Make code suggestions work aswell

README.md

@@ -3,7 +3,8 @@
 A read-only terminal UI for people receiving GitHub pull-request reviews. It
 shows open PRs, review threads with highlighted diff hunks and comment authors,
 reviewer/assignee state, and the latest commit's check rollup. Resolved threads
-start folded. The current PR is refreshed in the background.
+start folded. GitHub suggestion blocks are shown as syntax-highlighted
+remove/add previews. The current PR is refreshed in the background.
 
 ## Install and run
 

suggestions.go

@@ -0,0 +1,225 @@
+package main
+
+import (
+	"strings"
+
+	"github.com/charmbracelet/x/ansi"
+)
+
+type parsedCommentBody struct {
+	Prose       string
+	Suggestions []string
+}
+
+type codeRange struct {
+	Start int
+	End   int
+}
+
+func parseCommentBody(body string) parsedCommentBody {
+	var (
+		result       parsedCommentBody
+		prose        []string
+		suggestion   []string
+		openingLine  string
+		inSuggestion bool
+	)
+	for _, line := range strings.Split(body, "\n") {
+		trimmed := strings.TrimSpace(line)
+		if !inSuggestion && isSuggestionFence(trimmed) {
+			inSuggestion = true
+			openingLine = line
+			suggestion = nil
+			continue
+		}
+		if inSuggestion && trimmed == "```" {
+			result.Suggestions = append(result.Suggestions, strings.Join(suggestion, "\n"))
+			inSuggestion = false
+			openingLine = ""
+			continue
+		}
+		if inSuggestion {
+			suggestion = append(suggestion, line)
+		} else {
+			prose = append(prose, line)
+		}
+	}
+	if inSuggestion {
+		prose = append(prose, openingLine)
+		prose = append(prose, suggestion...)
+	}
+	result.Prose = strings.TrimSpace(strings.Join(prose, "\n"))
+	return result
+}
+
+func isSuggestionFence(line string) bool {
+	if !strings.HasPrefix(line, "```suggestion") {
+		return false
+	}
+	suffix := strings.TrimPrefix(line, "```suggestion")
+	return suffix == "" || strings.HasPrefix(suffix, ":")
+}
+
+func reviewedSourceLines(thread ReviewThread, comment ReviewComment) []string {
+	start, end := commentReviewAnchor(thread, comment)
+	parsed := parseDiff(comment.DiffHunk, start, end, thread.DiffSide)
+	lines := make([]string, 0, end-start+1)
+	for _, line := range parsed {
+		if !line.selected {
+			continue
+		}
+		lines = append(lines, sourceFromDiffLine(line.raw))
+	}
+	return lines
+}
+
+func sourceFromDiffLine(raw string) string {
+	if strings.HasPrefix(raw, "+") || strings.HasPrefix(raw, "-") || strings.HasPrefix(raw, " ") {
+		raw = raw[1:]
+	}
+	return strings.ReplaceAll(raw, "\t", "    ")
+}
+
+func normalizeSuggestion(removed []string, replacement string) ([]string, []string) {
+	added := []string(nil)
+	if replacement != "" {
+		added = strings.Split(replacement, "\n")
+		for i := range added {
+			added[i] = strings.ReplaceAll(added[i], "\t", "    ")
+		}
+	}
+	padding := commonSourceIndent(removed, added)
+	return trimSourceIndent(removed, padding), trimSourceIndent(added, padding)
+}
+
+func commonSourceIndent(groups ...[]string) int {
+	padding := -1
+	for _, lines := range groups {
+		for _, line := range lines {
+			if strings.TrimSpace(line) == "" {
+				continue
+			}
+			indent := len(line) - len(strings.TrimLeft(line, " "))
+			if padding == -1 || indent < padding {
+				padding = indent
