/**
 * DWG / DXF 图纸查看器 —— 界面与交互装配。
 *
 * 数据流：文件 → source.js(解析) → flatten.js(展平成显示列表) → render.js(画)
 * 这里只负责把 UI 事件接到上面三层，以及图层面板、测量/批注工具、导出等外围功能。
 */

import ACI from './libs/dxf-parser/AutoCadColorIndex.js'
import { flatten } from './js/flatten.js'
import { BACKGROUNDS, Renderer } from './js/render.js'
import { extOf, loadDrawing } from './js/source.js'
import { ANNO_MODES, AnnoTool, MEASURE_MODES, MeasureTool, Snapper } from './js/tools.js'

const $ = (id) => document.getElementById(id)
const params = new URLSearchParams(location.search)

// ---------------------------------------------------------------- 状态

const S = {
  doc: null,
  shapes: [],
  layerStats: new Map(),     // 图层名 → 图元数
  tool: 'select',            // select | measure | anno | zoomBox
  embed: params.get('embed') === '1',
}

const wrap = $('canvasWrap')
const renderer = new Renderer(wrap)
const snapper = new Snapper(renderer)
const measure = new MeasureTool(renderer, snapper, () => { renderStats(); renderer.requestDraw() })
const anno = new AnnoTool(renderer, () => renderer.requestDraw())

renderer.overlay = (ctx, r) => {
  anno.draw(ctx, r)
  if (S.tool === 'measure' || measure.results.length) measure.draw(ctx, r)
  drawRubber(ctx, r)
}

if (S.embed) document.body.classList.add('embed')

// ---------------------------------------------------------------- 加载

function setLoading(on, text) {
  $('loading').classList.toggle('hidden', !on)
  if (text) $('loadingText').textContent = text
}

function showError(msg) {
  let box = $('errBox')
  if (!box) {
    box = document.createElement('div')
    box.id = 'errBox'
    $('viewport').appendChild(box)
  }
  box.innerHTML = ''
  box.append(msg)
  const b = document.createElement('button')
  b.className = 'small-btn'
  b.textContent = '关闭'
  b.style.marginLeft = '12px'
  b.onclick = () => box.remove()
  box.appendChild(b)
}

async function openBuffer(name, buffer) {
  setLoading(true, '正在解析图纸...')
  const t0 = performance.now()
  try {
    const doc = await loadDrawing(name, buffer, (m) => setLoading(true, m))
    setLoading(true, '正在生成图形...')
    await nextFrame()
    const { shapes, bbox, stats } = flatten(doc)
    if (!shapes.length) throw new Error('图纸里没有可显示的图元（可能是空图或全部实体类型暂不支持）')

    S.doc = doc
    S.buffer = buffer          // 留着给「上传并生成嵌入链接」用
    applyShapes(doc, shapes, bbox)
    measure.clear()
    anno.clear()
    setUnit(unitLabel(doc), true)
    buildLayoutSelect(doc)

    $('fileName').textContent = `${name}　·　${doc.format}　·　${stats.entities} 实体 / ${shapes.length} 图元`
    renderInfo(stats, performance.now() - t0)
    setStatus(`已加载 ${name}`)
    $('modelInfo').textContent = `${shapes.length} 图元 · ${(performance.now() - t0).toFixed(0)}ms`
  } catch (e) {
    console.error(e)
    showError(`打开失败：${e && e.message ? e.message : e}`)
  } finally {
    setLoading(false)
  }
}

const nextFrame = () => new Promise((r) => requestAnimationFrame(() => r()))

/** 把一份显示列表装进渲染器并刷新左侧图层面板 */
function applyShapes(doc, shapes, bbox) {
  S.shapes = shapes
  S.layerStats = new Map()
  for (const s of shapes) S.layerStats.set(s.layer, (S.layerStats.get(s.layer) || 0) + 1)
  renderer.setDocument(doc, shapes, bbox)
  renderer.zoomExtents()
  isolated = null
  buildLayerPanel()
  renderer.draw()
}

/**
 * 模型空间 / 图纸空间布局切换。
 * 国内机械图多半把图框画在模型空间，所以只有布局里真有实体时才显示这个下拉。
 */
function buildLayoutSelect(doc) {
  const sel = $('layoutSelect')
  const used = (doc.layouts || []).filter((l) => l.entities && l.entities.length)
  sel.innerHTML = ''
  const add = (val, text) => { const o = document.createElement('option'); o.value = val; o.textContent = text; sel.appendChild(o) }
  add('model', '模型空间')
  used.forEach((l, i) => add(String(i), l.name.replace(/^\*/, '') || `布局 ${i + 1}`))
  $('layoutBox').classList.toggle('hidden', used.length === 0)
  sel.value = 'model'
  sel.onchange = () => {
    const ents = sel.value === 'model' ? doc.modelEntities : used[+sel.value].entities
    const { shapes, bbox } = flatten(doc, { entities: ents })
    if (!shapes.length) { showError('该布局里没有可显示的图元'); sel.value = 'model'; return }
    applyShapes(doc, shapes, bbox)
    $('modelInfo').textContent = `${shapes.length} 图元`
  }
}

