// populatePatch loads a patch into the project context, using patchId if provided.
// If patchId is blank, will try to infer the patch ID from the version already loaded
// into context, if available.
func (pc *projectContext) populatePatch(patchId string) error {
	var err error
	if len(patchId) > 0 {
		// The patch is explicitly identified in the URL, so fetch it
		if !patch.IsValidId(patchId) {
			return fmt.Errorf("patch id '%v' is not an object id", patchId)
		}
		pc.Patch, err = patch.FindOne(patch.ById(patch.NewId(patchId)).Project(patch.ExcludePatchDiff))
	} else if pc.Version != nil {
		// patch isn't in URL but the version in context has one, get it
		pc.Patch, err = patch.FindOne(patch.ByVersion(pc.Version.Id).Project(patch.ExcludePatchDiff))
	}
	if err != nil {
		return err
	}

	// If there's a finalized patch loaded into context but not a version, load the version
	// associated with the patch as the context's version.
	if pc.Version == nil && pc.Patch != nil && pc.Patch.Version != "" {
		pc.Version, err = version.FindOne(version.ById(pc.Patch.Version))
		if err != nil {
			return err
		}
	}
	return nil
}

// Returns a JSON response with the marshalled output of the version
// specified in the request.
func (restapi restAPI) getVersionInfo(w http.ResponseWriter, r *http.Request) {
	versionId := mux.Vars(r)["version_id"]

	srcVersion, err := version.FindOne(version.ById(versionId))
	if err != nil || srcVersion == nil {
		msg := fmt.Sprintf("Error finding version '%v'", versionId)
		statusCode := http.StatusNotFound

		if err != nil {
			evergreen.Logger.Logf(slogger.ERROR, "%v: %v", msg, err)
			statusCode = http.StatusInternalServerError
		}

		restapi.WriteJSON(w, statusCode, responseError{Message: msg})
		return
	}

	destVersion := &restVersion{}
	// Copy the contents from the database into our local version type
	err = angier.TransferByFieldNames(srcVersion, destVersion)
	if err != nil {
		msg := fmt.Sprintf("Error finding version '%v'", versionId)
		evergreen.Logger.Logf(slogger.ERROR, "%v: %v", msg, err)
		restapi.WriteJSON(w, http.StatusInternalServerError, responseError{Message: msg})
		return
	}
	for _, buildStatus := range srcVersion.BuildVariants {
		destVersion.BuildVariants = append(destVersion.BuildVariants, buildStatus.BuildVariant)
		evergreen.Logger.Logf(slogger.ERROR, "adding BuildVariant %v", buildStatus.BuildVariant)
	}

	restapi.WriteJSON(w, http.StatusOK, destVersion)
	return

}

// TryMarkPatchBuildFinished attempts to mark a patch as finished if all
// the builds for the patch are finished as well
func TryMarkPatchBuildFinished(b *build.Build, finishTime time.Time) error {
	v, err := version.FindOne(version.ById(b.Version))
	if err != nil {
		return err
	}
	if v == nil {
		return fmt.Errorf("Cannot find version for build %v with version %v", b.Id, b.Version)
	}

	// ensure all builds for this patch are finished as well
	builds, err := build.Find(build.ByIds(v.BuildIds).WithFields(build.StatusKey))
	if err != nil {
		return err
	}

	patchCompleted := true
	status := evergreen.PatchSucceeded
	for _, build := range builds {
		if !build.IsFinished() {
			patchCompleted = false
		}
		if build.Status != evergreen.BuildSucceeded {
			status = evergreen.PatchFailed
		}
	}

	// nothing to do if the patch isn't completed
	if !patchCompleted {
		return nil
	}

	return patch.TryMarkFinished(v.Id, finishTime, status)
}

// getTasksForLatestVersion sends back the TaskJSON data associated with the latest version.
func getTasksForLatestVersion(w http.ResponseWriter, r *http.Request) {

	name := mux.Vars(r)["name"]
	var jsonTask TaskJSON

	projects := []string{}
	err := util.ReadJSONInto(r.Body, &projects)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	versionData := []VersionData{}
	for _, project := range projects {
		err := db.FindOneQ(collection, db.Query(bson.M{NameKey: name,
			ProjectIdKey: project}).Sort([]string{"-" + RevisionOrderNumberKey}).WithFields(VersionIdKey), &jsonTask)
		if err != nil {
			if err != mgo.ErrNotFound {
				http.Error(w, err.Error(), http.StatusInternalServerError)
				return
			}
			http.Error(w, "{}", http.StatusNotFound)
			return
		}
		if jsonTask.VersionId == "" {
			http.Error(w, "{}", http.StatusNotFound)
		}
		jsonTasks, err := findTasksForVersion(jsonTask.VersionId, name)
		if jsonTasks == nil {
			http.Error(w, "{}", http.StatusNotFound)
			return
		}
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		// get the version commit info
		v, err := version.FindOne(version.ById(jsonTask.VersionId))
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		if v == nil {
			http.Error(w, "{}", http.StatusNotFound)
			return
		}