+			}
+		}
+	}
+	return max(0, padding)
+}
+
+func trimSourceIndent(lines []string, padding int) []string {
+	result := make([]string, len(lines))
+	for i, line := range lines {
+		result[i] = trimIndent(line, padding)
+	}
+	return result
+}
+
+func suggestionChangedRanges(removed, added []string) ([]codeRange, []codeRange) {
+	removedRanges := make([]codeRange, len(removed))
+	addedRanges := make([]codeRange, len(added))
+	matches := matchingLinePairs(removed, added)
+	matches = append(matches, [2]int{len(removed), len(added)})
+
+	oldStart, newStart := 0, 0
+	for _, match := range matches {
+		oldEnd, newEnd := match[0], match[1]
+		blockSize := max(oldEnd-oldStart, newEnd-newStart)
+		for offset := 0; offset < blockSize; offset++ {
+			oldIndex, newIndex := oldStart+offset, newStart+offset
+			switch {
+			case oldIndex < oldEnd && newIndex < newEnd:
+				removedRanges[oldIndex], addedRanges[newIndex] = changedRange(
+					removed[oldIndex], added[newIndex],
+				)
+			case oldIndex < oldEnd:
+				removedRanges[oldIndex] = fullCodeRange(removed[oldIndex])
+			case newIndex < newEnd:
+				addedRanges[newIndex] = fullCodeRange(added[newIndex])
+			}
+		}
+		if oldEnd < len(removed) && newEnd < len(added) {
+			oldStart, newStart = oldEnd+1, newEnd+1
+		} else {
+			oldStart, newStart = oldEnd, newEnd
+		}
+	}
+	return removedRanges, addedRanges
+}
+
+func matchingLinePairs(removed, added []string) [][2]int {
+	dp := make([][]int, len(removed)+1)
+	for i := range dp {
+		dp[i] = make([]int, len(added)+1)
+	}
+	for i := len(removed) - 1; i >= 0; i-- {
+		for j := len(added) - 1; j >= 0; j-- {
+			if removed[i] == added[j] {
+				dp[i][j] = dp[i+1][j+1] + 1
+			} else {
+				dp[i][j] = max(dp[i+1][j], dp[i][j+1])
+			}
+		}
+	}
+
+	var matches [][2]int
+	for i, j := 0, 0; i < len(removed) && j < len(added); {
+		switch {
+		case removed[i] == added[j]:
+			matches = append(matches, [2]int{i, j})
+			i++
+			j++
+		case dp[i+1][j] >= dp[i][j+1]:
+			i++
+		default:
+			j++
+		}
+	}
+	return matches
+}
+
+func changedRange(oldLine, newLine string) (codeRange, codeRange) {
+	oldRunes, newRunes := []rune(oldLine), []rune(newLine)
+	prefix := 0
+	for prefix < len(oldRunes) && prefix < len(newRunes) && oldRunes[prefix] == newRunes[prefix] {
+		prefix++
+	}
+	oldSuffix, newSuffix := len(oldRunes), len(newRunes)
+	for oldSuffix > prefix && newSuffix > prefix &&
+		oldRunes[oldSuffix-1] == newRunes[newSuffix-1] {
+		oldSuffix--
+		newSuffix--
+	}
+	return codeRange{
+			Start: ansi.StringWidth(string(oldRunes[:prefix])),
+			End:   ansi.StringWidth(string(oldRunes[:oldSuffix])),
+		}, codeRange{
+			Start: ansi.StringWidth(string(newRunes[:prefix])),
+			End:   ansi.StringWidth(string(newRunes[:newSuffix])),
+		}
+}
+
+func fullCodeRange(line string) codeRange {
+	return codeRange{End: ansi.StringWidth(line)}
+}
+
+func commentReviewAnchor(thread ReviewThread, comment ReviewComment) (int, int) {
+	end := comment.OriginalLine
+	start := comment.OriginalStartLine
+	if end == 0 {
+		end = comment.Line
+		start = comment.StartLine
+	}
+	if end > 0 {
+		if start == 0 {
+			start = end
+		}
+		return start, end
+	}
+	start = thread.StartLine
+	if start == 0 {
+		start = thread.Line
+	}
+	return start, thread.Line
+}