/** 单位：DWG 的 $INSUNITS 常年是默认值，所以给用户留了手动覆盖 */
function setUnit(u, fromFile) {
  measure.unit = u
  $('optUnit').value = u
  $('optUnitSrc').textContent = fromFile ? '自动' : '手动'
  measure.refresh()
  renderStats()
  renderer.requestDraw()
}

function openFile(file) {
  const ext = extOf(file.name)
  if (ext !== 'dwg' && ext !== 'dxf') { showError('只支持 .dwg 和 .dxf 文件'); return }
  S.loadPath = null               // 本地文件没有服务器路径，嵌入前要先上传
  const fr = new FileReader()
  fr.onload = () => openBuffer(file.name, fr.result)
  fr.onerror = () => showError('文件读取失败')
  setLoading(true, '正在读取文件...')
  fr.readAsArrayBuffer(file)
}

async function openUrl(url, loadPath) {
  setLoading(true, '正在读取图纸...')
  try {
    const { buffer, name } = await fetchDrawing(url)
    S.loadPath = loadPath || url      // 嵌入链接沿用真正打开的路径，别用裸文件名
    await openBuffer(name || url.split('/').pop() || url, buffer)
  } catch (e) {
    setLoading(false)
    showError(`读取失败：${e.message}（${url}）`)
  }
}

/**
 * 取图纸字节。
 *
 * 站内路径优先走「令牌 → 解密接口」：服务端用 .htaccess 封掉了 .dwg/.dxf/.enc 的直接 GET，
 * 只有拿到 5 分钟有效的 HMAC 令牌才能通过 api/model.php 读到内容，挡住直链下载和爬取。
 * 接口不存在时（比如本地 python 开发服务器没有 PHP）自动退回直连，不影响开发。
 */
async function fetchDrawing(url) {
  if (!/^https?:\/\//i.test(url)) {
    const via = await tryTokenFetch(url)
    if (via) return via
  }
  const res = await fetch(url)
  if (!res.ok) throw new Error(`HTTP ${res.status}`)
  return { buffer: await res.arrayBuffer(), name: '' }
}

/**
 * 走令牌接口取图纸；接口没部署就返回 null 让调用方直连。
 *
 * 判断「接口有没有部署」看的是响应内容而不是异常文本：本地开发用的 python
 * 静态服务器不会执行 PHP，会把 token.php 的源码当普通文件 200 发回来，
 * 只看状态码会误判成接口可用，然后 json() 直接炸掉。
 */
async function tryTokenFetch(url) {
  let tok
  try {
    const tr = await fetch(`api/token.php?f=${encodeURIComponent(url)}`, { cache: 'no-store' })
    if (!tr.ok) return null
    if (!/application\/json/i.test(tr.headers.get('content-type') || '')) return null
    tok = await tr.json()
  } catch {
    return null                       // 网络层失败：当作没部署
  }
  if (!tok || !tok.token) return null
  // 到这里说明接口确实在跑，它再拒绝就该明确报错，不能悄悄退回直连
  const mr = await fetch(
    `api/model.php?f=${encodeURIComponent(url)}&t=${tok.token}&e=${tok.expires}`, { cache: 'no-store' })
  if (!mr.ok) {
    const j = await mr.json().catch(() => ({}))
    throw new Error(j.error || `读取接口返回 ${mr.status}`)
  }
  // 落盘名是随机的，真实文件名由接口通过头带回
  const hdr = mr.headers.get('X-Filename')
  return { buffer: await mr.arrayBuffer(), name: hdr ? decodeURIComponent(hdr) : '' }
}

/** 把当前图纸上传到服务器（加密落盘 + 随机文件名），返回可用于嵌入的路径 */
async function uploadCurrent() {
  if (!S.buffer) throw new Error('还没有打开图纸')
  const res = await fetch('api/upload.php', {
    method: 'POST',
    headers: { 'X-Filename': encodeURIComponent(S.doc.name), 'Content-Type': 'application/octet-stream' },
    body: S.buffer,
  })
  const j = await res.json().catch(() => ({}))
  if (!res.ok) throw new Error(j.error || `HTTP ${res.status}`)
  return j.path
}

/**
 * $INSUNITS → 单位标签。
 * 只认公制的显式取值：0（未设）和 1（英寸）多半是 CAD 的默认值没改过，
 * 国内机械图实际都是毫米，直接按英寸显示会差 25.4 倍。用户可在设置里改。
 */
function unitLabel(doc) {
  const u = doc.header && doc.header.INSUNITS
  return ({ 2: 'ft', 4: 'mm', 5: 'cm', 6: 'm', 13: 'µm' })[u] || 'mm'
}

