package api

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

type contextKey string

const UserContextKey contextKey = "user"

// APIKeyAuth - Middleware fuer API-Key Authentifizierung
func APIKeyAuth(validKeys []string, next http.Handler) http.Handler {
	keySet := make(map[string]bool, len(validKeys))
	for _, k := range validKeys {
		keySet[k] = true
	}

	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		key := r.Header.Get("X-API-Key")
		if key == "" {
			key = r.URL.Query().Get("api_key")
		}
		if key == "" || !keySet[key] {
			http.Error(w, `{"error":"unauthorized"}`, http.StatusUnauthorized)
			return
		}
		next.ServeHTTP(w, r)
	})
}

// CombinedAuth - API-Key ODER JWT Token
func CombinedAuth(validKeys []string, auth *AuthHandler, next http.Handler) http.Handler {
	keySet := make(map[string]bool, len(validKeys))
	for _, k := range validKeys {
		keySet[k] = true
	}

	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Try API key first
		key := r.Header.Get("X-API-Key")
		if key == "" {
			key = r.URL.Query().Get("api_key")
		}
		if key != "" && keySet[key] {
			next.ServeHTTP(w, r)
			return
		}

		// Try JWT
		authHeader := r.Header.Get("Authorization")
		if strings.HasPrefix(authHeader, "Bearer ") {
			token := strings.TrimPrefix(authHeader, "Bearer ")
			claims, err := auth.ValidateToken(token)
			if err == nil {
				ctx := context.WithValue(r.Context(), UserContextKey, claims)
				next.ServeHTTP(w, r.WithContext(ctx))
				return
			}
		}

		http.Error(w, `{"error":"unauthorized"}`, http.StatusUnauthorized)
	})
}

// CORS Middleware
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")
		w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization, X-API-Key")
		if r.Method == "OPTIONS" {
			w.WriteHeader(http.StatusOK)
			return
		}
		next.ServeHTTP(w, r)
	})
}

// Logging - Request-Logging Middleware
func Logging(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		next.ServeHTTP(w, r)
		log.Printf("%s %s %s", r.Method, r.URL.Path, time.Since(start))
	})
}