(function () {
  const el = {
    statusText: document.getElementById('statusText'),
    viewUpload: document.getElementById('viewUpload'),
    viewProgress: document.getElementById('viewProgress'),
    viewResult: document.getElementById('viewResult'),
    dropzone: document.getElementById('dropzone'),
    fileInput: document.getElementById('fileInput'),
    fileList: document.getElementById('fileList'),
    btnClear: document.getElementById('btnClear'),
    btnStart: document.getElementById('btnStart'),
    concurrencyInput: document.getElementById('concurrencyInput'),
    timeoutInput: document.getElementById('timeoutInput'),
    progressPercent: document.getElementById('progressPercent'),
    progressBar: document.getElementById('progressBar'),
    statTotal: document.getElementById('statTotal'),
    statProcessed: document.getElementById('statProcessed'),
    statSuccess: document.getElementById('statSuccess'),
    statFailed: document.getElementById('statFailed'),
    currentFile: document.getElementById('currentFile'),
    speed: document.getElementById('speed'),
    remaining: document.getElementById('remaining'),
    btnCancel: document.getElementById('btnCancel'),
    resultTitle: document.getElementById('resultTitle'),
    taskMeta: document.getElementById('taskMeta'),
    resultSuccess: document.getElementById('resultSuccess'),
    resultFailed: document.getElementById('resultFailed'),
    btnDownloadExcel: document.getElementById('btnDownloadExcel'),
    btnBack: document.getElementById('btnBack'),
    failuresWrap: document.getElementById('failuresWrap'),
    failuresBody: document.getElementById('failuresBody'),
    errorAlert: document.getElementById('errorAlert'),
  }

  const state = {
    files: [],
    taskID: null,
    sse: null,
    lastProgress: null,
    status: 'idle',
  }

  function setStatus(text, kind) {
    el.statusText.textContent = text
    if (!kind) return
  }

  function showError(msg) {
    el.errorAlert.textContent = msg
    el.errorAlert.classList.remove('d-none')
  }

  function clearError() {
    el.errorAlert.classList.add('d-none')
    el.errorAlert.textContent = ''
  }

  function setView(name) {
    el.viewUpload.classList.toggle('d-none', name !== 'upload')
    el.viewProgress.classList.toggle('d-none', name !== 'progress')
    el.viewResult.classList.toggle('d-none', name !== 'result')
  }

  function renderFileList() {
    if (!state.files.length) {
      el.fileList.classList.add('text-muted')
      el.fileList.textContent = '暂无文件'
      el.btnStart.disabled = true
      return
    }

    el.fileList.classList.remove('text-muted')
    el.fileList.innerHTML = state.files.map((f, idx) => {
      const size = formatBytes(f.size)
      return `
        <div class="file-item">
          <div class="file-name">${escapeHtml(f.name)}</div>
          <div class="d-flex align-items-center gap-2">
            <div class="text-muted small">${size}</div>
            <button class="btn btn-sm btn-outline-danger" data-remove="${idx}">移除</button>
          </div>
        </div>
      `
    }).join('')

    el.btnStart.disabled = false
  }

  function bindFileListActions() {
    el.fileList.addEventListener('click', (e) => {
      const btn = e.target.closest('button[data-remove]')
      if (!btn) return
      const idx = parseInt(btn.getAttribute('data-remove'), 10)
      if (Number.isNaN(idx)) return
      state.files.splice(idx, 1)
      renderFileList()
    })
  }

  function setProgress(p) {
    const total = p.total || 0
    const processed = p.processed || 0
    const percent = total > 0 ? Math.min(100, Math.floor((processed / total) * 100)) : 0
    el.progressPercent.textContent = percent + '%'
    el.progressBar.style.width = percent + '%'
    el.statTotal.textContent = String(total)
    el.statProcessed.textContent = String(processed)
    el.statSuccess.textContent = String(p.success || 0)
    el.statFailed.textContent = String(p.failed || 0)
    el.currentFile.textContent = p.current || '-'
    el.speed.textContent = (typeof p.speed === 'number' ? p.speed.toFixed(1) : '-') 
    el.remaining.textContent = p.remaining || '-'
  }

  async function apiUpload(files) {
    const fd = new FormData()
    for (const f of files) fd.append('files', f)
    const res = await fetch('/api/upload', { method: 'POST', body: fd })
    const body = await safeJson(res)
    if (!res.ok || !body || body.code !== 200) {
      throw new Error((body && body.message) || '上传失败')
    }
    return body.data
  }

  async function apiScan(taskID, concurrency, timeout) {
    const res = await fetch('/api/scan', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ taskID, concurrency, timeout }),
    })
    const body = await safeJson(res)
    if (!res.ok || !body || body.code !== 200) {
      throw new Error((body && body.message) || '启动处理失败')
    }
    return body.data
  }

  async function apiResults(taskID) {
    const res = await fetch('/api/results/' + encodeURIComponent(taskID))
    const body = await safeJson(res)
    if (!res.ok || !body || body.code !== 200) {
      throw new Error((body && body.message) || '获取结果失败')
    }
    return body.data
  }

  async function apiCancel(taskID) {
    const res = await fetch('/api/cancel/' + encodeURIComponent(taskID), { method: 'POST' })
    const body = await safeJson(res)
    if (!res.ok || !body || body.code !== 200) {
      throw new Error((body && body.message) || '取消失败')
    }
    return body.data
  }