// ---------------------------------------------------------------- 图层面板

function buildLayerPanel() {
  const box = $('tree')
  box.innerHTML = ''
  if (!S.doc) return
  const names = [...S.doc.layers.keys()].sort((a, b) => a.localeCompare(b, 'zh'))
  // 没有任何图元的图层排到后面
  names.sort((a, b) => (S.layerStats.get(b) || 0) - (S.layerStats.get(a) || 0))
  $('layerCount').textContent = `(${names.length})`

  for (const name of names) {
    const layer = S.doc.layers.get(name)
    const n = S.layerStats.get(name) || 0
    const row = document.createElement('div')
    row.className = 'tree-row'
    row.dataset.layer = name

    const cb = document.createElement('input')
    cb.type = 'checkbox'
    cb.className = 'tree-check'
    cb.checked = !renderer.hidden.has(name)
    cb.onchange = () => {
      if (cb.checked) renderer.hidden.delete(name); else renderer.hidden.add(name)
      row.classList.toggle('off', !cb.checked)
      renderer.requestDraw()
    }

    const sw = document.createElement('span')
    sw.className = 'layer-swatch'
    sw.style.background = swatchColor(layer)

    const lb = document.createElement('span')
    lb.className = 'tree-label'
    lb.textContent = name
    lb.title = `${name}（${n} 个图元）`

    const num = document.createElement('span')
    num.className = 'tree-num'
    num.textContent = n || ''

    row.append(cb, sw, lb, num)
    // 点行（不含勾选框）= 只显示这一层
    row.onclick = (e) => {
      if (e.target === cb) return
      isolateLayer(name)
    }
    box.appendChild(row)
  }
  if (!names.length) box.innerHTML = '<div class="tree-empty">没有图层</div>'
}

function swatchColor(layer) {
  if (!layer) return '#000'
  let c = 0
  if (typeof layer.trueColor === 'number') c = layer.trueColor
  else if (layer.colorIndex != null) {
    const idx = Math.abs(layer.colorIndex)
    c = idx === 7 ? 0x000000 : ACI_CACHE[idx] || 0x000000
  }
  return `#${(c >>> 0).toString(16).padStart(6, '0')}`
}

const ACI_CACHE = ACI

let isolated = null
function isolateLayer(name) {
  if (isolated === name) {
    renderer.hidden.clear()
    isolated = null
  } else {
    renderer.hidden.clear()
    for (const k of S.doc.layers.keys()) if (k !== name) renderer.hidden.add(k)
    isolated = name
  }
  syncLayerChecks()
  renderer.requestDraw()
  setStatus(isolated ? `只显示图层「${name}」，再点一次恢复` : '已显示全部图层')
}

function syncLayerChecks() {
  for (const row of $('tree').children) {
    const cb = row.querySelector('input')
    if (!cb) continue
    cb.checked = !renderer.hidden.has(row.dataset.layer)
    row.classList.toggle('off', !cb.checked)
  }
}

$('treeSearch').addEventListener('input', () => {
  const q = $('treeSearch').value.trim().toLowerCase()
  for (const row of $('tree').children) {
    const name = (row.dataset.layer || '').toLowerCase()
    const hit = !q || name.includes(q)
    row.style.display = hit ? '' : 'none'
    row.classList.toggle('matched', !!q && hit)
  }
})
$('btnLayerAll').onclick = () => { renderer.hidden.clear(); isolated = null; syncLayerChecks(); renderer.requestDraw() }
$('btnLayerNone').onclick = () => {
  for (const k of S.doc ? S.doc.layers.keys() : []) renderer.hidden.add(k)
  isolated = null; syncLayerChecks(); renderer.requestDraw()
}
$('btnLayerInvert').onclick = () => {
  for (const k of S.doc ? S.doc.layers.keys() : []) {
    if (renderer.hidden.has(k)) renderer.hidden.delete(k); else renderer.hidden.add(k)
  }
  isolated = null; syncLayerChecks(); renderer.requestDraw()
}

// ---------------------------------------------------------------- 工具栏

function setTool(t) {
  S.tool = t
  for (const b of document.querySelectorAll('#toolbar .tool-btn[data-tool]')) {
    b.classList.toggle('active', b.dataset.tool === t)
  }
  const isMeasure = t === 'measure'
  const isAnno = t === 'anno'
  $('toolbar').classList.toggle('hidden', isMeasure || isAnno)
  $('measurePanel').classList.toggle('hidden', !isMeasure)
  $('annoPanel').classList.toggle('hidden', !isAnno)
  if (!isMeasure) measure.setMode(null)
  if (!isAnno) anno.setMode(null)
  wrap.classList.toggle('crosshair', isMeasure || isAnno || t === 'zoomBox')
  setStatus(TOOL_HINT[t] || '')
  renderer.requestDraw()
}

const TOOL_HINT = {
  select: '选择：点击图元查看属性 · 拖动平移 · 滚轮缩放 · 双击全图',
  measure: '测量：先选测量方式，再在图上点取（自动捕捉端点/中点/圆心）',
  anno: '批注：先选批注方式，在图上拖动绘制',
  zoomBox: '框选放大：按住左键拖出矩形',
}

for (const b of document.querySelectorAll('#toolbar .tool-btn[data-tool]')) {
  b.onclick = () => setTool(b.dataset.tool)
}

