import type { ClientContext } from '@deepseek-ai/dsh-client-runtime/client'
import type {
  InputTriggerSource,
  ReferenceInsert,
} from '@deepseek-ai/dsh-client-ui-input-trigger/client'
import type { QingSelection } from '../contracts.js'

export const QING_SELECTION_REFERENCE_SOURCE = 'qingagent-selection'

// 选区与批注共用同一段 chip label 预览预算:底层投影 label 定 chip 宽度,显示层
// (12px 覆盖文本「“选段:/✎ 批注:」+完整内容)按此宽度 ellipsis——10 个全角字的
// 16px 底宽≈14 个 12px 显示字,恰好容纳图标+前缀+10 字内容(用户裁定的下限)。
export const CHIP_LABEL_PREVIEW_LENGTH = 10

const CIRCLED_NUMBERS = ['①', '②', '③', '④', '⑤', '⑥', '⑦', '⑧', '⑨', '⑩', '⑪', '⑫', '⑬', '⑭', '⑮', '⑯', '⑰', '⑱', '⑲', '⑳'] as const

/** WORD JOINER(U+2060):零宽、禁断行。织入 label 字符间让整枚 chip 成为浏览器眼中
 *  的原子词——换行时整体挪行,从根上消灭「chip 中间被拆成两段、覆盖层只画一半」的
 *  空白块(用户实测)。零宽不改字符度量,textarea 与镜像同规则;发送展开走 ref,
 *  joiner 永不进入消息正文。 */
export const CHIP_ATOMIC_JOINER = '\u2060'

export function weaveAtomicLabel(label: string): string {
  return Array.from(label).join(CHIP_ATOMIC_JOINER)
}

export function unweaveAtomicLabel(label: string): string {
  return label.replaceAll(CHIP_ATOMIC_JOINER, '')
}

/** 多枚 chip 的投影 label 必须互不为前缀(setDraft diff 歧义会吞相邻 occurrence)。
 *  序号前置:首字符即分叉。选段连选相邻内容时前 10 字极易相同,与批注共用这道防线。 */
export function dedupeChipLabel(label: string, takenLabels: readonly string[]): string {
  const taken = takenLabels.map(unweaveAtomicLabel)
  if (!taken.some((existing) => existing.startsWith(label) || label.startsWith(existing))) {
    return label
  }
  const first = new Set(taken.map((existing) => existing.charAt(0)))
  const circled = CIRCLED_NUMBERS.find((mark) => !first.has(mark)) ?? `#${takenLabels.length + 1}`
  return `${circled}${label}`
}

/**
 * 模型侧的选段表示。ref 自身携带文稿、块与字符范围，不能依赖 bridge 中稍后会清掉的
 * 单槽 selection，也不能依赖只供复制/持久化的 clipboardText。
 */
export function selectionReferenceText(
  selection: QingSelection,
  title?: string | null,
  paragraphOrdinal?: number,
): string {
  // 展开文本会原样出现在发送气泡里:不带 UUID/块 ID/字符范围等机器噪音(用户实测嫌丑)。
  // 但引文全文多处相同时纯文本锚有歧义——补一个人类可读的「第 N 段」定位(有块索引时)。
  const documentTitle = title?.trim() || '当前文稿'
  const locator = paragraphOrdinal && paragraphOrdinal > 0 ? `第${paragraphOrdinal}段` : ''
  return `[选段]《${documentTitle}》${locator}:「${selection.quote}」`
}

/**
 * 解析选段 chip 的文稿名。匹配一律以 activeDoc 自带的 sessionId 为准,绝不信
 * activeEngineSessionId:切稿时后者由 binding-changed 同步更新,activeDoc 却要等
 * 异步 refresh 才换代——窗口期划词会把刚切出的稿名铸进 chip(评测 r4 席3 实证)。
 */
export function resolveSelectionTitle(
  snapshot: {
    activeDoc?: { sessionId?: string; title?: string | null }
    state?: { binding: { docs: ReadonlyArray<{ engineSessionId: string; title?: string | null }> } }
  },
  engineSessionId: string,
): string | undefined {
  const activeTitle = snapshot.activeDoc?.sessionId === engineSessionId
    ? snapshot.activeDoc.title
    : undefined
  return activeTitle ?? snapshot.state?.binding.docs.find(
    (doc) => doc.engineSessionId === engineSessionId,
  )?.title ?? undefined
}

export interface PmBlockNode {
  attrs?: { blockId?: string }
  content?: PmBlockNode[]
}