		commitInfo := CommitInfo{
			Author:     v.Author,
			Message:    v.Message,
			CreateTime: v.CreateTime,
			Revision:   v.Revision,
			VersionId:  jsonTask.VersionId,
		}

		versionData = append(versionData, VersionData{jsonTasks, commitInfo})
	}
	plugin.WriteJSON(w, http.StatusOK, versionData)
}

func TestUpdateBuildStatusForTask(t *testing.T) {
	Convey("With two tasks and a build", t, func() {
		testutil.HandleTestingErr(db.ClearCollections(task.Collection, build.Collection, version.Collection), t,
			"Error clearing task and build collections")
		displayName := "testName"
		b := &build.Build{
			Id:      "buildtest",
			Status:  evergreen.BuildStarted,
			Version: "abc",
		}
		v := &version.Version{
			Id:     b.Version,
			Status: evergreen.VersionStarted,
		}
		testTask := task.Task{
			Id:          "testone",
			DisplayName: displayName,
			Activated:   false,
			BuildId:     b.Id,
			Project:     "sample",
			Status:      evergreen.TaskFailed,
		}
		anotherTask := task.Task{
			Id:          "two",
			DisplayName: displayName,
			Activated:   true,
			BuildId:     b.Id,
			Project:     "sample",
			Status:      evergreen.TaskFailed,
		}

		b.Tasks = []build.TaskCache{
			{
				Id:     testTask.Id,
				Status: evergreen.TaskSucceeded,
			},
			{
				Id:     anotherTask.Id,
				Status: evergreen.TaskFailed,
			},
		}
		So(b.Insert(), ShouldBeNil)
		So(testTask.Insert(), ShouldBeNil)
		So(anotherTask.Insert(), ShouldBeNil)
		So(v.Insert(), ShouldBeNil)
		Convey("updating the build for a task should update the build's status and the version's status", func() {
			So(UpdateBuildAndVersionStatusForTask(testTask.Id), ShouldBeNil)
			b, err := build.FindOne(build.ById(b.Id))
			So(err, ShouldBeNil)
			So(b.Status, ShouldEqual, evergreen.BuildFailed)
			v, err := version.FindOne(version.ById(v.Id))
			So(v.Status, ShouldEqual, evergreen.VersionFailed)

		})

	})
}

// prependConfigToVersion modifies the project config with the given id
func prependConfigToVersion(t *testing.T, versionId, configData string) {
	v, err := version.FindOne(version.ById(versionId))
	testutil.HandleTestingErr(err, t, "failed to load version")
	if v == nil {
		err = fmt.Errorf("could not find version to update")
		testutil.HandleTestingErr(err, t, "failed to find version")
	}
	v.Config = configData + v.Config
	testutil.HandleTestingErr(dbutil.ClearCollections(version.Collection), t, "couldnt reset version")
	testutil.HandleTestingErr(v.Insert(), t, "failed to insert version")
}

func TestMarkStart(t *testing.T) {
	Convey("With a task, build and version", t, func() {
		testutil.HandleTestingErr(db.ClearCollections(task.Collection, build.Collection, version.Collection), t,
			"Error clearing task and build collections")
		displayName := "testName"
		b := &build.Build{
			Id:      "buildtest",
			Status:  evergreen.BuildCreated,
			Version: "abc",
		}
		v := &version.Version{
			Id:     b.Version,
			Status: evergreen.VersionCreated,
		}
		testTask := task.Task{
			Id:          "testTask",
			DisplayName: displayName,
			Activated:   true,
			BuildId:     b.Id,
			Project:     "sample",
			Status:      evergreen.TaskUndispatched,
			Version:     b.Version,
		}

