feat(pierre): add diff chunking and configurable review settings

internal/pierre/judge.go

@@ -9,7 +9,8 @@ import (
 	"git.schreifuchs.ch/schreifuchs/pierre-bot/internal/chatter"
 )
 
-const defaultChunkSize = 60000
+// DefaultChunkSize is the fallback maximum size (in bytes) for a diff chunk when no explicit value is configured.
+const DefaultChunkSize = 60000
 
 type Comment struct {
 	File    string `json:"file"`
@@ -26,36 +27,41 @@ func (s *Service) judgePR(ctx context.Context, diff io.Reader) (comments []Comme
 	// Determine chunk size (use default if not set)
 	maxSize := s.maxChunkSize
 	if maxSize <= 0 {
-		maxSize = defaultChunkSize // default 60KB ~ 15k tokens
+		maxSize = DefaultChunkSize // default 60KB ~ 15k tokens
 	}
 
 	chunks := splitDiffIntoChunks(diffBytes, maxSize)
 	allComments := []Comment{}
 
-	// Build optional guidelines text
+	// Build optional guidelines text (added as a separate section with a clear delimiter)
 	guidelinesText := ""
 	if len(s.guidelines) > 0 {
-		guidelinesText = "Project guidelines:\n"
+		// Two newlines ensure the guidelines start on a fresh paragraph.
+		guidelinesText = "\n\nProject guidelines:\n"
 		for _, g := range s.guidelines {
 			guidelinesText += "- " + g + "\n"
 		}
 	}
 
+	// System prompt that instructs the LLM precisely.
 	baseSystem := strings.TrimSpace(`
-You are a very strict senior software architect.
-You review **only** newly added or modified lines in a unified diff, together with the immediate hunk context.
-You do **not** report issues that appear **solely** in deleted lines (“-") or that have already been fixed by the change.
-No comments are made on pure formatting/whitespace changes or reordering that does not alter the program’s behavior.`) + guidelinesText
+You are a strict senior software architect.
+Only comment on newly added or modified lines in the diff; ignore deletions, pure formatting, or re‑ordering that does not change behavior.
+For each issue output a JSON object with fields "file", "line", and "message" (message should be concise, ≤2 sentences, and actionable).
+If project guidelines are provided, treat them as hard rules that must be respected.`) + guidelinesText
 
 	for i, chunk := range chunks {
-		// Add a small header so the model knows this is a fragment
-		header := fmt.Sprintf("\n--- Chunk %d of %d ---\n", i+1, len(chunks))
-		userContent := fmt.Sprintf("Hello please review my PR. Write comments where improvements are necessary in new lines.%s\nHere is the git diff of it: %s", header, chunk)
+		// Include the chunk identifier in the system message only if there are multiple chunks.
+		systemContent := baseSystem
+		if len(chunks) > 1 {
+			systemContent = fmt.Sprintf("%s\nChunk %d of %d.", baseSystem, i+1, len(chunks))
+		}
+		userContent := chunk
 
 		var chunkComments []Comment
 		err = s.chat.GenerateStructured(ctx, []chatter.Message{{
 			Role:    chatter.RoleSystem,
-			Content: baseSystem,
+			Content: systemContent,
 		}, {
 			Role:    chatter.RoleUser,
 			Content: userContent,

internal/pierre/review.go

@@ -26,15 +26,18 @@ func (s *Service) MakeReview(ctx context.Context, organisation string, repo stri
 
 	for _, c := range comments {
 		c.Message = fmt.Sprintf("%s (Generated by: %s)", c.Message, model)
-		fmt.Printf("File: %s\nLine: %d\nMessage: %s\n%s\n",
-			c.File, c.Line, c.Message, "---")
 
 		if s.disableComments {
-			log.Printf("dry-run: not posting comment for %s:%d", c.File, c.Line)
-		} else if err := s.git.AddComment(ctx, organisation, repo, prID, c); err != nil {
-			log.Printf("Failed to add comment: %v", err)
+			// Dry‑run: just log what would have been posted.
+			log.Printf("dry‑run: %s:%d => %s", c.File, c.Line, c.Message)
+		} else {
+			// Normal mode: print to stdout and post the comment to the VCS.
+			fmt.Printf("File: %s\nLine: %d\nMessage: %s\n%s\n",
+				c.File, c.Line, c.Message, "---")
+			if err := s.git.AddComment(ctx, organisation, repo, prID, c); err != nil {
+				log.Printf("Failed to add comment: %v", err)
+			}
 		}
-
 	}
 
 	return nil