suggestions_test.go

@@ -0,0 +1,178 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/charmbracelet/x/ansi"
+)
+
+func TestParseCommentBodyExtractsSuggestionFences(t *testing.T) {
+	body := "Use the clearer name:\n\n```suggestion:-0+0\n    better_name = value\n```\n\nThis also matches the API."
+	got := parseCommentBody(body)
+	if len(got.Suggestions) != 1 || got.Suggestions[0] != "    better_name = value" {
+		t.Fatalf("suggestions = %#v", got.Suggestions)
+	}
+	if strings.Contains(got.Prose, "```") || !strings.Contains(got.Prose, "Use the clearer name") ||
+		!strings.Contains(got.Prose, "matches the API") {
+		t.Fatalf("prose = %q", got.Prose)
+	}
+}
+
+func TestReviewedSourceLinesUseHistoricalSelection(t *testing.T) {
+	comment := ReviewComment{
+		DiffHunk:          "@@ -38,5 +38,5 @@\n context\n old_name = value\n return old_name\n context\n context",
+		OriginalStartLine: 39,
+		OriginalLine:      40,
+	}
+	got := reviewedSourceLines(ReviewThread{DiffSide: "RIGHT"}, comment)
+	want := []string{"old_name = value", "return old_name"}
+	if strings.Join(got, "\n") != strings.Join(want, "\n") {
+		t.Fatalf("reviewed source = %#v, want %#v", got, want)
+	}
+}
+
+func TestNormalizeSuggestionPreservesRelativeIndent(t *testing.T) {
+	removed, added := normalizeSuggestion(
+		[]string{"        if old:", "            run_old()"},
+		"        if new:\n            run_new()",
+	)
+	if strings.Join(removed, "\n") != "if old:\n    run_old()" {
+		t.Fatalf("removed = %#v", removed)
+	}
+	if strings.Join(added, "\n") != "if new:\n    run_new()" {
+		t.Fatalf("added = %#v", added)
+	}
+}
+
+func TestDetailRendersSuggestionAsRemovalAndAddition(t *testing.T) {
+	m := NewApp(nil, "o", "r", false, 50, 10)
+	m.width = 100
+	m.details = PRDetails{Threads: []ReviewThread{{
+		Path:     "example.py",
+		Line:     10,
+		DiffSide: "RIGHT",
+		Comments: []ReviewComment{{
+			Author:            "reviewer",
+			Body:              "Use this instead:\n```suggestion\nnew_value = compute()\nreturn new_value\n```",
+			DiffHunk:          "@@ -10,2 +10,2 @@\nold_value = compute()\nreturn old_value",
+			OriginalLine:      11,
+			OriginalStartLine: 10,
+		}},
+	}}}
+
+	var (
+		removed, added int
+		rendered       strings.Builder
+	)
+	for _, line := range m.detailLines(60) {
+		rendered.WriteString(ansi.Strip(line.rail + line.fixed + line.text))
+		rendered.WriteByte('\n')
+		switch line.suggestionChange {
+		case '-':
+			removed++
+		case '+':
+			added++
+		}
+	}
+	if removed != 2 || added != 2 {
+		t.Fatalf("suggestion rows: removed=%d added=%d\n%s", removed, added, rendered.String())
+	}
+	if strings.Contains(rendered.String(), "```suggestion") ||
+		!strings.Contains(rendered.String(), "│ @reviewer") ||
+		!strings.Contains(rendered.String(), "│ suggested change") {
+		t.Fatalf("suggestion was not rendered structurally:\n%s", rendered.String())
+	}
+}
+
+func TestSuggestionBackgroundIsDirectionalWithoutTextUnderline(t *testing.T) {
+	removed := suggestionHighlight("  - ", "old", 12, '-')
+	added := suggestionHighlight("  + ", "new", 12, '+')
+	if !strings.Contains(removed, "\x1b[48;5;52m") ||
+		!strings.Contains(added, "\x1b[48;5;22m") {
+		t.Fatalf("suggestion decorations missing: removed=%q added=%q", removed, added)
+	}
+	if strings.Contains(removed, "\x1b[4m") || strings.Contains(added, "\x1b[4m") ||