// 测量子面板
const mBox = $('measureModes')
for (const m of MEASURE_MODES) {
  const b = document.createElement('button')
  b.className = 'measure-btn'
  b.title = m.name
  b.innerHTML = `<img src="./icons/${m.icon}" alt=""><span>${m.name}</span>`
  b.onclick = () => {
    const on = measure.mode === m.id
    measure.setMode(on ? null : m.id)
    for (const x of mBox.children) x.classList.remove('active')
    if (!on) b.classList.add('active')
    setStatus(on ? '' : `${m.name}：在图上点取`)
  }
  mBox.appendChild(b)
}
$('btnMeasureClose').onclick = () => setTool('select')
$('btnMeasureClear').onclick = () => measure.clear()
$('btnStats').onclick = () => togglePanel('stats')

// 批注子面板
const aBox = $('annoModes')
for (const m of ANNO_MODES) {
  const b = document.createElement('button')
  b.className = 'measure-btn'
  b.title = m.name
  b.innerHTML = `<img src="./icons/${m.icon}" alt=""><span>${m.name}</span>`
  b.onclick = () => {
    const on = anno.mode === m.id
    anno.setMode(on ? null : m.id)
    for (const x of aBox.children) x.classList.remove('active')
    if (!on) b.classList.add('active')
  }
  aBox.appendChild(b)
}
$('btnAnnoClose').onclick = () => setTool('select')
$('btnAnnoClear').onclick = () => anno.clear()
$('btnAnnoUndo').onclick = () => anno.undo()
$('annoColor').oninput = (e) => { anno.color = e.target.value }
$('annoWidth').onchange = (e) => { anno.width = +e.target.value }

// 其它工具按钮
$('btnLayerPanel').onclick = (e) => {
  if (e) e.stopPropagation()   // 别让「点击外部收起抽屉」把这次打开又关掉
  if (window.innerWidth <= 768) {
    // 手机：图层面板是抽屉，点按钮开合（默认隐藏）
    document.body.classList.toggle('tree-open')
  } else {
    // 桌面：默认显示，点击隐藏/显示侧栏
    document.body.classList.toggle('no-tree')
  }
  renderer.resize()
}
// 手机抽屉：✕ 按钮关闭 + 点击抽屉外部自动收起
const btnTreeClose = $('btnTreeClose')
if (btnTreeClose) btnTreeClose.onclick = () => document.body.classList.remove('tree-open')
document.addEventListener('click', (e) => {
  if (window.innerWidth > 768 || !document.body.classList.contains('tree-open')) return
  if (!$('treePanel').contains(e.target)) document.body.classList.remove('tree-open')
})
$('btnFind').onclick = () => togglePanel('find')
$('btnSettings').onclick = () => togglePanel('settings')
$('btnInfo').onclick = () => togglePanel('info')
$('btnReset').onclick = () => { setRotation(0); renderer.zoomExtents(); renderer.requestDraw() }
$('btnLineWeight').onclick = () => {
  renderer.opts.lineWeight = !renderer.opts.lineWeight
  $('btnLineWeight').classList.toggle('active', renderer.opts.lineWeight)
  $('optLineWeight').checked = renderer.opts.lineWeight
  renderer.requestDraw()
}
$('btnSnapshot').onclick = snapshot
$('btnPrint').onclick = printDrawing
$('btnOpen').onclick = () => $('fileInput').click()
$('fileInput').onchange = (e) => { if (e.target.files[0]) openFile(e.target.files[0]) }
$('btnFullscreen').onclick = () => toggleFullscreen()
$('btnEmbed').onclick = () => { togglePanel('embed'); updateEmbed() }

for (const el of document.querySelectorAll('.panel-close')) {
  el.onclick = () => $(`${el.dataset.panel}Panel`).classList.add('hidden')
}

function togglePanel(name) {
  const p = $(`${name}Panel`)
  const willShow = p.classList.contains('hidden')
  for (const n of ['stats', 'find', 'settings', 'info', 'embed']) {
    if (n !== name) $(`${n}Panel`).classList.add('hidden')
  }
  p.classList.toggle('hidden', !willShow)
  if (willShow && name === 'find') $('findInput').focus()
}

