package main

import (
	"database/sql"
	"fmt"
	"log"
	"net/http"
	"os"
	"strings"

	_ "github.com/lib/pq" // PostgreSQL driver, imported for side effects
)

func main() {
	// Get database configuration from environment variables (NEVER hardcode credentials!)
	dbUser := strings.TrimSpace(os.Getenv("DB_USER"))
	dbPassword := strings.TrimSpace(os.Getenv("DB_PASSWORD"))
	dbName := strings.TrimSpace(os.Getenv("DB_NAME"))
	dbHost := strings.TrimSpace(os.Getenv("DB_HOST"))
	dbSSLMode := strings.TrimSpace(os.Getenv("DB_SSL_MODE"))

	// Set secure default for SSL mode
	if dbSSLMode == "" {
		dbSSLMode = "require"
	}

	// Build connection string from environment variables
	connStr := fmt.Sprintf("user=%s password=%s dbname=%s host=%s sslmode=%s",
		dbUser, dbPassword, dbName, dbHost, dbSSLMode)

	db, err := sql.Open("postgres", connStr)
	if err != nil {
		log.Fatalf("Error opening database: %v", err)
	}
	defer db.Close()

	// Ping the database to ensure connection is established
	err = db.Ping()
	if err != nil {
		log.Printf("Warning: Could not connect to database immediately: %v", err)
		// Don't fatal for example function, but in real app this might be.
	} else {
		fmt.Println("Successfully connected to database.")
	}

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Hello from Go Serverless Function!")
	})

	http.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("OK"))
	})

	fmt.Println("Go Serverless Function listening on :8080")
	log.Fatal(http.ListenAndServe(":8080", nil))
}