/** blockId 命中判定:顶层块自身或其任意后代——选中列表项/表格单元格等嵌套块时,
 *  「第 N 段」按包含它的顶层块计序(评测 r5 席3 实证:列表项选段丢段号)。 */
export function blockContainsId(block: PmBlockNode, blockId: string): boolean {
  if (block.attrs?.blockId === blockId) return true
  return block.content?.some((child) => blockContainsId(child, blockId)) ?? false
}

/** 底层投影 label 只留引文本体(10 字截断):图标与「选段:」前缀由呈现层覆盖文本
 *  提供,底层越短 chip 越紧凑(用户裁定宽度自适应,右侧不留空)。 */
export function selectionReferenceLabel(quote: string): string {
  const plain = quote.replace(/\s+/g, ' ').trim()
  return plain.length > CHIP_LABEL_PREVIEW_LENGTH
    ? `${plain.slice(0, CHIP_LABEL_PREVIEW_LENGTH)}…`
    : plain
}

export function createSelectionReference(
  selection: QingSelection,
  title?: string | null,
  paragraphOrdinal?: number,
  takenLabels: readonly string[] = [],
): ReferenceInsert {
  const ref = selectionReferenceText(selection, title, paragraphOrdinal)
  return {
    source: QING_SELECTION_REFERENCE_SOURCE,
    ref,
    label: weaveAtomicLabel(dedupeChipLabel(selectionReferenceLabel(selection.quote), takenLabels)),
    // 草稿持久化、复制与 owner 暂时不可用时也保留完整选段语义。
    clipboardText: ref,
  }
}

/**
 * 选段不是 slash token，使用当前草稿末尾的合法零宽 TokenSpan。事件的同步 true 回值
 * 表示 composer 已通过 phase + draftRev CAS 并实际插入 occurrence。
 */
export function insertSelectionReference(
  actx: ClientContext,
  selection: QingSelection,
  title?: string | null,
  paragraphOrdinal?: number,
): boolean {
  // 连续快速划词的竞态可能送来空引文单槽——铸出来就是一枚空白 chip(用户实测),拒插。
  if (!selection.quote.replace(/\s+/gu, ' ').trim()) return false
  const snapshot = actx.conversation.input.for(actx).state.getSnapshot()
  const takenLabels = (snapshot.occurrences ?? []).map((occurrence) => occurrence.label)
  const reference = createSelectionReference(selection, title, paragraphOrdinal, takenLabels)
  // 幂等守卫:bridge 状态重放/多路订阅可能对同一选段重复触发(用户实测双 chip);
  // 草稿里已有同 source+ref 的 occurrence 即视为已插入成功,由调用方清 ingress。
  if (snapshot.occurrences?.some((occurrence) =>
    occurrence.source === QING_SELECTION_REFERENCE_SOURCE && occurrence.ref === reference.ref)) {
    return true
  }
  const offset = snapshot.draft.length
  return actx.bail(actx, 'slash/input-insert-reference', {
    reference,
    span: {
      start: offset,
      end: offset,
      draftRev: snapshot.draftRev,
    },
  }) === true
}

/**
 * occurrence 提交时由 composer 按 source/ref 路由到这里；ref 已经是模型需要看到的
 * 完整锚点引文，serializer 只做恒等展开。
 */
export const qingSelectionReferenceSource: InputTriggerSource = {
  trigger: '@',
  name: QING_SELECTION_REFERENCE_SOURCE,
  order: Number.MAX_SAFE_INTEGER,
  candidates: async () => [],
  onPick: () => undefined,
  codec: {
    clipboardText: (ref) => ref,
    serialize: async (ref) => ref,
  },
}

