#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
系統健康檢查 API

Author: PANJIT IT Team
Created: 2024-01-28
Modified: 2024-01-28
"""

from datetime import datetime
from flask import Blueprint, jsonify
from app.utils.helpers import create_response
from app.utils.logger import get_logger
from app.models.job import TranslationJob
from app.utils.timezone import format_taiwan_time, now_taiwan

health_bp = Blueprint('health', __name__, url_prefix='/health')
logger = get_logger(__name__)


@health_bp.route('', methods=['GET'])
def health_check():
    """系統健康檢查"""
    try:
        status = {
            'timestamp': format_taiwan_time(datetime.utcnow(), "%Y-%m-%d %H:%M:%S"),
            'status': 'healthy',
            'services': {}
        }
        
        # 資料庫檢查
        try:
            from app import db
            from sqlalchemy import text
            db.session.execute(text('SELECT 1'))
            status['services']['database'] = {'status': 'healthy'}
        except Exception as e:
            status['services']['database'] = {
                'status': 'unhealthy',
                'error': str(e)
            }
            status['status'] = 'unhealthy'
        
        # Redis 檢查
        try:
            import redis
            from flask import current_app
            redis_client = redis.from_url(current_app.config['REDIS_URL'])
            redis_client.ping()
            status['services']['redis'] = {'status': 'healthy'}
        except Exception as e:
            status['services']['redis'] = {
                'status': 'unhealthy', 
                'error': str(e)
            }
            # Redis 暫時異常不影響整體狀態（如果沒有使用 Celery）
        
        # LDAP 檢查
        try:
            from app.utils.ldap_auth import LDAPAuthService
            ldap_service = LDAPAuthService()
            if ldap_service.test_connection():
                status['services']['ldap'] = {'status': 'healthy'}
            else:
                status['services']['ldap'] = {'status': 'unhealthy', 'error': 'Connection failed'}
        except Exception as e:
            status['services']['ldap'] = {
                'status': 'unhealthy',
                'error': str(e)
            }
            # LDAP 異常會影響整體狀態
            status['status'] = 'unhealthy'
        
        # 檔案系統檢查
        try:
            from pathlib import Path
            from flask import current_app
            upload_folder = Path(current_app.config['UPLOAD_FOLDER'])
            
            # 檢查上傳目錄是否可寫
            test_file = upload_folder / 'health_check.tmp'
            test_file.write_text('health_check')
            test_file.unlink()
            
            status['services']['filesystem'] = {'status': 'healthy'}
        except Exception as e:
            status['services']['filesystem'] = {
                'status': 'unhealthy',
                'error': str(e)
            }
            status['status'] = 'unhealthy'
        
        # 檢查 Dify API（如果配置了）
        try:
            from flask import current_app
            if current_app.config.get('DIFY_API_KEY') and current_app.config.get('DIFY_API_BASE_URL'):
                # 這裡會在實作 Dify 服務時加入連線測試
                status['services']['dify_api'] = {'status': 'not_tested'}
            else:
                status['services']['dify_api'] = {'status': 'not_configured'}
        except Exception as e:
            status['services']['dify_api'] = {
                'status': 'error',
                'error': str(e)
            }
        
        return jsonify(status), 200 if status['status'] == 'healthy' else 503
    
    except Exception as e:
        logger.error(f"Health check error: {str(e)}")
        return jsonify({
            'timestamp': format_taiwan_time(datetime.utcnow(), "%Y-%m-%d %H:%M:%S"),
            'status': 'error',
            'error': str(e)
        }), 500


@health_bp.route('/metrics', methods=['GET'])
def get_metrics():
    """系統指標"""
    try:
        # 統計任務狀態
        from app import db
        from sqlalchemy import func
        
        job_stats = db.session.query(
            TranslationJob.status,
            func.count(TranslationJob.id)
        ).group_by(TranslationJob.status).all()
        
        job_counts = {status: count for status, count in job_stats}
        
        # 系統指標
        metrics_data = {
            'timestamp': format_taiwan_time(datetime.utcnow(), "%Y-%m-%d %H:%M:%S"),
            'jobs': {
                'pending': job_counts.get('PENDING', 0),
                'processing': job_counts.get('PROCESSING', 0),
                'completed': job_counts.get('COMPLETED', 0),
                'failed': job_counts.get('FAILED', 0),
                'retry': job_counts.get('RETRY', 0),
                'total': sum(job_counts.values())
            }
        }
        
        # 添加最近24小時的統計
        from datetime import timedelta
        yesterday = datetime.utcnow() - timedelta(days=1)
        
        recent_jobs = db.session.query(
            TranslationJob.status,
            func.count(TranslationJob.id)
        ).filter(
            TranslationJob.created_at >= yesterday
        ).group_by(TranslationJob.status).all()
        
        recent_counts = {status: count for status, count in recent_jobs}
        
        metrics_data['recent_24h'] = {
            'pending': recent_counts.get('PENDING', 0),
            'processing': recent_counts.get('PROCESSING', 0),
            'completed': recent_counts.get('COMPLETED', 0),
            'failed': recent_counts.get('FAILED', 0),
            'retry': recent_counts.get('RETRY', 0),
            'total': sum(recent_counts.values())
        }
        
        return jsonify(create_response(
            success=True,
            data=metrics_data
        ))
    
    except Exception as e:
        logger.error(f"Get metrics error: {str(e)}")
        return jsonify(create_response(
            success=False,
            error='SYSTEM_ERROR',
            message='取得系統指標失敗'
        )), 500


@health_bp.route('/version', methods=['GET'])
def get_version():
    """取得版本資訊"""
    try:
        version_info = {
            'application': 'PANJIT Document Translator',
            'version': '1.0.0',
            'build_date': '2024-01-28',
            'python_version': None,
            'flask_version': None
        }
        
        # 取得 Python 版本
        import sys
        version_info['python_version'] = sys.version
        
        # 取得 Flask 版本
        import flask
        version_info['flask_version'] = flask.__version__
        
        return jsonify(create_response(
            success=True,
            data=version_info
        ))
    
    except Exception as e:
        logger.error(f"Get version error: {str(e)}")
        return jsonify(create_response(
            success=False,
            error='SYSTEM_ERROR',
            message='取得版本資訊失敗'
        )), 500


@health_bp.route('/ping', methods=['GET'])
def ping():
    """簡單的 ping 檢查"""
    return jsonify({
        'status': 'ok',
        'timestamp': format_taiwan_time(datetime.utcnow(), "%Y-%m-%d %H:%M:%S"),
        'message': 'pong'
    })