#!/usr/bin/env python3
"""List, create, and comment on Gitea pull requests."""

from __future__ import annotations

import argparse
import json
import sys

from common import (
    api_base,
    current_branch,
    load_token,
    remote_default_branch,
    request_json,
    resolve_repo,
)
from push_gitea import compute_push_plan, execute_push


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="List, create, and comment on Gitea pull requests."
    )
    parser.add_argument("--repo-url", help="Explicit target repo URL.")
    parser.add_argument("--repo", help="Shorthand owner/repo. Requires GITEA_BASE_URL.")
    parser.add_argument("--remote", default="origin", help="Git remote name. Default: origin")

    subparsers = parser.add_subparsers(dest="command", required=True)

    list_parser = subparsers.add_parser("list", help="List pull requests.")
    list_parser.add_argument(
        "--state",
        default="open",
        choices=("open", "closed", "all"),
        help="Pull request state filter.",
    )
    list_parser.add_argument(
        "--limit",
        default=20,
        type=int,
        help="Maximum number of pull requests to return.",
    )

    create_parser = subparsers.add_parser("create", help="Create a pull request.")
    create_parser.add_argument("--base", help="Base branch. Default: remote default branch.")
    create_parser.add_argument("--head", help="Head branch. Default: current branch.")
    create_parser.add_argument("--title", required=True, help="Pull request title.")
    create_parser.add_argument("--body", default="", help="Pull request body.")

    comment_parser = subparsers.add_parser("comment", help="Comment on a pull request.")
    comment_parser.add_argument("pr", type=int, help="Pull request number.")
    comment_parser.add_argument("--body", required=True, help="Comment body.")

    return parser.parse_args()


def summarize_pull_request(item: dict) -> dict:
    user = item.get("user") or {}
    head = item.get("head") or {}
    base = item.get("base") or {}
    return {
        "number": item.get("number"),
        "title": item.get("title"),
        "state": item.get("state"),
        "html_url": item.get("html_url"),
        "author": user.get("full_name") or user.get("login"),
        "head": head.get("ref"),
        "base": base.get("ref"),
        "created_at": item.get("created_at"),
        "updated_at": item.get("updated_at"),
    }


def list_pull_requests(args: argparse.Namespace) -> dict:
    context = resolve_repo(repo_url=args.repo_url, repo=args.repo, remote=args.remote)
    token = load_token(required=True)
    url = f"{api_base(context)}/pulls?state={args.state}&page=1&limit={args.limit}"
    data = request_json(url, token)
    if not isinstance(data, list):
        raise SystemExit("Unexpected pull request list response.")
    return {
        "action": "list",
        "repo_url": context.repo_url,
        "state": args.state,
        "limit": args.limit,
        "count": len(data),
        "pull_requests": [summarize_pull_request(item) for item in data],
    }


def create_pull_request(args: argparse.Namespace) -> dict:
    context = resolve_repo(repo_url=args.repo_url, repo=args.repo, remote=args.remote)
    token = load_token(required=True)
    head = args.head or current_branch()
    base = args.base or remote_default_branch(args.remote)

    push_plan = compute_push_plan(
        repo_url=args.repo_url,
        repo=args.repo,
        remote=args.remote,
        branch=head,
        force=False,
    )
    push_result = None
    if push_plan["needs_push"]:
        push_result = execute_push(push_plan, force=False)
    elif push_plan["status"] == "blocked":
        raise SystemExit(
            "Cannot create PR because the current branch has diverged from the remote branch."
        )

    payload = {"base": base, "head": head, "title": args.title, "body": args.body}
    created = request_json(f"{api_base(context)}/pulls", token, method="POST", payload=payload)
    if not isinstance(created, dict):
        raise SystemExit("Unexpected pull request creation response.")
    return {
        "action": "create",
        "repo_url": context.repo_url,
        "base": base,
        "head": head,
        "push": push_result,
        "pull_request": summarize_pull_request(created),
    }


def comment_pull_request(args: argparse.Namespace) -> dict:
    context = resolve_repo(repo_url=args.repo_url, repo=args.repo, remote=args.remote)
    token = load_token(required=True)
    payload = {"body": args.body}
    created = request_json(
        f"{api_base(context)}/issues/{args.pr}/comments",
        token,
        method="POST",
        payload=payload,
    )
    if not isinstance(created, dict):
        raise SystemExit("Unexpected PR comment response.")
    user = created.get("user") or {}
    return {
        "action": "comment",
        "repo_url": context.repo_url,
        "pull_request": args.pr,
        "comment": {
            "id": created.get("id"),
            "html_url": created.get("html_url"),
            "author": user.get("full_name") or user.get("login"),
            "created_at": created.get("created_at"),
        },
    }


def main() -> int:
    args = parse_args()
    if args.command == "list":
        payload = list_pull_requests(args)
    elif args.command == "create":
        payload = create_pull_request(args)
    else:
        payload = comment_pull_request(args)
    print(json.dumps(payload, ensure_ascii=False, indent=2))
    return 0


if __name__ == "__main__":
    sys.exit(main())