/**
 * chip hover 展示原始内容:宿主 chipLabel 定宽硬裁无 tooltip,这里以委托监听为可见 chip
 * 补 title(浏览器原生悬浮)。chip DOM 顺序与 InputState.occurrences 的 offset 顺序一致,
 * 按序配对;只给本插件来源的 occurrence 写 title(内容=完整锚点引文)。
 * 返回卸载函数,随会话作用域清理。
 */
export function installSelectionChipHoverTitles(
  getOccurrences: () => readonly { source: string; ref: string }[] | undefined,
): () => void {
  if (typeof document === 'undefined') return () => {}
  // chip 画在 pointer-events:none 的 backdrop 镜像层,鼠标事件全落在上层透明 textarea——
  // 用 mousemove 坐标命中,命中即显示自绘悬浮条(原生 title 有 ~1s 延迟,用户等不到)。
  const TIP_ID = 'qingagent-selection-tip'
  const ensureTip = (): HTMLDivElement => {
    let tip = document.getElementById(TIP_ID) as HTMLDivElement | null
    if (!tip) {
      tip = document.createElement('div')
      tip.id = TIP_ID
      tip.style.cssText = [
        'position:fixed', 'z-index:100500', 'display:none', 'pointer-events:none',
        'max-width:380px', 'padding:6px 10px', 'border-radius:8px',
        'background:var(--dsw-alias-bg-layer-3, #26282c)',
        'color:var(--dsw-alias-label-primary, #e8e8ea)',
        'border:1px solid var(--dsw-alias-border-l1, rgba(255,255,255,.12))',
        'box-shadow:var(--dsw-shadow-lv2, 0 8px 24px rgba(0,0,0,.35))',
        'font-size:12px', 'line-height:18px', 'white-space:pre-wrap', 'word-break:break-word',
      ].join(';')
      document.body.appendChild(tip)
    }
    return tip
  }
  const hideTip = () => {
    const tip = document.getElementById(TIP_ID)
    if (tip) tip.style.display = 'none'
  }
  let raf = 0
  const onMove = (event: MouseEvent) => {
    if (raf) return
    raf = requestAnimationFrame(() => {
      raf = 0
      const input = (event.target as Element | null)?.closest?.('textarea')
      if (!input) return hideTip()
      const scope = input.closest('[class*="card"]') ?? input.parentElement?.parentElement
      const labels = scope ? [...scope.querySelectorAll('[class*="chipLabel"]')] : []
      let hit = -1
      let hitRect: DOMRect | undefined
      for (let index = 0; index < labels.length; index += 1) {
        const rect = labels[index]!.getBoundingClientRect()
        if (event.clientX >= rect.left && event.clientX <= rect.right && event.clientY >= rect.top && event.clientY <= rect.bottom) {
          hit = index
          hitRect = rect
          break
        }
      }
      const occurrence = hit >= 0 ? getOccurrences()?.[hit] : undefined
      if (!occurrence || occurrence.source !== QING_SELECTION_REFERENCE_SOURCE || !hitRect) return hideTip()
      const tip = ensureTip()
      tip.textContent = occurrence.ref
      tip.style.display = 'block'
      // 先摆再量:置于 chip 上方,水平钳在视口内。
      const width = Math.min(380, tip.offsetWidth || 380)
      tip.style.left = `${Math.max(8, Math.min(hitRect.left, window.innerWidth - width - 8))}px`
      tip.style.top = `${Math.max(8, hitRect.top - tip.offsetHeight - 8)}px`
    })
  }
  const onLeave = () => hideTip()
  document.addEventListener('mousemove', onMove, { capture: true, passive: true })
  document.addEventListener('mousedown', onLeave, { capture: true, passive: true })
  return () => {
    if (raf) cancelAnimationFrame(raf)
    document.removeEventListener('mousemove', onMove, { capture: true })
    document.removeEventListener('mousedown', onLeave, { capture: true })
    document.getElementById(TIP_ID)?.remove()
  }
}