import { app } from 'electron'
import { existsSync, readFileSync, writeFileSync, mkdirSync } from 'fs'
import { join, sep } from 'path'
import { v4 as uuidv4 } from 'uuid'

export interface CustomGame {
  id: string
  name: string
  exe: string
  args: string[]
  image: string
  category: string
  source: 'custom'
}

export interface AppEntry {
  id: string
  name: string
  exe: string
  args: string[]
  image: string
  category: string
  source: 'app'
}

function getUserDataPath(filename: string): string {
  const dir = app.getPath('userData')
  if (!existsSync(dir)) mkdirSync(dir, { recursive: true })
  return join(dir, filename)
}

function readJsonList<T>(filename: string): T[] {
  const path = getUserDataPath(filename)
  if (!existsSync(path)) return []
  try {
    const data = JSON.parse(readFileSync(path, 'utf-8'))
    return Array.isArray(data?.items) ? data.items : []
  } catch {
    return []
  }
}

function writeJsonList<T>(filename: string, items: T[]): void {
  writeFileSync(getUserDataPath(filename), JSON.stringify({ items }, null, 2), 'utf-8')
}

// ── Custom games ─────────────────────────────────────────────────────────

export function readCustomGames(): CustomGame[] {
  // Support both old format (games.json with { games: [] }) and new format
  const path = getUserDataPath('games.json')
  if (!existsSync(path)) return []
  try {
    const data = JSON.parse(readFileSync(path, 'utf-8'))
    if (Array.isArray(data?.games)) return data.games   // legacy
    if (Array.isArray(data?.items)) return data.items   // new
    return []
  } catch {
    return []
  }
}

export function writeCustomGames(games: CustomGame[]): void {
  writeFileSync(getUserDataPath('games.json'), JSON.stringify({ items: games }, null, 2), 'utf-8')
}

export function addCustomGame(data: Omit<CustomGame, 'id' | 'source'>): CustomGame {
  const games = readCustomGames()
  const newGame: CustomGame = { ...data, id: uuidv4(), source: 'custom' }
  writeCustomGames([...games, newGame])
  return newGame
}

export function removeCustomGame(id: string): void {
  writeCustomGames(readCustomGames().filter((g) => g.id !== id))
}

export function updateCustomGame(updated: CustomGame): void {
  writeCustomGames(readCustomGames().map((g) => (g.id === updated.id ? { ...g, ...updated } : g)))
}

// ── App entries ──────────────────────────────────────────────────────────

export function readApps(): AppEntry[] {
  return readJsonList<AppEntry>('apps.json')
}

export function writeApps(apps: AppEntry[]): void {
  writeJsonList('apps.json', apps)
}

export function addApp(data: Omit<AppEntry, 'id' | 'source'>): AppEntry {
  const apps = readApps()
  const newApp: AppEntry = { ...data, id: uuidv4(), source: 'app' }
  writeApps([...apps, newApp])
  return newApp
}

export function removeApp(id: string): void {
  writeApps(readApps().filter((a) => a.id !== id))
}

export function updateApp(updated: AppEntry): void {
  writeApps(readApps().map((a) => (a.id === updated.id ? { ...a, ...updated } : a)))
}