package middleware

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

// CORS 跨域中间件
func CORS(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, HEAD, PATCH")
		w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type, Accept, Origin, X-Requested-With")
		w.Header().Set("Access-Control-Expose-Headers", "Content-Length, Content-Type, X-Docker-Token")
		w.Header().Set("Access-Control-Max-Age", "86400")

		if r.Method == "OPTIONS" {
			w.WriteHeader(http.StatusOK)
			return
		}

		next.ServeHTTP(w, r)
	})
}

// Logger 日志中间件
func Logger(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		wrapped := &responseWriter{ResponseWriter: w, statusCode: http.StatusOK}
		next.ServeHTTP(wrapped, r)
		// 简单日志输出
		_ = start
	})
}

type responseWriter struct {
	http.ResponseWriter
	statusCode int
}

func (rw *responseWriter) WriteHeader(code int) {
	rw.statusCode = code
	rw.ResponseWriter.WriteHeader(code)
}

// BasicAuth 基础认证中间件
func BasicAuth(username, password string) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			user, pass, ok := r.BasicAuth()
			if !ok || user != username || pass != password {
				w.Header().Set("WWW-Authenticate", `Basic realm="Admin Panel"`)
				http.Error(w, "Unauthorized", http.StatusUnauthorized)
				return
			}
			next.ServeHTTP(w, r)
		})
	}
}

// StripPrefix 安全地移除路径前缀
func StripPrefix(prefix string, h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p := strings.TrimPrefix(r.URL.Path, prefix)
		if p == r.URL.Path {
			http.NotFound(w, r)
			return
		}
		r.URL.Path = p
		h.ServeHTTP(w, r)
	})
}