package main

import (
	"flag"
	"fmt"
	"os"

	"mengstack/internal/config"
	"mengstack/migrations"

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

func main() {
	if len(os.Args) < 2 {
		fmt.Println("Usage: migrate <command> [flags]")
		fmt.Println("Commands: up, down, status")
		fmt.Println("  up [steps]     Run pending migrations (optional step count)")
		fmt.Println("  down [steps]   Rollback migrations (optional step count, 0=all)")
		fmt.Println("  status         Show current migration status")
		os.Exit(1)
	}

	cfg, err := config.Load()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
		os.Exit(1)
	}

	dsn := fmt.Sprintf(
		"postgres://%s:%s@%s:%d/%s?sslmode=%s&search_path=public",
		cfg.Database.User, cfg.Database.Password,
		cfg.Database.Host, cfg.Database.Port,
		cfg.Database.DBName, cfg.Database.SSLMode,
	)

	source, err := iofs.New(migrations.Files, ".")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error creating migration source: %v\n", err)
		os.Exit(1)
	}

	m, err := migrate.NewWithSourceInstance("iofs", source, dsn)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error creating migrator: %v\n", err)
		os.Exit(1)
	}

	cmd := os.Args[1]
	switch cmd {
	case "up":
		steps := 0
		fs := flag.NewFlagSet("up", flag.ExitOnError)
		fs.IntVar(&steps, "steps", 0, "number of migrations to run (0=all)")
		fs.Parse(os.Args[2:])

		if steps > 0 {
			err = m.Steps(steps)
		} else {
			err = m.Up()
		}
		if err != nil && err != migrate.ErrNoChange {
			fmt.Fprintf(os.Stderr, "Migration error: %v\n", err)
			os.Exit(1)
		}
		if err == migrate.ErrNoChange {
			fmt.Println("No pending migrations")
		} else {
			fmt.Println("Migrations applied successfully")
		}

	case "down":
		steps := 1
		fs := flag.NewFlagSet("down", flag.ExitOnError)
		fs.IntVar(&steps, "steps", 1, "number of migrations to rollback (0=all)")
		fs.Parse(os.Args[2:])

		if steps == 0 {
			err = m.Down()
		} else {
			err = m.Steps(-steps)
		}
		if err != nil && err != migrate.ErrNoChange {
			fmt.Fprintf(os.Stderr, "Rollback error: %v\n", err)
			os.Exit(1)
		}
		fmt.Println("Rollback completed")

	case "status":
		v, dirty, err := m.Version()
		if err != nil && err != migrate.ErrNoChange {
			fmt.Fprintf(os.Stderr, "Status error: %v\n", err)
			os.Exit(1)
		}
		if err == migrate.ErrNoChange {
			fmt.Println("No migrations applied yet")
		} else {
			fmt.Printf("Current version: %d, dirty: %v\n", v, dirty)
		}

	default:
		fmt.Fprintf(os.Stderr, "Unknown command: %s\n", cmd)
		os.Exit(1)
	}
}