		b.Tasks = []build.TaskCache{
			{
				Id:     testTask.Id,
				Status: evergreen.TaskUndispatched,
			},
		}
		So(b.Insert(), ShouldBeNil)
		So(testTask.Insert(), ShouldBeNil)
		So(v.Insert(), ShouldBeNil)
		Convey("when calling MarkStart, the task, version and build should be updated", func() {
			So(MarkStart(testTask.Id), ShouldBeNil)
			testTask, err := task.FindOne(task.ById(testTask.Id))
			So(err, ShouldBeNil)
			So(testTask.Status, ShouldEqual, evergreen.TaskStarted)
			b, err := build.FindOne(build.ById(b.Id))
			So(err, ShouldBeNil)
			So(b.Status, ShouldEqual, evergreen.BuildStarted)
			So(b.Tasks, ShouldNotBeNil)
			So(len(b.Tasks), ShouldEqual, 1)
			So(b.Tasks[0].Status, ShouldEqual, evergreen.TaskStarted)
			v, err := version.FindOne(version.ById(v.Id))
			So(err, ShouldBeNil)
			So(v.Status, ShouldEqual, evergreen.VersionStarted)
		})
	})
}

func (as *APIServer) GetVersion(w http.ResponseWriter, r *http.Request) {
	task := MustHaveTask(r)

	// Get the version for this task, so we can get its config data
	v, err := version.FindOne(version.ById(task.Version))
	if err != nil {
		as.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	if v == nil {
		http.Error(w, "version not found", http.StatusNotFound)
		return
	}

	as.WriteJSON(w, http.StatusOK, v)
}

// populateTaskBuildVersion takes a task, build, and version ID and populates a projectContext
// with as many of the task, build, and version documents as possible.
// If any of the provided IDs is blank, they will be inferred from the more selective ones.
// Returns the project ID of the data found, which may be blank if the IDs are empty.
func (pc *projectContext) populateTaskBuildVersion(taskId, buildId, versionId string) (string, error) {
	projectId := ""
	var err error
	// Fetch task if there's a task ID present; if we find one, populate build/version IDs from it
	if len(taskId) > 0 {
		pc.Task, err = task.FindOne(task.ById(taskId))
		if err != nil {
			return "", err
		}

		if pc.Task != nil {
			// override build and version ID with the ones this task belongs to
			buildId = pc.Task.BuildId
			versionId = pc.Task.Version
			projectId = pc.Task.Project
		}
	}

	// Fetch build if there's a build ID present; if we find one, populate version ID from it
	if len(buildId) > 0 {
		pc.Build, err = build.FindOne(build.ById(buildId))
		if err != nil {
			return "", err
		}
		if pc.Build != nil {
			versionId = pc.Build.Version
			projectId = pc.Build.Project
		}
	}
	if len(versionId) > 0 {
		pc.Version, err = version.FindOne(version.ById(versionId))
		if err != nil {
			return "", err
		}
		if pc.Version != nil {
			projectId = pc.Version.Identifier
		}
	}
	return projectId, nil

}

func (self *TaskNotificationHandler) constructChangeInfo(allTasks []task.Task,
	key *NotificationKey) ([]ChangeInfo, error) {
	changeInfoSlice := make([]ChangeInfo, 0)

	for _, task := range allTasks {
		// add blamelist information for each task
		v, err := version.FindOne(version.ById(task.Version))
		if err != nil {
			return changeInfoSlice, err
		}
		if v == nil {
			return changeInfoSlice, fmt.Errorf("No version found for task %v with version id %v",
				task.Id, task.Version)
		}
		changeInfo := constructChangeInfo(v, key)
		changeInfo.Pushtime = task.PushTime.Format(time.RFC850)
		changeInfoSlice = append(changeInfoSlice, *changeInfo)
	}

	return changeInfoSlice, nil
}

func (self *BuildNotificationHandler) constructChangeInfo(allBuilds []build.Build,
	key *NotificationKey) ([]ChangeInfo, error) {
	changeInfoSlice := make([]ChangeInfo, 0)

	for _, build := range allBuilds {
		// add blamelist information for each build
		v, err := version.FindOne(version.ById(build.Version))
		if err != nil {
			return changeInfoSlice, err
		}

		if v == nil {
			err = fmt.Errorf("No version found for build %v with version id %v",
				build.Id, build.Version)
			return changeInfoSlice, err
		}
		changeInfo := constructChangeInfo(v, key)
		changeInfo.Pushtime = build.PushTime.Format(time.RFC850)
		changeInfoSlice = append(changeInfoSlice, *changeInfo)
	}
	return changeInfoSlice, nil
}

