import type { LucideIcon } from 'lucide-react'
import type { ClipboardEvent, DragEvent, KeyboardEvent, ReactElement } from 'react'
import type { Ask } from './qa'
import type { PendingImage } from './qaImages'
import type { ProfileChoice, QaEntryView } from './types'
import type { CopyState } from '@/hooks/useCopyText'
import { Check, ChevronDown, ChevronRight, CircleStop, Copy, Hourglass, LoaderCircle, MessageSquareText, Search, SendHorizontal, Sparkles, Trash2, TriangleAlert, X } from 'lucide-react'
import { useEffect, useRef, useState } from 'react'
import { createPortal } from 'react-dom'
import { SelectMenu } from '@/components/ui/select-menu'
import { useCopyText } from '@/hooks/useCopyText'
import { renderMarkdown, renderMarkdownOnce } from './markdown'
import { answerPreview, relativeTime, unfinished } from './qa'
import { MAX_IMAGES, pickImages, readImage, transferFiles } from './qaImages'
import { MarkdownPreview } from './TextPreview'
import { showInViewport } from './useReveal'

/** 一种对话在界面上怎么称呼：区域的名字、图标、「问过 N 次」、删一条、输入框的提示和名字、回答长出来时的状态 */
export interface ThreadWording {
  label: string
  icon: LucideIcon
  summary: (count: number) => string
  deleteLabel: string
  /** first：还没说过；hint：「问」后面的对象 */
  placeholder: (first: boolean, hint: string) => string
  inputLabel: string
  answering: string
}

export const ASK_THREAD: ThreadWording = {
  label: '问 AI',
  icon: Sparkles,
  summary: count => `问过 ${count} 次`,
  deleteLabel: '已理解，删除',
  placeholder: (first, hint) => first ? `问${hint}…` : '继续问…',
  inputLabel: '问 AI 的问题',
  answering: '正在回答…',
}

/** 「了解一块代码」的对话页：第一轮是侧栏里问的那句话，输入框里接着说哪里漏了、哪些不相关，AI 改完整栏换成新结果 */
export const FEATURE_THREAD: ThreadWording = {
  label: '了解一块代码',
  icon: Search,
  summary: count => `说过 ${count} 次`,
  deleteLabel: '删除这一轮',
  placeholder: () => '接着说：还漏了什么、哪些不相关…',
  inputLabel: '接着说的话',
  answering: '正在找…',
}

/** 重写注释：第一轮由块右上角的按钮发技能命令，输入框里说的是对这段注释的修改意见 */
export const REWRITE_THREAD: ThreadWording = {
  label: '按注释规范重写',
  icon: MessageSquareText,
  summary: count => `重写过 ${count} 次`,
  deleteLabel: '删除这条记录',
  placeholder: () => '说说这段注释要怎么改…',
  inputLabel: '对这段注释的修改意见',
  answering: '正在写…',
}

/** 问题带的图片：一排小缩略图，点一张看大图；给了 onRemove 的（贴了还没发的）右上角有「去掉」。没有图片时什么都不画。 */
function Thumbs({ urls, pending, onOpen, onRemove }: { urls: string[], pending?: boolean, onOpen: (url: string) => void, onRemove?: (index: number) => void }): ReactElement | null {
  if (urls.length === 0)
    return null
  return (
    <div className="cr-qa-thumbs" data-pending={pending ? '' : undefined}>
      {urls.map((url, index) => (
        // 同一张图可能贴两次、地址一样；缩略图没有自己的状态，按位置认就行
        <span key={index} className="cr-qa-thumb">
          <button type="button" className="cr-qa-thumb-open" data-tooltip="看大图" aria-label={`看第 ${index + 1} 张图片的大图`} onClick={() => onOpen(url)}>
            <img src={url} alt="" />
          </button>
          {onRemove && (
            <button type="button" className="cr-qa-thumb-remove" data-tooltip="去掉这张图片" aria-label={`去掉第 ${index + 1} 张图片`} onClick={() => onRemove(index)}>
              <X size={10} strokeWidth={2.4} aria-hidden />
            </button>
          )}
        </span>
      ))}
    </div>
  )
}

