import { readFile, existsSync } from 'fs'
import { join } from 'path'
import { promisify } from 'util'

const readFileAsync = promisify(readFile)

// CDragon base URL for fallback
const CDRAGON_BASE = 'https://raw.communitydragon.org/'

// Cache directory - can be configured via environment variable
// Default to dev/cdragon for development
const getCacheDir = () => {
  if (process.env.CDRAGON_CACHE_DIR) {
    return process.env.CDRAGON_CACHE_DIR
  }
  // Default to dev/cdragon relative to project root
  return join(process.cwd(), '..', 'dev', 'data', 'cdragon')
}

/**
 * Get the current patch from the patch.txt file or fallback to 'latest'
 * Converts patch format for CDragon: "16.4.1" -> "16.4"
 */
async function getCurrentPatch(): Promise<string> {
  const cacheDir = getCacheDir()
  const patchFile = join(cacheDir, 'latest', 'patch.txt')

  if (existsSync(patchFile)) {
    const patch = await readFileAsync(patchFile, 'utf-8')
    const trimmedPatch = patch.trim()
    // Convert patch format for CDragon: "16.4.1" -> "16.4"
    return trimmedPatch.split('.').slice(0, 2).join('.')
  }

  // Fallback to 'latest' if no patch file exists
  return 'latest'
}

/**
 * Cached CDragon data types
 */
interface CDragonCacheOptions {
  patch?: string
}

/**
 * Fetch data from local cache with CDragon fallback
 */
async function fetchFromCache<T>(
  assetName: string,
  cdragonPath: string,
  options?: CDragonCacheOptions
): Promise<T> {
  const cacheDir = getCacheDir()
  const patch = options?.patch || (await getCurrentPatch())
  const cachePath = join(cacheDir, patch, assetName)

  // Try to read from cache first
  if (existsSync(cachePath)) {
    try {
      const data = await readFileAsync(cachePath, 'utf-8')
      return JSON.parse(data) as T
    } catch (error) {
      console.error(`Error reading cache file ${cachePath}:`, error)
    }
  }

  // Fallback to CDragon
  console.log(`Cache miss for ${assetName}, fetching from CDragon...`)
  const url = `${CDRAGON_BASE}${patch}/${cdragonPath}`
  const response = await fetch(url)

  if (!response.ok) {
    throw new Error(`Failed to fetch ${assetName} from CDragon: ${response.status}`)
  }

  return (await response.json()) as T
}

/**
 * Get items data from cache
 */
async function getItems(patch?: string): Promise<CDragonItem[]> {
  return fetchFromCache<CDragonItem[]>(
    'items.json',
    'plugins/rcp-be-lol-game-data/global/default/v1/items.json',
    { patch }
  )
}

/**
 * Get perks (runes) data from cache
 */
async function getPerks(patch?: string): Promise<CDragonPerk[]> {
  return fetchFromCache<CDragonPerk[]>(
    'perks.json',
    'plugins/rcp-be-lol-game-data/global/default/v1/perks.json',
    { patch }
  )
}

/**
 * Get perk styles data from cache
 */
async function getPerkStyles(patch?: string): Promise<CDragonPerkStyles> {
  return fetchFromCache<CDragonPerkStyles>(
    'perkstyles.json',
    'plugins/rcp-be-lol-game-data/global/default/v1/perkstyles.json',
    { patch }
  )
}

/**
 * Get summoner spells data from cache
 */
async function getSummonerSpells(patch?: string): Promise<CDragonSummonerSpell[]> {
  return fetchFromCache<CDragonSummonerSpell[]>(
    'summoner-spells.json',
    'plugins/rcp-be-lol-game-data/global/default/v1/summoner-spells.json',
    { patch }
  )
}

/**
 * Get champion summary data from cache
 */
async function getChampionSummary(patch?: string): Promise<CDragonChampionSummary[]> {
  return fetchFromCache<CDragonChampionSummary[]>(
    'champion-summary.json',
    'plugins/rcp-be-lol-game-data/global/default/v1/champion-summary.json',
    { patch }
  )
}

// Type definitions for CDragon data
interface CDragonItem {
  id: number
  name: string
  iconPath: string
  description?: string
  plaintext?: string
  into?: number[]
  from?: number[]
  gold?: {
    base: number
    total: number
    sell: number
  }
}

interface CDragonPerk {
  id: number
  name: string
  iconPath: string
  shortDesc?: string
  longDesc?: string
}

interface CDragonPerkStyle {
  id: number
  name: string
  iconPath: string
  slots: Array<{
    type: string
    perks: number[]
  }>
}

interface CDragonPerkStyles {
  styles: CDragonPerkStyle[]
}

interface CDragonSummonerSpell {
  id: number
  name: string
  iconPath: string
  description?: string
}

interface CDragonChampionSummary {
  id: number
  name: string
  alias: string
  squarePortraitPath: string
  roles?: string[]
}

export {
  getItems,
  getPerks,
  getPerkStyles,
  getSummonerSpells,
  getChampionSummary,
  getCurrentPatch,
  CDRAGON_BASE
}

export type {
  CDragonItem,
  CDragonPerk,
  CDragonPerkStyle,
  CDragonPerkStyles,
  CDragonSummonerSpell,
  CDragonChampionSummary
}