// Modifies part of the version specified in the request, and returns a
// JSON response with the marshalled output of its new state.
func (restapi restAPI) modifyVersionInfo(w http.ResponseWriter, r *http.Request) {
	versionId := mux.Vars(r)["version_id"]

	var input struct {
		Activated *bool `json:"activated"`
	}
	json.NewDecoder(r.Body).Decode(&input)

	v, err := version.FindOne(version.ById(versionId))
	if err != nil || v == nil {
		msg := fmt.Sprintf("Error finding version '%v'", versionId)
		statusCode := http.StatusNotFound

		if err != nil {
			evergreen.Logger.Logf(slogger.ERROR, "%v: %v", msg, err)
			statusCode = http.StatusInternalServerError
		}

		restapi.WriteJSON(w, statusCode, responseError{Message: msg})
		return
	}

	if input.Activated != nil {
		if err = model.SetVersionActivation(v.Id, *input.Activated); err != nil {
			state := "inactive"
			if *input.Activated {
				state = "active"
			}

			msg := fmt.Sprintf("Error marking version '%v' as %v", versionId, state)
			restapi.WriteJSON(w, http.StatusInternalServerError, responseError{Message: msg})
			return
		}
	}

	restapi.getVersionInfo(w, r)
}

// Takes in a version id and a map of "key -> buildvariant" (where "key" is of
// type "versionBuildVariant") and updates the map with an entry for the
// buildvariants associated with "versionStr"
func (self *Scheduler) updateVersionBuildVarMap(versionStr string,
	versionBuildVarMap map[versionBuildVariant]model.BuildVariant) (err error) {
	version, err := version.FindOne(version.ById(versionStr))
	if err != nil {
		return
	}
	if version == nil {
		return fmt.Errorf("nil version returned for version id '%v'", versionStr)
	}
	project := &model.Project{}

	err = model.LoadProjectInto([]byte(version.Config), version.Identifier, project)
	if err != nil {
		return fmt.Errorf("unable to load project config for version %v: "+
			"%v", versionStr, err)
	}

	// create buildvariant map (for accessing purposes)
	for _, buildVariant := range project.BuildVariants {
		key := versionBuildVariant{versionStr, buildVariant.Name}
		versionBuildVarMap[key] = buildVariant
	}
	return
}

func (uis *UIServer) buildHistory(w http.ResponseWriter, r *http.Request) {
	buildId := mux.Vars(r)["build_id"]

	before, err := getIntValue(r, "before", 3)
	if err != nil {
		http.Error(w, fmt.Sprintf("invalid param 'before': %v", r.FormValue("before")), http.StatusBadRequest)
		return
	}

	after, err := getIntValue(r, "after", 3)
	if err != nil {
		http.Error(w, fmt.Sprintf("invalid param 'after': %v", r.FormValue("after")), http.StatusBadRequest)
		return
	}

	builds, err := getBuildVariantHistory(buildId, before, after)
	if err != nil {
		http.Error(w, fmt.Sprintf("error getting build history: %v", err), http.StatusInternalServerError)
		return
	}

	history := &struct {
		Builds      []*uiBuild `json:"builds"`
		LastSuccess *uiBuild   `json:"lastSuccess"`
	}{}

	history.Builds = make([]*uiBuild, len(builds))
	for i := 0; i < len(builds); i++ {
		v, err := version.FindOne(version.ById(builds[i].Version))
		if err != nil {
			http.Error(w, fmt.Sprintf("error getting version for build %v: %v", builds[i].Id, err), http.StatusInternalServerError)
			return
		}
		if v == nil {
			http.Error(w, fmt.Sprintf("no version found for build %v", builds[i].Id), http.StatusNotFound)
			return
		}
		history.Builds[i] = &uiBuild{
			Build:       builds[i],
			CurrentTime: time.Now().UnixNano(),
			Elapsed:     time.Now().Sub(builds[i].StartTime),
			RepoOwner:   v.Owner,
			Repo:        v.Repo,
			Version:     *v,
		}
	}

	lastSuccess, err := getBuildVariantHistoryLastSuccess(buildId)
	if err == nil && lastSuccess != nil {
		v, err := version.FindOne(version.ById(lastSuccess.Version))
		if err != nil {
			http.Error(
				w, fmt.Sprintf("error getting last successful build version: %v", err),
				http.StatusInternalServerError)
			return
		}
		if v == nil {
			http.Error(w, fmt.Sprintf("no version '%v' found", lastSuccess.Version), http.StatusNotFound)
			return
		}
		history.LastSuccess = &uiBuild{
			Build:       *lastSuccess,
			CurrentTime: time.Now().UnixNano(),
			Elapsed:     time.Now().Sub(lastSuccess.StartTime),
			RepoOwner:   v.Owner,
			Repo:        v.Repo,
			Version:     *v,
		}
	}

