package main

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

var iconsDir string

func initStorage(dir string) error {
	iconsDir = dir
	return os.MkdirAll(dir, 0755)
}

// hashToPath converts a SHA-256 hex hash to a sharded file path.
// e.g., "abcdef1234..." → "icons/ab/cd/ef/abcdef1234..."
func hashToPath(hash string) string {
	if len(hash) < 6 {
		return filepath.Join(iconsDir, hash)
	}
	return filepath.Join(iconsDir, hash[:2], hash[2:4], hash[4:6], hash)
}

// iconExists checks if an icon is already stored on disk (for dedup).
func iconExists(hash string) bool {
	_, err := os.Stat(hashToPath(hash))
	return err == nil
}

// iconWrite saves icon data to disk in the sharded directory structure.
func iconWrite(hash string, data []byte) error {
	path := hashToPath(hash)
	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
		return fmt.Errorf("mkdir: %w", err)
	}
	return os.WriteFile(path, data, 0644)
}