+		strings.Contains(removed, "\x1b[4;") || strings.Contains(added, "\x1b[4;") ||
+		strings.Contains(removed, "\x1b[58;") || strings.Contains(added, "\x1b[58;") {
+		t.Fatal("suggestion rendering still enables terminal underlining")
+	}
+	if ansi.StringWidth(removed) != 12 || ansi.StringWidth(added) != 12 {
+		t.Fatal("suggestion backgrounds do not fill the row")
+	}
+	if !strings.Contains(removed, "\x1b[0m\x1b[48;5;52m     ") ||
+		!strings.Contains(added, "\x1b[0m\x1b[48;5;22m     ") {
+		t.Fatal("padded row remainder is still underlined")
+	}
+}
+
+func TestMultipleSuggestionsStayInsideCommentBlock(t *testing.T) {
+	m := NewApp(nil, "o", "r", false, 50, 10)
+	m.width = 100
+	m.details = PRDetails{Threads: []ReviewThread{{
+		Path: "main.go", Line: 1, DiffSide: "RIGHT",
+		Comments: []ReviewComment{{
+			Author: "alice", OriginalLine: 1,
+			DiffHunk: "@@ -1 +1 @@\nold",
+			Body:     "```suggestion\nfirst\n```\n```suggestion\nsecond\n```",
+		}},
+	}}}
+	var rendered strings.Builder
+	for _, line := range m.detailLines(60) {
+		rendered.WriteString(ansi.Strip(line.rail + line.fixed + line.text))
+		rendered.WriteByte('\n')
+	}
+	if !strings.Contains(rendered.String(), "│ @alice") ||
+		!strings.Contains(rendered.String(), "│ suggested change 1/2") ||
+		!strings.Contains(rendered.String(), "│ suggested change 2/2") {
+		t.Fatalf("suggestions escaped the comment block:\n%s", rendered.String())
+	}
+}
+
+func TestSuggestionGutterHasNoLeadingPadding(t *testing.T) {
+	lines := wrapSuggestionLine("main.go", "replacement()", '+', fullCodeRange("replacement()"), 30)
+	if len(lines) == 0 || ansi.Strip(lines[0].fixed) != "+ " {
+		t.Fatalf("suggestion gutter = %q, want compact marker", ansi.Strip(lines[0].fixed))
+	}
+}
+
+func TestSuggestionChangedRangesAlignInsertedLines(t *testing.T) {
+	removed := []string{"def setup():", "    if ready:", "        run()"}
+	added := []string{"def setup():", "    super().setup()", "    if ready:", "        run()"}
+	removedRanges, addedRanges := suggestionChangedRanges(removed, added)
+
+	for i, changed := range removedRanges {
+		if changed.End != changed.Start {
+			t.Fatalf("unchanged removed line %d marked as changed: %#v", i, changed)
+		}
+	}
+	for _, index := range []int{0, 2, 3} {
+		if changed := addedRanges[index]; changed.End != changed.Start {
+			t.Fatalf("unchanged added line %d marked as changed: %#v", index, changed)
+		}
+	}
+	if addedRanges[1] != fullCodeRange(added[1]) {
+		t.Fatalf("inserted line range = %#v", addedRanges[1])
+	}
+}
+
+func TestSuggestionChangedRangeIsCharacterPrecise(t *testing.T) {
+	removed, added := changedRange("value = old_name()", "value = new_name()")
+	if got := "value = old_name()"[removed.Start:removed.End]; got != "old" {
+		t.Fatalf("removed range selected %q", got)
+	}
+	if got := "value = new_name()"[added.Start:added.End]; got != "new" {
+		t.Fatalf("added range selected %q", got)
+	}
+}
+
+func TestChangedSnippetGetsDarkerBackground(t *testing.T) {
+	code := highlightedSource("go", "value := oldName()")
+	decorated := highlightCodeRange(code, codeRange{Start: 9, End: 16}, '-')
+	if !strings.Contains(decorated, "\x1b[48;2;55;0;0m") {
+		t.Fatalf("darker intra-line background missing: %q", decorated)
+	}
+	if ansi.Strip(decorated) != "value := oldName()" {
+		t.Fatalf("highlight altered source: %q", ansi.Strip(decorated))
+	}
+}