	uis.WriteJSON(w, http.StatusOK, history)
}

// loadAlertContext fetches details from the database for all documents that are associated with the
// AlertRequest. For example, it populates the task/build/version/project using the
// task/build/version/project ids in the alert request document.
func (qp *QueueProcessor) loadAlertContext(a *alert.AlertRequest) (*AlertContext, error) {
	aCtx := &AlertContext{AlertRequest: a}
	aCtx.Settings = qp.config
	taskId, projectId, buildId, versionId := a.TaskId, a.ProjectId, a.BuildId, a.VersionId
	patchId := a.PatchId
	var err error
	if len(a.HostId) > 0 {
		aCtx.Host, err = host.FindOne(host.ById(a.HostId))
		if err != nil {
			return nil, err
		}
	}
	// Fetch task if there's a task ID present; if we find one, populate build/version IDs from it
	if len(taskId) > 0 {
		aCtx.Task, err = model.FindTask(taskId)
		if err != nil {
			return nil, err
		}
		if aCtx.Task != nil && aCtx.Task.Execution != a.Execution {
			oldTaskId := fmt.Sprintf("%s_%v", taskId, a.Execution)
			aCtx.Task, err = model.FindOneOldTask(bson.M{"_id": oldTaskId}, db.NoProjection, db.NoSort)
			if err != nil {
				return nil, err
			}
		}

		if aCtx.Task != nil {
			// override build and version ID with the ones this task belongs to
			buildId = aCtx.Task.BuildId
			versionId = aCtx.Task.Version
			projectId = aCtx.Task.Project
			aCtx.FailedTests = []model.TestResult{}
			for _, test := range aCtx.Task.TestResults {
				if test.Status == "fail" {
					aCtx.FailedTests = append(aCtx.FailedTests, test)
				}
			}
		}
	}

	// Fetch build if there's a build ID present; if we find one, populate version ID from it
	if len(buildId) > 0 {
		aCtx.Build, err = build.FindOne(build.ById(buildId))
		if err != nil {
			return nil, err
		}
		if aCtx.Build != nil {
			versionId = aCtx.Build.Version
			projectId = aCtx.Build.Project
		}
	}
	if len(versionId) > 0 {
		aCtx.Version, err = version.FindOne(version.ById(versionId))
		if err != nil {
			return nil, err
		}
		if aCtx.Version != nil {
			projectId = aCtx.Version.Identifier
		}
	}

	if len(patchId) > 0 {
		if !patch.IsValidId(patchId) {
			return nil, fmt.Errorf("patch id '%v' is not an object id", patchId)
		}
		aCtx.Patch, err = patch.FindOne(patch.ById(patch.NewId(patchId)).Project(patch.ExcludePatchDiff))
	} else if aCtx.Version != nil {
		// patch isn't in URL but the version in context has one, get it
		aCtx.Patch, err = patch.FindOne(patch.ByVersion(aCtx.Version.Id).Project(patch.ExcludePatchDiff))
	}

	// If there's a finalized patch loaded into context but not a version, load the version
	// associated with the patch as the context's version.
	if aCtx.Version == nil && aCtx.Patch != nil && aCtx.Patch.Version != "" {
		aCtx.Version, err = version.FindOne(version.ById(aCtx.Patch.Version).WithoutFields(version.ConfigKey))
		if err != nil {
			return nil, err
		}
	}

	if len(projectId) > 0 {
		aCtx.ProjectRef, err = qp.findProject(projectId)
		if err != nil {
			return nil, err
		}
	}
	return aCtx, nil
}

