Add extension normalization command

tests/contract/extension_command_test.go

@@ -0,0 +1,137 @@
+package contract
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/rogeecn/renamer/internal/extension"
+	"github.com/rogeecn/renamer/internal/listing"
+)
+
+func TestExtensionPreviewAndApply(t *testing.T) {
+	t.Parallel()
+
+	tmp := t.TempDir()
+	writeTestFile(t, filepath.Join(tmp, "photo.jpeg"))
+	writeTestFile(t, filepath.Join(tmp, "banner.JPG"))
+	writeTestFile(t, filepath.Join(tmp, "logo.jpg"))
+	writeTestFile(t, filepath.Join(tmp, "notes.txt"))
+
+	scope := &listing.ListingRequest{
+		WorkingDir:         tmp,
+		IncludeDirectories: false,
+		Recursive:          false,
+		IncludeHidden:      false,
+		Extensions:         nil,
+		Format:             listing.FormatTable,
+	}
+	if err := scope.Validate(); err != nil {
+		t.Fatalf("validate scope: %v", err)
+	}
+
+	req := extension.NewRequest(scope)
+	req.SetExecutionMode(true, false)
+
+	sources := []string{".jpeg", ".JPG", ".jpg"}
+	canonical, display, duplicates := extension.NormalizeSourceExtensions(sources)
+	target := extension.NormalizeTargetExtension(".jpg")
+	targetCanonical := extension.CanonicalExtension(target)
+
+	filteredCanonical := make([]string, 0, len(canonical))
+	filteredDisplay := make([]string, 0, len(display))
+	noOps := make([]string, 0)
+	for i, canon := range canonical {
+		if canon == targetCanonical {
+			noOps = append(noOps, display[i])
+			continue
+		}
+		filteredCanonical = append(filteredCanonical, canon)
+		filteredDisplay = append(filteredDisplay, display[i])
+	}
+
+	if len(filteredCanonical) == 0 {
+		t.Fatalf("expected canonical sources after filtering")
+	}
+
+	req.SetExtensions(filteredCanonical, filteredDisplay, target)
+	req.SetWarnings(duplicates, noOps)
+
+	var buf bytes.Buffer
+	summary, planned, err := extension.Preview(context.Background(), req, &buf)
+	if err != nil {
+		t.Fatalf("Preview error: %v", err)
+	}
+
+	if summary.TotalCandidates != 3 {
+		t.Fatalf("expected 3 candidates, got %d", summary.TotalCandidates)
+	}
+	if summary.TotalChanged != 2 {
+		t.Fatalf("expected 2 changed entries, got %d", summary.TotalChanged)
+	}
+	if summary.NoChange != 1 {
+		t.Fatalf("expected 1 no-change entry, got %d", summary.NoChange)
+	}
+	if len(planned) != 2 {
+		t.Fatalf("expected 2 planned renames, got %d", len(planned))
+	}
+
+	output := buf.String()
+	if !strings.Contains(output, "photo.jpeg -> photo.jpg") {
+		t.Fatalf("expected preview to include photo rename, output: %s", output)
+	}
+	if !strings.Contains(output, "banner.JPG -> banner.jpg") {
+		t.Fatalf("expected preview to include banner rename, output: %s", output)
+	}
+	if !strings.Contains(output, "logo.jpg (no change)") {
+		t.Fatalf("expected preview to mark logo as no change, output: %s", output)
+	}
+	if !strings.Contains(output, "Summary: 3 candidates, 2 will change, 1 already target extension") {
+		t.Fatalf("expected summary line, output: %s", output)
+	}
+
+	if len(summary.Warnings) == 0 {
+		t.Fatalf("expected warnings for duplicates/no-ops")
+	}
+
+	req.SetExecutionMode(false, true)
+	entry, err := extension.Apply(context.Background(), req, planned, summary)
+	if err != nil {
+		t.Fatalf("Apply error: %v", err)
+	}
+	if len(entry.Operations) != len(planned) {
+		t.Fatalf("expected %d ledger operations, got %d", len(planned), len(entry.Operations))
+	}
+
+	if _, err := os.Stat(filepath.Join(tmp, "photo.jpg")); err != nil {
+		t.Fatalf("expected photo.jpg after apply: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(tmp, "banner.jpg")); err != nil {
+		t.Fatalf("expected banner.jpg after apply: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(tmp, "logo.jpg")); err != nil {
+		t.Fatalf("expected logo.jpg to remain: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(tmp, "photo.jpeg")); !errors.Is(err, os.ErrNotExist) {
+		t.Fatalf("expected photo.jpeg to be renamed, err=%v", err)
+	}
+
+	ledger := filepath.Join(tmp, ".renamer")
+	if _, err := os.Stat(ledger); err != nil {
+		t.Fatalf("expected ledger file to be created: %v", err)
+	}
+}
+
+func writeTestFile(t *testing.T, path string) {
+	t.Helper()
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		t.Fatalf("mkdir %s: %v", path, err)
+	}
+	if err := os.WriteFile(path, []byte("test"), 0o644); err != nil {
+		t.Fatalf("write file %s: %v", path, err)
+	}
+}