feat: show git diff in reverted messages

packages/tui/internal/components/diff/parse.go

@@ -0,0 +1,58 @@
+package diff
+
+import (
+	"bufio"
+	"fmt"
+	"strings"
+)
+
+type DiffStats struct {
+	Added    int
+	Removed  int
+	Modified int
+}
+
+func ParseStats(diff string) (map[string]DiffStats, error) {
+	stats := make(map[string]DiffStats)
+	var currentFile string
+	scanner := bufio.NewScanner(strings.NewReader(diff))
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "---") {
+			continue
+		} else if strings.HasPrefix(line, "+++") {
+			parts := strings.SplitN(line, " ", 2)
+			if len(parts) == 2 {
+				currentFile = strings.TrimPrefix(parts[1], "b/")
+			}
+			continue
+		}
+		if strings.HasPrefix(line, "@@") {
+			continue
+		}
+		if currentFile == "" {
+			continue
+		}
+
+		fileStats := stats[currentFile]
+		switch {
+		case strings.HasPrefix(line, "+"):
+			fileStats.Added++
+		case strings.HasPrefix(line, "-"):
+			fileStats.Removed++
+		}
+		stats[currentFile] = fileStats
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("error reading diff string: %w", err)
+	}
+
+	for file, fileStats := range stats {
+		fileStats.Modified = fileStats.Added + fileStats.Removed
+		stats[file] = fileStats
+	}
+
+	return stats, nil
+}