package main

import (
	"context"
	"database/sql"
	"fmt"
	"time"

	_ "github.com/lib/pq"
)

var DB *sql.DB

func InitDB() {
	dbURL := "postgres://5803024006:5803024006@202.46.28.160:45432/tgs03_5803024006?sslmode=disable"

	var err error
	DB, err = sql.Open("postgres", dbURL)
	if err != nil {
		panic(err)
	}

	// setting pool
	DB.SetMaxOpenConns(10)
	DB.SetMaxIdleConns(5)
	DB.SetConnMaxLifetime(time.Minute * 5)

	// test koneksi
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	if err = DB.PingContext(ctx); err != nil {
		panic(fmt.Sprintf("gagal koneksi database: %v", err))
	}

	fmt.Println("✅ Database connected!")
}

// ===== CRUD Contoh =====

func CreateUser(name, email string) (int, error) {
	var id int
	err := DB.QueryRow(`INSERT INTO users (name, email) VALUES ($1, $2) RETURNING id`, name, email).Scan(&id)
	return id, err
}

func CreateCourse(title, desc string) (int, error) {
	var id int
	err := DB.QueryRow(`INSERT INTO courses (title, description) VALUES ($1, $2) RETURNING id`, title, desc).Scan(&id)
	return id, err
}

func EnrollUser(userID, courseID int) error {
	_, err := DB.Exec(`INSERT INTO enrollments (user_id, course_id) VALUES ($1, $2) ON CONFLICT (user_id, course_id) DO NOTHING`, userID, courseID)
	return err
}

func ListEnrollments() error {
	rows, err := DB.Query(`SELECT u.name, c.title, e.created_at 
                           FROM enrollments e
                           JOIN users u ON e.user_id = u.id
                           JOIN courses c ON e.course_id = c.id`)
	if err != nil {
		return err
	}
	defer rows.Close()

	fmt.Println("=== Enrollments ===")
	for rows.Next() {
		var name, title string
		var created time.Time
		_ = rows.Scan(&name, &title, &created)
		fmt.Printf("%s enrolled in %s at %v\n", name, title, created)
	}
	return nil
}