tui.go

@@ -437,7 +437,15 @@ func (m App) threadDetail(width, height int) string {
 	rendered := make([]string, 0, len(visible))
 	innerWidth := max(1, width-2)
 	for _, line := range visible {
-		renderedLine := ansi.Truncate(line.fixed+line.text, innerWidth, "…")
+		railWidth := ansi.StringWidth(line.rail)
+		contentWidth := max(1, innerWidth-railWidth)
+		var renderedLine string
+		if line.suggestionChange != 0 {
+			renderedLine = suggestionHighlight(line.fixed, line.text, contentWidth, line.suggestionChange)
+		} else {
+			renderedLine = ansi.Truncate(line.fixed+line.text, contentWidth, "…")
+		}
+		renderedLine = line.rail + renderedLine
 		if line.selected {
 			renderedLine = selectedBackground(renderedLine, innerWidth)
 		}
@@ -447,9 +455,11 @@ func (m App) threadDetail(width, height int) string {
 }
 
 type detailLine struct {
-	text     string
+	text             string
-	fixed    string
+	fixed            string
-	selected bool
+	rail             string
+	selected         bool
+	suggestionChange byte
 }
 
 func (m App) detailLines(width int) []detailLine {
@@ -481,9 +491,40 @@ func (m App) detailLines(width int) []detailLine {
 			}
 		}
 		for _, comment := range thread.Comments {
-			lines = append(lines, detailLine{}, detailLine{text: authorStyle(comment.Author).Render("@"+comment.Author) + " " + dimStyle.Render(comment.CreatedAt.Local().Format("2006-01-02 15:04"))})
+			content := parseCommentBody(comment.Body)
-			for _, commentLine := range strings.Split(wrap(comment.Body, max(10, width-4)), "\n") {
+			rail := lipgloss.NewStyle().Foreground(authorColor(comment.Author)).Render("│ ")
-				lines = append(lines, detailLine{text: commentLine})
+			lines = append(lines, detailLine{}, detailLine{
+				rail: rail,
+				text: authorStyle(comment.Author).Render("@"+comment.Author) + " " +
+					dimStyle.Render(comment.CreatedAt.Local().Format("2006-01-02 15:04")),
+			})
+			if content.Prose != "" {
+				for _, commentLine := range strings.Split(wrap(content.Prose, max(10, width-4)), "\n") {
+					lines = append(lines, detailLine{rail: rail, text: commentLine})
+				}
+			}
+			for suggestionIndex, suggestion := range content.Suggestions {
+				removed, added := normalizeSuggestion(reviewedSourceLines(thread, comment), suggestion)
+				removedRanges, addedRanges := suggestionChangedRanges(removed, added)
+				label := "suggested change"
+				if len(content.Suggestions) > 1 {
+					label = fmt.Sprintf("suggested change %d/%d", suggestionIndex+1, len(content.Suggestions))
+				}
+				lines = append(lines, detailLine{rail: rail}, detailLine{rail: rail, text: dimStyle.Render(label)})
+				for sourceIndex, source := range removed {
+					lines = append(lines, addCommentRail(
+						wrapSuggestionLine(
+							thread.Path, source, '-', removedRanges[sourceIndex], max(1, width-4),
+						), rail,
+					)...)
+				}
+				for sourceIndex, source := range added {
+					lines = append(lines, addCommentRail(
+						wrapSuggestionLine(
+							thread.Path, source, '+', addedRanges[sourceIndex], max(1, width-4),
+						), rail,
+					)...)
+				}
 			}
 		}
 		if thread.IsTruncated {
@@ -520,6 +561,53 @@ func wrapDiffLine(line highlightedDiffLine, width int) []detailLine {
 	return result
 }
 
