package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"os"

	"git.petrovv.com/nikola/go_sql_schema_migrate"
	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/joho/godotenv"
)

func main() {
	// Parse flags
	schemaDir := flag.String("dir", "schema", "Directory containing desired schema SQL files")
	cmd := flag.String("cmd", "", "Command: generate or apply")
	flag.Parse()

	if *cmd == "" {
		fmt.Println("Usage:")
		fmt.Println("  go run main.go -cmd=generate -dir=schema  - Compare schema and generate migrations")
		fmt.Println("  go run main.go -cmd=apply -dir=schema      - Apply pending migrations")
		fmt.Println("\nFlags:")
		flag.PrintDefaults()
		return
	}

	switch *cmd {
	case "generate":
		generateMigrations(*schemaDir)
	case "apply":
		applyMigrations(*schemaDir)
	default:
		fmt.Println("Unknown command:", *cmd)
		fmt.Println("Use 'generate' or 'apply'")
	}
}

func generateMigrations(schemaDir string) {
	_ = godotenv.Load()
	db := getDBConnection()
	defer db.Close()
	ctx := context.Background()

	migrations, err := go_sql_schema_migrate.GetMigrations(ctx, db, schemaDir)
	if err != nil {
		log.Fatal(err)
	}

	if len(migrations) == 0 {
		fmt.Println("Database schema is up to date")
		return
	}

	fmt.Println("-- Migration SQL")
	for _, m := range migrations {
		fmt.Println(m)
	}
}

func applyMigrations(schemaDir string) {
	_ = godotenv.Load()
	db := getDBConnection()
	defer db.Close()
	ctx := context.Background()

	migrations, err := go_sql_schema_migrate.GetMigrations(ctx, db, schemaDir)
	if err != nil {
		log.Fatal(err)
	}

	if len(migrations) == 0 {
		fmt.Println("Database schema is up to date")
		return
	}

	fmt.Println("Applying migrations...")
	for _, m := range migrations {
		fmt.Printf("Executing: %s\n", m)
		_, err := db.Exec(ctx, m)
		if err != nil {
			log.Fatalf("failed to execute %s: %v", m, err)
		}
	}

	fmt.Println("All migrations applied successfully")
}

func getDBConnection() *pgxpool.Pool {
	dbUser := os.Getenv("DB_USER")
	dbPass := os.Getenv("DB_PASS")
	dbHost := os.Getenv("DB_HOST")
	dbPort := os.Getenv("DB_PORT")
	dbName := os.Getenv("DB_NAME")

	dsn := fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=disable", dbUser, dbPass, dbHost, dbPort, dbName)

	pool, err := pgxpool.New(context.Background(), dsn)
	if err != nil {
		log.Fatalf("Unable to connect to database: %v", err)
	}
	return pool
}