package main

import (
	"database/sql"
	"encoding/json"
	"log"
	"net/http"
	"os"

	"github.com/gorilla/handlers"
	"github.com/gorilla/mux"
	"github.com/joho/godotenv"
	_ "github.com/lib/pq"
)

type CartItem struct {
	ID       int     `json:"id"`
	Title    string  `json:"title"`
	Price    float64 `json:"price"`
	Quantity int     `json:"quantity"`
}

var db *sql.DB

func main() {
	// Load environment variables
	err := godotenv.Load()
	if err != nil {
		log.Fatal("Error loading .env file")
	}

	// Connect to the database
	connStr := os.Getenv("DATABASE_URL")
	db, err = sql.Open("postgres", connStr)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	// Create the cart table if it doesn't exist
	_, err = db.Exec(`
		CREATE TABLE IF NOT EXISTS cart_items (
			id SERIAL PRIMARY KEY,
			title TEXT NOT NULL,
			price DECIMAL(10, 2) NOT NULL,
			quantity INTEGER NOT NULL
		)
	`)
	if err != nil {
		log.Fatal(err)
	}

	r := mux.NewRouter()

	r.HandleFunc("/cart", getCart).Methods("GET")
	r.HandleFunc("/cart", saveCart).Methods("POST")
	r.HandleFunc("/cart", clearCart).Methods("DELETE")

	// Add CORS middleware
	corsHandler := handlers.CORS(
		handlers.AllowedOrigins([]string{"http://localhost:3000"}),
		handlers.AllowedMethods([]string{"GET", "POST", "DELETE", "OPTIONS"}),
		handlers.AllowedHeaders([]string{"Content-Type"}),
	)

	log.Println("Server starting on :8080")
	log.Fatal(http.ListenAndServe(":8080", corsHandler(r)))
}

func getCart(w http.ResponseWriter, r *http.Request) {
	rows, err := db.Query("SELECT id, title, price, quantity FROM cart_items")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	defer rows.Close()

	var cart []CartItem
	for rows.Next() {
		var item CartItem
		err := rows.Scan(&item.ID, &item.Title, &item.Price, &item.Quantity)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		cart = append(cart, item)
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(cart)
}

func saveCart(w http.ResponseWriter, r *http.Request) {
	cookie, err := r.Cookie("cart")
	if err != nil {
		http.Error(w, "Cart not found in cookies", http.StatusBadRequest)
		return
	}

	var newCart []CartItem
	err = json.Unmarshal([]byte(cookie.Value), &newCart)
	if err != nil {
		http.Error(w, "Invalid cart data", http.StatusBadRequest)
		return
	}

	// Clear the existing cart
	_, err = db.Exec("DELETE FROM cart_items")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Insert new items
	for _, item := range newCart {
		_, err = db.Exec("INSERT INTO cart_items (title, price, quantity) VALUES ($1, $2, $3)",
			item.Title, item.Price, item.Quantity)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	}

	w.WriteHeader(http.StatusOK)
}

func clearCart(w http.ResponseWriter, r *http.Request) {
	_, err := db.Exec("DELETE FROM cart_items")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.WriteHeader(http.StatusOK)
}