// Takes a request for a task's file to be copied from
// one s3 location to another. Ensures that if the destination
// file path already exists, no file copy is performed.
func S3CopyHandler(w http.ResponseWriter, r *http.Request) {
	task := plugin.GetTask(r)
	if task == nil {
		http.Error(w, "task not found", http.StatusNotFound)
		return
	}
	s3CopyReq := &S3CopyRequest{}
	err := util.ReadJSONInto(r.Body, s3CopyReq)
	if err != nil {
		evergreen.Logger.Errorf(slogger.ERROR, "error reading push request: %v", err)
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Get the version for this task, so we can check if it has
	// any already-done pushes
	v, err := version.FindOne(version.ById(task.Version))
	if err != nil {
		evergreen.Logger.Logf(slogger.ERROR, "error querying task %v with version id %v: %v",
			task.Id, task.Version, err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Check for an already-pushed file with this same file path,
	// but from a conflicting or newer commit sequence num
	if v == nil {
		evergreen.Logger.Logf(slogger.ERROR, "no version found for build %v", task.BuildId)
		http.Error(w, "version not found", http.StatusNotFound)
		return
	}

	copyFromLocation := strings.Join([]string{s3CopyReq.S3SourceBucket, s3CopyReq.S3SourcePath}, "/")
	copyToLocation := strings.Join([]string{s3CopyReq.S3DestinationBucket, s3CopyReq.S3DestinationPath}, "/")

	newestPushLog, err := model.FindPushLogAfter(copyToLocation, v.RevisionOrderNumber)
	if err != nil {
		evergreen.Logger.Logf(slogger.ERROR, "error querying for push log at %v: %v", copyToLocation, err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	if newestPushLog != nil {
		evergreen.Logger.Logf(slogger.ERROR, "conflict with existing pushed file: "+
			"%v", copyToLocation)
		http.Error(w, "conflicting push target for this file already exists.", http.StatusConflict)
		return
	}

	// It's now safe to put the file in its permanent location.
	newPushLog := model.NewPushLog(v, task, copyToLocation)
	err = newPushLog.Insert()
	if err != nil {
		evergreen.Logger.Logf(slogger.ERROR, "failed to create new push log: %v %v", newPushLog, err)
		http.Error(w, fmt.Sprintf("failed to create push log: %v", err), http.StatusInternalServerError)
		return
	}

	// Now copy the file into the permanent location
	auth := &aws.Auth{
		AccessKey: s3CopyReq.AwsKey,
		SecretKey: s3CopyReq.AwsSecret,
	}

	evergreen.Logger.Logf(slogger.INFO, "performing S3 copy: '%v' => '%v'",
		copyFromLocation, copyToLocation)

	_, err = util.RetryArithmeticBackoff(func() error {
		err := thirdparty.S3CopyFile(auth,
			s3CopyReq.S3SourceBucket,
			s3CopyReq.S3SourcePath,
			s3CopyReq.S3DestinationBucket,
			s3CopyReq.S3DestinationPath,
			string(s3.PublicRead),
		)
		if err != nil {
			evergreen.Logger.Logf(slogger.ERROR, "S3 copy failed for task %v, "+
				"retrying: %v", task.Id, err)
			return util.RetriableError{err}
		} else {
			err := newPushLog.UpdateStatus(model.PushLogSuccess)
			if err != nil {
				evergreen.Logger.Logf(slogger.ERROR, "updating pushlog status failed"+
					" for task %v: %v", task.Id, err)
			}
			return err
		}
	}, s3CopyRetryNumRetries, s3CopyRetrySleepTimeSec*time.Second)

	if err != nil {
		message := fmt.Sprintf("S3 copy failed for task %v: %v", task.Id, err)
		evergreen.Logger.Logf(slogger.ERROR, message)
		err = newPushLog.UpdateStatus(model.PushLogFailed)
		if err != nil {
			evergreen.Logger.Logf(slogger.ERROR, "updating pushlog status failed: %v", err)
		}
		http.Error(w, message, http.StatusInternalServerError)
//.........这里部分代码省略.........

// getTasksForLatestVersion sends back the TaskJSON data associated with the latest version.
func getTasksForLatestVersion(w http.ResponseWriter, r *http.Request) {
	project := mux.Vars(r)["project_id"]
	name := mux.Vars(r)["name"]
	skip, err := util.GetIntValue(r, "skip", 0)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	if skip < 0 {
		http.Error(w, "negative skip", http.StatusBadRequest)
		return
	}
	pipeline := []bson.M{
		// match on name and project
		{"$match": bson.M{
			NameKey:      name,
			ProjectIdKey: project,
		}},

		// sort on the revision number
		{"$sort": bson.M{
			RevisionOrderNumberKey: -1,
		}},

		// group by version id
		{"$group": bson.M{
			"_id": bson.M{
				"r":   "$" + RevisionOrderNumberKey,
				"vid": "$" + VersionIdKey,
			},
			"t": bson.M{
				"$push": bson.M{
					"d":    "$" + DataKey,
					"t_id": "$" + TaskIdKey,
					"tn":   "$" + TaskNameKey,
					"var":  "$" + VariantKey,
				},
			},
		}},

