package middleware

import (
	"net/http"
	"os"
	"strings"
	"time"

	"photography-backend/internal/config"

	"github.com/zeromicro/go-zero/core/logx"
)

// MiddlewareManager 中间件管理器
type MiddlewareManager struct {
	config         config.Config
	corsMiddleware *CORSMiddleware
	logMiddleware  *LoggerMiddleware
	errorMiddleware *ErrorMiddleware
	authMiddleware *AuthMiddleware
}

// NewMiddlewareManager 创建中间件管理器
func NewMiddlewareManager(c config.Config) *MiddlewareManager {
	return &MiddlewareManager{
		config:          c,
		corsMiddleware:  NewCORSMiddleware(getCORSConfig(c)),
		logMiddleware:   NewLoggerMiddleware(getLoggerConfig(c)),
		errorMiddleware: NewErrorMiddleware(getErrorConfig(c)),
		authMiddleware:  NewAuthMiddleware(c.Auth.AccessSecret),
	}
}

// getCORSConfig 获取CORS配置
func getCORSConfig(c config.Config) CORSConfig {
	env := getEnvironment()
	
	if env == "production" {
		// 生产环境使用严格的CORS配置
		return ProductionCORSConfig(getProductionOrigins())
	}
	
	// 开发环境使用宽松的CORS配置
	return DefaultCORSConfig()
}

// getLoggerConfig 获取日志配置
func getLoggerConfig(c config.Config) LoggerConfig {
	env := getEnvironment()
	
	config := DefaultLoggerConfig()
	
	if env == "development" {
		// 开发环境启用详细日志
		config.EnableRequestBody = true
		config.EnableResponseBody = true
		config.MaxBodySize = 4096
	}
	
	return config
}

// getErrorConfig 获取错误配置
func getErrorConfig(c config.Config) ErrorConfig {
	env := getEnvironment()
	
	if env == "development" {
		return DevelopmentErrorConfig()
	}
	
	return DefaultErrorConfig()
}

// getEnvironment 获取环境变量
func getEnvironment() string {
	env := os.Getenv("GO_ENV")
	if env == "" {
		env = os.Getenv("ENV")
	}
	if env == "" {
		// 默认为开发环境
		env = "development"
	}
	return strings.ToLower(env)
}

// getProductionOrigins 获取生产环境允许的来源
func getProductionOrigins() []string {
	origins := os.Getenv("CORS_ALLOWED_ORIGINS")
	if origins == "" {
		return []string{
			"https://photography.iriver.top",
			"https://admin.photography.iriver.top",
		}
	}
	return strings.Split(origins, ",")
}

// Chain 链式中间件
func (m *MiddlewareManager) Chain(handler http.HandlerFunc, middlewares ...func(http.HandlerFunc) http.HandlerFunc) http.HandlerFunc {
	// 从右到左包装中间件
	for i := len(middlewares) - 1; i >= 0; i-- {
		handler = middlewares[i](handler)
	}
	return handler
}

// GetGlobalMiddlewares 获取全局中间件
func (m *MiddlewareManager) GetGlobalMiddlewares() []func(http.HandlerFunc) http.HandlerFunc {
	return []func(http.HandlerFunc) http.HandlerFunc{
		m.errorMiddleware.Handle,  // 错误处理 (最外层)
		m.corsMiddleware.Handle,   // CORS 处理
		m.logMiddleware.Handle,    // 日志记录
	}
}

// GetAuthMiddleware 获取认证中间件
func (m *MiddlewareManager) GetAuthMiddleware() func(http.HandlerFunc) http.HandlerFunc {
	return m.authMiddleware.Handle
}

// ApplyGlobalMiddlewares 应用全局中间件
func (m *MiddlewareManager) ApplyGlobalMiddlewares(handler http.HandlerFunc) http.HandlerFunc {
	return m.Chain(handler, m.GetGlobalMiddlewares()...)
}

// ApplyAuthMiddlewares 应用认证中间件
func (m *MiddlewareManager) ApplyAuthMiddlewares(handler http.HandlerFunc) http.HandlerFunc {
	middlewares := append(m.GetGlobalMiddlewares(), m.GetAuthMiddleware())
	return m.Chain(handler, middlewares...)
}

// HealthCheck 健康检查处理器 (不使用中间件)
func (m *MiddlewareManager) HealthCheck(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	w.Write([]byte(`{"status":"ok","timestamp":"` + 
		time.Now().Format("2006-01-02T15:04:05Z07:00") + `"}`))
}

// Middleware 中间件接口
type Middleware interface {
	Handle(next http.HandlerFunc) http.HandlerFunc
}

// MiddlewareFunc 中间件函数类型
type MiddlewareFunc func(next http.HandlerFunc) http.HandlerFunc

// Handle 实现Middleware接口
func (f MiddlewareFunc) Handle(next http.HandlerFunc) http.HandlerFunc {
	return f(next)
}

// Use 应用中间件到处理器
func Use(handler http.HandlerFunc, middlewares ...Middleware) http.HandlerFunc {
	for i := len(middlewares) - 1; i >= 0; i-- {
		handler = middlewares[i].Handle(handler)
	}
	return handler
}

// Recovery 通用恢复中间件
func Recovery() MiddlewareFunc {
	return func(next http.HandlerFunc) http.HandlerFunc {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			defer func() {
				if err := recover(); err != nil {
					fields := map[string]interface{}{
						"error":  err,
						"method": r.Method,
						"path":   r.URL.Path,
					}
					logx.WithContext(r.Context()).Errorf("Panic recovered in Recovery middleware: %+v", fields)
					
					http.Error(w, "Internal Server Error", http.StatusInternalServerError)
				}
			}()
			next(w, r)
		})
	}
}

// RequestID 请求ID中间件
func RequestID() MiddlewareFunc {
	return func(next http.HandlerFunc) http.HandlerFunc {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			requestID := r.Header.Get("X-Request-ID")
			if requestID == "" {
				requestID = generateRequestID()
			}
			
			w.Header().Set("X-Request-ID", requestID)
			r.Header.Set("X-Request-ID", requestID)
			
			next(w, r)
		})
	}
}

// generateRequestID 生成请求ID
func generateRequestID() string {
	return randomString(16)
}