package store

import (
	"context"
	"database/sql"
	"sync"

	"github.com/pkg/errors"
	"gorm.io/gorm"
)

type Store struct {
	getDatabase func(ctx context.Context) (*gorm.DB, error)
}

func New(db *gorm.DB) *Store {
	return &Store{
		getDatabase: createGetDatabase(db),
	}
}

func (s *Store) Do(ctx context.Context, fn func(db *gorm.DB) error) error {
	db, err := s.getDatabase(ctx)
	if err != nil {
		return errors.WithStack(err)
	}

	if err := fn(db); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

func (s *Store) Tx(ctx context.Context, fn func(db *gorm.DB) error, opts ...*sql.TxOptions) error {
	return errors.WithStack(s.Do(ctx, func(db *gorm.DB) error {
		err := db.Transaction(func(tx *gorm.DB) error {
			if err := fn(tx); err != nil {
				return errors.WithStack(err)
			}
			return nil
		}, opts...)
		if err != nil {
			return errors.WithStack(err)
		}
		return nil
	}))
}

func createGetDatabase(db *gorm.DB) func(ctx context.Context) (*gorm.DB, error) {
	var (
		migrateOnce sync.Once
		migrateErr  error
	)

	return func(ctx context.Context) (*gorm.DB, error) {
		migrateOnce.Do(func() {
			if err := db.AutoMigrate(models...); err != nil {
				migrateErr = errors.WithStack(err)
				return
			}

			if err := db.Exec("PRAGMA journal_mode=WAL; PRAGMA busy_timeout=500; PRAGMA txlock=deferred; PRAGMA synchronous=normal; PRAGMA encoding='UTF-8';").Error; err != nil {
				migrateErr = errors.WithStack(err)
				return
			}
		})
		if migrateErr != nil {
			return nil, errors.WithStack(migrateErr)
		}

		return db, nil
	}
}