/**
 * 看大图：盖住整个预览，点哪儿或按 Esc 关上；打开时焦点在「关闭」上，关上后回到点开它的地方。
 * 平时 portal 到 body；`inPlace` 时就画在原处（定义卡片浮窗里：指针在大图上也算在浮窗里，浮窗不收）。
 */
function ImagePreview({ url, inPlace = false, onClose }: { url: string, inPlace?: boolean, onClose: () => void }): ReactElement {
  const close = useRef<HTMLButtonElement>(null)
  useEffect(() => {
    const opener = document.activeElement
    close.current?.focus({ preventScroll: true })
    return () => {
      if (opener instanceof HTMLElement)
        opener.focus({ preventScroll: true })
    }
  }, [])
  const onKeyDown = (event: KeyboardEvent<HTMLDivElement>): void => {
    if (event.key === 'Escape') {
      // 只关大图：不收起问答区，也不清名字高亮（那边认 defaultPrevented）
      event.preventDefault()
      event.stopPropagation()
      onClose()
    }
  }
  const lightbox = (
    <div className="cr-qa-lightbox" role="dialog" aria-modal="true" aria-label="图片大图" onClick={onClose} onKeyDown={onKeyDown}>
      <img src={url} alt="" />
      <button ref={close} type="button" className="cr-qa-lightbox-close" data-tooltip="关闭（Esc）" aria-label="关闭大图">
        <X size={16} strokeWidth={1.8} aria-hidden />
      </button>
    </div>
  )
  return inPlace ? lightbox : createPortal(lightbox, document.body)
}

/** 复制按钮在每种复制结果下的图标和名字。 */
const COPY_LOOKS: Record<CopyState, { icon: LucideIcon, label: string }> = {
  idle: { icon: Copy, label: '复制回答' },
  copied: { icon: Check, label: '已复制' },
  failed: { icon: TriangleAlert, label: '复制失败' },
}

/** 头部右边的「复制回答」：把 `answer` 原样的 Markdown 连同里面的仓库链接放进剪贴板，好拿到别的会话里接着用；点完图标和名字换成复制的结果，两秒后复原。 */
function CopyAnswerButton({ answer }: { answer: string }): ReactElement {
  const { state, copy } = useCopyText()
  const { icon: Icon, label } = COPY_LOOKS[state]
  return (
    <button type="button" className="cr-tool cr-qa-action" data-failed={state === 'failed' ? '' : undefined} data-tooltip={label} aria-label={label} onClick={() => void copy(answer)}>
      <Icon size={13} strokeWidth={1.8} aria-hidden />
    </button>
  )
}

/** 说过的一次展开后的整段回答：按 Markdown 排，在历史里是灰字。 */
function HistoryAnswer({ answer }: { answer: string }): ReactElement {
  return <MarkdownPreview html={renderMarkdown(answer, 'answer')} className="cr-qa-answer" />
}

/**
 * 说过的一次，灰字：说的话、时间、复制回答、删除（问答叫「已理解，删除」），带的图片，下面回答的前两行；点问题或预览展开整段回答（照样灰字，按 Markdown 排）。
 * 重写记录没写进文件时，最下面写着原因
 */
function HistoryItem({ entry, wording, now, onDelete, onOpenImage }: { entry: QaEntryView, wording: ThreadWording, now: number, onDelete: () => void, onOpenImage: (url: string) => void }): ReactElement {
  const [expanded, setExpanded] = useState(false)
  const toggle = (): void => setExpanded(value => !value)
  const Icon = wording.icon
  return (
    <div className="cr-qa-entry" data-history="">
      <div className="cr-qa-head">
        <Icon size={12} strokeWidth={1.8} className="cr-qa-icon" aria-hidden />
        <button type="button" className="cr-qa-question" aria-expanded={expanded} data-tooltip={expanded ? '收起回答' : '展开整段回答'} onClick={toggle}>
          {entry.question}
        </button>
        <span className="cr-qa-when">
          <time dateTime={entry.createdAt} data-tooltip={new Date(entry.createdAt).toLocaleString()}>
            {relativeTime(entry.createdAt, now)}
          </time>
          {entry.profile && <span data-tooltip="用这个 Claude Code 配置（profile）答的">{` · ${entry.profile}`}</span>}
        </span>
        <CopyAnswerButton answer={entry.answer} />
        <button type="button" className="cr-tool cr-qa-action" data-tooltip={wording.deleteLabel} aria-label={wording.deleteLabel} onClick={onDelete}>
          <Trash2 size={13} strokeWidth={1.8} aria-hidden />
        </button>
      </div>
      <Thumbs urls={entry.images ?? []} onOpen={onOpenImage} />
      {expanded
        ? <HistoryAnswer answer={entry.answer} />
        : (
            <button type="button" className="cr-qa-preview" onClick={toggle}>
              {answerPreview(entry.answer)}
            </button>
          )}
      {entry.error && (
        <div className="cr-qa-status" data-warning="">
          <TriangleAlert size={12} strokeWidth={1.8} className="shrink-0" aria-hidden />
          {`没写进文件：${entry.error}`}
        </div>
      )}
    </div>
  )
}

