import { useState, useEffect, useCallback } from "react"
import {
  useReactTable,
  getCoreRowModel,
  flexRender,
  type ColumnDef,
} from "@tanstack/react-table"
import { Search, Pencil, Eye } from "lucide-react"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select"
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table"
import { Badge } from "@/components/ui/badge"
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog"
import { Label } from "@/components/ui/label"
import { Textarea } from "@/components/ui/textarea"
import { fetchKnowledgeCards, updateKnowledgeCard } from "@/lib/api/knowledge-card-api"
import type { KnowledgeCardItem, UpdateKnowledgeCardData } from "@/lib/api/knowledge-card-api"
import { fetchCategories } from "@/lib/api/category-api"
import type { Category } from "@/types/category"

const BASIC_MAX = 100
const DEEP_MAX = 300

type CardStatus = "all" | "complete" | "incomplete"

function getCardStatus(item: KnowledgeCardItem): "complete" | "incomplete" {
  return item.summary && item.summary.trim().length > 0 ? "complete" : "incomplete"
}

export default function KnowledgeCardsPage() {
  const [cards, setCards] = useState<KnowledgeCardItem[]>([])
  const [categories, setCategories] = useState<Category[]>([])
  const [loading, setLoading] = useState(true)
  const [search, setSearch] = useState("")
  const [statusFilter, setStatusFilter] = useState<CardStatus>("all")

  // 编辑对话框
  const [editOpen, setEditOpen] = useState(false)
  const [editingCard, setEditingCard] = useState<KnowledgeCardItem | null>(null)
  const [editForm, setEditForm] = useState<UpdateKnowledgeCardData>({ summary: "", deepDive: "", sourceRef: "" })
  const [submitting, setSubmitting] = useState(false)

  // 详情对话框
  const [detailOpen, setDetailOpen] = useState(false)
  const [detailCard, setDetailCard] = useState<KnowledgeCardItem | null>(null)

  useEffect(() => {
    fetchCategories({}).then((res) => setCategories(res.data))
  }, [])

  const loadCards = useCallback(async () => {
    setLoading(true)
    try {
      const res = await fetchKnowledgeCards({
        search: search || undefined,
        status: statusFilter,
      })
      setCards(res.data)
    } catch {
      setCards([])
    } finally {
      setLoading(false)
    }
  }, [search, statusFilter])

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

  function getCategoryName(categoryId: string): string {
    return categories.find((c) => c.id === categoryId)?.name ?? categoryId
  }

  function openEdit(card: KnowledgeCardItem) {
    setEditingCard(card)
    setEditForm({
      summary: card.summary,
      deepDive: card.deepDive || "",
      sourceRef: card.sourceRef || "",
    })
    setEditOpen(true)
  }

  function openDetail(card: KnowledgeCardItem) {
    setDetailCard(card)
    setDetailOpen(true)
  }

  async function handleSave() {
    if (!editingCard) return
    setSubmitting(true)
    try {
      await updateKnowledgeCard(editingCard.id, editForm)
      setEditOpen(false)
      await loadCards()
    } finally {
      setSubmitting(false)
    }
  }

