pcmt/modules/db/db.go

package db

import (
	"context"

	"git.dotya.ml/mirre-mt/pcmt/ent"
	"git.dotya.ml/mirre-mt/pcmt/ent/migrate"
	"git.dotya.ml/mirre-mt/pcmt/slogging"
)

// CtxKey serves as a key to context values for this package.
type CtxKey struct{}

// DropAll deletes an re-creates the whole db.
func DropAll(ctx context.Context, client *ent.Client) error {
	log := ctx.Value(CtxKey{}).(*slogging.Logger)

	err := client.Schema.
		Create(
			ctx,
			migrate.WithDropIndex(true),
			migrate.WithDropColumn(true),
		)
	if err != nil {
		log.Errorf("failed to recreate schema resources: %v", err)
		return err
	}

	return err
}

// IsSetUp deletes the whole db.
func IsSetUp(ctx context.Context, client *ent.Client) (bool, error) {
	log := ctx.Value(CtxKey{}).(*slogging.Logger)
	is, err := client.Setup.
		Query().
		Only(ctx)

	if is != nil {
		log.Debug("apparently the db is already set up")
	} else {
		log.Debug("apparently the db was not yet set up")
	}

	switch {
	case ent.IsNotFound(err) && is == nil:
		return false, nil

	case ent.IsNotSingular(err):
		return true, err

	case err != nil:
		return false, err

	case err == nil && is != nil:
		return true, nil
	}

	return false, nil
}

// SetUp creates the set-up record indicating that the DB has been set up.
func SetUp(ctx context.Context, client *ent.Client) error {
	isSetup, err := IsSetUp(ctx, client)

	switch {
	case err == nil && isSetup:
		return nil

	case err != nil && isSetup:
		return err

	case err != nil && !isSetup:
		err = DropAll(ctx, client)
		if err != nil {
			return nil
		}

		// create a set-up record.
		_, err = client.Setup.
			Create().
			Save(ctx)
		if err != nil {
			return err
		}
	}

	return err
}