'use strict'

const { runGame, runTool } = require('../runner')
const { importGame, importGameFromPrefix } = require('../importer')
const library = require('../library')

function killProcessGroup(pid) {
  try {
    process.kill(-pid, 'SIGKILL')
  } catch {}
  try {
    process.kill(pid, 'SIGKILL')
  } catch {}
}

function sendToWindow(win, channel, data) {
  if (win && !win.isDestroyed()) win.webContents.send(channel, data)
}

// Game-process state: id -> { pid (null while the process is starting), the
// prefix name and wine id the run was resolved to }. Both are frozen here:
// the default prefix/wine can be switched and the app's own config edited
// while it plays, and the in-use guards have to name what the process really
// locked - not what the registry says now. Editing an app's own prefix while
// it runs does not move the process, so the new folder is blocked next to the
// snapshot (a pre-edit prefix does not exist in it yet).
// onGamesChanged fires in the MAIN process whenever the running-games set
// changes (the tray menu rebuilds itself from it).
const STARTUP_GRACE_MS = 60000

function createGamesService({ getWindow, onGamesChanged }) {
  const running = new Map()
  const startedAt = new Map()
  const killRequests = new Set()
  let onGameExit = null
  const notifyChanged = () => {
    if (typeof onGamesChanged === 'function') onGamesChanged()
  }

  function alive(pid) {
    if (!pid) return false
    try {
      process.kill(pid, 0)
      return true
    } catch {
      return false
    }
  }

  // A game is "running" only while its process really is. An entry left behind
  // by a launch that never got a pid (the binary could not be executed, so the
  // spawn failed) or whose pid is gone (the game crashed, the launcher was
  // restarted) would otherwise answer every later Play with "already
  // running".
  function prune() {
    for (const [id, entry] of [...running]) {
      if (alive(entry.pid)) continue
      const age = Date.now() - (startedAt.get(id) || 0)
      if (!entry.pid && age < STARTUP_GRACE_MS) continue // may still be starting
      running.delete(id)
      startedAt.delete(id)
    }
  }

  const isRunning = id => {
    prune()
    return running.has(id)
  }
  const listRunning = () => {
    prune()
    return [...running.keys()]
  }
  // What the still-running games actually use, for the "is this prefix/wine in
  // use?" guards: [{ id, name, prefixes: [snapshot, ...], wine }]. The
  // snapshot alone goes stale when a running app is pointed at another prefix
  // (the process keeps its folder open); the live name alone misses the folder
  // it currently holds. Together they name every folder the run touches.
  const runningInfo = () => {
    prune()
    const out = []
    for (const [id, entry] of running) {
      const game = library.getGame(id)
      const live = game && game.prefix ? library.prefixNameForGame(game) : ''
      const prefixes = live && live !== entry.prefix ? [entry.prefix, live] : [entry.prefix]
      out.push({ id, name: (game && game.name) || id, prefixes, wine: entry.wine })
    }
    return out
  }

  // "Open with PLWL" handoff: queue the file for the renderer (picker popup
  // with wine version + prefix). Safe to call at any time - if the window is
  // not up yet, the renderer picks the file up right after boot.
  function openExternally(openPath) {
    require('../openwith').setPending(openPath)
    sendToWindow(getWindow(), 'openwith:file', openPath)
  }

  function resolveWine(game) {
    return require('../wines').resolveWine(game.wine || 'system')
  }

  function handleExit(id) {
    running.delete(id)
    startedAt.delete(id)
    sendToWindow(getWindow(), 'games:changed')
    notifyChanged()
    if (onGameExit) onGameExit(id)
  }

  async function start(win, id, openFile) {
    const game = library.getGame(id)
    if (!game) return { ok: false, error: 'game-not-found' }
    prune()
    let wine
    try {
      wine = resolveWine(game)
    } catch {
      return { ok: false, error: 'wine-not-found' }
    }
    if (running.has(id)) {
      // Opening a document in an app that is already running is a HANDOFF,
      // exactly like Windows: a second process receives the file and the app's
      // own single-instance logic takes it over. It is not a tracked run -
      // playtime, the tray and the kill switch belong to the first process.
      if (!openFile) return { ok: false, error: 'already-running' }
      try {
        await runGame({ game, wine, systemWine: wine.type === 'system', openFile, handoff: true })
        return { ok: true, pid: null, logFile: null }
      } catch (err) {
        return { ok: false, error: String((err && err.message) || err) }
      }
    }
    running.set(id, { pid: null, prefix: library.prefixNameForGame(game), wine: wine.id })
    startedAt.set(id, Date.now())
    try {
      const res = await runGame({ game, wine, systemWine: wine.type === 'system', onExit: () => handleExit(id), openFile })
      // stop was requested while the process was still starting: kill it and
      // leave nothing in the running set
      if (killRequests.has(id)) {
        killRequests.delete(id)
        if (res.pid) killProcessGroup(res.pid)
        running.delete(id)
        startedAt.delete(id)
        sendToWindow(win, 'games:changed')
        notifyChanged()
        return { ok: true, pid: null, logFile: res.logFile || null }
      }
      // no pid means the process was not started after all - never keep such
      // an entry, it would block the next launch with "already running"
      if (!res.pid) {
        running.delete(id)
        startedAt.delete(id)
        return { ok: false, error: 'not-started' }
      }
      const entry = running.get(id)
      if (entry) entry.pid = res.pid
      sendToWindow(win, 'games:changed')
      notifyChanged()
      return { ok: true, pid: res.pid, logFile: res.logFile || null }
    } catch (err) {
      running.delete(id)
      startedAt.delete(id)
      return { ok: false, error: String((err && err.message) || err) }
    }
  }

  // Stop always clears the state: whether the process was running, still
  // starting (kill request for as soon as it has a pid) or already gone.
  async function kill(id) {
    const entry = running.get(id)
    if (entry) killProcessGroup(entry.pid)
    else if (running.has(id)) killRequests.add(id)
    running.delete(id)
    startedAt.delete(id)
    sendToWindow(getWindow(), 'games:changed')
    notifyChanged()
    return { ok: true }
  }

  async function runToolFor(id, tool, args) {
    const game = library.getGame(id)
    if (!game) return { ok: false, error: 'game-not-found' }
    let wine
    try {
      wine = resolveWine(game)
    } catch {
      return { ok: false, error: 'wine-not-found' }
    }
    try {
      await runTool({ game, wine, tool, args, systemWine: wine.type === 'system' })
      return { ok: true }
    } catch (err) {
      return { ok: false, error: String((err && err.message) || err) }
    }
  }

  // subscribe to game exits (used by the tray/headless mode to e.g. quit when
  // the game that auto-started the launcher has finished)
  function setOnGameExit(fn) {
    onGameExit = typeof fn === 'function' ? fn : null
  }

  async function importTo(win, srcDir, mode) {
    return importGame(srcDir, mode, data => sendToWindow(win, 'import:progress', data))
  }

  // prefix import: nothing is copied, the game just gets registered with
  // paths relative to the prefix (wine sees it as a normal C:\ install)
  async function importFromPrefix(win, prefix, srcDir) {
    return importGameFromPrefix(prefix, srcDir)
  }

  return { isRunning, listRunning, runningInfo, start, kill, runToolFor, import: importTo, importFromPrefix, setOnGameExit, openExternally }
}

module.exports = { createGamesService, killProcessGroup, sendToWindow }