import { clear, h, icon, LOGO_SVG } from './dom'
import { initTheme } from './theme'
import {
  formatBytes,
  formatTimeAgo,
  detectKind,
  kindMeta,
  mimeForKind,
  readHead,
  SUPPORTED_ACCEPT,
  viewerFor,
  type FileKind
} from './files'
import { clearRecent, deleteRecent, listRecent, loadRecentFile, saveRecent, type RecentItem } from './recent'
import { createViewerHost, type ViewerHost } from './viewerHost'
import { toast } from './toast'
import { confirmDialog, modalMessage } from '../ui/modal'
import { showGuide } from '../ui/guide'

interface ActiveViewer {
  destroy: () => void
}

let host: ViewerHost | null = null
let activeViewer: ActiveViewer | null = null
let busy = false
let recentItems: RecentItem[] = []
let dropDepth = 0
let openToken = 0

let homeEl: HTMLElement
let viewerRoot: HTMLElement
let recentWrap: HTMLElement
let recentSection: HTMLElement
let fileInput: HTMLInputElement
let dropOverlay: HTMLElement

export function initApp(): void {
  initTheme()
  const app = document.getElementById('app')
  if (!app) throw new Error('app root missing')

  homeEl = buildHome()
  viewerRoot = h('div', { class: 'viewer-root', hidden: true })
  app.append(homeEl, viewerRoot)

  fileInput = h('input', {
    type: 'file',
    accept: SUPPORTED_ACCEPT,
    class: 'hidden-input',
    'aria-hidden': 'true',
    tabindex: '-1'
  })
  fileInput.addEventListener('change', () => {
    const file = fileInput.files?.[0]
    fileInput.value = ''
    if (file) void openFile(file)
  })
  document.body.appendChild(fileInput)

  dropOverlay = h(
    'div',
    { class: 'drop-overlay' },
    h('div', { class: 'drop-box' }, h('span', { class: 'drop-icon', html: icon('folder-open', 40) }), h('strong', { text: '松开以打开文件' }), h('span', { text: 'DWG · PDF · EPUB · XPS · CBZ · 图片' }))
  )
  document.body.appendChild(dropOverlay)

  bindGlobalEvents()
  void refreshRecent()
  handleLaunchQueue()
  ;(window as unknown as { __phoneViewerBack?: () => boolean }).__phoneViewerBack = () => {
    const modalClose = document.querySelector<HTMLButtonElement>('.modal-backdrop.show .modal-close')
    if (modalClose) {
      modalClose.click()
      return true
    }
    const sheet = document.querySelector<HTMLElement>('.sheet-backdrop.open')
    if (sheet) {
      sheet.classList.remove('open')
      return true
    }
    const menu = document.querySelector<HTMLElement>('.doc-menu.open')
    if (menu) {
      menu.classList.remove('open')
      return true
    }
    const searchClose = document.querySelector<HTMLButtonElement>(
      '.doc-search button[aria-label="关闭查找"]'
    )
    if (searchClose) {
      searchClose.click()
      return true
    }
    if (activeViewer) {
      closeActiveViewer()
      return true
    }
    return false
  }
  ;(window as unknown as { __phoneViewerOpenFile?: (file: File) => void }).__phoneViewerOpenFile = (
    file: File
  ) => {
    if (file) void openFile(file)
  }
}

function buildHome(): HTMLElement {
  const guideBtn = h(
    'button',
    { class: 'guide-btn', type: 'button', 'aria-label': '使用指南' },
    h('span', { html: icon('book-open', 18) }),
    h('span', { text: '使用指南' })
  )
  guideBtn.addEventListener('click', () => showGuide())

  const brand = h(
    'div',
    { class: 'home-brand' },
    h('div', { class: 'brand-mark', html: LOGO_SVG }),
    h('div', { class: 'brand-text' }, h('div', { class: 'brand-name', text: '万能看图' }))
  )

  const top = h(
    'header',
    { class: 'home-top simple-top' },
    brand,
    h('div', { class: 'home-actions' }, guideBtn)
  )

  const openBtn = h(
    'button',
    { class: 'open-file-card', type: 'button' },
    h('span', { class: 'open-file-icon', html: icon('folder-open', 24) }),
    h('span', { class: 'open-file-text' }, h('strong', { text: '打开图纸' })),
    h('span', { class: 'open-file-arrow', html: icon('chevron-right', 20) })
  )
  openBtn.addEventListener('click', () => fileInput.click())