/** 只读列表里问过的一次，灰字：只有问题一行，点了在下面展开带的图片和整段回答（同 [HistoryItem] 展开后的），再点收起。 */
function AskedItem({ entry, onOpenImage }: { entry: QaEntryView, onOpenImage: (url: string) => void }): ReactElement {
  const [expanded, setExpanded] = useState(false)
  return (
    <div className="cr-qa-entry" data-history="">
      <div className="cr-qa-head">
        <Sparkles size={12} strokeWidth={1.8} className="cr-qa-icon" aria-hidden />
        <button type="button" className="cr-qa-question" aria-expanded={expanded} data-tooltip={expanded ? '收起回答' : '展开回答'} onClick={() => setExpanded(value => !value)}>
          {entry.question}
        </button>
      </div>
      {expanded && (
        <>
          <Thumbs urls={entry.images ?? []} onOpen={onOpenImage} />
          <HistoryAnswer answer={entry.answer} />
        </>
      )}
    </div>
  )
}

/** 当前这一轮说的一次，照常颜色：说的话（答完了右边能复制回答），回答逐字长出来（按 Markdown 排），排着队、在做的事、出错（重写注释没写进文件也算）、停止写在下面 */
function CurrentItem({ ask, wording, onOpenImage }: { ask: Ask, wording: ThreadWording, onOpenImage: (url: string) => void }): ReactElement {
  const running = ask.status === 'running'
  const label = ask.activity ?? (ask.text === '' ? '正在想…' : wording.answering)
  const Icon = wording.icon
  return (
    <div className="cr-qa-entry" data-current="">
      <div className="cr-qa-head">
        <Icon size={12} strokeWidth={1.8} className="cr-qa-icon" aria-hidden />
        <span className="cr-qa-question">{ask.question}</span>
        {!unfinished(ask) && ask.text !== '' && <CopyAnswerButton answer={ask.text} />}
      </div>
      <Thumbs urls={ask.images ?? []} onOpen={onOpenImage} />
      {ask.text !== '' && (
        <MarkdownPreview
          html={running ? renderMarkdownOnce(ask.text) : renderMarkdown(ask.text, 'answer')}
          className="cr-qa-answer"
          streaming={running}
        />
      )}
      {running && (
        <div className="cr-qa-status" role="status">
          <LoaderCircle size={12} strokeWidth={1.8} className="cr-qa-spin" aria-hidden />
          {label}
        </div>
      )}
      {ask.status === 'queued' && (
        <div className="cr-qa-status" role="status">
          <Hourglass size={12} strokeWidth={1.8} aria-hidden />
          排队中，前面的写完就开始
        </div>
      )}
      {ask.error !== undefined && !unfinished(ask) && (
        <div className="cr-qa-error" role="alert">
          <TriangleAlert size={13} strokeWidth={1.8} className="mt-[3px] shrink-0" aria-hidden />
          <span>{ask.error}</span>
        </div>
      )}
      {ask.status === 'stopped' && <div className="cr-qa-status">已停止，这次没存。</div>}
    </div>
  )
}

/** 底下的输入框：Enter 发送、Shift+Enter 换行、Esc 收起；正在答时发送换成停止，排着队时换成取消排队。能贴图、拖图，贴的图在输入框上面一排，随下一个问题发 */
/** 把光标放进输入框；它不在视口里时交给[滚动所有者](vscode/webview-ui/src/codeReader/scrollOwner.ts#ScrollOwner)滚过去（见 [showInViewport]），不让浏览器自己滚。 */
function focusField(field: HTMLTextAreaElement | null): void {
  if (!field)
    return
  field.focus({ preventScroll: true })
  showInViewport(() => field.isConnected ? field : null)
}