  const columns: ColumnDef<KnowledgeCardItem>[] = [
    {
      accessorKey: "questionStem",
      header: "关联题目",
      cell: ({ row }) => {
        const stem = row.original.questionStem
        return (
          <span className="line-clamp-2 max-w-xs" title={stem}>
            {stem.length > 60 ? stem.slice(0, 60) + "..." : stem}
          </span>
        )
      },
    },
    {
      accessorKey: "categoryId",
      header: "分类",
      cell: ({ row }) => (
        <span className="text-muted-foreground">
          {getCategoryName(row.original.categoryId)}
        </span>
      ),
    },
    {
      id: "basicStatus",
      header: "基础卡",
      cell: ({ row }) => {
        const hasBasic = row.original.summary?.trim().length > 0
        return (
          <Badge variant={hasBasic ? "default" : "outline"}>
            {hasBasic ? `${row.original.summary.length} 字` : "未填写"}
          </Badge>
        )
      },
    },
    {
      id: "deepStatus",
      header: "深度卡",
      cell: ({ row }) => {
        const hasDeep = (row.original.deepDive?.trim().length ?? 0) > 0
        return (
          <Badge variant={hasDeep ? "secondary" : "outline"}>
            {hasDeep ? `${row.original.deepDive!.length} 字` : "未填写"}
          </Badge>
        )
      },
    },
    {
      id: "completeness",
      header: "完成度",
      cell: ({ row }) => {
        const status = getCardStatus(row.original)
        return (
          <Badge variant={status === "complete" ? "default" : "destructive"}>
            {status === "complete" ? "完整" : "待补充"}
          </Badge>
        )
      },
    },
    {
      accessorKey: "updatedAt",
      header: "更新时间",
      cell: ({ row }) => (
        <span className="text-muted-foreground text-xs">
          {new Date(row.original.updatedAt).toLocaleDateString("zh-CN")}
        </span>
      ),
    },
    {
      id: "actions",
      header: "操作",
      cell: ({ row }) => (
        <div className="flex gap-2">
          <Button variant="ghost" size="icon-xs" onClick={() => openDetail(row.original)} title="查看">
            <Eye className="size-3.5" />
          </Button>
          <Button variant="ghost" size="icon-xs" onClick={() => openEdit(row.original)} title="编辑">
            <Pencil className="size-3.5" />
          </Button>
        </div>
      ),
    },
  ]

  const table = useReactTable({
    data: cards,
    columns,
    getCoreRowModel: getCoreRowModel(),
  })

  // 统计
  const totalCards = cards.length
  const completeCards = cards.filter((c) => getCardStatus(c) === "complete").length

  return (
    <>
      <div className="space-y-6">
        {/* 页面头部 */}
        <div className="flex items-center justify-between">
          <div>
            <h1 className="text-2xl font-bold">知识卡管理</h1>
            <p className="text-sm text-muted-foreground">
              管理{totalCards} 张知识卡，{completeCards} 张已完成，{totalCards - completeCards} 张待补充
            </p>
          </div>
        </div>

        {/* 筛选栏 */}
        <div className="flex flex-wrap items-center gap-3">
          <div className="relative max-w-xs flex-1">
            <Search className="absolute left-2.5 top-2.5 size-4 text-muted-foreground" />
            <Input
              placeholder="搜索关联题目..."
              className="pl-9"
              value={search}
              onChange={(e) => setSearch(e.target.value)}
            />
          </div>

          <Select value={statusFilter} onValueChange={(val) => setStatusFilter(val as CardStatus)}>
            <SelectTrigger className="w-32">
              <SelectValue />
            </SelectTrigger>
            <SelectContent>
              <SelectItem value="all">全部状态</SelectItem>
              <SelectItem value="complete">已完成</SelectItem>
              <SelectItem value="incomplete">待补充</SelectItem>
            </SelectContent>
          </Select>
        </div>

        {/* 表格 */}
        <div className="rounded-lg border">
          <Table>
            <TableHeader>
              {table.getHeaderGroups().map((headerGroup) => (
                <TableRow key={headerGroup.id}>
                  {headerGroup.headers.map((header) => (
                    <TableHead key={header.id}>
                      {header.isPlaceholder
                        ? null
                        : flexRender(header.column.columnDef.header, header.getContext())}
                    </TableHead>
                  ))}
                </TableRow>
              ))}
            </TableHeader>
            <TableBody>
              {loading ? (
                <TableRow>
                  <TableCell colSpan={columns.length} className="h-24 text-center text-muted-foreground">
                    加载中...
                  </TableCell>
                </TableRow>
              ) : cards.length === 0 ? (
                <TableRow>
                  <TableCell colSpan={columns.length} className="h-24 text-center text-muted-foreground">
                    暂无知识卡数据
                  </TableCell>
                </TableRow>
              ) : (
                table.getRowModel().rows.map((row) => (
                  <TableRow key={row.id}>
                    {row.getVisibleCells().map((cell) => (
                      <TableCell key={cell.id}>
                        {flexRender(cell.column.columnDef.cell, cell.getContext())}
                      </TableCell>
                    ))}
                  </TableRow>
                ))
              )}
            </TableBody>
          </Table>
        </div>
      </div>

