Github bridge: Refactor

1 files changed, 177 insertions, 208 deletions

diff --git a/bridge/github/import.go b/bridge/github/import.go
index 5337c474..ceb35ef0 100644
--- a/bridge/github/import.go
+++ b/bridge/github/import.go
@@ -54,64 +54,80 @@ func (gi *githubImporter) ImportAll(ctx context.Context, repo *cache.RepoCache,
 
 	go func() {
 		defer close(gi.out)
-
-		// Loop over all matching issues
-		for event := range gi.mediator.Issues {
-			var issue issue
-			var issueEdits <-chan userContentEditEvent
-			var timelineItems <-chan timelineEvent
-			switch e := event.(type) {
-			case messageEvent:
-				fmt.Println(e.msg)
-				continue
-			case issueData:
-				issue = e.issue
-				issueEdits = e.issueEdits
-				timelineItems = e.timelineItems
-			default:
-				panic(fmt.Sprint("Unknown event type"))
+		var currBug *cache.BugCache
+		var currEvent ImportEvent
+		var nextEvent ImportEvent
+		var err error
+		for {
+			// We need the current event and one look ahead event.
+			currEvent = nextEvent
+			if currEvent == nil {
+				currEvent = gi.mediator.NextImportEvent()
 			}
-			// create issue
-			b, err := gi.ensureIssue(ctx, repo, &issue, issueEdits)
-			if err != nil {
-				err := fmt.Errorf("issue creation: %v", err)
-				out <- core.NewImportError(err, "")
-				return
+			if currEvent == nil {
+				break
 			}
-
-			// loop over timeline items
-			for event := range timelineItems {
-				var item timelineItem
-				var edits <-chan userContentEditEvent
-				switch e := event.(type) {
-				case messageEvent:
-					fmt.Println(e.msg)
-					continue
-				case timelineData:
-					item = e.timelineItem
-					edits = e.userContentEdits
+			nextEvent = gi.mediator.NextImportEvent()
+
+			switch event := currEvent.(type) {
+			case MessageEvent:
+				fmt.Println(event.msg)
+			case IssueEvent:
+				// first: commit what is being held in currBug
+				if err = gi.commit(currBug, out); err != nil {
+					out <- core.NewImportError(err, "")
+					return
+				}
+				// second: create new issue
+				switch next := nextEvent.(type) {
+				case IssueEditEvent:
+					// consuming and using next event
+					nextEvent = nil
+					currBug, err = gi.ensureIssue(ctx, repo, &event.issue, &next.userContentEdit)
 				default:
-					panic(fmt.Sprint("Unknown event type"))
+					currBug, err = gi.ensureIssue(ctx, repo, &event.issue, nil)
+				}
+				if err != nil {
+					err := fmt.Errorf("issue creation: %v", err)
+					out <- core.NewImportError(err, "")
+					return
+				}
+			case IssueEditEvent:
+				err = gi.ensureIssueEdit(ctx, repo, currBug, event.issueId, &event.userContentEdit)
+				if err != nil {
+					err = fmt.Errorf("issue edit: %v", err)
+					out <- core.NewImportError(err, "")
+					return
+				}
+			case TimelineEvent:
+				if next, ok := nextEvent.(CommentEditEvent); ok && event.Typename == "IssueComment" {
+					// consuming and using next event
+					nextEvent = nil
+					err = gi.ensureComment(ctx, repo, currBug, &event.timelineItem.IssueComment, &next.userContentEdit)
+				} else {
+					err = gi.ensureTimelineItem(ctx, repo, currBug, &event.timelineItem)
 				}
-				err := gi.ensureTimelineItem(ctx, repo, b, &item, edits)
 				if err != nil {
 					err = fmt.Errorf("timeline item creation: %v", err)
 					out <- core.NewImportError(err, "")
 					return
 				}
-			}
-
-			if !b.NeedCommit() {
-				out <- core.NewImportNothing(b.Id(), "no imported operation")
-			} else if err := b.Commit(); err != nil {
-				// commit bug state
-				err = fmt.Errorf("bug commit: %v", err)
-				out <- core.NewImportError(err, "")
-				return
+			case CommentEditEvent:
+				err = gi.ensureCommentEdit(ctx, repo, currBug, event.commentId, &event.userContentEdit)
+				if err != nil {
+					err = fmt.Errorf("comment edit: %v", err)
+					out <- core.NewImportError(err, "")
+					return
+				}
+			default:
+				panic("Unknown event type")
 			}
 		}
-
-		if err := gi.mediator.Error(); err != nil {
+		// commit what is being held in currBug before returning
+		if err = gi.commit(currBug, out); err != nil {
+			out <- core.NewImportError(err, "")
+		}
+		if err = gi.mediator.Error(); err != nil {
 			gi.out <- core.NewImportError(err, "")
 		}
 	}()
@@ -119,27 +135,21 @@ func (gi *githubImporter) ImportAll(ctx context.Context, repo *cache.RepoCache,
 	return out, nil
 }
 