		// sort on the _id
		{"$sort": bson.M{
			"_id.r": -1,
		}},

		{"$skip": skip},
		{"$limit": 2},
	}

	tasksForVersions := []TasksForVersion{}
	err = db.Aggregate(collection, pipeline, &tasksForVersions)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	if len(tasksForVersions) == 0 {
		http.Error(w, "no tasks found", http.StatusNotFound)
		return
	}

	// we default have another revision
	lastRevision := false
	currentVersion := tasksForVersions[0]

	// if there is only one version, then we are at the last revision.
	if len(tasksForVersions) < 2 {
		lastRevision = true
	}

	// get the version commit info
	v, err := version.FindOne(version.ById(currentVersion.Id.VersionId))
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if v == nil {
		http.Error(w, "{}", http.StatusNotFound)
		return
	}

	commitInfo := CommitInfo{
		Author:     v.Author,
		Message:    v.Message,
		CreateTime: v.CreateTime,
		Revision:   v.Revision,
		VersionId:  v.Id,
	}

	data := VersionData{currentVersion.Tasks, commitInfo, lastRevision}
	plugin.WriteJSON(w, http.StatusOK, data)
}

func (uis *UIServer) variantHistory(w http.ResponseWriter, r *http.Request) {
	projCtx := MustHaveProjectContext(r)
	variant := mux.Vars(r)["variant"]
	beforeCommitId := r.FormValue("before")
	isJson := (r.FormValue("format") == "json")

	var beforeCommit *version.Version
	var err error
	beforeCommit = nil
	if beforeCommitId != "" {
		beforeCommit, err = version.FindOne(version.ById(beforeCommitId))
		if err != nil {
			uis.LoggedError(w, r, http.StatusInternalServerError, err)
			return
		}
		if beforeCommit == nil {
			evergreen.Logger.Logf(slogger.WARN, "'before' was specified but query returned nil")
		}
	}

	project, err := model.FindProject("", projCtx.ProjectRef)
	if err != nil {
		uis.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	bv := project.FindBuildVariant(variant)
	if bv == nil {
		http.Error(w, "variant not found", http.StatusNotFound)
		return
	}

	iter := model.NewBuildVariantHistoryIterator(variant, bv.Name, projCtx.Project.Identifier)
	tasks, versions, err := iter.GetItems(beforeCommit, 50)
	if err != nil {
		uis.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	var suites []string
	for _, task := range bv.Tasks {
		suites = append(suites, task.Name)
	}

	sort.Strings(suites)

	data := struct {
		Variant   string
		Tasks     []bson.M
		TaskNames []string
		Versions  []version.Version
		Project   string
	}{variant, tasks, suites, versions, projCtx.Project.Identifier}
	if isJson {
		uis.WriteJSON(w, http.StatusOK, data)
		return
	}
	uis.WriteHTML(w, http.StatusOK, struct {
		ProjectData projectContext
		User        *user.DBUser
		Flashes     []interface{}
		Data        interface{}
	}{projCtx, GetUser(r), []interface{}{}, data}, "base",
		"build_variant_history.html", "base_angular.html", "menu.html")
}

func TestTaskHistory(t *testing.T) {

	Convey("With a task history iterator", t, func() {

		buildVariants := []string{"bv_0", "bv_1", "bv_2"}
		projectName := "project"
		taskHistoryIterator := NewTaskHistoryIterator(evergreen.CompileStage,
			buildVariants, projectName)

		Convey("when finding task history items", func() {

			testutil.HandleTestingErr(db.ClearCollections(version.Collection, TasksCollection),
				t, "Error clearing test collections")

			for i := 10; i < 20; i++ {
				projectToUse := projectName
				if i == 14 {
					projectToUse = "otherBranch"
				}

				vid := fmt.Sprintf("v%v", i)
				ver := &version.Version{
					Id:                  vid,
					RevisionOrderNumber: i,
					Revision:            vid,
					Requester:           evergreen.RepotrackerVersionRequester,
					Project:             projectToUse,
				}

				testutil.HandleTestingErr(ver.Insert(), t,
					"Error inserting version")
				for j := 0; j < 3; j++ {
					task := &Task{
						Id:                  fmt.Sprintf("t%v_%v", i, j),
						BuildVariant:        fmt.Sprintf("bv_%v", j),
						DisplayName:         evergreen.CompileStage,
						RevisionOrderNumber: i,
						Revision:            vid,
						Requester:           evergreen.RepotrackerVersionRequester,
						Project:             projectToUse,
					}
					testutil.HandleTestingErr(task.Insert(), t,
						"Error inserting task")
				}

