/** 对话历史页:按场景分组列表、查看详情、保密模式密码验证、删除会话 */
import { useEffect, useState, useCallback } from 'react'
import { toast } from 'sonner'
import {
  History,
  Lock,
  Trash2,
  Loader2,
  MessageSquare,
  Shield,
  ChevronRight,
  ArrowLeft,
  BookOpen,
  Sparkles,
} from 'lucide-react'
import { PageLayout } from '@/components/common/PageLayout'
import { EmptyState } from '@/components/common/EmptyState'
import { LoadingState } from '@/components/common/LoadingState'
import { ErrorState } from '@/components/common/ErrorState'
import { Markdown } from '@/components/common/Markdown'
import { Card, CardContent } from '@/components/ui/card'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { Label } from '@/components/ui/label'
import { Badge } from '@/components/ui/badge'
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from '@/components/ui/dialog'
import { api } from '@/lib/api'
import { cn, formatTime } from '@/lib/utils'
import type { HistorySession, HistoryMessage, SessionMode } from '@/types'

/** 模式标签配置 */
const MODE_CONFIG: Record<SessionMode, { label: string; icon: typeof History; color: string }> = {
  normal: { label: '普通模式', icon: MessageSquare, color: 'bg-blue-100 text-blue-700' },
  confidential: { label: '保密模式', icon: Lock, color: 'bg-amber-100 text-amber-700' },
  ephemeral: { label: '阅后即焚', icon: Shield, color: 'bg-rose-100 text-rose-700' },
}

/** 风险等级颜色 */
const RISK_COLORS: Record<string, string> = {
  green: 'bg-green-100 text-green-700',
  amber: 'bg-yellow-100 text-yellow-700',
  orange: 'bg-orange-100 text-orange-700',
  red: 'bg-red-100 text-red-700',
}

/** 知识库文档类型标签映射 */
const DOC_TYPE_LABELS: Record<string, string> = {
  law: '法规',
  case: '案例',
  guide: '指南',
  industry: '行业',
  template: '模板',
}

/** 场景中文映射 */
const SCENE_LABELS: Record<string, string> = {
  legal: '私人法务',
  decision: '经营决策',
  life: '生活助理',
  emotion: '情绪中心',
}

export function ChatHistory() {
  const [sessions, setSessions] = useState<HistorySession[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [modeFilter, setModeFilter] = useState<'all' | 'normal' | 'confidential'>('all')

  // 当前查看的会话
  const [currentSession, setCurrentSession] = useState<HistorySession | null>(null)
  const [messages, setMessages] = useState<HistoryMessage[]>([])
  const [msgLoading, setMsgLoading] = useState(false)
  const [msgError, setMsgError] = useState<string | null>(null)
  const [needVerify, setNeedVerify] = useState(false)

  // 保密模式密码验证
  const [verifyPassword, setVerifyPassword] = useState('')
  const [verifying, setVerifying] = useState(false)

  // 删除确认
  const [deleteTarget, setDeleteTarget] = useState<HistorySession | null>(null)
  const [deleting, setDeleting] = useState(false)

  const loadSessions = useCallback(async () => {
    setLoading(true)
    setError(null)
    try {
      const mode = modeFilter === 'all' ? undefined : modeFilter
      const res = await api.listHistorySessions(mode)
      setSessions(res.results)
    } catch (err) {
      setError(err instanceof Error ? err.message : '加载失败')
    } finally {
      setLoading(false)
    }
  }, [modeFilter])

  useEffect(() => {
    loadSessions()
  }, [loadSessions])

  /** 查看会话历史 */
  const handleView = useCallback(async (session: HistorySession) => {
    setCurrentSession(session)
    setMessages([])
    setMsgError(null)
    setNeedVerify(false)
    setVerifyPassword('')
    setMsgLoading(true)
    try {
      const res = await api.getHistoryMessages(session.session_id)
      if (res.need_verify) {
        setNeedVerify(true)
      } else {
        setMessages(res.messages || [])
      }
    } catch (err) {
      setMsgError(err instanceof Error ? err.message : '加载失败')
    } finally {
      setMsgLoading(false)
    }
  }, [])