  function openSSE(taskID) {
    closeSSE()
    const url = '/api/progress/' + encodeURIComponent(taskID) + '/stream'
    const es = new EventSource(url)
    state.sse = es
    es.onmessage = (ev) => {
      try {
        const p = JSON.parse(ev.data)
        state.lastProgress = p
        setProgress(p)
        if (p.status === 'completed' || p.status === 'canceled' || p.status === 'failed') {
          closeSSE()
          void loadResultsAndShow()
        }
      } catch (_) {}
    }
    es.onerror = () => {
      closeSSE()
      showError('进度连接中断（SSE）')
      setStatus('出错')
    }
  }

  function closeSSE() {
    if (state.sse) {
      state.sse.close()
      state.sse = null
    }
  }

  async function loadResultsAndShow() {
    try {
      setStatus('整理结果')
      const data = await apiResults(state.taskID)
      renderResults(data)
      setView('result')
      clearError()
      if (data.status === 'canceled') {
        el.resultTitle.textContent = '已取消'
      } else if (data.status === 'failed') {
        el.resultTitle.textContent = '任务失败'
      } else {
        el.resultTitle.textContent = '处理完成！'
      }
      setStatus('就绪')
    } catch (e) {
      showError(e.message || '获取结果失败')
    }
  }

  function renderResults(data) {
    el.taskMeta.textContent = data.taskID || '-'
    const items = Array.isArray(data.items) ? data.items : []
    let success = 0
    let failed = 0
    const failures = []

    for (const it of items) {
      if (it.success) {
        success++
      } else {
        failed++
        failures.push(it)
      }
    }

    el.resultSuccess.textContent = String(success)
    el.resultFailed.textContent = String(failed)

    if (!failures.length) {
      el.failuresWrap.classList.add('d-none')
      el.failuresBody.innerHTML = ''
      return
    }

    el.failuresWrap.classList.remove('d-none')
    el.failuresBody.innerHTML = failures.map((it, idx) => {
      return `
        <tr>
          <td>${idx + 1}</td>
          <td class="text-break">${escapeHtml(it.file_path || '')}</td>
          <td class="text-break">${escapeHtml(it.error_message || '')}</td>
        </tr>
      `
    }).join('')
  }

  function resetAll() {
    closeSSE()
    state.files = []
    state.taskID = null
    state.lastProgress = null
    state.status = 'idle'
    el.fileInput.value = ''
    renderFileList()
    clearError()
    setProgress({ total: 0, processed: 0, success: 0, failed: 0, speed: 0, remaining: '' })
    setView('upload')
    setStatus('就绪')
  }

  function setupDropzone() {
    el.dropzone.addEventListener('click', () => el.fileInput.click())

    el.dropzone.addEventListener('dragover', (e) => {
      e.preventDefault()
      el.dropzone.classList.add('dragover')
    })
    el.dropzone.addEventListener('dragleave', () => el.dropzone.classList.remove('dragover'))
    el.dropzone.addEventListener('drop', (e) => {
      e.preventDefault()
      el.dropzone.classList.remove('dragover')
      const files = Array.from(e.dataTransfer.files || [])
      if (!files.length) return
      state.files.push(...files)
      renderFileList()
    })
  }

  el.fileInput.addEventListener('change', () => {
    const files = Array.from(el.fileInput.files || [])
    state.files.push(...files)
    renderFileList()
  })

  el.btnClear.addEventListener('click', () => {
    state.files = []
    el.fileInput.value = ''
    renderFileList()
  })

  el.btnStart.addEventListener('click', async () => {
    clearError()
    if (!state.files.length) return

    try {
      setStatus('上传中')
      el.btnStart.disabled = true
      const upload = await apiUpload(state.files)
      state.taskID = upload.taskID

      const concurrency = clampInt(parseInt(el.concurrencyInput.value, 10), 1, 32, 4)
      const timeout = clampInt(parseInt(el.timeoutInput.value, 10), 1, 60, 30)

      setStatus('启动处理中')
      await apiScan(state.taskID, concurrency, timeout)

      setView('progress')
      setStatus('处理中')
      openSSE(state.taskID)
    } catch (e) {
      showError(e.message || '处理失败')
      setStatus('出错')
      el.btnStart.disabled = false
    }
  })

  el.btnCancel.addEventListener('click', async () => {
    clearError()
    if (!state.taskID) return
    try {
      setStatus('取消中')
      await apiCancel(state.taskID)
      closeSSE()
      await loadResultsAndShow()
    } catch (e) {
      showError(e.message || '取消失败')
    }
  })

  el.btnDownloadExcel.addEventListener('click', () => {
    if (!state.taskID) return
    window.location.href = '/api/export/' + encodeURIComponent(state.taskID)
  })

  el.btnBack.addEventListener('click', () => resetAll())

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

  function formatBytes(bytes) {
    if (!bytes || bytes < 0) return '0 B'
    const units = ['B', 'KB', 'MB', 'GB']
    let n = bytes
    let i = 0
    while (n >= 1024 && i < units.length - 1) {
      n /= 1024
      i++
    }
    return n.toFixed(i === 0 ? 0 : 1) + ' ' + units[i]
  }

  async function safeJson(res) {
    try {
      return await res.json()
    } catch (_) {
      return null
    }
  }

  function clampInt(v, min, max, fallback) {
    if (!Number.isFinite(v)) return fallback
    if (v < min) return min
    if (v > max) return max
    return v
  }

  bindFileListActions()
  setupDropzone()
  resetAll()
})()