package setup

import (
	"context"
	"database/sql"
	"errors"
)

var ErrSetupAlreadyDone = errors.New("setup already completed")

// Storer is the interface for setup-related DB operations.
type Storer interface {
	NeedsSetup(ctx context.Context) (bool, error)
	CreateAdmin(ctx context.Context, name, email, hashedPassword string) (int64, error)
}

type Store struct {
	db *sql.DB
}

func NewStore(db *sql.DB) *Store {
	return &Store{db: db}
}

// NeedsSetup returns true when the volunteers table has zero rows.
func (s *Store) NeedsSetup(ctx context.Context) (bool, error) {
	var count int
	err := s.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM volunteers`).Scan(&count)
	if err != nil {
		return false, err
	}
	return count == 0, nil
}

// CreateAdmin atomically checks that no users exist and inserts the first admin.
func (s *Store) CreateAdmin(ctx context.Context, name, email, hashedPassword string) (int64, error) {
	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return 0, err
	}
	defer tx.Rollback()

	var count int
	if err := tx.QueryRowContext(ctx, `SELECT COUNT(*) FROM volunteers`).Scan(&count); err != nil {
		return 0, err
	}
	if count > 0 {
		return 0, ErrSetupAlreadyDone
	}

	res, err := tx.ExecContext(ctx,
		`INSERT INTO volunteers (name, email, password, role, active, operational_roles) VALUES (?, ?, ?, 'admin', 1, '')`,
		name, email, hashedPassword,
	)
	if err != nil {
		return 0, err
	}

	id, err := res.LastInsertId()
	if err != nil {
		return 0, err
	}

	if err := tx.Commit(); err != nil {
		return 0, err
	}
	return id, nil
}