package indexer

import (
	"bytes"
	"os/exec"
	"strings"

	"github.com/odvcencio/gotreesitter/grammars"
)

// WalkFiles returns all git-tracked files that tree-sitter can parse.
// It uses `git ls-files` to respect .gitignore rules correctly.
func WalkFiles(root string) ([]string, error) {
	cmd := exec.Command("git", "ls-files", "--cached", "--others", "--exclude-standard")
	cmd.Dir = root
	out, err := cmd.Output()
	if err != nil {
		return nil, err
	}

	var files []string
	for _, line := range bytes.Split(out, []byte("\n")) {
		relPath := strings.TrimSpace(string(line))
		if relPath == "" {
			continue
		}

		// Check if tree-sitter can handle this file
		// DetectLanguage works on filename, not full path
		parts := strings.Split(relPath, "/")
		filename := parts[len(parts)-1]
		if entry := grammars.DetectLanguage(filename); entry != nil {
			files = append(files, relPath)
		}
	}

	return files, nil
}