"""
系统健康检查端点
提供系统状态监控和健康检查功能
"""

from flask import Blueprint, jsonify, current_app
from datetime import datetime
from app import db
from app.models import Product, License, Device, Admin
from sqlalchemy import text
import os
import psutil
import platform

health_bp = Blueprint('health', __name__)


@health_bp.route('/health', methods=['GET'])
def health_check():
    """
    基本健康检查
    """
    return jsonify({
        'status': 'healthy',
        'timestamp': datetime.utcnow().isoformat(),
        'service': 'KaMiXiTong'
    }), 200


@health_bp.route('/health/detailed', methods=['GET'])
def detailed_health_check():
    """
    详细健康检查
    检查数据库连接、磁盘空间、内存使用等
    """
    health_status = {
        'status': 'healthy',
        'timestamp': datetime.utcnow().isoformat(),
        'service': 'KaMiXiTong',
        'checks': {}
    }

    overall_healthy = True

    # 1. 数据库连接检查
    try:
        db.session.execute(text('SELECT 1'))
        health_status['checks']['database'] = {
            'status': 'healthy',
            'message': '数据库连接正常'
        }
    except Exception as e:
        overall_healthy = False
        health_status['checks']['database'] = {
            'status': 'unhealthy',
            'message': f'数据库连接失败: {str(e)}'
        }

    # 2. 磁盘空间检查
    try:
        disk_usage = psutil.disk_usage('/')
        disk_percent = disk_usage.percent
        if disk_percent > 90:
            overall_healthy = False
            disk_status = 'unhealthy'
        elif disk_percent > 80:
            disk_status = 'warning'
        else:
            disk_status = 'healthy'

        health_status['checks']['disk'] = {
            'status': disk_status,
            'usage_percent': disk_percent,
            'free_gb': round(disk_usage.free / (1024**3), 2),
            'total_gb': round(disk_usage.total / (1024**3), 2),
            'message': f'磁盘使用率: {disk_percent}%'
        }
    except Exception as e:
        health_status['checks']['disk'] = {
            'status': 'unknown',
            'message': f'无法获取磁盘信息: {str(e)}'
        }

    # 3. 内存使用检查
    try:
        memory = psutil.virtual_memory()
        memory_percent = memory.percent
        if memory_percent > 90:
            overall_healthy = False
            memory_status = 'unhealthy'
        elif memory_percent > 80:
            memory_status = 'warning'
        else:
            memory_status = 'healthy'

        health_status['checks']['memory'] = {
            'status': memory_status,
            'usage_percent': memory_percent,
            'available_gb': round(memory.available / (1024**3), 2),
            'total_gb': round(memory.total / (1024**3), 2),
            'message': f'内存使用率: {memory_percent}%'
        }
    except Exception as e:
        health_status['checks']['memory'] = {
            'status': 'unknown',
            'message': f'无法获取内存信息: {str(e)}'
        }

    # 4. 数据统计
    try:
        stats = {
            'products': Product.query.count(),
            'licenses': License.query.count(),
            'devices': Device.query.count(),
            'admins': Admin.query.count()
        }
        health_status['checks']['statistics'] = {
            'status': 'healthy',
            'data': stats
        }
    except Exception as e:
        overall_healthy = False
        health_status['checks']['statistics'] = {
            'status': 'unhealthy',
            'message': f'统计查询失败: {str(e)}'
        }

    # 5. 系统信息
    health_status['system'] = {
        'os': platform.system(),
        'os_version': platform.version(),
        'python_version': platform.python_version(),
        'hostname': platform.node(),
        'process_id': os.getpid()
    }

    # 设置整体状态
    health_status['status'] = 'healthy' if overall_healthy else 'unhealthy'
    status_code = 200 if overall_healthy else 503

    return jsonify(health_status), status_code


@health_bp.route('/health/ready', methods=['GET'])
def readiness_check():
    """
    就绪检查 - 检查应用是否准备好接收流量
    """
    try:
        # 检查数据库连接
        db.session.execute(text('SELECT 1'))

        # 检查关键配置
        required_config = ['SECRET_KEY', 'AUTH_SECRET_KEY', 'SQLALCHEMY_DATABASE_URI']
        missing_config = []
        for config_key in required_config:
            if not current_app.config.get(config_key):
                missing_config.append(config_key)

        if missing_config:
            return jsonify({
                'status': 'not_ready',
                'message': f'缺少配置: {", ".join(missing_config)}'
            }), 503

        return jsonify({
            'status': 'ready',
            'message': '应用已就绪'
        }), 200

    except Exception as e:
        return jsonify({
            'status': 'not_ready',
            'message': f'就绪检查失败: {str(e)}'
        }), 503


@health_bp.route('/health/live', methods=['GET'])
def liveness_check():
    """
    存活检查 - 检查应用是否还在运行
    """
    return jsonify({
        'status': 'alive',
        'timestamp': datetime.utcnow().isoformat()
    }), 200