'use strict'

const installerApi = window.installer

// I18N 사전: locales/installer/ko-kr.json. 처음 한 번 메인 프로세스에서 받아오고
// 그 뒤로는 동기적으로 lookup. tt() 가 호출될 때 사전이 비어 있어도 키를 그대로 반환해
// 화면이 깨지지는 않는다.
var I18N = {}
function tt(key, params) {
  var parts = key.split('.')
  var cur = I18N
  for (var i = 0; i < parts.length; i++) {
    if (cur && typeof cur === 'object' && parts[i] in cur) cur = cur[parts[i]]
    else { cur = null; break }
  }
  var tpl = (typeof cur === 'string') ? cur : key
  if (!params) return tpl
  return tpl.replace(/\{\{\s*(\w+)\s*\}\}/g, function (_m, name) {
    return (name in params) ? String(params[name]) : ('{{' + name + '}}')
  })
}

const state = {
  packs: [],
  selectedPackKey: null,
  mode: null, // 'single' | 'multi'
  serverInstall: {
    path: '',
    jdk: '',
    eulaAccepted: false,
    ram: null,
    portStatus: null
  },
  client: {
    installPlatform: true
  },
  finishToggles: {
    desktopShortcut: true,
    startServer: true,
    startLauncher: true
  },
  stepDone: { 1: false, 2: false, 3: false, 4: false }
}

const pageHost = document.getElementById('pageHost')
const stepIndicator = document.getElementById('stepIndicator')
const logViewer = document.getElementById('logViewer')
const logBody = document.getElementById('logBody')
const logToggle = document.getElementById('logToggle')

function applyStaticI18n() {
  document.title = tt('app.browserTitle')
  var headerH1 = document.querySelector('.appHeader h1')
  if (headerH1) headerH1.textContent = tt('app.headerTitle')
  stepIndicator.querySelectorAll('li').forEach(function (item) {
    var step = Number(item.getAttribute('data-step'))
    item.textContent = tt('stepIndicator.step' + step)
  })
  var logHeader = logViewer.querySelector('h2')
  if (logHeader) logHeader.textContent = tt('logViewer.title')
  logToggle.textContent = tt('common.collapse')
}

logToggle.addEventListener('click', function () {
  logViewer.classList.toggle('collapsed')
  if (logViewer.classList.contains('collapsed')) {
    logViewer.style.height = '36px'
    logToggle.textContent = tt('common.expand')
  } else {
    logViewer.style.height = ''
    logToggle.textContent = tt('common.collapse')
  }
})

installerApi.onLog(function (line) {
  logViewer.hidden = false
  logBody.textContent += line + '\n'
  logBody.scrollTop = logBody.scrollHeight
})

function setActiveStep(step) {
  stepIndicator.querySelectorAll('li').forEach(function (item) {
    var index = Number(item.getAttribute('data-step'))
    item.classList.remove('active', 'done')
    if (index < step) item.classList.add('done')
    if (index === step) item.classList.add('active')
  })
}

function clearPage() {
  pageHost.innerHTML = ''
}

function renderStep1() {
  setActiveStep(1)
  clearPage()
  var section = document.createElement('section')
  section.className = 'page'
  section.innerHTML =
    '<h2>' + tt('step1.heading') + '</h2>' +
    '<div id="packList" class="cardChoice"><p class="formMessage">' + tt('step1.loading') + '</p></div>' +
    '<div class="actionRow"><span></span><button class="primaryBtn" id="next" disabled>' + tt('common.next') + '</button></div>'
  pageHost.appendChild(section)
  var listEl = section.querySelector('#packList')
  var nextBtn = section.querySelector('#next')

  function renderList() {
    listEl.innerHTML = ''
    if (state.packs.length === 0) {
      listEl.innerHTML = '<p class="formMessage error">' + tt('step1.empty') + '</p>'
      return
    }
    state.packs.forEach(function (pack) {
      var btn = document.createElement('button')
      btn.type = 'button'
      btn.innerHTML = '<strong>' + pack.name + '</strong><br><small>' +
        tt('step1.subtitle', { mc: pack.pack.mcVersion, platform: pack.pack.platform.type }) + '</small>'
      if (state.selectedPackKey === pack.key) btn.classList.add('selected')
      btn.addEventListener('click', function () {
        state.selectedPackKey = pack.key
        nextBtn.disabled = false
        renderList()
      })
      listEl.appendChild(btn)
    })
  }

  nextBtn.addEventListener('click', async function () {
    if (!state.selectedPackKey) return
    await installerApi.setSelectedPack(state.selectedPackKey)
    state.stepDone[1] = true
    renderStep2()
  })