  /** 保密模式密码验证 */
  const handleVerify = useCallback(async () => {
    if (!currentSession || !verifyPassword) return
    setVerifying(true)
    setMsgError(null)
    try {
      const res = await api.verifyHistory(currentSession.session_id, verifyPassword)
      setMessages(res.messages)
      setNeedVerify(false)
      toast.success('验证通过,已解密历史消息')
    } catch (err) {
      setMsgError(err instanceof Error ? err.message : '验证失败')
    } finally {
      setVerifying(false)
    }
  }, [currentSession, verifyPassword])

  /** 删除会话历史 */
  const handleDelete = useCallback(async () => {
    if (!deleteTarget) return
    setDeleting(true)
    try {
      await api.deleteHistory(deleteTarget.session_id)
      toast.success('已删除该会话历史')
      setDeleteTarget(null)
      // 如果删除的是当前查看的会话,返回列表
      if (currentSession?.session_id === deleteTarget.session_id) {
        setCurrentSession(null)
      }
      loadSessions()
    } catch (err) {
      toast.error(err instanceof Error ? err.message : '删除失败')
    } finally {
      setDeleting(false)
    }
  }, [deleteTarget, currentSession, loadSessions])

  /** 返回列表 */
  const handleBack = useCallback(() => {
    setCurrentSession(null)
    setMessages([])
    setNeedVerify(false)
    setVerifyPassword('')
  }, [])

  // ===== 会话详情视图 =====
  if (currentSession) {
    const modeCfg = MODE_CONFIG[currentSession.mode]
    return (
      <PageLayout
        title="对话历史"
        description="查看和管理历史对话记录"
        actions={
          <div className="flex items-center gap-2">
            <Button variant="outline" size="sm" onClick={handleBack}>
              <ArrowLeft className="mr-1 h-4 w-4" />
              返回列表
            </Button>
            <Button
              variant="outline"
              size="sm"
              className="text-destructive hover:text-destructive"
              onClick={() => setDeleteTarget(currentSession)}
            >
              <Trash2 className="mr-1 h-4 w-4" />
              删除
            </Button>
          </div>
        }
      >
        <Card>
          <CardContent className="p-4">
            <div className="mb-4 flex items-center gap-3 border-b pb-3">
              <modeCfg.icon className="h-5 w-5 text-muted-foreground" />
              <div className="flex-1">
                <p className="font-medium">{currentSession.title || '未命名对话'}</p>
                <div className="mt-0.5 flex flex-wrap items-center gap-2">
                  <span className="text-xs text-muted-foreground">{modeCfg.label}</span>
                  {currentSession.scene && (
                    <Badge variant="secondary" className="text-xs">
                      {SCENE_LABELS[currentSession.scene] || currentSession.scene}
                    </Badge>
                  )}
                  <span className="text-xs text-muted-foreground">
                    {formatTime(currentSession.first_message_at)} ~ {formatTime(currentSession.last_message_at)}
                    {' · '}{currentSession.message_count} 条消息
                  </span>
                </div>
              </div>
            </div>

            {/* 保密模式密码验证 */}
            {needVerify ? (
              <div className="mx-auto max-w-sm py-8">
                <div className="mb-4 flex flex-col items-center gap-2 text-center">
                  <div className="flex h-12 w-12 items-center justify-center rounded-full bg-amber-100">
                    <Lock className="h-6 w-6 text-amber-600" />
                  </div>
                  <p className="text-sm font-medium">保密模式历史</p>
                  <p className="text-xs text-muted-foreground">
                    该会话为加密存储,请输入登录密码验证后查看
                  </p>
                </div>
                <div className="space-y-3">
                  <div>
                    <Label htmlFor="verify-pwd" className="text-xs">登录密码</Label>
                    <Input
                      id="verify-pwd"
                      type="password"
                      value={verifyPassword}
                      onChange={(e) => setVerifyPassword(e.target.value)}
                      onKeyDown={(e) => e.key === 'Enter' && handleVerify()}
                      placeholder="请输入登录密码"
                      className="mt-1"
                    />
                  </div>
                  {msgError && <p className="text-xs text-destructive">{msgError}</p>}
                  <Button
                    className="w-full"
                    onClick={handleVerify}
                    disabled={verifying || !verifyPassword}
                  >
                    {verifying ? (
                      <><Loader2 className="mr-1 h-4 w-4 animate-spin" />验证中</>
                    ) : (
                      '验证并查看'
                    )}
                  </Button>
                </div>
              </div>
            ) : msgLoading ? (
              <LoadingState label="加载历史消息..." />
            ) : msgError ? (
              <ErrorState message={msgError} onRetry={() => handleView(currentSession)} />
            ) : messages.length === 0 ? (
              <EmptyState icon={MessageSquare} title="暂无消息" description="该会话没有历史记录" />
            ) : (
              <div className="space-y-4">
                {messages.map((msg) => (
                  <MessageBubble key={msg.id} message={msg} />
                ))}
              </div>
            )}
          </CardContent>
        </Card>

