#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Gitea Webhook 处理器
验证签名并解析 Webhook 事件
"""
import hmac
import hashlib
import logging
from typing import Dict, Any, Optional

logger = logging.getLogger(__name__)


class GiteaWebhookHandler:
    """Gitea Webhook 处理器"""

    def __init__(self, config: Dict[str, Any]):
        """
        初始化 Webhook 处理器

        Args:
            config: Gitea 配置
        """
        self.config = config
        self.base_url = config.get('base_url', 'http://localhost:3000')
        self.webhook_secret = config.get('webhook_secret', '')

    def verify_signature(self, payload: bytes, signature: str, secret: str) -> bool:
        """
        验证 Webhook 签名

        Args:
            payload: 请求体
            signature: 请求头中的签名
            secret: 密钥

        Returns:
            签名是否有效
        """
        if not secret:
            logger.warning('未配置 Webhook 密钥，跳过验证')
            return True

        try:
            # Gitea 使用 SHA256 HMAC
            expected_signature = hmac.new(
                secret.encode('utf-8'),
                payload,
                hashlib.sha256
            ).hexdigest()

            # 比较签名（使用 constant time 比较防止时序攻击）
            return hmac.compare_digest(f'sha256={expected_signature}', signature)
        except Exception as e:
            logger.error(f'签名验证失败: {str(e)}')
            return False

    def parse_push_event(self, payload: Dict[str, Any]) -> Dict[str, Any]:
        """
        解析 Push 事件

        Args:
            payload: Webhook payload

        Returns:
            解析后的提交信息
        """
        repo = payload.get('repository', {})
        commits = payload.get('commits', [])
        ref = payload.get('ref', '')

        return {
            'repo_name': repo.get('full_name', ''),
            'repo_url': repo.get('clone_url', ''),
            'web_url': repo.get('web_url', ''),
            'branch': ref.replace('refs/heads/', ''),
            'commits': [
                {
                    'id': commit.get('id', '')[:8],
                    'message': commit.get('message', ''),
                    'author': commit.get('author', {}).get('name', ''),
                    'email': commit.get('author', {}).get('email', ''),
                    'timestamp': commit.get('timestamp', ''),
                    'added': commit.get('added', []),
                    'modified': commit.get('modified', []),
                    'removed': commit.get('removed', []),
                }
                for commit in commits
            ],
            'pusher': payload.get('pusher', {}).get('name', ''),
            'before': payload.get('before', ''),
            'after': payload.get('after', ''),
        }

    def get_changed_files(self, commit: Dict[str, Any]) -> list:
        """
        获取提交中变更的文件列表

        Args:
            commit: 提交信息

        Returns:
            变更的文件列表
        """
        files = []
        files.extend(commit.get('added', []))
        files.extend(commit.get('modified', []))
        files.extend(commit.get('removed', []))
        return files

    def filter_by_extension(self, files: list, extensions: list) -> list:
        """
        按文件扩展名过滤文件

        Args:
            files: 文件列表
            extensions: 扩展名列表（如 ['.py', '.js']）

        Returns:
            过滤后的文件列表
        """
        return [
            f for f in files
            if any(f.endswith(ext) for ext in extensions)
        ]

    def parse_pull_request_event(self, payload: Dict[str, Any]) -> Dict[str, Any]:
        """
        解析 Pull Request 事件

        Args:
            payload: Webhook payload

        Returns:
            解析后的 PR 信息
        """
        action = payload.get('action', '')
        pr = payload.get('pull_request', {})
        repo = payload.get('repository', {})

        # 只处理 PR 创建和更新事件
        if action not in ['opened', 'reopened', 'synchronize', 'ready_for_review']:
            return None

        # 获取 PR 的源分支和目标分支
        head = pr.get('head', {})
        base = pr.get('base', {})

        return {
            'action': action,
            'repo_name': repo.get('full_name', ''),
            'repo_url': repo.get('clone_url', ''),
            'web_url': repo.get('web_url', ''),
            'pr_number': pr.get('number', 0),
            'pr_title': pr.get('title', ''),
            'pr_body': pr.get('body', ''),
            'pr_url': pr.get('html_url', ''),
            'source_branch': head.get('ref', ''),
            'source_sha': head.get('sha', '')[:8],
            'target_branch': base.get('ref', ''),
            'target_sha': base.get('sha', '')[:8],
            'author': pr.get('user', {}).get('login', ''),
            'author_email': pr.get('user', {}).get('email', ''),
            'state': pr.get('state', ''),
            'merged': pr.get('merged', False),
        }

    def get_pr_diff_files(self, payload: Dict[str, Any]) -> list:
        """
        从 Pull Request 事件中获取变更的文件列表

        Args:
            payload: Webhook payload

        Returns:
            变更的文件列表
        """
        pr = payload.get('pull_request', {})
        files = pr.get('changed_files', [])

        # 如果没有 changed_files 字段，尝试从 commits 中获取
        if not files:
            commits = pr.get('commits', [])
            files = []
            for commit in commits:
                files.extend(self.get_changed_files(commit))

        return files