// ---------------------------------------------------------------- 显示设置

// ---- 背景（浅灰 / 米白 / 黑，与新迪 2D 一致）----
const bgBox = $('bgSwatches')
for (const b of BACKGROUNDS) {
  const el = document.createElement('button')
  el.className = 'bg-swatch'
  el.dataset.bg = b.id
  el.title = b.name
  el.style.background = b.color
  el.onclick = () => setBackground(b.id)
  bgBox.appendChild(el)
}

/** 背景偏好存本地，下次打开还是上次那个底 */
function setBackground(id) {
  const b = BACKGROUNDS.find((x) => x.id === id) || BACKGROUNDS[0]
  renderer.opts.bg = b.color
  for (const el of bgBox.children) el.classList.toggle('active', el.dataset.bg === b.id)
  $('btnBg').classList.toggle('active', renderer.isDarkBg)
  try { localStorage.setItem('dwgviewer.bg', b.id) } catch { /* 隐私模式下写不了，忽略 */ }
  renderer.requestDraw()
}

/** 工具栏那个按钮循环切三种底 */
$('btnBg').onclick = () => {
  const i = BACKGROUNDS.findIndex((b) => b.color === renderer.opts.bg)
  const next = BACKGROUNDS[(i + 1) % BACKGROUNDS.length]
  setBackground(next.id)
  setStatus(`背景：${next.name}`)
}
$('optContrast').onchange = (e) => { renderer.opts.autoContrast = e.target.checked; renderer.requestDraw() }

// ---- 视图旋转 ----
function setRotation(rad, fromSlider) {
  renderer.setRotation(rad)
  const deg = Math.round((renderer.view.rot * 180) / Math.PI)
  if (!fromSlider) $('optRot').value = deg
  $('optRotVal').textContent = `${deg}°`
  renderer.requestDraw()
}
/** 转 90°：原本铺满视口的话转完继续铺满，已经放大过就保持倍数不动 */
function rotate90(dir) {
  const wasFitted = renderer.isFitted()
  setRotation(renderer.view.rot + dir * Math.PI / 2)
  if (wasFitted) renderer.zoomExtents()
  renderer.requestDraw()
}
$('btnRotL2').onclick = () => rotate90(1)
$('btnRotR2').onclick = () => rotate90(-1)
$('btnRot0').onclick = () => setRotation(0)
$('optRot').oninput = (e) => setRotation((+e.target.value * Math.PI) / 180, true)

// ---- 全屏（底部工具栏那个在嵌入模式下也能点到）----
function toggleFullscreen() {
  if (document.fullscreenElement) document.exitFullscreen()
  else document.documentElement.requestFullscreen()
}
$('btnFull').onclick = toggleFullscreen
$('optText').onchange = (e) => { renderer.opts.showText = e.target.checked; renderer.requestDraw() }
$('optHatch').onchange = (e) => { renderer.opts.showHatch = e.target.checked; renderer.requestDraw() }
$('optLineWeight').onchange = (e) => {
  renderer.opts.lineWeight = e.target.checked
  $('btnLineWeight').classList.toggle('active', e.target.checked)
  renderer.requestDraw()
}
$('optLwScale').oninput = (e) => {
  renderer.opts.lineWeightScale = e.target.value / 100
  $('optLwVal').textContent = `${(e.target.value / 100).toFixed(1)}x`
  if (renderer.opts.lineWeight) renderer.requestDraw()
}
$('optUnit').onchange = (e) => setUnit(e.target.value, false)
$('optPrec').oninput = (e) => {
  measure.precision = +e.target.value
  $('optPrecVal').textContent = e.target.value
  measure.refresh()
  renderStats()
  renderer.requestDraw()
}

// ---------------------------------------------------------------- 鼠标交互

let drag = null
let rubber = null           // 框选/框放大的临时矩形（屏幕 CSS 像素）

wrap.addEventListener('contextmenu', (e) => e.preventDefault())

wrap.addEventListener('pointerdown', (e) => {
  wrap.setPointerCapture(e.pointerId)
  const pos = local(e)
  // 中键/右键始终是平移；左键看当前工具
  if (e.button === 1 || e.button === 2) {
    drag = { mode: 'pan', x: e.clientX, y: e.clientY }
    wrap.classList.add('panning')
    return
  }
  if (e.button !== 0) return

  if (S.tool === 'zoomBox') { rubber = { x0: pos.x, y0: pos.y, x1: pos.x, y1: pos.y, kind: 'zoom' }; return }
  if (S.tool === 'anno' && anno.mode) { if (anno.down(pos.x, pos.y)) { drag = { mode: 'anno' }; return } }
  if (S.tool === 'measure' && measure.mode) return   // 测量在 pointerup 里按点击处理

  drag = { mode: 'maybe-pan', x: e.clientX, y: e.clientY, sx: pos.x, sy: pos.y, moved: false }
})

wrap.addEventListener('pointermove', (e) => {
  const pos = local(e)
  updateCoord(pos)