			}

			Convey("the specified number of task history items should be"+
				" fetched, starting at the specified version", func() {

				taskHistoryChunk, err := taskHistoryIterator.GetChunk(nil, 5, 0, false)
				versions := taskHistoryChunk.Versions
				tasks := taskHistoryChunk.Tasks
				So(err, ShouldBeNil)
				So(taskHistoryChunk.Exhausted.Before, ShouldBeFalse)
				So(taskHistoryChunk.Exhausted.After, ShouldBeTrue)
				So(len(versions), ShouldEqual, 5)
				So(len(tasks), ShouldEqual, len(versions))
				So(versions[0].Id, ShouldEqual, tasks[0]["_id"])
				So(versions[len(versions)-1].Id, ShouldEqual, "v15")
				So(tasks[len(tasks)-1]["_id"], ShouldEqual,
					versions[len(versions)-1].Id)

			})

			Convey("tasks from a different project should be filtered"+
				" out", func() {

				vBefore, err := version.FindOne(version.ById("v15"))
				So(err, ShouldBeNil)

				taskHistoryChunk, err := taskHistoryIterator.GetChunk(vBefore, 5, 0, false)
				versions := taskHistoryChunk.Versions
				tasks := taskHistoryChunk.Tasks
				So(err, ShouldBeNil)
				So(taskHistoryChunk.Exhausted.Before, ShouldBeTrue)
				So(taskHistoryChunk.Exhausted.After, ShouldBeFalse)
				// Should skip 14 because its in another project
				So(versions[0].Id, ShouldEqual, "v13")
				So(versions[0].Id, ShouldEqual, tasks[0]["_id"])
				So(len(tasks), ShouldEqual, 4)
				So(len(tasks), ShouldEqual, len(versions))
				So(tasks[len(tasks)-1]["_id"], ShouldEqual,
					versions[len(versions)-1].Id)

			})

		})

	})

}

func getVersionHistory(versionId string, N int) ([]version.Version, error) {
	v, err := version.FindOne(version.ById(versionId))
	if err != nil {
		return nil, err
	} else if v == nil {
		return nil, fmt.Errorf("Version '%v' not found", versionId)
	}

	// Versions in the same push event, assuming that no two push events happen at the exact same time
	// Never want more than 2N+1 versions, so make sure we add a limit

	siblingVersions, err := version.Find(db.Query(
		bson.M{
			"order":  v.RevisionOrderNumber,
			"r":      evergreen.RepotrackerVersionRequester,
			"branch": v.Project,
		}).WithoutFields(version.ConfigKey).Sort([]string{"order"}).Limit(2*N + 1))
	if err != nil {
		return nil, err
	}

	versionIndex := -1
	for i := 0; i < len(siblingVersions); i++ {
		if siblingVersions[i].Id == v.Id {
			versionIndex = i
		}
	}

	numSiblings := len(siblingVersions) - 1
	versions := siblingVersions

	if versionIndex < N {
		// There are less than N later versions from the same push event
		// N subsequent versions plus the specified one
		subsequentVersions, err := version.Find(
			//TODO encapsulate this query in version pkg
			db.Query(bson.M{
				"order":  bson.M{"$gt": v.RevisionOrderNumber},
				"r":      evergreen.RepotrackerVersionRequester,
				"branch": v.Project,
			}).WithoutFields(version.ConfigKey).Sort([]string{"order"}).Limit(N - versionIndex))
		if err != nil {
			return nil, err
		}

		// Reverse the second array so we have the versions ordered "newest one first"
		for i := 0; i < len(subsequentVersions)/2; i++ {
			subsequentVersions[i], subsequentVersions[len(subsequentVersions)-1-i] = subsequentVersions[len(subsequentVersions)-1-i], subsequentVersions[i]
		}

		versions = append(subsequentVersions, versions...)
	}

	if numSiblings-versionIndex < N {
		previousVersions, err := version.Find(db.Query(bson.M{
			"order":  bson.M{"$lt": v.RevisionOrderNumber},
			"r":      evergreen.RepotrackerVersionRequester,
			"branch": v.Project,
		}).WithoutFields(version.ConfigKey).Sort([]string{"-order"}).Limit(N))
		if err != nil {
			return nil, err
		}
		versions = append(versions, previousVersions...)
	}

	return versions, nil
}