// Copyright (c) 2023 Open Anolis Community Distro SIG, all rights reserved.
//
// Author: Jacob Wang <jacob.wang@openanolis.org>
//         Xiao Lun <xiaolun@linux.alibaba.com>
//         Zhao Hang <zhaohang_mskdxl@qq.com>

package directives

import (
	"errors"
	"fmt"
	"io/ioutil"
	"os"

	"github.com/go-git/go-git/v5"
	pkgcrewpb "pkgcrew/pb"
	"pkgcrew/pkg/data"
)

func replace(cfg *pkgcrewpb.Cfg, pd *data.ProcessData, _ *data.ModeData, patchTree *git.Worktree, pushTree *git.Worktree) error {
	for _, replace := range cfg.Replace {
		filePath := replace.File
		stat, err := pushTree.Filesystem.Stat(filePath)
		if replace.File == "" || err != nil {
			return errors.New(fmt.Sprintf("INVALID_FILE:%s", filePath))
		}

		err = pushTree.Filesystem.Remove(filePath)
		if err != nil {
			return errors.New(fmt.Sprintf("COULD_NOT_REMOVE_OLD_FILE:%s", filePath))
		}

		f, err := pushTree.Filesystem.OpenFile(filePath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, stat.Mode())
		if err != nil {
			return errors.New(fmt.Sprintf("COULD_NOT_OPEN_REPLACEMENT:%s", filePath))
		}

		switch replacing := replace.Replacing.(type) {
		case *pkgcrewpb.Replace_WithFile:
			fPatch, err := patchTree.Filesystem.OpenFile(replacing.WithFile, os.O_RDONLY, 0o644)
			if err != nil {
				return errors.New(fmt.Sprintf("COULD_NOT_OPEN_REPLACING:%s", replacing.WithFile))
			}

			replacingBytes, err := ioutil.ReadAll(fPatch)
			if err != nil {
				return errors.New(fmt.Sprintf("COULD_NOT_READ_REPLACING:%s", replacing.WithFile))
			}

			_, err = f.Write(replacingBytes)
			if err != nil {
				return errors.New(fmt.Sprintf("COULD_NOT_WRITE_REPLACING:%s", replacing.WithFile))
			}
			break
		case *pkgcrewpb.Replace_WithInline:
			_, err := f.Write([]byte(replacing.WithInline))
			if err != nil {
				return errors.New(fmt.Sprintf("COULD_NOT_WRITE_INLINE:%s", filePath))
			}
			break
		case *pkgcrewpb.Replace_WithLookaside:
			bts, err := pd.BlobStorage.Read(replacing.WithLookaside)
			if err != nil {
				return err
			}
			hasher := pd.CompareHash(bts, replacing.WithLookaside)
			if hasher == nil {
				return errors.New("LOOKASIDE_FILE_AND_HASH_NOT_MATCHING")
			}

			_, err = f.Write(bts)
			if err != nil {
				return errors.New(fmt.Sprintf("COULD_NOT_WRITE_LOOKASIDE:%s", filePath))
			}
			break
		}
	}

	return nil
}