  recentWrap = h('div', { class: 'recent-grid simple-recent-grid' })
  const clearBtn = h('button', {
    class: 'btn btn-ghost btn-sm recent-clear',
    type: 'button',
    text: '清空记录',
    hidden: true
  })
  clearBtn.addEventListener('click', () => void clearAllRecent())

  recentSection = h(
    'section',
    { class: 'recent-section simple-recent' },
    h('div', { class: 'section-head' }, h('h2', { text: '最近打开' }), clearBtn),
    recentWrap
  )

  return h(
    'div',
    { class: 'home home-simple' },
    h('div', { class: 'home-inner simple-inner' }, top, openBtn, recentSection)
  )
}

async function refreshRecent(): Promise<void> {
  recentItems = await listRecent()
  renderRecent()
}

function renderRecent(): void {
  if (!recentWrap) return
  clear(recentWrap)
  const clearBtn = recentSection.querySelector<HTMLButtonElement>('.recent-clear')
  if (clearBtn) clearBtn.hidden = recentItems.length === 0
  if (!recentItems.length) {
    recentWrap.appendChild(
      h(
        'div',
        { class: 'recent-empty' },
        h('span', { class: 'recent-empty-icon', html: icon('file', 26) }),
        h('strong', { text: '还没有最近文件' }),
        h('span', { text: '打开过的文件会显示在这里。' })
      )
    )
    return
  }
  for (const item of recentItems) {
    const meta = kindMeta(item.kind)
    const card = h('div', {
      class: 'recent-card',
      role: 'button',
      tabindex: '0',
      'aria-label': `打开 ${item.name}`
    })
    const iconEl = h('span', { class: `recent-icon tone-${meta.tone}`, html: icon(meta.icon, 22) })
    const info = h(
      'span',
      { class: 'recent-info' },
      h('span', { class: 'recent-name', text: item.name, title: item.name }),
      h('span', {
        class: 'recent-meta',
        text: `${meta.label} · ${formatBytes(item.size)} · ${formatTimeAgo(item.lastOpened)}${item.hasBlob ? '' : ' · 内容未保存'}`
      })
    )
    const del = h('button', { class: 'recent-del', type: 'button', 'aria-label': `删除 ${item.name}` })
    del.innerHTML = icon('trash', 16)
    del.addEventListener('click', (ev) => {
      ev.stopPropagation()
      void removeRecent(item)
    })
    card.append(iconEl, info, del)
    const activate = () => void openRecent(item)
    card.addEventListener('click', activate)
    card.addEventListener('keydown', (ev) => {
      if (ev.key === 'Enter' || ev.key === ' ') {
        ev.preventDefault()
        activate()
      }
    })
    recentWrap.appendChild(card)
  }
}

async function openRecent(item: RecentItem): Promise<void> {
  const file = await loadRecentFile(item.id, item.name)
  if (!file) {
    toast('文件内容没有被浏览器保存，请重新选择文件', 'info', 3800)
    fileInput.click()
    return
  }
  await openFile(file)
}

async function removeRecent(item: RecentItem): Promise<void> {
  await deleteRecent(item.id)
  await refreshRecent()
  toast('已从最近记录移除', 'success', 1600)
}

async function clearAllRecent(): Promise<void> {
  const ok = await confirmDialog('清空最近记录？', '所有最近打开的文件内容将从本机浏览器中删除。', '清空', {
    danger: true
  })
  if (!ok) return
  await clearRecent()
  await refreshRecent()
  toast('最近记录已清空', 'success', 1600)
}

async function openFile(file: File): Promise<void> {
  if (busy) {
    toast('正在打开文件，请稍候…', 'info', 1600)
    return
  }
  if (!file.size) {
    toast('文件为空', 'error')
    return
  }
  let kind: FileKind
  try {
    const head = await readHead(file)
    kind = detectKind(file.name, file.type, head)
  } catch {
    kind = detectKind(file.name, file.type)
  }
  const target = viewerFor(kind)
  if (!target) {
    toast('暂不支持这种文件类型', 'error', 3200)
    return
  }

  busy = true
  closeActiveViewer()
  const token = ++openToken
  host = createViewerHost(() => closeActiveViewer())
  host.setFileInfo(file.name, kindMeta(kind).label, kindMeta(kind).short, kindMeta(kind).tone, formatBytes(file.size))
  host.showLoader('正在准备…', file.name)
  viewerRoot.appendChild(host.root)
  viewerRoot.hidden = false
  homeEl.hidden = true
  document.title = `${file.name} · 万能看图`
  await new Promise<void>((resolve) => requestAnimationFrame(() => resolve()))