-// getNextUserContentEdit reads the input channel, handles messages, and returns the next
-// userContentEditData.
-func getNextUserContentEdit(in <-chan userContentEditEvent) (*userContentEditData, bool) {
-	for {
-		event, hasEvent := <-in
-		if !hasEvent {
-			return nil, false
-		}
-		switch e := event.(type) {
-		case messageEvent:
-			fmt.Println(e.msg)
-			continue
-		case userContentEditData:
-			return &e, true
-		default:
-			panic(fmt.Sprint("Unknown event type"))
-		}
+func (gi *githubImporter) commit(b *cache.BugCache, out chan<- core.ImportResult) error {
+	if b == nil {
+		return nil
 	}
+	if !b.NeedCommit() {
+		out <- core.NewImportNothing(b.Id(), "no imported operation")
+		return nil
+	} else if err := b.Commit(); err != nil {
+		// commit bug state
+		return fmt.Errorf("bug commit: %v", err)
+	}
+	return nil
 }
 
-func (gi *githubImporter) ensureIssue(ctx context.Context, repo *cache.RepoCache, issue *issue, issueEditEvents <-chan userContentEditEvent) (*cache.BugCache, error) {
+func (gi *githubImporter) ensureIssue(ctx context.Context, repo *cache.RepoCache, issue *issue, issueEdit *userContentEdit) (*cache.BugCache, error) {
 	author, err := gi.ensurePerson(ctx, repo, issue.Author)
 	if err != nil {
 		return nil, err
@@ -150,14 +160,13 @@ func (gi *githubImporter) ensureIssue(ctx context.Context, repo *cache.RepoCache
 		return excerpt.CreateMetadata[core.MetaKeyOrigin] == target &&
 			excerpt.CreateMetadata[metaKeyGithubId] == parseId(issue.Id)
 	})
-	if err != nil && err != bug.ErrBugNotExist {
+	if err == nil {
+		return b, nil
+	}
+	if err != bug.ErrBugNotExist {
 		return nil, err
 	}
 
-	// get first issue edit
-	// if it exists, then it holds the bug creation
-	firstEdit, hasEdit := getNextUserContentEdit(issueEditEvents)
-
 	// At Github there exist issues with seemingly empty titles. An example is
 	// https://github.com/NixOS/nixpkgs/issues/72730 .
 	// The title provided by the GraphQL API actually consists of a space followed by a
@@ -168,70 +177,49 @@ func (gi *githubImporter) ensureIssue(ctx context.Context, repo *cache.RepoCache
 		title = EMPTY_TITLE_PLACEHOLDER
 	}
 
-	if err == bug.ErrBugNotExist {
-		var textInput string
-		if hasEdit {
-			// use the first issue edit: it represents the bug creation itself
-			textInput = string(*firstEdit.Diff)
-		} else {
-			// if there are no issue edits then the issue struct holds the bug creation
-			textInput = string(issue.Body)
-		}
-		cleanText, err := text.Cleanup(textInput)
-		if err != nil {
-			return nil, err
-		}
-		// create bug
-		b, _, err = repo.NewBugRaw(
-			author,
-			issue.CreatedAt.Unix(),
-			title, // TODO: this is the *current* title, not the original one
-			cleanText,
-			nil,
-			map[string]string{
-				core.MetaKeyOrigin: target,
-				metaKeyGithubId:    parseId(issue.Id),
-				metaKeyGithubUrl:   issue.Url.String(),
-			})
-		if err != nil {
-			return nil, err
-		}
-		// importing a new bug
-		gi.out <- core.NewImportBug(b.Id())
+	var textInput string
+	if issueEdit != nil {
+		// use the first issue edit: it represents the bug creation itself
+		textInput = string(*issueEdit.Diff)
+	} else {
+		// if there are no issue edits then the issue struct holds the bug creation
+		textInput = string(issue.Body)
 	}
-	if b == nil {
-		return nil, fmt.Errorf("finding or creating issue")
+	cleanText, err := text.Cleanup(textInput)
+	if err != nil {
+		return nil, err
 	}
-	// process remaining issue edits, if they exist
-	for {
-		edit, hasEdit := getNextUserContentEdit(issueEditEvents)
-		if !hasEdit {
-			break
-		}
-		// other edits will be added as CommentEdit operations
-		target, err := b.ResolveOperationWithMetadata(metaKeyGithubId, parseId(issue.Id))
-		if err == cache.ErrNoMatchingOp {
-			// original comment is missing somehow, issuing a warning
-			gi.out <- core.NewImportWarning(fmt.Errorf("comment ID %s to edit is missing", parseId(issue.Id)), b.Id())
-			continue
-		}
-		if err != nil {
-			return nil, err
-		}
 
