feat: add PR comments sliding right panel

internal/app/app.go

@@ -68,6 +68,7 @@ type App struct {
 	AllDiagnostics     map[string][]ui.Diagnostic
 	Keybindings        []config.KeyBinding
 	LspNotified        map[string]bool
+	CommentPanel       *ui.CommentPanelWidget
 	Reg                *command.Registry
 	Running            *bool
 	quitPending        bool

internal/app/commands_git.go

@@ -341,4 +341,9 @@ func registerPRCommands(app *App) {
 		Keywords: []string{"git", "pull request", "github"},
 		Handler:  func() { app.Changes.RemovePRGroups() },
 	})
+	reg.Register(command.Command{
+		ID: "pr.showComments", Title: "Git: Show PR Comments",
+		Keywords: []string{"git", "pull request", "github", "comments", "review"},
+		Handler:  app.ShowPRCommentsDialog,
+	})
 }

internal/app/eventloop.go

@@ -275,6 +275,40 @@ func RunEventLoop(
 						dv.FinishLoading()
 					}
 				}
+			case *PRCommentsResult:
+				if v.Err != nil {
+					app.StatusError("Failed to fetch PR comments: " + v.Err.Error())
+					if app.CommentPanel != nil {
+						app.CommentPanel.Loading = false
+					}
+				} else {
+					if app.CommentPanel != nil {
+						var items []ui.CommentItem
+						for _, c := range v.Comments {
+							items = append(items, ui.CommentItem{
+								ID:        c.ID,
+								Author:    c.User,
+								Timestamp: c.CreatedAt,
+								Body:      c.Body,
+								FilePath:  c.Path,
+								Line:      c.Line,
+								IsInline:  c.IsInline,
+								InReplyTo: c.InReplyTo,
+							})
+						}
+						app.CommentPanel.SetComments(items)
+						count := len(items)
+						app.StatusNotify(fmt.Sprintf("Loaded %d comment(s)", count))
+					}
+				}
+			case *PRCommentSubmitResult:
+				if v.Err != nil {
+					app.StatusError("Failed to submit comment: " + v.Err.Error())
+				} else {
+					app.StatusNotify("Comment submitted")
+					// Refresh comments
+					app.FetchPRComments(v.Owner, v.Repo, v.Number, v.Title)
+				}
 			case *PrFetchResult:
 				app.Changes.Loading = false
 				if v.Err != nil {

internal/app/pr.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/eugenioenko/ttt/internal/github"
+	"github.com/eugenioenko/ttt/internal/ui"
 
 	"github.com/gdamore/tcell/v2"
 )
@@ -22,6 +23,25 @@ type DiffContentResult struct {
 	Err      error
 }
 