  ;(async function () {
    try {
      var packs = await installerApi.loadPacks()
      state.packs = packs
      renderList()
    } catch (err) {
      listEl.innerHTML = '<p class="formMessage error">' + tt('step1.fetchFailed', { message: err.message }) + '</p>'
    }
  })()
}

function renderStep2() {
  setActiveStep(2)
  clearPage()
  var section = document.createElement('section')
  section.className = 'page'
  section.innerHTML =
    '<h2>' + tt('step2.heading') + '</h2>' +
    '<div class="cardChoice">' +
    '<button id="single" type="button" data-mode="single"><strong>' + tt('step2.singleTitle') + '</strong><br><small>' + tt('step2.singleHint') + '</small></button>' +
    '<button id="multi" type="button" data-mode="multi"><strong>' + tt('step2.multiTitle') + '</strong><br><small>' + tt('step2.multiHint') + '</small></button>' +
    '</div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next" disabled>' + tt('common.next') + '</button></div>'
  pageHost.appendChild(section)
  var nextBtn = section.querySelector('#next')
  var modeButtons = section.querySelectorAll('[data-mode]')

  function applySelection(mode) {
    state.mode = mode
    modeButtons.forEach(function (btn) {
      if (btn.getAttribute('data-mode') === mode) btn.classList.add('selected')
      else btn.classList.remove('selected')
    })
    nextBtn.disabled = false
  }

  modeButtons.forEach(function (btn) {
    btn.addEventListener('click', function () {
      applySelection(btn.getAttribute('data-mode'))
    })
  })

  if (state.mode === 'single' || state.mode === 'multi') applySelection(state.mode)

  nextBtn.addEventListener('click', function () {
    if (!state.mode) return
    state.stepDone[2] = true
    if (state.mode === 'single') renderStep4()
    else renderStep3()
  })
  section.querySelector('#back').addEventListener('click', renderStep1)
}

function renderStep3() {
  setActiveStep(3)
  clearPage()
  var section = document.createElement('section')
  section.className = 'page'
  section.innerHTML =
    '<h2>' + tt('step3.heading') + '</h2>' +
    '<div class="subStep" id="subHost"></div>'
  pageHost.appendChild(section)
  var subHost = section.querySelector('#subHost')

  function show31() { subHost.innerHTML = ''; renderSubStep31(subHost, renderStep2, show32) }
  function show32() { subHost.innerHTML = ''; renderSubStep32(subHost, show31, show33) }
  function show33() { subHost.innerHTML = ''; renderSubStep33(subHost, show32, show34) }
  function show34() { subHost.innerHTML = ''; renderSubStep34(subHost, show33, show35) }
  function show35() {
    subHost.innerHTML = ''
    renderSubStep35(subHost, show34, function () {
      state.stepDone[3] = true
      renderStep4()
    })
  }
  show31()
}

function renderSubStep31(host, back, done) {
  host.innerHTML =
    '<h3>' + tt('step3.sub31.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step3.sub31.description') + '</p>' +
    '<div class="fieldset"><label><input id="installPath" type="text" placeholder="C:\\MusicQuizServer" value="' + (state.serverInstall.path || '') + '" /></label>' +
    '<button class="secondaryBtn" id="pickFolder">' + tt('step3.sub31.pickFolder') + '</button></div>' +
    '<div class="formMessage" id="msg"></div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next">' + tt('common.next') + '</button></div>'
  var input = host.querySelector('#installPath')
  var msg = host.querySelector('#msg')
  host.querySelector('#pickFolder').addEventListener('click', async function () {
    var picked = await installerApi.pickFolder()
    if (picked) input.value = picked
  })
  host.querySelector('#back').addEventListener('click', back)
  host.querySelector('#next').addEventListener('click', async function () {
    var result = await installerApi.validateInstallPath(input.value.trim())
    if (!result.ok) {
      msg.textContent = result.message || tt('step3.sub31.invalidPath')
      msg.classList.add('error')
      return
    }
    msg.textContent = tt('step3.sub31.confirmed', { message: result.message })
    msg.classList.remove('error')
    msg.classList.add('success')
    state.serverInstall.path = input.value.trim()
    done()
  })
}

