package core

import (
	"os"
	"path/filepath"
	"strings"
)

// CollectImageFiles walks root and returns all supported image files,
// optionally filtered by a glob pattern applied to the bare filename.
func CollectImageFiles(root, glob string) (*ImageSummary, error) {
	validExts := map[string]bool{
		".jpg":  true,
		".jpeg": true,
		".png":  true,
		".webp": true,
		".tif":  true,
		".tiff": true,
		".bmp":  true,
	}

	readOnlyExts := map[string]bool{
		".webp": true,
		".bmp":  true,
	}

	summary := &ImageSummary{
		ByExt: make(map[string]int),
	}

	seen := map[string]bool{}

	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() {
			return nil
		}

		ext := strings.ToLower(filepath.Ext(path))
		if !validExts[ext] {
			return nil
		}

		if glob != "" {
			matched, merr := filepath.Match(glob, filepath.Base(path))
			if merr != nil || !matched {
				return nil
			}
		}

		summary.Files = append(summary.Files, path)
		summary.ByExt[ext]++

		if readOnlyExts[ext] && !seen[ext] {
			summary.ReadOnlyExts = append(summary.ReadOnlyExts, ext)
			seen[ext] = true
		}

		return nil
	})

	return summary, err
}