'use strict'

const path = require('path')
const fs = require('fs')
const { spawn } = require('child_process')
const { DIRS } = require('./paths')
const { prefixPath } = require('./prefixes')

function ensureFakeSteam() {
  const fake = DIRS.FAKE_STEAM
  fs.mkdirSync(path.join(fake, 'steamapps'), { recursive: true })
  return fake
}

function linkPrefix(compatData, prefixDir) {
  try {
    const st = fs.lstatSync(compatData)
    if (st.isSymbolicLink()) {
      if (fs.readlinkSync(compatData) === prefixDir) return
      fs.unlinkSync(compatData)
    } else {
      return
    }
  } catch {}
  try {
    fs.symlinkSync(prefixDir, compatData, 'dir')
  } catch {}
}

function buildEnv({ game, wine, workdir, systemWine }) {
  const env = { ...process.env }
  const isProton = wine && wine.type === 'proton'
  let prefixDir = game.prefix ? prefixPath(game.prefix) : null
  if (!prefixDir) {
    const defs = require('./prefixes').listPrefixes()
    prefixDir = prefixPath(defs.default || 'default')
  }

  if (isProton) {
    const fakeSteam = ensureFakeSteam()
    const buildRoot = path.resolve(wine.path, '..')
    env.STEAM_COMPAT_CLIENT_INSTALL_PATH = fakeSteam
    env.STEAM_COMPAT_DATA_PATH = path.join(DIRS.DATA, 'compat', game.id)
    env.STEAM_COMPAT_APP_ID = '0'
    env.SteamAppId = '0'
    env.SteamGameId = '0'
    env.WINEPREFIX = path.join(env.STEAM_COMPAT_DATA_PATH, 'pfx')
    env.PROTON_LOG_DIR = path.join(DIRS.DATA, 'logs')
    fs.mkdirSync(path.join(env.PROTON_LOG_DIR), { recursive: true })
    linkPrefix(env.STEAM_COMPAT_DATA_PATH, prefixDir)
    if (!fs.existsSync(env.STEAM_COMPAT_DATA_PATH)) {
      fs.mkdirSync(env.STEAM_COMPAT_DATA_PATH, { recursive: true })
    }
  } else if (!systemWine) {
    env.WINEPREFIX = prefixDir
  } else {
    env.WINEPREFIX = prefixDir
  }

  env.WINEDLLOVERRIDES = (game.dllOverrides || [])
    .filter(o => o && o.dll && o.setting)
    .map(o => `${o.dll}=${o.setting}`)
    .join(';')
  if (!env.WINEDLLOVERRIDES) delete env.WINEDLLOVERRIDES

  for (const [k, v] of Object.entries(game.env || {})) env[k] = v
  return { env, prefixDir }
}

function parseArgs(args) {
  const out = []
  const re = /"([^"]*)"|'([^']*)'|(\S+)/g
  let m
  while ((m = re.exec(String(args || '')))) out.push(m[1] ?? m[2] ?? m[3])
  return out
}

const GRACE_MS = 60000

// Live playtime: while the game runs, update ONLY the tiny playtime file
// (a number of seconds) every 30s - apps.json is left untouched to spare the
// disk. lastPlayed is stamped once at start, final totals are mirrored into
// the registry once on exit.
function startPlaytimeTicker({ game, startedAt }) {
  const library = require('./library')
  const base = game.playSeconds || 0
  const timer = setInterval(() => {
    const counted = Math.max(0, Math.round((Date.now() - startedAt - GRACE_MS) / 1000))
    library.writePlaySeconds(game.id, base + counted)
  }, 30000)
  return () => clearInterval(timer)
}

function latestLogPath(gameId) {
  return path.join(DIRS.DATA, 'logs', `${gameId}-latest.log`)
}

function openLatestLog(gameId) {
  const logFile = latestLogPath(gameId)
  fs.mkdirSync(path.dirname(logFile), { recursive: true })
  // Keep only the latest run's log: truncate the file from the previous session
  // and clean up logs left by older versions (<id>-<timestamp>.log).
  try {
    for (const f of fs.readdirSync(path.dirname(logFile))) {
      if (f.startsWith(`${gameId}-`) && f.endsWith('.log') && f !== `${gameId}-latest.log`) {
        fs.rmSync(path.join(path.dirname(logFile), f), { force: true })
      }
    }
  } catch {}
  return fs.createWriteStream(logFile, { flags: 'w' })
}

function runGame({ game, wine, systemWine, onExit }) {
  const isProton = wine && wine.type === 'proton'
  const { env } = buildEnv({ game, wine })
  const exe = game.exePath
  const workdir = game.workdir || path.dirname(exe)
  const argList = parseArgs(game.args)

  let cmd
  let base
  if (isProton) {
    cmd = wine.wineBin || path.join(wine.path, 'proton')
    base = ['run', exe, ...argList]
  } else {
    cmd = systemWine ? 'wine' : wine.wineBin
    base = [exe, ...argList]
  }

  fs.mkdirSync(DIRS.DATA, { recursive: true })
  return new Promise((resolve, reject) => {
    let child
    try {
      child = spawn(cmd, base, {
        cwd: workdir,
        env,
        stdio: ['ignore', 'pipe', 'pipe'],
        detached: true
      })
    } catch (err) {
      return reject(err)
    }
    const logFile = latestLogPath(game.id)
    const ws = openLatestLog(game.id)
    child.stdout.pipe(ws)
    child.stderr.pipe(ws)
    child.on('error', reject)
    child.unref()
    const startedAt = Date.now()
    const stopTicker = startPlaytimeTicker({ game, startedAt })
    // stamp "last played" once at start so it is correct even if we crash later
    require('./library').updateGame(game.id, { lastPlayed: startedAt })
    child.on('exit', (code, signal) => {
      stopTicker()
      ws.end()
      const counted = Math.max(0, Math.round((Date.now() - startedAt - GRACE_MS) / 1000))
      require('./library').updateGame(game.id, {
        lastPlayed: startedAt,
        playSeconds: (game.playSeconds || 0) + counted
      })
      if (onExit) onExit(code, signal)
    })
    resolve({ pid: child.pid, logFile })
  })
}

function runTool({ game, wine, tool, args, systemWine }) {
  const isProton = wine && wine.type === 'proton'
  const { env } = buildEnv({ game, wine })
  const exe = game.exePath
  const workdir = game.workdir || path.dirname(exe)
  const argList = parseArgs(args)

  let cmd
  let base
  if (isProton) {
    cmd = wine.wineBin || path.join(wine.path, 'proton')
    base = ['run', tool, ...argList]
  } else if (systemWine) {
    cmd = tool
    base = argList
  } else {
    cmd = wine.wineBin
    base = [tool, ...argList]
  }
  return new Promise((resolve, reject) => {
    const child = spawn(cmd, base, { cwd: workdir, env, stdio: 'ignore', detached: true })
    child.on('error', reject)
    child.unref()
    resolve({ pid: child.pid })
  })
}

module.exports = { buildEnv, runGame, runTool, parseArgs, latestLogPath }