"""Flask应用工厂"""
from flask import Flask, g, request, send_from_directory
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
import os

db = SQLAlchemy()
migrate = Migrate()


def create_app(config_name='default'):
    """创建Flask应用实例"""
    from app.config import config_map
    
    app = Flask(__name__)
    app.config.from_object(config_map[config_name])
    
    # 初始化扩展
    db.init_app(app)
    migrate.init_app(app, db)
    
    # 确保数据目录和上传目录存在
    data_dir = os.path.join(app.root_path, '..', 'data')
    uploads_dir = os.path.join(app.root_path, '..', 'uploads')
    os.makedirs(data_dir, exist_ok=True)
    os.makedirs(uploads_dir, exist_ok=True)
    
    # 配置上传目录
    app.config['UPLOAD_FOLDER'] = uploads_dir
    
    # 注册蓝图
    from app.routes.frontend import frontend_bp
    from app.routes.admin import admin_bp
    
    app.register_blueprint(frontend_bp)
    app.register_blueprint(admin_bp, url_prefix='/admin')
    
    # 注册上传文件路由（在蓝图之前，确保全局可访问）
    @app.route('/uploads/<path:filename>')
    def serve_upload(filename):
        """提供上传文件访问"""
        return send_from_directory(uploads_dir, filename)
    
    # 注册模板过滤器
    register_filters(app)
    
    # 注册命令
    register_commands(app)
    
    # 注册请求钩子（访问统计和网站配置）
    register_hooks(app)
    
    return app


def register_filters(app):
    """注册自定义模板过滤器"""
    from datetime import datetime
    
    @app.template_filter('datetime_format')
    def datetime_format(value, format='%Y-%m-%d %H:%M'):
        """格式化日期时间"""
        if value is None:
            return ''
        return value.strftime(format)
    
    @app.template_filter('truncate_content')
    def truncate_content(value, length=200):
        """截断文章内容用于预览"""
        if len(value) <= length:
            return value
        return value[:length] + '...'


def register_commands(app):
    """注册自定义命令"""
    import click
    
    @app.cli.command('init-db')
    def init_db():
        """初始化数据库"""
        db.create_all()
        click.echo('数据库初始化完成。')
    
    @app.cli.command('create-admin')
    @click.argument('username')
    @click.argument('password')
    def create_admin(username, password):
        """创建管理员账户"""
        from app.models.admin import Admin
        from werkzeug.security import generate_password_hash
        
        admin = Admin.query.filter_by(username=username).first()
        if admin:
            click.echo(f'管理员 {username} 已存在！')
            return
        
        admin = Admin(
            username=username,
            password_hash=generate_password_hash(password)
        )
        db.session.add(admin)
        db.session.commit()
        click.echo(f'管理员 {username} 创建成功！')


def register_hooks(app):
    """注册请求钩子"""
    from app.services import SiteConfigService, VisitService
    
    @app.before_request
    def before_request():
        """请求前处理：注入网站配置"""
        # 获取网站配置并注入到g对象
        g.site_config = SiteConfigService.get_dict()
    
    @app.after_request
    def after_request(response):
        """请求后处理：记录访问日志"""
        # 只记录前端请求，不记录静态资源和后台
        if request.path.startswith('/static') or request.path.startswith('/admin'):
            return response
        
        # 只记录成功的请求
        if response.status_code == 200:
            # 检查是否是文章详情页
            article_id = None
            if hasattr(g, 'current_article_id'):
                article_id = g.current_article_id
            
            # 记录访问
            try:
                VisitService.log_visit(request, article_id)
            except Exception:
                pass  # 忽略记录错误，不影响正常响应
        
        return response