        {/* 删除确认弹窗 */}
        <DeleteDialog
          open={!!deleteTarget}
          onOpenChange={(o) => !o && setDeleteTarget(null)}
          onConfirm={handleDelete}
          deleting={deleting}
        />
      </PageLayout>
    )
  }

  // ===== 会话列表视图 =====
  return (
    <PageLayout
      title="对话历史"
      description="普通模式可直接查看,保密模式需密码验证,阅后即焚不落库"
      actions={
        <div className="flex flex-wrap items-center gap-1 rounded-md border bg-card p-1">
          {(['all', 'normal', 'confidential'] as const).map((m) => (
            <Button
              key={m}
              variant={modeFilter === m ? 'default' : 'ghost'}
              size="sm"
              className="h-7 text-xs"
              onClick={() => setModeFilter(m)}
            >
              {m === 'all' ? '全部' : m === 'normal' ? '普通' : '保密'}
            </Button>
          ))}
        </div>
      }
    >
      {loading ? (
        <LoadingState label="加载历史会话..." />
      ) : error ? (
        <ErrorState message={error} onRetry={loadSessions} />
      ) : sessions.length === 0 ? (
        <EmptyState
          icon={History}
          title="暂无历史会话"
          description="普通模式和保密模式的对话会保存在这里,阅后即焚不落库"
        />
      ) : (
        <div className="space-y-6">
          {/* 按场景分组,每组内按时间倒序 */}
          {(() => {
            // 定义场景顺序
            const SCENE_ORDER = ['legal', 'decision', 'life', 'emotion']
            // 按 scene 分组(无 scene 归为"其他")
            const groups = new Map<string, HistorySession[]>()
            for (const s of sessions) {
              const key = s.scene || 'other'
              if (!groups.has(key)) groups.set(key, [])
              groups.get(key)!.push(s)
            }
            // 每组内按 last_message_at 倒序
            for (const items of groups.values()) {
              items.sort((a, b) => {
                const ta = a.last_message_at ? new Date(a.last_message_at).getTime() : 0
                const tb = b.last_message_at ? new Date(b.last_message_at).getTime() : 0
                return tb - ta
              })
            }
            // 渲染:按 SCENE_ORDER 顺序,最后是 other
            const orderedKeys = [...SCENE_ORDER.filter(k => groups.has(k)), ...['other']].filter(k => groups.has(k))
            return orderedKeys.map((key) => (
              <div key={key}>
                <p className="mb-2 px-1 text-xs font-medium uppercase tracking-wider text-muted-foreground/70">
                  {SCENE_LABELS[key] || '其他'}
                  <span className="ml-1.5 text-muted-foreground/50">{groups.get(key)!.length}</span>
                </p>
                <div className="space-y-2">
                  {groups.get(key)!.map((session) => {
                    const modeCfg = MODE_CONFIG[session.mode]
                    return (
                      <Card
                        key={session.session_id}
                        className="cursor-pointer transition-colors hover:bg-accent/50"
                        onClick={() => handleView(session)}
                      >
                        <CardContent className="flex items-center gap-3 p-4">
                          <div className={cn('flex h-10 w-10 items-center justify-center rounded-lg', modeCfg.color)}>
                            <modeCfg.icon className="h-5 w-5" />
                          </div>
                          <div className="min-w-0 flex-1">
                            <p className="truncate text-sm font-medium">{session.title || '未命名对话'}</p>
                            <div className="mt-0.5 flex flex-wrap items-center gap-2">
                              <span className="text-xs text-muted-foreground">{modeCfg.label}</span>
                              <span className="text-xs text-muted-foreground">
                                {session.message_count} 条 · {formatTime(session.last_message_at)}
                              </span>
                            </div>
                          </div>
                          <ChevronRight className="h-4 w-4 text-muted-foreground" />
                        </CardContent>
                      </Card>
                    )
                  })}
                </div>
              </div>
            ))
          })()}
        </div>
      )}

