package database

import (
	"database/sql"
	"fmt"
	"gotemplate/internal/env"
	"log"
	"os"
	"path"

	"github.com/golang-migrate/migrate/v4"
	"github.com/golang-migrate/migrate/v4/database/postgres"
	_ "github.com/golang-migrate/migrate/v4/source/file"
)

func createDB() {
	dbUser := env.GetRequired("DB_USER")
	dbPass := env.GetRequired("DB_PASS")
	dbHost := env.GetRequired("DB_HOST")
	dbPort := env.GetRequired("DB_PORT")
	dbName := env.GetRequired("DB_NAME")
	driver := "postgres"
	connStr := fmt.Sprintf("%s://%s:%s@%s:%s?sslmode=disable", driver, dbUser, dbPass, dbHost, dbPort)

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

	result, err := db.Exec(fmt.Sprintf("SELECT 'CREATE DATABASE %s' WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = '%s')", dbName, dbName))
	if err != nil {
		log.Fatalf("Error creating database: %v", err)
	}

	rows, err := result.RowsAffected()
	if err != nil {
		log.Fatal(err)
	} else if rows == 0 {
		log.Printf("Database already exists: %s", dbName)
	} else {
		log.Printf("Database created: %s", dbName)
	}
}

func RunMigrations() {
	createDB()

	connStr := createConnectionString()
	driver := "postgres"

	db, err := sql.Open(driver, connStr)
	if err != nil {
		log.Fatalf("failed to open database: %v", err)
	}
	defer db.Close()

	if err = db.Ping(); err != nil {
		log.Fatal("Failed to connect to database:", err)
	}

	conn, err := postgres.WithInstance(db, &postgres.Config{})
	if err != nil {
		log.Fatal(err)
	}

	migPath := "file://" + path.Join(os.Getenv("PWD"), "database/migrations")
	m, err := migrate.NewWithDatabaseInstance(
		migPath,
		driver,
		conn,
	)
	if err != nil {
		log.Fatalf("failed to create migrate instance: %v", err)
	}

	err = m.Up()
	if err == migrate.ErrNoChange {
		log.Println("No changes required")
	} else if err != nil {
		log.Fatalf("failed to apply migrations: %v", err)
	} else {
		log.Println("Migrations applied successfully!")
	}
}