package repository

import (
	"errors"
	"fmt"
	"os"

	"codeberg.org/lindenii/furgit/objectid"
	"codeberg.org/lindenii/furgit/refstore"
	refchain "codeberg.org/lindenii/furgit/refstore/chain"
	refloose "codeberg.org/lindenii/furgit/refstore/loose"
	refpacked "codeberg.org/lindenii/furgit/refstore/packed"
)

//nolint:ireturn
func openRefStore(root *os.Root, algo objectid.Algorithm) (out refstore.Store, err error) {
	looseRoot, err := root.OpenRoot(".")
	if err != nil {
		return nil, fmt.Errorf("repository: open root for loose refs: %w", err)
	}

	looseStore, err := refloose.New(looseRoot, algo)
	if err != nil {
		_ = looseRoot.Close()

		return nil, err
	}

	backends := []refstore.Store{looseStore}

	_, err = root.Stat("packed-refs")
	if err == nil {
		packedStore, packedErr := refpacked.New(root, algo)
		if packedErr != nil {
			_ = looseStore.Close()

			return nil, packedErr
		}

		backends = append(backends, packedStore)
	} else if !errors.Is(err, os.ErrNotExist) {
		_ = looseStore.Close()

		return nil, fmt.Errorf("repository: stat packed-refs: %w", err)
	}

	return refchain.New(backends...), nil
}

// Refs returns the configured ref store.
//
//nolint:ireturn
func (repo *Repository) Refs() refstore.Store {
	return repo.refs
}