package main

import (
	"fmt"
	"html/template"
	"os"
	"path/filepath"
	"sort"
)

type IndexData struct {
	Dir   string
	Files []string
}

func generateIndex(dir string) error {
	entries, err := os.ReadDir(dir)
	if err != nil {
		return fmt.Errorf("failed to read directory: %w", err)
	}

	var files []string
	for _, entry := range entries {
		name := entry.Name()
		// Skip the index.html itself and hidden files
		if name != "index.html" && !filepath.HasPrefix(name, ".") {
			files = append(files, name)
		}
	}
	sort.Strings(files)

	templatePath := "build/index.html.tmpl"
	tmpl, err := template.ParseFiles(templatePath)
	if err != nil {
		return fmt.Errorf("failed to parse template: %w", err)
	}

	indexPath := filepath.Join(dir, "index.html")
	f, err := os.Create(indexPath)
	if err != nil {
		return fmt.Errorf("failed to create index.html: %w", err)
	}
	defer f.Close()

	data := IndexData{
		Dir:   filepath.Base(dir),
		Files: files,
	}

	if err := tmpl.Execute(f, data); err != nil {
		return fmt.Errorf("failed to execute template: %w", err)
	}

	fmt.Printf("Generated index.html in %s\n", dir)
	return nil
}

func main() {
	if len(os.Args) < 2 {
		fmt.Println("Usage: generate-index <directory> [<directory>...]")
		os.Exit(1)
	}

	for _, dir := range os.Args[1:] {
		if err := generateIndex(dir); err != nil {
			fmt.Fprintf(os.Stderr, "Error processing %s: %v\n", dir, err)
			os.Exit(1)
		}
	}
}