+// PRCommentsResult carries async comment fetch results back to the event loop.
+type PRCommentsResult struct {
+	Owner    string
+	Repo     string
+	Number   int
+	Title    string
+	Comments []github.PRComment
+	Err      error
+}
+
+// PRCommentSubmitResult carries async comment submission results.
+type PRCommentSubmitResult struct {
+	Owner  string
+	Repo   string
+	Number int
+	Title  string
+	Err    error
+}
+
 func (a *App) FetchAndOpenPR(url string) {
 	owner, repo, number, err := github.ParsePRURL(url)
 	if err != nil {
@@ -49,3 +69,127 @@ func (a *App) FetchAndOpenPR(url string) {
 		a.Screen.PostEvent(tcell.NewEventInterrupt(&PrFetchResult{URL: url, Info: info, Diffs: diffs}))
 	}()
 }
+
+// FetchPRComments fetches PR comments asynchronously and shows them in the panel.
+func (a *App) FetchPRComments(owner, repo string, number int, title string) {
+	// If a panel is already open, reuse it (just refresh comments)
+	if a.CommentPanel != nil {
+		a.CommentPanel.Loading = true
+	} else {
+		// Create and show the panel immediately with loading state
+		panel := ui.NewCommentPanelWidget(fmt.Sprintf("PR #%d: %s", number, title))
+		panel.Borders = a.Borders
+		panel.Loading = true
+		panel.OnClose = func() {
+			a.DismissCommentPanel()
+		}
+		panel.OnOpenFile = func(path string, line int) {
+			a.EditorGroup.OpenFile(path)
+			if line > 0 {
+				a.EditorGroup.GoToLine(line)
+			}
+			a.Root.SetFocus(a.EditorGroup)
+		}
+		panel.OnSubmit = func(body string) {
+			a.submitPRComment(owner, repo, number, title, body)
+		}
+		a.CommentPanel = panel
+		a.Root.PushOverlay(ui.Overlay{Widget: panel, Modal: false})
+		a.Root.SetFocus(panel)
+	}
+
+	// Fetch comments in background
+	go func() {
+		comments, err := github.FetchPRComments(owner, repo, number)
+		a.Screen.PostEvent(tcell.NewEventInterrupt(&PRCommentsResult{
+			Owner:    owner,
+			Repo:     repo,
+			Number:   number,
+			Title:    title,
+			Comments: comments,
+			Err:      err,
+		}))
+	}()
+}
+
+// submitPRComment sends a comment to a PR and refreshes the thread.
+func (a *App) submitPRComment(owner, repo string, number int, title, body string) {
+	a.StatusNotify("Submitting comment...")
+	go func() {
+		err := github.AddPRComment(owner, repo, number, body)
+		a.Screen.PostEvent(tcell.NewEventInterrupt(&PRCommentSubmitResult{
+			Owner:  owner,
+			Repo:   repo,
+			Number: number,
+			Title:  title,
+			Err:    err,
+		}))
+	}()
+}
+
+// DismissCommentPanel removes the comment panel overlay.
+func (a *App) DismissCommentPanel() {
+	if a.CommentPanel != nil {
+		a.Root.PopOverlay()
+		a.CommentPanel = nil
+		a.FocusEditor()
+	}
+}
+
+// ShowPRCommentsForGroup opens the comment panel for a PR group.
+func (a *App) ShowPRCommentsForGroup() {
+	// Find the first PR group in changes
+	for _, g := range a.Changes.Groups {
+		if g.IsPR {
+			owner := g.PROwner
+			repo := g.PRRepo
+			// Parse number from group name
+			var number int
+			fmt.Sscanf(g.Name, "PR #%d:", &number)
+			if number == 0 {
+				continue
+			}
+			title := g.Name
+			a.FetchPRComments(owner, repo, number, title)
+			return
+		}
+	}
+	a.StatusWarn("No PR open. Use 'Git: Review PR' first.")
+}
+
+// ShowPRCommentsDialog prompts for a PR URL and opens comments.
+func (a *App) ShowPRCommentsDialog() {
+	if a.Root.HasOverlay() {
+		return
+	}
+	if !github.IsGHInstalled() {
+		a.StatusError("GitHub CLI (gh) is required. Install from https://cli.github.com/")
+		return
+	}
+	// If there's already a PR open, show its comments directly
+	for _, g := range a.Changes.Groups {
+		if g.IsPR {
+			a.ShowPRCommentsForGroup()
+			return
+		}
+	}
+	// Otherwise prompt for URL
+	dialog := ui.NewInputDialogWidget("PR Comments", "https://github.com/owner/repo/pull/123", "")
+	dialog.ConfirmLabel = "Show Comments"
+	dialog.Borders = a.Borders
+	dialog.OnSubmit = func(url string) {
+		a.DismissDialog()
+		if url != "" {
+			owner, repo, number, err := github.ParsePRURL(url)
+			if err != nil {
+				a.StatusError("Invalid PR URL: " + err.Error())
+				return
+			}
+			a.FetchPRComments(owner, repo, number, fmt.Sprintf("PR #%d", number))
+		}
+	}
+	dialog.OnDismiss = func() {
+		a.DismissDialog()
+	}
+	a.ShowDialog(dialog)
+}

internal/github/github.go

@@ -133,6 +133,117 @@ func FetchFileContent(owner, repo, path, ref string) (string, error) {
 	return string(out), nil
 }
 