+func wrapSuggestionLine(path, source string, change byte, changed codeRange, width int) []detailLine {
+	marker := badStyle.Render(string(change))
+	if change == '+' {
+		marker = okStyle.Render(string(change))
+	}
+	code := highlightedSource(lexerForPath(path), source)
+	code = highlightCodeRange(code, changed, change)
+	lines := wrapDiffLine(highlightedDiffLine{
+		gutter: marker + " ",
+		code:   code,
+	}, width)
+	for i := range lines {
+		lines[i].suggestionChange = change
+	}
+	return lines
+}
+
+func highlightCodeRange(code string, changed codeRange, change byte) string {
+	if changed.End <= changed.Start {
+		return code
+	}
+	totalWidth := ansi.StringWidth(code)
+	start := clamp(changed.Start, 0, totalWidth)
+	end := clamp(changed.End, start, totalWidth)
+	if end <= start {
+		return code
+	}
+
+	background := "\x1b[48;2;55;0;0m"
+	if change == '+' {
+		background = "\x1b[48;2;0;55;0m"
+	}
+	const reset = "\x1b[0m"
+	before := ansi.Cut(code, 0, start)
+	middle := ansi.Cut(code, start, end)
+	after := ansi.Cut(code, end, totalWidth)
+	middle = strings.ReplaceAll(middle, reset, reset+background)
+	return before + background + middle + reset + after
+}
+
+func addCommentRail(lines []detailLine, rail string) []detailLine {
+	for i := range lines {
+		lines[i].rail = rail
+	}
+	return lines
+}
+
 func wrapCodeWithIndent(code string, width int) []string {
 	if width <= 0 || ansi.StringWidth(code) <= width {
 		return []string{code}
@@ -580,25 +668,9 @@ func isCodeBreakpoint(r rune) bool {
 
 func reviewAnchor(thread ReviewThread) (int, int) {
 	if len(thread.Comments) > 0 {
-		comment := thread.Comments[0]
+		return commentReviewAnchor(thread, thread.Comments[0])
-		end := comment.OriginalLine
-		start := comment.OriginalStartLine
-		if end == 0 {
-			end = comment.Line
-			start = comment.StartLine
-		}
-		if end > 0 {
-			if start == 0 {
-				start = end
-			}
-			return start, end
-		}
 	}
-	start := thread.StartLine
+	return commentReviewAnchor(thread, ReviewComment{})
-	if start == 0 {
-		start = thread.Line
-	}
-	return start, thread.Line
 }
 
 func shortOID(oid string) string {
@@ -618,6 +690,25 @@ func selectedBackground(line string, width int) string {
 	return background + line + reset
 }
 
+func suggestionHighlight(gutter, code string, width int, change byte) string {
+	background := "\x1b[48;5;52m"
+	if change == '+' {
+		background = "\x1b[48;5;22m"
+	}
+	const reset = "\x1b[0m"
+	gutter = ansi.Truncate(gutter, width, "")
+	gutter = strings.ReplaceAll(gutter, reset, reset+background)
+	codeWidth := max(0, width-ansi.StringWidth(gutter))
+	code = ansi.Truncate(code, codeWidth, "")
+	code = strings.ReplaceAll(code, reset, reset+background)
+	content := background + gutter + code + reset
+	padding := max(0, width-ansi.StringWidth(gutter)-ansi.StringWidth(code))
+	if padding > 0 {
+		content += background + strings.Repeat(" ", padding) + reset
+	}
+	return content
+}
+
 var authorPalette = []lipgloss.Color{
 	"#61AFEF", "#C678DD", "#56B6C2", "#E5C07B",
 	"#E06C75", "#98C379", "#D19A66", "#7FC8FF",