      <DeleteDialog
        open={!!deleteTarget}
        onOpenChange={(o) => !o && setDeleteTarget(null)}
        onConfirm={handleDelete}
        deleting={deleting}
      />
    </PageLayout>
  )
}

/** 单条消息气泡 */
function MessageBubble({ message }: { message: HistoryMessage }) {
  const isUser = message.role === 'user'
  const riskLevel = message.risk?.level
  return (
    <div className={cn('flex', isUser ? 'justify-end' : 'justify-start')}>
      <div className={cn('max-w-[80%] rounded-lg p-3', isUser ? 'bg-primary text-primary-foreground' : 'bg-muted')}>
        {/* 消息正文:用户消息纯文本,AI 消息 Markdown 渲染 */}
        {isUser ? (
          <p className="whitespace-pre-wrap text-sm">{message.content}</p>
        ) : (
          <Markdown content={message.content} className="text-sm" />
        )}

        {/* AI 回复的风险卡信息 */}
        {!isUser && riskLevel && (
          <div className="mt-2 space-y-1 border-t border-border/30 pt-2">
            <div className="flex items-center gap-2">
              <Badge className={cn('text-xs', RISK_COLORS[riskLevel])}>
                {riskLevel === 'green' ? '低风险' : riskLevel === 'amber' ? '需补证' : riskLevel === 'orange' ? '建议复核' : '高风险'}
              </Badge>
              {message.risk?.escalation && (
                <Badge variant="destructive" className="text-xs">建议升级</Badge>
              )}
              {message.meta?.inference_location && (
                <span className="text-[10px] opacity-70">
                  {message.meta.inference_location === 'cloud' ? '云端' : '本地'}
                </span>
              )}
            </div>
            {message.risk?.actions && message.risk.actions.length > 0 && (
              <ul className="text-xs opacity-80">
                {message.risk.actions.map((a, i) => (
                  <li key={i}>• {a}</li>
                ))}
              </ul>
            )}
          </div>
        )}

        {/* 参考来源:知识库引用 tag 或 AI 提供 tag */}
        {!isUser && (
          <div className="mt-2 border-t border-border/30 pt-2">
            <div className="mb-1 flex items-center gap-1 text-[10px] text-muted-foreground">
              <BookOpen className="h-3 w-3" /> 参考来源
            </div>
            {message.meta?.rag_context && message.meta.rag_context.length > 0 ? (
              <div className="space-y-1">
                {message.meta.rag_context.map((doc, i) => (
                  <div key={i} className="flex flex-wrap items-center gap-1 text-xs">
                    <span className="font-medium">{doc.title}</span>
                    {doc.doc_type && (
                      <Badge variant="secondary" className="text-[10px]">
                        {DOC_TYPE_LABELS[doc.doc_type] || doc.doc_type}
                      </Badge>
                    )}
                    {doc.region && (
                      <Badge variant="outline" className="text-[10px]">{doc.region}</Badge>
                    )}
                  </div>
                ))}
              </div>
            ) : (
              <div className="flex items-center gap-1 text-xs text-muted-foreground">
                <Sparkles className="h-3 w-3" />
                <Badge variant="outline" className="text-[10px]">AI 提供</Badge>
              </div>
            )}
          </div>
        )}

        {/* 时间戳 */}
        <p className={cn('mt-1 text-[10px]', isUser ? 'text-primary-foreground/60' : 'text-muted-foreground')}>
          {formatTime(message.created_at)}
        </p>
      </div>
    </div>
  )
}

/** 删除确认弹窗 */
function DeleteDialog({
  open,
  onOpenChange,
  onConfirm,
  deleting,
}: {
  open: boolean
  onOpenChange: (open: boolean) => void
  onConfirm: () => void
  deleting: boolean
}) {
  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent>
        <DialogHeader>
          <DialogTitle>删除对话历史</DialogTitle>
          <DialogDescription>
            确定要删除该会话的所有历史消息吗?此操作不可恢复。
            {open && ' 保密模式的加密数据将一并清除。'}
          </DialogDescription>
        </DialogHeader>
        <DialogFooter>
          <Button variant="outline" onClick={() => onOpenChange(false)} disabled={deleting}>
            取消
          </Button>
          <Button variant="destructive" onClick={onConfirm} disabled={deleting}>
            {deleting ? (
              <><Loader2 className="mr-1 h-4 w-4 animate-spin" />删除中</>
            ) : (
              '确认删除'
            )}
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  )
}