function renderSubStep32(host, back, done) {
  host.innerHTML =
    '<h3>' + tt('step3.sub32.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step3.sub32.description') + '</p>' +
    '<div class="fieldset"><label><input id="jdkPath" type="text" placeholder="C:\\Program Files\\Java\\jdk-17" value="' + (state.serverInstall.jdk || '') + '" /></label>' +
    '<button class="secondaryBtn" id="pickJdk">' + tt('step3.sub32.pickFolder') + '</button>' +
    '<button class="secondaryBtn" id="auto">' + tt('step3.sub32.auto') + '</button>' +
    '<button class="secondaryBtn" id="install">' + tt('step3.sub32.install') + '</button></div>' +
    '<div class="formMessage" id="msg"></div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next">' + tt('common.next') + '</button></div>'
  var input = host.querySelector('#jdkPath')
  var msg = host.querySelector('#msg')
  var installBtn = host.querySelector('#install')
  var autoBtn = host.querySelector('#auto')
  var pickBtn = host.querySelector('#pickJdk')
  var nextBtn = host.querySelector('#next')
  var installing = false

  function setInstallingUi(on) {
    installing = on
    if (on) {
      installBtn.textContent = tt('step3.sub32.installCancel')
      installBtn.classList.remove('secondaryBtn')
      installBtn.classList.add('dangerBtn')
      autoBtn.disabled = true
      pickBtn.disabled = true
      nextBtn.disabled = true
      input.disabled = true
    } else {
      installBtn.textContent = tt('step3.sub32.install')
      installBtn.classList.remove('dangerBtn')
      installBtn.classList.add('secondaryBtn')
      autoBtn.disabled = false
      pickBtn.disabled = false
      nextBtn.disabled = false
      input.disabled = false
    }
  }

  autoBtn.addEventListener('click', async function () {
    if (installing) return
    var detect = await installerApi.detectJdk()
    if (detect.found) {
      input.value = detect.path
      msg.textContent = tt('step3.sub32.found', { path: detect.path })
      msg.classList.remove('error')
      msg.classList.add('success')
    } else {
      msg.textContent = tt('step3.sub32.notFound')
      msg.classList.remove('success')
      msg.classList.add('error')
    }
  })
  pickBtn.addEventListener('click', async function () {
    if (installing) return
    var picked = await installerApi.pickFolder()
    if (picked) input.value = picked
  })
  installBtn.addEventListener('click', async function () {
    if (installing) {
      // 진행 중이면 취소.
      msg.textContent = tt('step3.sub32.cancelRequested')
      msg.classList.remove('success', 'error')
      await installerApi.cancelJdkInstall()
      return
    }
    setInstallingUi(true)
    msg.classList.remove('success', 'error')
    msg.textContent = tt('step3.sub32.downloading')
    try {
      var result = await installerApi.installJdk()
      if (result.ok && result.path) {
        input.value = result.path
        state.serverInstall.jdk = result.path
        msg.textContent = tt('step3.sub32.installComplete', { path: result.path })
        msg.classList.add('success')
      } else {
        var raw = result.message || tt('common.unknownError')
        msg.textContent = raw === '취소됨'
          ? tt('step3.sub32.installCanceled')
          : tt('step3.sub32.installFailed', { message: raw })
        msg.classList.add('error')
      }
    } catch (err) {
      msg.textContent = tt('step3.sub32.installError', { message: (err && err.message) ? err.message : String(err) })
      msg.classList.add('error')
    } finally {
      setInstallingUi(false)
    }
  })
  host.querySelector('#back').addEventListener('click', function () {
    if (installing) return
    back()
  })
  nextBtn.addEventListener('click', function () {
    if (installing) return
    if (!input.value.trim()) {
      msg.textContent = tt('step3.sub32.pathRequired')
      msg.classList.add('error')
      return
    }
    state.serverInstall.jdk = input.value.trim()
    done()
  })
  ;(async function () {
    var detect = await installerApi.detectJdk()
    if (detect.found && !input.value) {
      input.value = detect.path
      msg.textContent = tt('step3.sub32.autoDetected', { path: detect.path })
      msg.classList.add('success')
    } else if (!detect.found) {
      msg.textContent = tt('step3.sub32.notFoundHint')
    }
  })()
}

