package git

import (
	"fmt"
	"io"
	"net/http"

	"github.com/golang/protobuf/jsonpb"
	pb "gitlab.com/gitlab-org/gitaly-proto/go"

	"gitlab.com/gitlab-org/gitlab-workhorse/internal/gitaly"
	"gitlab.com/gitlab-org/gitlab-workhorse/internal/helper"
	"gitlab.com/gitlab-org/gitlab-workhorse/internal/log"
	"gitlab.com/gitlab-org/gitlab-workhorse/internal/senddata"
)

type patch struct{ senddata.Prefix }
type patchParams struct {
	RepoPath        string
	ShaFrom         string
	ShaTo           string
	GitalyServer    gitaly.Server
	RawPatchRequest string
}

var SendPatch = &patch{"git-format-patch:"}

func (p *patch) Inject(w http.ResponseWriter, r *http.Request, sendData string) {
	var params patchParams
	if err := p.Unpack(&params, sendData); err != nil {
		helper.Fail500(w, r, fmt.Errorf("SendPatch: unpack sendData: %v", err))
		return
	}
	if params.GitalyServer.Address != "" {
		handleSendPatchWithGitaly(w, r, &params)
	} else {
		handleSendPatchLocally(w, r, &params)
	}
}

func handleSendPatchWithGitaly(w http.ResponseWriter, r *http.Request, params *patchParams) {
	request := &pb.RawPatchRequest{}
	if err := jsonpb.UnmarshalString(params.RawPatchRequest, request); err != nil {
		helper.Fail500(w, r, fmt.Errorf("diff.RawPatch: %v", err))
	}

	diffClient, err := gitaly.NewDiffClient(params.GitalyServer)
	if err != nil {
		helper.Fail500(w, r, fmt.Errorf("diff.RawPatch: %v", err))
	}

	if err := diffClient.SendRawPatch(r.Context(), w, request); err != nil {
		helper.LogError(
			r,
			&copyError{fmt.Errorf("diff.RawPatch: request=%v, err=%v", request, err)},
		)
	}
}

func handleSendPatchLocally(w http.ResponseWriter, r *http.Request, params *patchParams) {
	log.WithFields(r.Context(), log.Fields{
		"shaFrom": params.ShaFrom,
		"shaTo":   params.ShaTo,
		"path":    r.URL.Path,
	}).Print("SendPatch: sending patch")

	gitRange := fmt.Sprintf("%s..%s", params.ShaFrom, params.ShaTo)
	gitPatchCmd := gitCommand("git", "--git-dir="+params.RepoPath, "format-patch", gitRange, "--stdout")

	stdout, err := gitPatchCmd.StdoutPipe()
	if err != nil {
		helper.Fail500(w, r, fmt.Errorf("SendPatch: create stdout pipe: %v", err))
		return
	}

	if err := gitPatchCmd.Start(); err != nil {
		helper.Fail500(w, r, fmt.Errorf("SendPatch: start %v: %v", gitPatchCmd.Args, err))
		return
	}
	defer helper.CleanUpProcessGroup(gitPatchCmd)

	w.Header().Del("Content-Length")
	if _, err := io.Copy(w, stdout); err != nil {
		helper.LogError(r, &copyError{fmt.Errorf("SendPatch: copy %v stdout: %v", gitPatchCmd.Args, err)})
		return
	}
	if err := gitPatchCmd.Wait(); err != nil {
		helper.LogError(r, fmt.Errorf("SendPatch: wait for %v: %v", gitPatchCmd.Args, err))
		return
	}
}