-		err = gi.ensureCommentEdit(ctx, repo, b, target, &edit.userContentEdit)
-		if err != nil {
-			return nil, err
-		}
+	// create bug
+	b, _, err = repo.NewBugRaw(
+		author,
+		issue.CreatedAt.Unix(),
+		title, // TODO: this is the *current* title, not the original one
+		cleanText,
+		nil,
+		map[string]string{
+			core.MetaKeyOrigin: target,
+			metaKeyGithubId:    parseId(issue.Id),
+			metaKeyGithubUrl:   issue.Url.String(),
+		})
+	if err != nil {
+		return nil, err
 	}
+	// importing a new bug
+	gi.out <- core.NewImportBug(b.Id())
+
 	return b, nil
 }
 
-func (gi *githubImporter) ensureTimelineItem(ctx context.Context, repo *cache.RepoCache, b *cache.BugCache, item *timelineItem, commentEdits <-chan userContentEditEvent) error {
+func (gi *githubImporter) ensureIssueEdit(ctx context.Context, repo *cache.RepoCache, bug *cache.BugCache, ghIssueId githubv4.ID, edit *userContentEdit) error {
+	return gi.ensureCommentEdit(ctx, repo, bug, ghIssueId, edit)
+}
+
+func (gi *githubImporter) ensureTimelineItem(ctx context.Context, repo *cache.RepoCache, b *cache.BugCache, item *timelineItem) error {
 
 	switch item.Typename {
 	case "IssueComment":
-		err := gi.ensureComment(ctx, repo, b, &item.IssueComment, commentEdits)
+		err := gi.ensureComment(ctx, repo, b, &item.IssueComment, nil)
 		if err != nil {
 			return fmt.Errorf("timeline comment creation: %v", err)
 		}
@@ -390,75 +378,62 @@ func (gi *githubImporter) ensureTimelineItem(ctx context.Context, repo *cache.Re
 	return nil
 }
 
-func (gi *githubImporter) ensureComment(ctx context.Context, repo *cache.RepoCache, b *cache.BugCache, comment *issueComment, commentEditEvents <-chan userContentEditEvent) error {
-	author, err := gi.ensurePerson(ctx, repo, comment.Author)
+func (gi *githubImporter) ensureCommentEdit(ctx context.Context, repo *cache.RepoCache, b *cache.BugCache, ghTargetId githubv4.ID, edit *userContentEdit) error {
+	// find comment
+	target, err := b.ResolveOperationWithMetadata(metaKeyGithubId, parseId(ghTargetId))
 	if err != nil {
 		return err
 	}
-
-	targetOpID, err := b.ResolveOperationWithMetadata(metaKeyGithubId, parseId(comment.Id))
-	if err != nil && err != cache.ErrNoMatchingOp {
+	_, err = b.ResolveOperationWithMetadata(metaKeyGithubId, parseId(edit.Id))
+	if err == nil {
+		return nil
+	}
+	if err != cache.ErrNoMatchingOp {
 		// real error
 		return err
 	}
-	firstEdit, hasEdit := getNextUserContentEdit(commentEditEvents)
-	if err == cache.ErrNoMatchingOp {
-		var textInput string
-		if hasEdit {
-			// use the first comment edit: it represents the comment creation itself
-			textInput = string(*firstEdit.Diff)
-		} else {
-			// if there are not comment edits, then the comment struct holds the comment creation
-			textInput = string(comment.Body)
-		}
-		cleanText, err := text.Cleanup(textInput)
-		if err != nil {
-			return err
-		}
 