function renderSubStep33(host, back, done) {
  host.innerHTML =
    '<h3>' + tt('step3.sub33.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step3.sub33.description') + '</p>' +
    '<div class="formMessage" id="downloadStatus">' + tt('step3.sub33.waiting') + '</div>' +
    '<div id="ramSection" hidden style="margin-top:14px;">' +
    '<h4>' + tt('step3.sub33.ramHeading') + '</h4>' +
    '<div class="formMessage" id="ramMsg">' + tt('step3.sub33.ramChecking') + '</div>' +
    '</div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next" disabled>' + tt('common.next') + '</button></div>'

  var statusEl = host.querySelector('#downloadStatus')
  var ramSection = host.querySelector('#ramSection')
  var ramMsg = host.querySelector('#ramMsg')
  var nextBtn = host.querySelector('#next')

  host.querySelector('#back').addEventListener('click', back)
  nextBtn.addEventListener('click', function () {
    if (!state.serverInstall.eulaAccepted) return
    done()
  })

  // 이미 통과했던 상태 복원: 사용자가 다음→이전으로 돌아왔을 때 재다운로드 강요하지 않는다.
  if (state.serverInstall.eulaAccepted && state.serverInstall.ram) {
    statusEl.textContent = tt('step3.sub33.doneSummary')
    statusEl.classList.add('success')
    showRamResult(state.serverInstall.ram)
    nextBtn.disabled = false
    return
  }

  // 페이지 진입 즉시 자동 다운로드
  ;(async function () {
    state.serverInstall.eulaAccepted = false
    nextBtn.disabled = true
    statusEl.classList.remove('success', 'error')
    statusEl.textContent = tt('step3.sub33.downloading')
    try {
      await installerApi.startServerInstall({
        packKey: state.selectedPackKey,
        installPath: state.serverInstall.path,
        jdkPath: state.serverInstall.jdk
      })
      statusEl.textContent = tt('step3.sub33.eulaPrompt')
      var accepted = await openEulaPopup(state.serverInstall.path)
      if (!accepted) {
        statusEl.textContent = tt('step3.sub33.eulaRejected')
        statusEl.classList.add('error')
        return
      }
      try {
        await installerApi.acceptEula(state.serverInstall.path)
      } catch (err) {
        statusEl.textContent = tt('step3.sub33.eulaSaveFailed', { message: err.message })
        statusEl.classList.add('error')
        return
      }
      state.serverInstall.eulaAccepted = true
      statusEl.textContent = tt('step3.sub33.doneSummary')
      statusEl.classList.add('success')
      var ram = await installerApi.checkRam(state.selectedPackKey)
      state.serverInstall.ram = ram
      showRamResult(ram)
      if (ram.decision === 'tooLow') return
      nextBtn.disabled = false
    } catch (err) {
      statusEl.textContent = tt('step3.sub33.downloadFailed', { message: (err && err.message) ? err.message : String(err) })
      statusEl.classList.add('error')
    }
  })()

  function showRamResult(result) {
    ramSection.hidden = false
    ramMsg.classList.remove('error', 'warn', 'success')
    if (result.decision === 'tooLow') {
      var pack = state.packs.find(function (p) { return p.key === state.selectedPackKey })
      var minRam = pack ? pack.pack.serverMinRam : 0
      ramMsg.innerHTML = tt('step3.sub33.ramTooLow', { system: result.systemRamMb, min: minRam })
      ramMsg.classList.add('error')
    } else if (result.decision === 'minOk') {
      ramMsg.innerHTML = tt('step3.sub33.ramMinOk', { system: result.systemRamMb, applied: result.appliedRamMb })
      ramMsg.classList.add('warn')
    } else {
      ramMsg.textContent = tt('step3.sub33.ramMaxOk', { system: result.systemRamMb, applied: result.appliedRamMb })
      ramMsg.classList.add('success')
    }
  }
}