  let createdViewer: ActiveViewer | null = null
  try {
    if (target === 'cad') {
      const { FlyfishCadViewer } = await import('../cad/flyfishViewer')
      const viewer = new FlyfishCadViewer(host!, file, { onBack: () => closeActiveViewer() })
      createdViewer = viewer
      await viewer.load()
      if (token !== openToken) {
        viewer.destroy()
        return
      }
      activeViewer = viewer
      host?.hideLoader()
    } else {
      const [{ loadMuPDF }, { DocViewer }] = await Promise.all([
        import('../doc/mupdfLoader'),
        import('../doc/docViewer')
      ])
      const mupdf = await loadMuPDF()
      host?.setLoaderMessage('正在读取文件…', file.name)
      const bytes = new Uint8Array(await file.arrayBuffer())
      const magic =
        kind === 'xps' && /\.oxps$/i.test(file.name)
          ? 'application/oxps'
          : mimeForKind(kind, file.type)
      const viewer = new DocViewer(host!, mupdf, bytes, file.name, file.size, kind, magic)
      await viewer.init()
      if (token !== openToken) {
        viewer.destroy()
        return
      }
      createdViewer = viewer
      activeViewer = viewer
    }
    void saveRecent(file, kind)
      .catch(() => {})
      .then(() => refreshRecent())
      .catch(() => {})
  } catch (error) {
    if (createdViewer) {
      createdViewer.destroy()
    } else {
      host?.destroy()
    }
    host = null
    activeViewer = null
    viewerRoot.hidden = true
    homeEl.hidden = false
    document.title = '万能看图 · DWG/PDF 浏览器'
    const message = error instanceof Error ? error.message : String(error)
    console.error(error)
    modalMessage(
      '无法打开文件',
      message,
      kind === 'dwg' ? '提示：DWG 需要由 AutoCAD 2000 及之后的版本保存；过旧或加密的图纸可能暂时无法解析。' : undefined
    )
  } finally {
    busy = false
  }
}

function closeActiveViewer(): void {
  openToken++
  const viewer = activeViewer
  const previousHost = host
  activeViewer = null
  host = null
  if (viewer) {
    viewer.destroy()
  } else if (previousHost) {
    previousHost.destroy()
  }
  viewerRoot.innerHTML = ''
  viewerRoot.hidden = true
  homeEl.hidden = false
  document.title = '万能看图 · DWG/PDF 浏览器'
  void refreshRecent()
}

function bindGlobalEvents(): void {
  window.addEventListener('dragenter', (ev) => {
    if (!ev.dataTransfer?.types.includes('Files')) return
    ev.preventDefault()
    dropDepth++
    dropOverlay.classList.add('show')
  })
  window.addEventListener('dragover', (ev) => {
    if (!ev.dataTransfer?.types.includes('Files')) return
    ev.preventDefault()
    ev.dataTransfer.dropEffect = 'copy'
  })
  window.addEventListener('dragleave', (ev) => {
    if (!ev.dataTransfer?.types.includes('Files')) return
    dropDepth = Math.max(0, dropDepth - 1)
    if (dropDepth === 0) dropOverlay.classList.remove('show')
  })
  window.addEventListener('drop', (ev) => {
    if (!ev.dataTransfer?.files?.length) return
    ev.preventDefault()
    dropDepth = 0
    dropOverlay.classList.remove('show')
    const file = ev.dataTransfer.files[0]
    if (file) void openFile(file)
  })
  window.addEventListener('paste', (ev) => {
    const file = ev.clipboardData?.files?.[0]
    if (file) {
      ev.preventDefault()
      void openFile(file)
    }
  })
}

function handleLaunchQueue(): void {
  const launchQueue = (window as unknown as { launchQueue?: { setConsumer: (cb: (params: { files: Array<{ getFile: () => Promise<File> }> }) => void) => void } }).launchQueue
  if (!launchQueue) return
  launchQueue.setConsumer((params) => {
    const first = params.files?.[0]
    if (!first) return
    void first
      .getFile()
      .then((file) => openFile(file))
      .catch(() => toast('无法读取系统传入的文件', 'error'))
  })
}