      {/* 查看详情 */}
      <Dialog open={detailOpen} onOpenChange={setDetailOpen}>
        <DialogContent className="max-w-lg">
          <DialogHeader>
            <DialogTitle>知识卡详情</DialogTitle>
          </DialogHeader>
          {detailCard && (
            <div className="space-y-4 py-4">
              <div>
                <Label className="text-muted-foreground">关联题目</Label>
                <p className="mt-1 text-sm">{detailCard.questionStem}</p>
              </div>
              <div>
                <div className="flex items-center gap-2 mb-1">
                  <Label>基础知识卡</Label>
                  <Badge variant="secondary" className="text-xs">所有用户</Badge>
                </div>
                <p className="text-sm leading-relaxed bg-muted/30 rounded-md p-3">
                  {detailCard.summary || <span className="italic text-muted-foreground">未填写</span>}
                </p>
              </div>
              {detailCard.deepDive && (
                <div>
                  <div className="flex items-center gap-2 mb-1">
                    <Label>深度知识卡</Label>
                    <Badge variant="outline" className="text-xs">Pro 用户</Badge>
                  </div>
                  <p className="text-sm leading-relaxed bg-muted/30 rounded-md p-3 text-muted-foreground">
                    {detailCard.deepDive}
                  </p>
                </div>
              )}
              {detailCard.sourceRef && (
                <div>
                  <Label className="text-muted-foreground">来源参考</Label>
                  <p className="text-sm">{detailCard.sourceRef}</p>
                </div>
              )}
            </div>
          )}
          <DialogFooter>
            <Button variant="outline" onClick={() => setDetailOpen(false)}>关闭</Button>
            <Button onClick={() => { setDetailOpen(false); if (detailCard) openEdit(detailCard) }}>
              编辑
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>

      {/* 编辑对话框 */}
      <Dialog open={editOpen} onOpenChange={setEditOpen}>
        <DialogContent className="max-w-lg">
          <DialogHeader>
            <DialogTitle>编辑知识卡</DialogTitle>
            <DialogDescription>
              编辑知识卡内容。基础版所有用户可见，深度版仅 Pro 用户可见。
            </DialogDescription>
          </DialogHeader>

          <div className="space-y-4 py-4">
            {editingCard && (
              <div className="rounded-md bg-muted/30 p-3">
                <Label className="text-muted-foreground text-xs">关联题目</Label>
                <p className="text-sm mt-1 line-clamp-2">{editingCard.questionStem}</p>
              </div>
            )}

            <div>
              <div className="flex items-center justify-between mb-2">
                <Label htmlFor="edit-basic">基础知识卡</Label>
                <span className={`text-xs ${editForm.summary.length > BASIC_MAX ? "text-destructive font-medium" : "text-muted-foreground"}`}>
                  {editForm.summary.length}/{BASIC_MAX}
                </span>
              </div>
              <Textarea
                id="edit-basic"
                value={editForm.summary}
                onChange={(e) => setEditForm({ ...editForm, summary: e.target.value })}
                rows={3}
                placeholder="2-3 句趣味解读..."
              />
            </div>

            <div>
              <div className="flex items-center justify-between mb-2">
                <Label htmlFor="edit-deep">深度知识卡（Pro）</Label>
                <span className={`text-xs ${editForm.deepDive && editForm.deepDive.length > DEEP_MAX ? "text-destructive font-medium" : "text-muted-foreground"}`}>
                  {(editForm.deepDive?.length ?? 0)}/{DEEP_MAX}
                </span>
              </div>
              <Textarea
                id="edit-deep"
                value={editForm.deepDive ?? ""}
                onChange={(e) => setEditForm({ ...editForm, deepDive: e.target.value })}
                rows={5}
                placeholder="扩展背景故事、趣味延伸..."
              />
            </div>

            <div>
              <Label htmlFor="edit-sourceRef">来源参考（选填）</Label>
              <Input
                id="edit-sourceRef"
                value={editForm.sourceRef ?? ""}
                onChange={(e) => setEditForm({ ...editForm, sourceRef: e.target.value })}
                placeholder="如：《旧唐书·太宗本纪》"
                className="mt-2"
              />
            </div>
          </div>

          <DialogFooter>
            <Button variant="outline" onClick={() => setEditOpen(false)} disabled={submitting}>
              取消
            </Button>
            <Button onClick={handleSave} disabled={submitting}>
              {submitting ? "保存中..." : "保存"}
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </>
  )
}