// EULA 동의 팝업. resolve(true) = 동의, resolve(false) = 비동의/창 닫힘.
async function openEulaPopup(installPath) {
  var read = await installerApi.readEula(installPath)
  var bodyHtml = ''
  if (read.exists) {
    bodyHtml = '<p class="formMessage">' + tt('step3.eulaModal.fromFile') + '</p>' +
      '<pre class="eulaPre">' + escapeHtml(read.content) + '</pre>'
  } else {
    var fetched = await installerApi.fetchMinecraftEula()
    if (fetched.html) {
      bodyHtml = '<p class="formMessage">' + tt('step3.eulaModal.fromMojang', { url: fetched.url }) + '</p>' +
        '<iframe class="eulaFrame" sandbox srcdoc="' + escapeAttr(fetched.html) + '"></iframe>'
    } else {
      bodyHtml = '<p class="formMessage error">' + tt('step3.eulaModal.loadFailed') + '</p>'
    }
  }
  return new Promise(function (resolve) {
    var overlay = document.createElement('div')
    overlay.className = 'modalOverlay'
    overlay.innerHTML =
      '<div class="modalCard" role="dialog" aria-modal="true">' +
      '<header><h3>' + tt('step3.eulaModal.title') + '</h3><button type="button" class="modalClose" aria-label="' + tt('common.close') + '">×</button></header>' +
      '<div class="modalBody">' + bodyHtml + '</div>' +
      '<footer class="actionRow">' +
      '<button type="button" class="secondaryBtn" data-action="reject">' + tt('common.reject') + '</button>' +
      '<button type="button" class="primaryBtn" data-action="accept">' + tt('common.agree') + '</button>' +
      '</footer>' +
      '</div>'
    document.body.appendChild(overlay)

    var settled = false
    function close(result) {
      if (settled) return
      settled = true
      overlay.remove()
      resolve(result)
    }
    overlay.querySelector('[data-action="accept"]').addEventListener('click', function () { close(true) })
    overlay.querySelector('[data-action="reject"]').addEventListener('click', function () { close(false) })
    overlay.querySelector('.modalClose').addEventListener('click', function () { close(false) })
    overlay.addEventListener('click', function (event) {
      if (event.target === overlay) close(false)
    })
  })
}

function escapeHtml(text) {
  return String(text).replace(/[&<>"']/g, function (ch) {
    return { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[ch]
  })
}

function escapeAttr(text) {
  return String(text).replace(/&/g, '&amp;').replace(/"/g, '&quot;')
}

function renderSubStep34(host, back, done) {
  host.innerHTML =
    '<h3>' + tt('step3.sub34.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step3.sub34.description') + '</p>' +
    '<button class="secondaryBtn" id="open">' + tt('step3.sub34.open') + '</button>' +
    '<div class="formMessage" id="editorMsg"></div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next">' + tt('common.next') + '</button></div>'
  host.querySelector('#open').addEventListener('click', async function () {
    var msg = host.querySelector('#editorMsg')
    try {
      var result = await installerApi.startServerConfigEditor(state.serverInstall.path)
      msg.innerHTML = tt('step3.sub34.openedAt', { url: result.url })
    } catch (err) {
      msg.textContent = tt('step3.sub34.openFailed', { message: err.message })
      msg.classList.add('error')
    }
  })
  host.querySelector('#back').addEventListener('click', back)
  host.querySelector('#next').addEventListener('click', done)
}

function renderSubStep35(host, back, done) {
  host.innerHTML =
    '<h3>' + tt('step3.sub35.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step3.sub35.description') + '</p>' +
    '<div class="fieldset"><label>' + tt('step3.sub35.portLabel') + ' <input id="port" type="text" value="25565" /></label></div>' +
    '<button class="secondaryBtn" id="run">' + tt('step3.sub35.recheck') + '</button>' +
    '<div class="formMessage" id="resultMsg"></div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next" disabled>' + tt('common.next') + '</button></div>'
  var resultMsg = host.querySelector('#resultMsg')
  var nextBtn = host.querySelector('#next')
  var runBtn = host.querySelector('#run')
  host.querySelector('#back').addEventListener('click', back)

