_commit = subprocess.check_output(
                ["git", "rev-parse", "HEAD"], text=True
            ).strip()
            successful_pr_id_commits.append((pr_number, current_commit))
        except subprocess.CalledProcessError:
            subprocess.check_call(["git", "cherry-pick", "--abort"])

    if not successful_pr_id_commits:
        print("No PRs successfully backported!")
        return 1

    body = f"Backport to {target_branch}:\n"
    for pr_number, _ in successful_pr_id_commits:
        body += f"- #{pr_number}\n"

    subprocess.check_call(["git", "push", "origin", f"HEAD:{branchname}"])
    backport_pr = repo.create_pull(
        title=f"{target_branch} backports",
        body=body,
        head=f"{gh.get_user().login}:{branchname}",
        base=target_branch,
    )
    wait_for_complete(repo, backport_pr, console)

    for pr_number, commit in track(
        successful_pr_id_commits, console=console, description="Commenting on backported PRs..."
    ):
        mark_as_backported(repo, backport_pr.number, pr_number, commit)

    subprocess.check_call(["git", "push", "origin", "--delete", branchname])
    subprocess.check_call(["git", "checkout", target_branch])
    subprocess.check_call(["git", "branch", "--delete", "--force", branchname])
    subprocess.check_call(["git", "pull"])
    return 0


if __name__ == "__main__":
    typer.run(main)