#!/usr/bin/env python3
"""
从 Gitea API 拉取过去 N 天的 commits 和 merged PR 数据。
自动从 git remote origin 解析 Gitea 实例地址和仓库路径。

可选环境变量：
  GITEA_TOKEN - 私有仓库访问令牌（公开仓库无需配置）
"""

import json
import os
import subprocess
import sys
import urllib.request
import urllib.error
from datetime import datetime, timedelta, timezone
from urllib.parse import urlparse


def get_remote_info() -> tuple[str, str, str]:
    """从 git remote origin 解析 base_url、owner、repo"""
    try:
        url = subprocess.check_output(
            ["git", "remote", "get-url", "origin"],
            stderr=subprocess.DEVNULL,
            text=True,
        ).strip()
    except subprocess.CalledProcessError:
        print("错误：当前目录不是 git 仓库，或没有 origin remote", file=sys.stderr)
        sys.exit(1)

    # 去掉 .git 后缀
    if url.endswith(".git"):
        url = url[:-4]

    parsed = urlparse(url)
    base_url = f"{parsed.scheme}://{parsed.netloc}"
    # path 格式: /owner/repo
    parts = parsed.path.strip("/").split("/")
    if len(parts) < 2:
        print(f"错误：无法从 remote URL 解析 owner/repo：{url}", file=sys.stderr)
        sys.exit(1)

    owner, repo = parts[0], parts[1]
    return base_url, owner, repo


def gitea_get(base_url: str, path: str) -> object:
    """调用 Gitea API，自动附加 token（如有）"""
    token = os.environ.get("GITEA_TOKEN", "")
    headers = {"Content-Type": "application/json"}
    if token:
        headers["Authorization"] = f"token {token}"

    url = f"{base_url}/api/v1{path}"
    req = urllib.request.Request(url, headers=headers)

    try:
        with urllib.request.urlopen(req, timeout=15) as resp:
            return json.loads(resp.read().decode())
    except urllib.error.HTTPError as e:
        if e.code == 401:
            print("错误：API 返回 401，私有仓库需要设置 GITEA_TOKEN 环境变量", file=sys.stderr)
            sys.exit(1)
        print(f"错误：API 请求失败 {url} -> HTTP {e.code}", file=sys.stderr)
        sys.exit(1)
    except urllib.error.URLError as e:
        print(f"错误：无法连接到 Gitea 实例 {base_url} - {e.reason}", file=sys.stderr)
        sys.exit(1)


def fetch_commits(base_url: str, owner: str, repo: str, since: datetime) -> list[dict]:
    """拉取指定日期之后的所有 commits（分页）"""
    since_str = since.strftime("%Y-%m-%dT%H:%M:%SZ")
    commits = []
    page = 1
    while True:
        data = gitea_get(
            base_url,
            f"/repos/{owner}/{repo}/commits?sha=main&limit=50&page={page}&since={since_str}",
        )
        if not data:
            break
        commits.extend(data)
        if len(data) < 50:
            break
        page += 1
    return commits


def fetch_merged_prs(base_url: str, owner: str, repo: str, since: datetime) -> list[dict]:
    """拉取已关闭的 PR，过滤出 since 之后合并的"""
    prs = []
    page = 1
    while True:
        data = gitea_get(
            base_url,
            f"/repos/{owner}/{repo}/pulls?state=closed&limit=50&page={page}",
        )
        if not data:
            break
        for pr in data:
            merged_at = pr.get("merged_at") or pr.get("merged")
            if not merged_at:
                continue
            # 解析合并时间
            try:
                merged_dt = datetime.fromisoformat(merged_at.replace("Z", "+00:00"))
            except ValueError:
                continue
            if merged_dt >= since:
                prs.append(pr)
        # 如果最后一条 PR 的合并时间早于 since，可以提前退出
        if data:
            last_merged = data[-1].get("merged_at") or data[-1].get("merged")
            if last_merged:
                try:
                    last_dt = datetime.fromisoformat(last_merged.replace("Z", "+00:00"))
                    if last_dt < since:
                        break
                except ValueError:
                    pass
        if len(data) < 50:
            break
        page += 1
    return prs


def group_by_author(commits: list[dict], prs: list[dict]) -> dict:
    """按作者分组整理数据"""
    authors = {}

    for c in commits:
        commit_info = c.get("commit", {})
        author = commit_info.get("author", {})
        name = author.get("name", "unknown")
        email = author.get("email", "")
        key = name

        if key not in authors:
            authors[key] = {"name": name, "email": email, "commits": [], "prs": []}
        authors[key]["commits"].append({
            "sha": c.get("sha", "")[:8],
            "message": commit_info.get("message", "").split("\n")[0],
            "date": author.get("date", "")[:10],
            "files": [f.get("filename") for f in c.get("files", [])],
        })

    for pr in prs:
        author = pr.get("user", {}) or pr.get("poster", {})
        name = author.get("login", "unknown")
        key = name

        if key not in authors:
            authors[key] = {"name": name, "email": "", "commits": [], "prs": []}
        authors[key]["prs"].append({
            "number": pr.get("number"),
            "title": pr.get("title", ""),
            "merged_at": (pr.get("merged_at") or "")[:10],
            "additions": pr.get("additions", 0),
            "deletions": pr.get("deletions", 0),
        })

    return authors


def main():
    import argparse

    parser = argparse.ArgumentParser(description="拉取 Gitea 仓库过去 N 天的数据")
    parser.add_argument("--days", type=int, default=7, help="统计天数（默认7天）")
    parser.add_argument("--output", default="-", help="输出 JSON 文件路径（默认输出到 stdout）")
    args = parser.parse_args()

    base_url, owner, repo = get_remote_info()
    since = datetime.now(timezone.utc) - timedelta(days=args.days)

    print(f"仓库：{base_url}/{owner}/{repo}", file=sys.stderr)
    print(f"统计范围：{since.strftime('%Y-%m-%d')} 至今", file=sys.stderr)

    print("正在拉取 commits...", file=sys.stderr)
    commits = fetch_commits(base_url, owner, repo, since)
    print(f"  共 {len(commits)} 条", file=sys.stderr)

    print("正在拉取已合并 PR...", file=sys.stderr)
    prs = fetch_merged_prs(base_url, owner, repo, since)
    print(f"  共 {len(prs)} 条", file=sys.stderr)

    result = {
        "meta": {
            "base_url": base_url,
            "owner": owner,
            "repo": repo,
            "since": since.strftime("%Y-%m-%d"),
            "generated_at": datetime.now().strftime("%Y-%m-%d %H:%M"),
        },
        "summary": {
            "total_commits": len(commits),
            "total_prs": len(prs),
            "contributors": 0,
        },
        "by_author": group_by_author(commits, prs),
        "all_prs": prs,
    }
    result["summary"]["contributors"] = len(result["by_author"])

    output = json.dumps(result, ensure_ascii=False, indent=2)

    if args.output == "-":
        print(output)
    else:
        with open(args.output, "w", encoding="utf-8") as f:
            f.write(output)
        print(f"数据已写入 {args.output}", file=sys.stderr)


if __name__ == "__main__":
    main()