  if (rubber) { rubber.x1 = pos.x; rubber.y1 = pos.y; renderer.requestDraw(); return }
  if (drag && drag.mode === 'anno') { anno.move(pos.x, pos.y); renderer.requestDraw(); return }
  if (drag && (drag.mode === 'pan' || drag.mode === 'maybe-pan')) {
    const dx = e.clientX - drag.x, dy = e.clientY - drag.y
    if (drag.mode === 'maybe-pan' && Math.hypot(dx, dy) < 3) return
    if (drag.mode === 'maybe-pan') { drag.mode = 'pan'; drag.moved = true; wrap.classList.add('panning') }
    renderer.panByPixels(dx, dy)
    drag.x = e.clientX; drag.y = e.clientY
    renderer.requestDraw()
    return
  }

  if (S.tool === 'measure' && measure.mode) { measure.hover(pos.x, pos.y); renderer.requestDraw(); return }
  if (S.tool === 'select') {
    const idx = renderer.pick(pos.x, pos.y, 6)
    if (idx !== renderer.highlight) { renderer.highlight = idx; renderer.requestDraw() }
  }
})

wrap.addEventListener('pointerup', (e) => {
  const pos = local(e)
  wrap.classList.remove('panning')
  try { wrap.releasePointerCapture(e.pointerId) } catch { /* 指针已释放 */ }

  if (rubber) {
    const r = rubber; rubber = null
    if (Math.abs(r.x1 - r.x0) > 6 && Math.abs(r.y1 - r.y0) > 6) {
      const a = renderer.toWorld(r.x0, r.y0), b = renderer.toWorld(r.x1, r.y1)
      renderer.zoomToBox([Math.min(a.x, b.x), Math.min(a.y, b.y), Math.max(a.x, b.x), Math.max(a.y, b.y)])
      setTool('select')
    }
    renderer.requestDraw()
    return
  }
  if (drag && drag.mode === 'anno') { anno.up(); drag = null; return }
  const wasPan = drag && drag.mode === 'pan'
  const wasClick = drag && drag.mode === 'maybe-pan'
  drag = null
  if (wasPan) return

  if (e.button !== 0) return
  if (S.tool === 'measure' && measure.mode) { measure.click(pos.x, pos.y); renderer.requestDraw(); return }
  if (S.tool === 'select' && wasClick) selectAt(pos)
})

wrap.addEventListener('dblclick', () => {
  if (S.tool === 'measure' && measure.mode) { measure.finish(); return }
  renderer.zoomExtents()
  renderer.requestDraw()
})

wrap.addEventListener('wheel', (e) => {
  e.preventDefault()
  const pos = local(e)
  const f = e.deltaY < 0 ? 1.18 : 1 / 1.18
  renderer.zoomAt(pos.x, pos.y, f)
  renderer.requestDraw()
  updateCoord(pos)
}, { passive: false })

function local(e) {
  const r = wrap.getBoundingClientRect()
  return { x: e.clientX - r.left, y: e.clientY - r.top }
}

function updateCoord(pos) {
  const w = renderer.toWorld(pos.x, pos.y)
  $('coordText').textContent = S.doc ? `X ${w.x.toFixed(2)}   Y ${w.y.toFixed(2)}   1:${(1 / renderer.view.scale * renderer.dpr).toFixed(2)}` : ''
}

function selectAt(pos) {
  const idx = renderer.pick(pos.x, pos.y, 6)
  renderer.selection.clear()
  if (idx != null) {
    renderer.selection.add(idx)
    showProps(renderer.shapes[idx])
  } else {
    $('propPanel').classList.add('hidden')
  }
  renderer.requestDraw()
}

function drawRubber(ctx, r) {
  if (!rubber) return
  const d = r.dpr
  ctx.save()
  // 框选矩形是屏幕上的物件，不跟着图纸转，所以撤掉 overlay 的视图旋转
  ctx.setTransform(1, 0, 0, 1, 0, 0)
  ctx.strokeStyle = '#2b9ae8'
  ctx.fillStyle = 'rgba(43,154,232,.12)'
  ctx.lineWidth = 1.5 * d
  ctx.setLineDash([5 * d, 4 * d])
  const x = Math.min(rubber.x0, rubber.x1) * d, y = Math.min(rubber.y0, rubber.y1) * d
  const w = Math.abs(rubber.x1 - rubber.x0) * d, h = Math.abs(rubber.y1 - rubber.y0) * d
  ctx.fillRect(x, y, w, h)
  ctx.strokeRect(x, y, w, h)
  ctx.restore()
}

document.addEventListener('keydown', (e) => {
  if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return
  if (e.key === 'Escape') {
    measure.cancel(); anno.setMode(anno.mode); rubber = null
    renderer.selection.clear(); $('propPanel').classList.add('hidden')
    renderer.requestDraw()
  } else if (e.key === 'Enter') {
    measure.finish(); renderer.requestDraw()
  } else if (e.key === 'e' || e.key === 'E') {
    renderer.zoomExtents(); renderer.requestDraw()
  }
})