+// PRComment represents a single comment on a pull request.
+type PRComment struct {
+	ID        int
+	Body      string
+	User      string
+	CreatedAt string
+	Path      string // non-empty for inline/review comments
+	Line      int    // line number for inline comments
+	IsInline  bool
+	InReplyTo int // ID of parent comment for threaded replies
+}
+
+// FetchPRComments fetches both review (inline) comments and general issue
+// comments for a pull request and returns them merged chronologically.
+func FetchPRComments(owner, repo string, number int) ([]PRComment, error) {
+	var comments []PRComment
+
+	// Fetch inline/review comments
+	endpoint := fmt.Sprintf("repos/%s/%s/pulls/%d/comments", owner, repo, number)
+	cmd := exec.Command("gh", "api", endpoint, "--paginate",
+		"--jq", `[.[] | {id: .id, body: .body, user: .user.login, created_at: .created_at, path: .path, line: (.line // .original_line // 0), in_reply_to_id: (.in_reply_to_id // 0)}]`)
+	out, err := cmd.Output()
+	if err == nil && len(out) > 0 {
+		var items []struct {
+			ID          int    `json:"id"`
+			Body        string `json:"body"`
+			User        string `json:"user"`
+			CreatedAt   string `json:"created_at"`
+			Path        string `json:"path"`
+			Line        int    `json:"line"`
+			InReplyToID int    `json:"in_reply_to_id"`
+		}
+		if err := json.Unmarshal(out, &items); err == nil {
+			for _, item := range items {
+				comments = append(comments, PRComment{
+					ID:        item.ID,
+					Body:      item.Body,
+					User:      item.User,
+					CreatedAt: item.CreatedAt,
+					Path:      item.Path,
+					Line:      item.Line,
+					IsInline:  true,
+					InReplyTo: item.InReplyToID,
+				})
+			}
+		}
+	}
+
+	// Fetch general issue comments
+	endpoint = fmt.Sprintf("repos/%s/%s/issues/%d/comments", owner, repo, number)
+	cmd = exec.Command("gh", "api", endpoint, "--paginate",
+		"--jq", `[.[] | {id: .id, body: .body, user: .user.login, created_at: .created_at}]`)
+	out, err = cmd.Output()
+	if err == nil && len(out) > 0 {
+		var items []struct {
+			ID        int    `json:"id"`
+			Body      string `json:"body"`
+			User      string `json:"user"`
+			CreatedAt string `json:"created_at"`
+		}
+		if err := json.Unmarshal(out, &items); err == nil {
+			for _, item := range items {
+				comments = append(comments, PRComment{
+					ID:        item.ID,
+					Body:      item.Body,
+					User:      item.User,
+					CreatedAt: item.CreatedAt,
+					IsInline:  false,
+				})
+			}
+		}
+	}
+
+	// Sort by creation time
+	sortCommentsByTime(comments)
+	return comments, nil
+}
+
+func sortCommentsByTime(comments []PRComment) {
+	for i := 1; i < len(comments); i++ {
+		for j := i; j > 0 && comments[j].CreatedAt < comments[j-1].CreatedAt; j-- {
+			comments[j], comments[j-1] = comments[j-1], comments[j]
+		}
+	}
+}
+
+// AddPRComment adds a general comment to a pull request.
+func AddPRComment(owner, repo string, number int, body string) error {
+	endpoint := fmt.Sprintf("repos/%s/%s/issues/%d/comments", owner, repo, number)
+	cmd := exec.Command("gh", "api", endpoint, "-X", "POST", "-f", "body="+body)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("add comment failed: %s", string(out))
+	}
+	return nil
+}
+
+// AddPRReviewComment adds an inline review comment to a pull request.
+func AddPRReviewComment(owner, repo string, number int, body, path string, line int, commitSHA string) error {
+	endpoint := fmt.Sprintf("repos/%s/%s/pulls/%d/comments", owner, repo, number)
+	cmd := exec.Command("gh", "api", endpoint, "-X", "POST",
+		"-f", "body="+body,
+		"-f", "path="+path,
+		"-F", fmt.Sprintf("line=%d", line),
+		"-f", "commit_id="+commitSHA,
+	)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("add review comment failed: %s", string(out))
+	}
+	return nil
+}
+
 func SplitMultiFileDiff(unified string) map[string]string {
 	result := make(map[string]string)
 	lines := strings.Split(unified, "\n")