package handlers

import (
	"encoding/json"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"slideshowApp/env"
	"sync"

	"github.com/gorilla/websocket"
)

var (
	// Keep track of all open slideshow connections
	clients   = make(map[*websocket.Conn]bool)
	clientsMu sync.Mutex
)

func UploadHandler(w http.ResponseWriter, r *http.Request) {
	r.ParseMultipartForm(50 << 20)
	files := r.MultipartForm.File["myPictures"]
	uploadDir := env.PhotoDir.GetValue()
	os.MkdirAll(uploadDir, os.ModePerm)

	for _, fileHeader := range files {
		file, _ := fileHeader.Open()
		dstPath := filepath.Join(uploadDir, fileHeader.Filename)
		dst, _ := os.Create(dstPath)
		io.Copy(dst, file)
		file.Close()
		dst.Close()
	}

	// NEW: Tell all slideshows to update their lists
	notifyClients()

	http.Redirect(w, r, "/", http.StatusSeeOther)
}

func ListFilesHandler(w http.ResponseWriter, r *http.Request) {
	files, err := os.ReadDir(env.PhotoDir.GetValue())
	if err != nil {
		http.Error(w, "Unable to read directory", http.StatusInternalServerError)
		return
	}
	var fileNames []string
	for _, file := range files {
		if !file.IsDir() {
			fileNames = append(fileNames, file.Name())
		}
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(fileNames)
}

func DeleteHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// 1. Get filenames from request body
	var filenames []string
	err := json.NewDecoder(r.Body).Decode(&filenames)
	if err != nil {
		http.Error(w, "Invalid request", http.StatusBadRequest)
		return
	}

	uploadDir := env.PhotoDir.GetValue()

	// 2. Delete each file
	for _, name := range filenames {
		fullPath := filepath.Join(uploadDir, filepath.Base(name))
		os.Remove(fullPath)
	}

	// 3. Notify slideshows to refresh their lists
	notifyClients()

	w.WriteHeader(http.StatusOK)
}

func notifyClients() {
	clientsMu.Lock()
	defer clientsMu.Unlock()
	for client := range clients {
		err := client.WriteMessage(websocket.TextMessage, []byte("refresh"))
		if err != nil {
			client.Close()
			delete(clients, client)
		}
	}
}