// ---------------------------------------------------------------- 面板内容

function renderStats() {
  const box = $('statsList')
  box.innerHTML = ''
  if (!measure.results.length) { box.innerHTML = '<div class="stats-empty">暂无测量结果</div>'; return }
  measure.results.forEach((r, i) => {
    const row = document.createElement('div')
    row.className = 'stats-row'
    row.innerHTML = `<span class="stats-type">${r.type}</span><span class="stats-value" title="${r.text}">${r.text}</span>`
    const del = document.createElement('span')
    del.className = 'stats-del'
    del.textContent = '×'
    del.onclick = () => measure.remove(i)
    row.appendChild(del)
    box.appendChild(row)
  })
}

function renderInfo(stats, ms) {
  const d = S.doc
  const b = renderer.bbox
  const kv = (k, v) => `<div class="kv"><b>${k}</b><span>${v}</span></div>`
  const types = Object.entries(stats.byType).sort((a, b2) => b2[1] - a[1])
    .map(([k, v]) => `${k} ${v}`).join('、')
  $('infoBody').innerHTML =
    kv('文件', d.name) +
    kv('格式', d.format) +
    kv('图层', d.layers.size) +
    kv('块', d.blocks.size) +
    kv('实体', stats.entities) +
    kv('图元', S.shapes.length) +
    kv('范围', `${(b[2] - b[0]).toFixed(1)} × ${(b[3] - b[1]).toFixed(1)} ${measure.unit}`) +
    kv('解析耗时', `${ms.toFixed(0)} ms`) +
    kv('实体分布', types || '—') +
    `<div class="lic">解析内核：${d.format === 'DWG' ? 'LibreDWG (WebAssembly)' : 'dxf-parser'}　许可证 ${d.license}。
     ${d.format === 'DWG' ? 'GPL-3.0 会传染到分发的前端代码，商用前请评估，或把 DWG 解析换成服务端/商业 SDK。' : ''}</div>`
}

function showProps(s) {
  if (!s) return
  const e = s.ent || {}
  const kv = (k, v) => (v == null || v === '' ? '' : `<div class="kv"><b>${k}</b><span>${v}</span></div>`)
  const b = s.bbox
  $('propBody').innerHTML =
    kv('类型', e.type || s.kind) +
    kv('图层', s.layer) +
    kv('句柄', e.handle) +
    kv('颜色', `#${(s.color >>> 0).toString(16).padStart(6, '0')}`) +
    kv('线型', s.lt || 'Continuous') +
    kv('线宽', s.lw >= 0 ? `${(s.lw / 100).toFixed(2)} mm` : '随层') +
    kv('文字', s.plain ? s.plain.slice(0, 200) : '') +
    kv('半径', s.kind === 'arc' ? s.rx.toFixed(3) : '') +
    kv('包围盒', `${(b[2] - b[0]).toFixed(2)} × ${(b[3] - b[1]).toFixed(2)}`)
  $('propPanel').classList.remove('hidden')
}

// ---------------------------------------------------------------- 文字查找

$('findInput').addEventListener('keydown', (e) => { if (e.key === 'Enter') doFind() })

function doFind() {
  const q = $('findInput').value.trim().toLowerCase()
  const box = $('findResult')
  box.innerHTML = ''
  if (!q) { box.innerHTML = '<div class="stats-empty">输入关键字后回车</div>'; return }
  const hits = []
  for (const s of S.shapes) {
    if (!s.plain) continue
    if (s.plain.toLowerCase().includes(q)) hits.push(s)
    if (hits.length >= 300) break
  }
  if (!hits.length) { box.innerHTML = '<div class="stats-empty">没有匹配的文字</div>'; return }
  for (const s of hits) {
    const row = document.createElement('div')
    row.className = 'find-row'
    row.innerHTML = `${escapeHtml(s.plain.slice(0, 60))}<span class="find-layer">${escapeHtml(s.layer)}</span>`
    row.onclick = () => {
      const b = s.bbox
      const pad = Math.max((b[2] - b[0]), (b[3] - b[1])) * 6 + 1
      renderer.zoomToBox([b[0] - pad, b[1] - pad, b[2] + pad, b[3] + pad])
      renderer.selection.clear()
      renderer.selection.add(s.i)
      renderer.requestDraw()
    }
    box.appendChild(row)
  }
  setStatus(`找到 ${hits.length} 处文字`)
}