-		// add comment operation
-		op, err := b.AddCommentRaw(
-			author,
-			comment.CreatedAt.Unix(),
-			cleanText,
-			nil,
-			map[string]string{
-				metaKeyGithubId:  parseId(comment.Id),
-				metaKeyGithubUrl: comment.Url.String(),
-			},
-		)
-		if err != nil {
-			return err
-		}
+	editor, err := gi.ensurePerson(ctx, repo, edit.Editor)
+	if err != nil {
+		return err
+	}
 
-		gi.out <- core.NewImportComment(op.Id())
-		targetOpID = op.Id()
+	if edit.DeletedAt != nil {
+		// comment deletion, not supported yet
+		return nil
 	}
-	if targetOpID == "" {
-		return fmt.Errorf("finding or creating issue comment")
+
+	cleanText, err := text.Cleanup(string(*edit.Diff))
+	if err != nil {
+		return err
 	}
-	// process remaining comment edits, if they exist
-	for {
-		edit, hasEdit := getNextUserContentEdit(commentEditEvents)
-		if !hasEdit {
-			break
-		}
-		// ensure editor identity
-		_, err := gi.ensurePerson(ctx, repo, edit.Editor)
-		if err != nil {
-			return err
-		}
 
-		err = gi.ensureCommentEdit(ctx, repo, b, targetOpID, &edit.userContentEdit)
-		if err != nil {
-			return err
-		}
+	// comment edition
+	op, err := b.EditCommentRaw(
+		editor,
+		edit.CreatedAt.Unix(),
+		target,
+		cleanText,
+		map[string]string{
+			metaKeyGithubId: parseId(edit.Id),
+		},
+	)
+
+	if err != nil {
+		return err
 	}
+
+	gi.out <- core.NewImportCommentEdition(op.Id())
 	return nil
 }
 
-func (gi *githubImporter) ensureCommentEdit(ctx context.Context, repo *cache.RepoCache, b *cache.BugCache, target entity.Id, edit *userContentEdit) error {
-	_, err := b.ResolveOperationWithMetadata(metaKeyGithubId, parseId(edit.Id))
+func (gi *githubImporter) ensureComment(ctx context.Context, repo *cache.RepoCache, b *cache.BugCache, comment *issueComment, firstEdit *userContentEdit) error {
+	author, err := gi.ensurePerson(ctx, repo, comment.Author)
+	if err != nil {
+		return err
+	}
+
+	_, err = b.ResolveOperationWithMetadata(metaKeyGithubId, parseId(comment.Id))
 	if err == nil {
 		return nil
 	}
@@ -467,41 +442,35 @@ func (gi *githubImporter) ensureCommentEdit(ctx context.Context, repo *cache.Rep
 		return err
 	}
 
-	editor, err := gi.ensurePerson(ctx, repo, edit.Editor)
+	var textInput string
+	if firstEdit != nil {
+		// use the first comment edit: it represents the comment creation itself
+		textInput = string(*firstEdit.Diff)
+	} else {
+		// if there are not comment edits, then the comment struct holds the comment creation
+		textInput = string(comment.Body)
+	}
+	cleanText, err := text.Cleanup(textInput)
 	if err != nil {
 		return err
 	}
 
-	switch {
-	case edit.DeletedAt != nil:
-		// comment deletion, not supported yet
-		return nil
-
-	case edit.DeletedAt == nil:
-
-		cleanText, err := text.Cleanup(string(*edit.Diff))
-		if err != nil {
-			return err
-		}
-
-		// comment edition
-		op, err := b.EditCommentRaw(
-			editor,
-			edit.CreatedAt.Unix(),
-			target,
-			cleanText,
-			map[string]string{
-				metaKeyGithubId: parseId(edit.Id),
-			},
-		)
-
-		if err != nil {
-			return err
-		}
-
-		gi.out <- core.NewImportCommentEdition(op.Id())
-		return nil
+	// add comment operation
+	op, err := b.AddCommentRaw(
+		author,
+		comment.CreatedAt.Unix(),
+		cleanText,
+		nil,
+		map[string]string{
+			metaKeyGithubId:  parseId(comment.Id),
+			metaKeyGithubUrl: comment.Url.String(),
+		},
+	)
+	if err != nil {
+		return err
 	}
+
+	gi.out <- core.NewImportComment(op.Id())
 	return nil
 }