  async function runCheck() {
    runBtn.disabled = true
    resultMsg.classList.remove('success', 'warn', 'error')
    resultMsg.textContent = tt('step3.sub35.checking')
    var port = Number(host.querySelector('#port').value) || 25565
    try {
      var result = await installerApi.checkPortForward(port)
      state.serverInstall.portStatus = result
      if (result.status === 'preForwarded') {
        resultMsg.innerHTML = tt('step3.sub35.preForwarded', { ip: result.externalIp, port: result.port })
        resultMsg.classList.add('success')
      } else if (result.status === 'upnpOk') {
        resultMsg.innerHTML = tt('step3.sub35.upnpOk', { ip: result.externalIp, port: result.port })
        resultMsg.classList.add('success')
      } else {
        var ip = result.externalIp || tt('step3.sub35.ipUnknown')
        resultMsg.innerHTML = (result.message || tt('step3.sub35.manualHint')) +
          tt('step3.sub35.manualDetail', { ip: ip, port: result.port })
        resultMsg.classList.add('warn')
      }
      nextBtn.disabled = false
    } catch (err) {
      resultMsg.textContent = tt('step3.sub35.checkFailed', { message: (err && err.message) ? err.message : String(err) })
      resultMsg.classList.add('error')
    } finally {
      runBtn.disabled = false
    }
  }

  runBtn.addEventListener('click', runCheck)
  nextBtn.addEventListener('click', done)
  // 페이지 진입 즉시 자동 점검
  runCheck()
}

function renderStep4() {
  setActiveStep(4)
  clearPage()
  var pack = state.packs.find(function (p) { return p.key === state.selectedPackKey })
  var section = document.createElement('section')
  section.className = 'page'
  section.innerHTML =
    '<h2>' + tt('step4.heading') + '</h2>' +
    '<div class="subStep" id="subHost"></div>'
  pageHost.appendChild(section)
  var subHost = section.querySelector('#subHost')
  function backToPrevStep() { if (state.mode === 'multi') renderStep3(); else renderStep2() }

  function show41() { subHost.innerHTML = ''; renderSubStep41(subHost, pack, backToPrevStep, show42) }
  function show42() { subHost.innerHTML = ''; renderSubStep42(subHost, show41, show43) }
  function show43() {
    subHost.innerHTML = ''
    renderSubStep43(subHost, show42, function () {
      state.stepDone[4] = true
      renderStep5()
    })
  }
  show41()
}

function renderSubStep41(host, pack, back, done) {
  var platformType = pack ? pack.pack.platform.type : 'vanilla'
  if (platformType === 'vanilla') {
    state.client.installPlatform = false
    host.innerHTML =
      '<h3>' + tt('step4.sub41.heading') + '</h3>' +
      '<p class="formMessage">' + tt('step4.sub41.vanillaInfo') + '</p>' +
      '<p class="formMessage">' + tt('step4.sub41.vanillaNoInstall') + '</p>' +
      '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next">' + tt('common.next') + '</button></div>'
    host.querySelector('#back').addEventListener('click', back)
    host.querySelector('#next').addEventListener('click', done)
    return
  }

  host.innerHTML =
    '<h3>' + tt('step4.sub41.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step4.sub41.info', { platform: platformType }) + '</p>' +
    '<div class="cardChoice">' +
    '<button type="button" data-choice="install"><strong>' + tt('step4.sub41.installTitle') + '</strong><br><small>' + tt('step4.sub41.installHint', { platform: platformType }) + '</small></button>' +
    '<button type="button" data-choice="skip"><strong>' + tt('step4.sub41.skipTitle') + '</strong><br><small>' + tt('step4.sub41.skipHint') + '</small></button>' +
    '</div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next" disabled>' + tt('common.next') + '</button></div>'

  var nextBtn = host.querySelector('#next')
  var choiceButtons = host.querySelectorAll('[data-choice]')

  function applyChoice(choice) {
    state.client.installPlatform = choice === 'install'
    choiceButtons.forEach(function (btn) {
      if (btn.getAttribute('data-choice') === choice) btn.classList.add('selected')
      else btn.classList.remove('selected')
    })
    nextBtn.disabled = false
  }

  choiceButtons.forEach(function (btn) {
    btn.addEventListener('click', function () {
      applyChoice(btn.getAttribute('data-choice'))
    })
  })

  if (typeof state.client.installPlatform === 'boolean') {
    applyChoice(state.client.installPlatform ? 'install' : 'skip')
  }

  host.querySelector('#back').addEventListener('click', back)
  nextBtn.addEventListener('click', done)
}

function renderSubStep42(host, back, done) {
  host.innerHTML =
    '<h3>' + tt('step4.sub42.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step4.sub42.description') + '</p>' +
    '<div class="formMessage" id="msg">' + tt('step4.sub42.installing') + '</div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next" disabled>' + tt('common.next') + '</button></div>'
  var msg = host.querySelector('#msg')
  var nextBtn = host.querySelector('#next')
  host.querySelector('#back').addEventListener('click', back)
  nextBtn.addEventListener('click', done)