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

// ---------------------------------------------------------------- 导出

function snapshot() {
  renderer.draw()
  renderer.canvas.toBlob((blob) => {
    const a = document.createElement('a')
    a.href = URL.createObjectURL(blob)
    a.download = `${(S.doc && S.doc.name || 'drawing').replace(/\.[^.]+$/, '')}.png`
    a.click()
    setTimeout(() => URL.revokeObjectURL(a.href), 5000)
  }, 'image/png')
}

function printDrawing() {
  if (!S.doc) return
  renderer.draw()
  const url = renderer.canvas.toDataURL('image/png')
  const w = window.open('', '_blank')
  if (!w) { showError('浏览器拦截了打印窗口，请允许弹出窗口'); return }
  w.document.write(`<!DOCTYPE html><html><head><meta charset="utf-8"><title>${escapeHtml(S.doc.name)}</title>
    <style>@page{size:auto;margin:8mm}body{margin:0}img{width:100%}</style></head>
    <body><img src="${url}" onload="window.focus();window.print();"></body></html>`)
  w.document.close()
}

// ---------------------------------------------------------------- 嵌入

function updateEmbed() {
  // 默认沿用图纸真正打开时的路径（相对查看器目录），避免生成打不开的裸文件名链接；
  // 本地拖进来的图纸没有服务器路径，得先「上传当前图纸」。
  // 用 ?file= 打开时把真实路径回填到输入框（与 STEPViewer 行为一致），
  // 否则「图纸路径」框空着、只有地址生成，容易误以为坏了。
  if (S.loadPath && !$('embedPath').value.trim()) $('embedPath').value = S.loadPath
  const path = $('embedPath').value.trim()
  const base = location.origin + location.pathname
  if (!path) {
    $('embedUrl').value = ''
    $('embedCode').value = ''
    return
  }
  const url = `${base}?file=${encodeURIComponent(path)}&embed=1`
  $('embedUrl').value = url
  $('embedCode').value = `<iframe src="${url}" width="100%" height="640" frameborder="0" allowfullscreen></iframe>`
}
$('embedPath').addEventListener('input', updateEmbed)
$('btnUpload').onclick = async () => {
  const btn = $('btnUpload')
  btn.disabled = true
  btn.textContent = '上传中...'
  try {
    const path = await uploadCurrent()
    if (!path) throw new Error('上传接口返回异常（接口未部署）')
    $('embedPath').value = path
    updateEmbed()
    setStatus(`已加密上传：${path}`)
    // 嵌在入口页里时通知它刷新首页数模库
    try { window.parent.postMessage({ type: 'library-updated' }, '*') } catch { /* 独立打开 */ }
  } catch (e) {
    showError(`上传失败：${e.message}（本地开发服务器没有 PHP，需要在正式站点上试）`)
  } finally {
    btn.disabled = false
    btn.textContent = '上传当前图纸'
  }
}
$('btnCopyUrl').onclick = () => copy($('embedUrl').value)
$('btnCopyCode').onclick = () => copy($('embedCode').value)
function copy(t) {
  navigator.clipboard.writeText(t).then(() => setStatus('已复制到剪贴板'), () => setStatus('复制失败，请手动选择'))
}

// ---------------------------------------------------------------- 杂项

function setStatus(t) { $('statusText').textContent = t || TOOL_HINT[S.tool] || '就绪' }

new ResizeObserver(() => renderer.resize()).observe(wrap)

// 拖拽打开
let dragDepth = 0
document.addEventListener('dragenter', (e) => { e.preventDefault(); dragDepth++; $('dropOverlay').classList.remove('hidden') })
document.addEventListener('dragleave', () => { if (--dragDepth <= 0) { dragDepth = 0; $('dropOverlay').classList.add('hidden') } })
document.addEventListener('dragover', (e) => e.preventDefault())
document.addEventListener('drop', (e) => {
  e.preventDefault()
  dragDepth = 0
  $('dropOverlay').classList.add('hidden')
  const f = e.dataTransfer.files[0]
  if (f) openFile(f)
})

// 调试用：控制台里可以直接摸到渲染器、文档和工具
window.__R = renderer
window.__S = S
window.__ANNO = anno
window.__MEASURE = measure

// 恢复上次的背景偏好；嵌入时可用 ?bg=black|beige|grey 直接指定
let savedBg = BACKGROUNDS[0].id
try { savedBg = params.get('bg') || localStorage.getItem('dwgviewer.bg') || savedBg } catch { /* 隐私模式读不到 */ }
setBackground(savedBg === 'dark' ? 'black' : savedBg)

// 先画一次底色，否则 alpha:false 的画布初始是黑的
renderer.draw()
setStatus()

// 统一入口（../index.html）在 iframe 里把用户选的图纸传进来
window.addEventListener('message', (e) => {
  const data = e.data
  if (!data || data.type !== 'viewer-file' || data.kind !== 'dwg') return
  try { if (e.origin !== location.origin) return } catch { return }
  openBuffer(data.name || 'drawing.dwg', data.buffer)
})
try { window.parent.postMessage({ type: 'viewer-ready' }, '*') } catch { /* 没嵌在入口里 */ }

// URL 参数直接打开
const fileParam = params.get('file')
if (fileParam) openUrl(fileParam, fileParam)