function AskInput({ active, placeholder, label, profiles, onSelectProfile, onAsk, onStop, onClose, closable, onOpenImage, autoFocus, focusToken }: {
  /** 正在答或排着队的那一轮 */
  active: Ask | undefined
  /** 输入框里的提示（后面接着怎么发送、收起） */
  placeholder: string
  /** 输入框读屏用的名字 */
  label: string
  profiles: ProfileChoice
  onSelectProfile: (id: string) => void
  onAsk: (question: string, images: PendingImage[]) => void
  onStop: (askId: string) => void
  onClose: () => void
  /** Esc 收起。顶部那条一直摊开，不收 */
  closable: boolean
  onOpenImage: (url: string) => void
  /** 展开时把光标放进输入框。顶部那条一直摊开，不要抢阅读时光标 */
  autoFocus: boolean
  /** 大于 0 时再放一次光标；侧栏「问 AI」打开已经在的预览时用 */
  focusToken: number
}): ReactElement {
  const [value, setValue] = useState('')
  const stopLabel = active?.status === 'queued' ? '取消排队' : '停止'
  const [images, setImages] = useState<PendingImage[]>([])
  /** 贴的、拖的有没加上的：给人看的原因，下次贴图或发送时清掉 */
  const [notice, setNotice] = useState<string>()
  const textarea = useRef<HTMLTextAreaElement>(null)
  useEffect(() => {
    if (autoFocus)
      focusField(textarea.current)
  }, [autoFocus])
  useEffect(() => {
    if (focusToken > 0)
      focusField(textarea.current)
  }, [focusToken])
  const attach = (files: File[]): void => {
    if (files.length === 0)
      return
    const picked = pickImages(files, images.length)
    setNotice(picked.notice)
    Promise.all(picked.accepted.map(readImage)).then(
      read => setImages(current => [...current, ...read].slice(0, MAX_IMAGES)),
      () => setNotice('有图片读不出来，没加上。'),
    )
  }
  const send = (): void => {
    const question = value.trim()
    if (question === '' || active)
      return
    onAsk(question, images)
    setValue('')
    setImages([])
    setNotice(undefined)
  }
  const onKeyDown = (event: KeyboardEvent<HTMLTextAreaElement>): void => {
    // 输入法选字时的回车不算发送
    if (event.key === 'Enter' && !event.shiftKey && !event.nativeEvent.isComposing) {
      event.preventDefault()
      send()
    }
    else if (closable && event.key === 'Escape') {
      event.preventDefault()
      onClose()
    }
  }
  // 剪贴板里的图片加到上面的缩略图里；文字照常粘进输入框，不拦
  const onPaste = (event: ClipboardEvent<HTMLTextAreaElement>): void => attach(transferFiles(event.clipboardData.items))
  const onDragOver = (event: DragEvent<HTMLDivElement>): void => {
    if (event.dataTransfer.types.includes('Files')) {
      event.preventDefault()
      event.dataTransfer.dropEffect = 'copy'
    }
  }
  const onDrop = (event: DragEvent<HTMLDivElement>): void => {
    const files = transferFiles(event.dataTransfer.items)
    if (files.length > 0) {
      event.preventDefault()
      attach(files)
    }
  }
  const remove = (index: number): void => {
    setImages(current => current.filter((_, i) => i !== index))
    focusField(textarea.current)
  }
  return (
    <>
      <Thumbs urls={images.map(image => image.url)} pending onOpen={onOpenImage} onRemove={remove} />
      {notice && <div className="cr-qa-notice" role="status">{notice}</div>}
      <div className="cr-qa-input" onDragOver={onDragOver} onDrop={onDrop}>
        <textarea
          ref={textarea}
          rows={1}
          value={value}
          placeholder={`${placeholder}  Enter 发送${closable ? '，Esc 收起' : ''}`}
          aria-label={label}
          onChange={event => setValue(event.target.value)}
          onKeyDown={onKeyDown}
          onPaste={onPaste}
        />
        <SelectMenu
          variant="ghost"
          value={profiles.selected}
          options={profiles.options.map(option => ({ value: option.id, label: option.label }))}
          onChange={onSelectProfile}
          placeholder="默认"
          tooltip="用哪个 Claude Code 配置（profile）回答，下一个问题起用它"
          className="cr-qa-profile"
        />
        {active
          ? (
              <button type="button" className="cr-tool" data-tooltip={stopLabel} aria-label={stopLabel} onClick={() => onStop(active.askId)}>
                <CircleStop size={14} strokeWidth={1.8} aria-hidden />
              </button>
            )
          : (
              <button type="button" className="cr-tool" data-tooltip="发送（Enter）" aria-label="发送" disabled={value.trim() === ''} onClick={send}>
                <SendHorizontal size={14} strokeWidth={1.8} aria-hidden />
              </button>
            )}
      </div>
    </>
  )
}

