package config

import (
	"flag"
	"strconv"

	"github.com/pkg/errors"
)

type Flags struct {
	// Utility flags
	EnvDoc  bool
	ShowEnv bool
	GenEnv  string
	EnvFile string
	DevMode bool
	Staging bool

	// Database reset (destructive)
	ResetDB bool

	// Migration commands
	MigrateUp       string
	MigrateRollback string
	MigrateStatus   bool
	MigrateCreate   string
	MigrateDryRun   bool

	// Backup control
	MigrateNoBackup bool
}

func SetupFlags() (*Flags, error) {
	// Utility flags
	envDoc := flag.Bool("envdoc", false, "Print all environment variables and their documentation")
	showEnv := flag.Bool("showenv", false, "Print all environment variable values and their documentation")
	genEnv := flag.String("genenv", "", "Generate a .env file with all environment variables (specify filename)")
	envfile := flag.String("envfile", ".env", "Specify a .env file to use for the configuration")
	devMode := flag.Bool("dev", false, "Run the server in dev mode")
	staging := flag.Bool("staging", false, "Show a staging banner")

	// Database reset (destructive)
	resetDB := flag.Bool("reset-db", false, "⚠️  DESTRUCTIVE: Drop and recreate all tables (dev only)")

	// Migration commands
	migrateUp := flag.String("migrate-up", "", "Run pending database migrations (usage: --migrate-up [count|all], default: 1)")
	migrateRollback := flag.String("migrate-rollback", "", "Rollback migrations (usage: --migrate-rollback [count|all], default: 1)")
	migrateStatus := flag.Bool("migrate-status", false, "Show database migration status")
	migrateCreate := flag.String("migrate-create", "", "Create a new migration file with the given name")
	migrateDryRun := flag.Bool("migrate-dry-run", false, "Preview pending migrations without applying them")

	// Backup control
	migrateNoBackup := flag.Bool("no-backup", false, "Skip automatic backups (dev only - faster but less safe)")

	flag.Parse()

	// Validate: can't use multiple migration commands at once
	commands := 0
	if *migrateUp != "" {
		commands++
	}
	if *migrateRollback != "" {
		commands++
	}
	if *migrateStatus {
		commands++
	}
	if *migrateDryRun {
		commands++
	}
	if *resetDB {
		commands++
	}

	if commands > 1 {
		return nil, errors.New("cannot use multiple migration commands simultaneously")
	}

	// Validate migration count values
	if *migrateUp != "" {
		if err := validateMigrationCount(*migrateUp); err != nil {
			return nil, errors.Wrap(err, "invalid --migrate-up value")
		}
	}
	if *migrateRollback != "" {
		if err := validateMigrationCount(*migrateRollback); err != nil {
			return nil, errors.Wrap(err, "invalid --migrate-rollback value")
		}
	}

	flags := &Flags{
		EnvDoc:          *envDoc,
		ShowEnv:         *showEnv,
		GenEnv:          *genEnv,
		EnvFile:         *envfile,
		DevMode:         *devMode,
		Staging:         *staging,
		ResetDB:         *resetDB,
		MigrateUp:       *migrateUp,
		MigrateRollback: *migrateRollback,
		MigrateStatus:   *migrateStatus,
		MigrateCreate:   *migrateCreate,
		MigrateDryRun:   *migrateDryRun,
		MigrateNoBackup: *migrateNoBackup,
	}
	return flags, nil
}

// validateMigrationCount validates a migration count value
// Valid values: "all" or a positive integer (1, 2, 3, ...)
func validateMigrationCount(value string) error {
	if value == "" {
		return nil
	}
	if value == "all" {
		return nil
	}

	// Try parsing as integer
	count, err := strconv.Atoi(value)
	if err != nil {
		return errors.New("must be a positive integer or 'all'")
	}
	if count < 1 {
		return errors.New("must be a positive integer (1 or greater)")
	}

	return nil
}