package main

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

	_ "github.com/lib/pq"
)

type Response struct {
	Message string `json:"message"`
	DBStatus string `json:"db_status"`
}

var db *sql.DB

func main() {
	// PostgreSQL connection
	dbHost := getEnv("DB_HOST", "localhost")
	dbPort := getEnv("DB_PORT", "5432")
	dbUser := getEnv("DB_USER", "postgres")
	dbPassword := getEnv("DB_PASSWORD", "postgres")
	dbName := getEnv("DB_NAME", "hellodb")

	connStr := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=disable",
		dbHost, dbPort, dbUser, dbPassword, dbName)

	var err error
	db, err = sql.Open("postgres", connStr)
	if err != nil {
		log.Printf("Warning: Could not connect to database: %v", err)
	} else {
		defer db.Close()
	}

	// HTTP handlers
	http.HandleFunc("/api/hello", corsMiddleware(helloHandler))
	http.HandleFunc("/api/health", corsMiddleware(healthHandler))

	port := getEnv("PORT", "8080")
	log.Printf("Server starting on port %s", port)
	log.Fatal(http.ListenAndServe(":"+port, nil))
}

func helloHandler(w http.ResponseWriter, r *http.Request) {
	dbStatus := "disconnected"

	if db != nil {
		err := db.Ping()
		if err == nil {
			dbStatus = "connected"
		}
	}

	response := Response{
		Message:  "Hello World! - Go + PostgreSQL + Next.js",
		DBStatus: dbStatus,
	}

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

func healthHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]string{"status": "ok"})
}

func corsMiddleware(next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
		w.Header().Set("Access-Control-Allow-Headers", "Content-Type")

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

		next(w, r)
	}
}

func getEnv(key, defaultValue string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return defaultValue
}