export interface AskThreadProps {
  history: QaEntryView[]
  asks: Ask[]
  /** 点了「问 AI」：展开全部历史、当前这一轮和输入框 */
  open: boolean
  /** 输入框旁边的 profile 下拉 */
  profiles: ProfileChoice
  /** 「问」后面的对象，默认「这块代码」 */
  hint?: string
  /** 哪种对话，默认问 AI */
  wording?: ThreadWording
  /** 展开时聚焦输入框，默认聚焦。一直摊开的顶部聊天不聚焦 */
  autoFocus?: boolean
  /** 变大时把光标放进输入框 */
  focusToken?: number
  /** Esc 能不能收起，默认能。顶部聊天不收 */
  closable?: boolean
  now?: number
  onSelectProfile: (id: string) => void
  /** images 是贴进输入框的图片，随这句话一起发 */
  onAsk: (question: string, images: PendingImage[]) => void
  onStop: (askId: string) => void
  onDelete: (entryId: string) => void
  onClose: () => void
}

/**
 * 块下面的对话区（问 AI、重写注释，左边一条竖线）：展开时是灰字的历史、当前这一轮、输入框；
 * 没展开但说过的块是一行「问过 N 次」（重写注释是「重写过 N 次」）、下面默认摊开灰字历史，点这一行收起 / 再摊开，读代码时一眼看到这里说过什么。
 */
export function AskThread({ history, asks, open, profiles, hint = '这块代码', wording = ASK_THREAD, autoFocus = true, focusToken = 0, closable = true, now = Date.now(), onSelectProfile, onAsk, onStop, onDelete, onClose }: AskThreadProps): ReactElement | null {
  const [showHistory, setShowHistory] = useState(true)
  /** 正在看大图的那张 */
  const [preview, setPreview] = useState<string>()
  const lightbox = preview !== undefined && <ImagePreview url={preview} onClose={() => setPreview(undefined)} />
  const Icon = wording.icon
  const historyItems = history.map(entry => <HistoryItem key={entry.id} entry={entry} wording={wording} now={now} onDelete={() => onDelete(entry.id)} onOpenImage={setPreview} />)
  if (!open) {
    if (history.length === 0)
      return null
    const Chevron = showHistory ? ChevronDown : ChevronRight
    return (
      <div className="cr-qa" data-collapsed="">
        <button type="button" className="cr-qa-summary" aria-expanded={showHistory} onClick={() => setShowHistory(value => !value)}>
          <Icon size={12} strokeWidth={1.8} className="cr-qa-icon" aria-hidden />
          {wording.summary(history.length)}
          <Chevron size={12} strokeWidth={1.8} aria-hidden />
        </button>
        {showHistory && historyItems}
        {lightbox}
      </div>
    )
  }
  return (
    <section className="cr-qa" aria-label={wording.label}>
      {historyItems}
      {history.length > 0 && asks.length > 0 && <hr className="cr-qa-divider" />}
      {asks.map(ask => <CurrentItem key={ask.askId} ask={ask} wording={wording} onOpenImage={setPreview} />)}
      <AskInput
        active={asks.find(unfinished)}
        placeholder={wording.placeholder(history.length === 0 && asks.length === 0, hint)}
        label={wording.inputLabel}
        profiles={profiles}
        onSelectProfile={onSelectProfile}
        onAsk={onAsk}
        onStop={onStop}
        onClose={onClose}
        closable={closable}
        onOpenImage={setPreview}
        autoFocus={autoFocus}
        focusToken={focusToken}
      />
      {lightbox}
    </section>
  )
}

/**
 * 只读的问答列表（定义卡片底部那一节）：一行「问过 AI（N）」，下面按 `entries` 的先后只列问题，点一条展开 / 收起它的回答；不能删、不能接着问。
 * 看大图画在列表自己里面（见 [ImagePreview] 的 `inPlace`），没问过时什么都不画。
 */
export function AskedList({ entries }: { entries: QaEntryView[] }): ReactElement | null {
  /** 正在看大图的那张 */
  const [preview, setPreview] = useState<string>()
  if (entries.length === 0)
    return null
  return (
    <section className="cr-qa" aria-label="问过 AI">
      <div className="cr-qa-title">
        <Sparkles size={12} strokeWidth={1.8} className="cr-qa-icon" aria-hidden />
        {`问过 AI（${entries.length}）`}
      </div>
      {entries.map(entry => <AskedItem key={entry.id} entry={entry} onOpenImage={setPreview} />)}
      {preview !== undefined && <ImagePreview url={preview} inPlace onClose={() => setPreview(undefined)} />}
    </section>
  )
}