  // 이미 설치됐다면 다시 돌리지 않음
  if (state.client.clientInstalled) {
    msg.textContent = tt('step4.sub42.done')
    msg.classList.add('success')
    nextBtn.disabled = false
    return
  }

  // 페이지 진입 즉시 자동 설치
  ;(async function () {
    try {
      await installerApi.installClient({
        packKey: state.selectedPackKey,
        installPlatform: !!state.client.installPlatform
      })
      msg.textContent = tt('step4.sub42.done')
      msg.classList.add('success')
      state.client.clientInstalled = true
      nextBtn.disabled = false
    } catch (err) {
      msg.textContent = tt('step4.sub42.failed', { message: (err && err.message) ? err.message : String(err) })
      msg.classList.add('error')
    }
  })()
}

function renderSubStep43(host, back, done) {
  host.innerHTML =
    '<h3>' + tt('step4.sub43.heading') + '</h3>' +
    '<p class="formMessage">' + tt('step4.sub43.description') + '</p>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="next">' + tt('step4.sub43.goStep5') + '</button></div>'
  host.querySelector('#back').addEventListener('click', back)
  host.querySelector('#next').addEventListener('click', done)
}

function renderStep5() {
  setActiveStep(5)
  clearPage()
  var section = document.createElement('section')
  section.className = 'page'
  var multi = state.mode === 'multi'
  section.innerHTML =
    '<h2>' + tt('step5.heading') + '</h2>' +
    '<p>' + tt('step5.summary') + '</p>' +
    (multi ? '<div class="subStep">' +
      '<h3>' + tt('step5.serverHeading') + '</h3>' +
      '<button class="secondaryBtn" id="openFolder">' + tt('step5.openServerFolder') + '</button>' +
      '<label class="toggleRow"><input type="checkbox" id="shortcut" checked /> ' + tt('step5.shortcut') + '</label>' +
      '<label class="toggleRow"><input type="checkbox" id="startServer" checked /> ' + tt('step5.startServer') + '</label>' +
      '</div>' : '') +
    '<div class="subStep">' +
    '<h3>' + tt('step5.launcherHeading') + '</h3>' +
    '<label class="toggleRow"><input type="checkbox" id="startLauncher" checked /> ' + tt('step5.startLauncher') + '</label>' +
    '</div>' +
    '<div class="actionRow"><button class="secondaryBtn" id="back">' + tt('common.back') + '</button><button class="primaryBtn" id="finish">' + tt('step5.finish') + '</button></div>'
  pageHost.appendChild(section)
  section.querySelector('#back').addEventListener('click', renderStep4)
  if (multi) {
    section.querySelector('#openFolder').addEventListener('click', function () {
      installerApi.openServerFolder()
    })
  }
  section.querySelector('#finish').addEventListener('click', async function () {
    var finishBtn = section.querySelector('#finish')
    finishBtn.disabled = true
    finishBtn.textContent = tt('step5.finishing')
    try {
      if (multi) {
        if (section.querySelector('#shortcut').checked) await installerApi.createDesktopShortcut()
        if (section.querySelector('#startServer').checked) await installerApi.startServer()
      }
      if (section.querySelector('#startLauncher').checked) await installerApi.startMinecraftLauncher()
    } catch (err) {
      // 마무리 액션 실패는 무시하고 종료 진행
    }
    finishBtn.textContent = tt('step5.finished')
    if (installerApi.quitApp) installerApi.quitApp()
  })
}

// 시작 진입점: 사전을 먼저 받아서 정적 텍스트 갱신 후 첫 페이지 렌더.
;(async function () {
  try {
    I18N = (await installerApi.loadLocale()) || {}
  } catch (_) { I18N = {} }
  applyStaticI18n()
  renderStep1()
})()