1 files changed, 102 insertions, 0 deletions
diff --git a/internal/image/download_policy.go b/internal/image/download_policy.go
new file mode 100644
index 0000000..b62e011
--- /dev/null
+++ b/internal/image/download_policy.go
@@ -0,0 +1,102 @@
+package image
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+)
+
+type downloadPathPolicy struct {
+	options *DownloadOptions
+}
+
+func newDownloadPathPolicy(options *DownloadOptions) downloadPathPolicy {
+	return downloadPathPolicy{options: options}
+}
+
+func (p downloadPathPolicy) generateFileName(word string, result *SearchResult, index int) string {
+	filename := ""
+	if p.options != nil {
+		filename = p.options.FileNamePattern
+	}
+	if filename == "" {
+		filename = "{word}_{source}"
+	}
+
+	filename = strings.ReplaceAll(filename, "{word}", sanitizeFileName(word))
+	if result != nil {
+		filename = strings.ReplaceAll(filename, "{source}", sanitizeFileName(result.Source))
+		filename = strings.ReplaceAll(filename, "{id}", sanitizeFileName(result.ID))
+	}
+	filename = strings.ReplaceAll(filename, "{index}", fmt.Sprintf("%d", index))
+
+	ext := ""
+	if result != nil {
+		ext = filepath.Ext(result.URL)
+		if strings.HasPrefix(result.URL, geminiDataPrefix) {
+			ext = ".png"
+		} else if ext == "" || len(ext) > 5 {
+			ext = ".jpg"
+		}
+	}
+
+	if filepath.Ext(filename) == "" {
+		filename += ext
+	}
+
+	return filename
+}
+
+func (p downloadPathPolicy) resolveOutputPath(name string) (string, error) {
+	baseDir := "./images"
+	if p.options != nil && p.options.OutputDir != "" {
+		baseDir = p.options.OutputDir
+	}
+
+	if strings.TrimSpace(baseDir) == "" {
+		baseDir = "."
+	}
+
+	cleanBase, err := filepath.Abs(baseDir)
+	if err != nil {
+		return "", fmt.Errorf("resolve base dir: %w", err)
+	}
+
+	fullPath, err := filepath.Abs(filepath.Join(cleanBase, name))
+	if err != nil {
+		return "", fmt.Errorf("resolve output path: %w", err)
+	}
+
+	rel, err := filepath.Rel(cleanBase, fullPath)
+	if err != nil {
+		return "", fmt.Errorf("relativize output path: %w", err)
+	}
+	if rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) {
+		return "", fmt.Errorf("path escapes base dir")
+	}
+
+	return fullPath, nil
+}
+
+func sanitizeFileName(name string) string {
+	replacer := strings.NewReplacer(
+		"/", "_",
+		"\\", "_",
+		":", "_",
+		"*", "_",
+		"?", "_",
+		"\"", "_",
+		"<", "_",
+		">", "_",
+		"|", "_",
+		" ", "_",
+		".", "_",
+	)
+
+	sanitized := replacer.Replace(name)
+	if len(sanitized) > 50 {
+		sanitized = sanitized[:50]
+	}
+
+	return sanitized
+}