"use client"

import type React from "react"

import { useState, useEffect } from "react"
import { ProtectedRoute } from "@/components/protected-route"
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
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 { Alert, AlertDescription } from "@/components/ui/alert"
import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs"
import {
  ArrowLeft,
  Upload,
  Download,
  Brain,
  Lightbulb,
  FileSpreadsheet,
  CheckCircle,
  AlertCircle,
  Info,
  Loader2,
  ChevronLeft,
  ChevronRight,
} from "lucide-react"
import Link from "next/link"
import { parseExcelFile, type ImportResult, exportLogicQuestionsToExcel, exportCreativeQuestionsToExcel } from "@/lib/utils/excel-parser"

// 定義題目類型
interface LogicQuestion {
  id: number
  question: string
  option_a: string
  option_b: string
  option_c: string
  option_d: string
  option_e?: string
  correct_answer: string
  explanation: string
}

interface CreativeQuestion {
  id: number
  statement: string
  category: string
  is_reverse: boolean
}

export default function QuestionsManagementPage() {
  return (
    <ProtectedRoute adminOnly>
      <QuestionsManagementContent />
    </ProtectedRoute>
  )
}

function QuestionsManagementContent() {
  const [activeTab, setActiveTab] = useState("logic")
  const [isImporting, setIsImporting] = useState(false)
  const [importResult, setImportResult] = useState<ImportResult | null>(null)
  const [selectedFile, setSelectedFile] = useState<File | null>(null)
  const [importType, setImportType] = useState<"logic" | "creative">("logic")
  
  // 題目狀態
  const [logicQuestions, setLogicQuestions] = useState<LogicQuestion[]>([])
  const [creativeQuestions, setCreativeQuestions] = useState<CreativeQuestion[]>([])
  const [isLoading, setIsLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  
  // 分頁狀態
  const [currentPage, setCurrentPage] = useState(1)
  const [currentLogicPage, setCurrentLogicPage] = useState(1)
  const [itemsPerPage] = useState(10)

  // 分頁計算
  const totalPages = Math.ceil(creativeQuestions.length / itemsPerPage)
  const startIndex = (currentPage - 1) * itemsPerPage
  const endIndex = startIndex + itemsPerPage
  const currentCreativeQuestions = creativeQuestions.slice(startIndex, endIndex)

  // 邏輯題目分頁計算
  const totalLogicPages = Math.ceil(logicQuestions.length / itemsPerPage)
  const logicStartIndex = (currentLogicPage - 1) * itemsPerPage
  const logicEndIndex = logicStartIndex + itemsPerPage
  const currentLogicQuestions = logicQuestions.slice(logicStartIndex, logicEndIndex)

  // 分頁處理函數
  const handlePageChange = (page: number) => {
    setCurrentPage(page)
  }

  const handlePreviousPage = () => {
    if (currentPage > 1) {
      setCurrentPage(currentPage - 1)
    }
  }

  const handleNextPage = () => {
    if (currentPage < totalPages) {
      setCurrentPage(currentPage + 1)
    }
  }

  // 邏輯題目分頁處理函數
  const handleLogicPageChange = (page: number) => {
    setCurrentLogicPage(page)
  }

  const handleLogicPreviousPage = () => {
    if (currentLogicPage > 1) {
      setCurrentLogicPage(currentLogicPage - 1)
    }
  }

  const handleLogicNextPage = () => {
    if (currentLogicPage < totalLogicPages) {
      setCurrentLogicPage(currentLogicPage + 1)
    }
  }

  // 從資料庫獲取題目
  useEffect(() => {
    const fetchQuestions = async () => {
      try {
        setIsLoading(true)
        setError(null)

        // 並行獲取兩種題目
        const [logicResponse, creativeResponse] = await Promise.all([
          fetch('/api/questions/logic'),
          fetch('/api/questions/creative')
        ])

        if (!logicResponse.ok || !creativeResponse.ok) {
          throw new Error('獲取題目失敗')
        }

        const logicData = await logicResponse.json()
        const creativeData = await creativeResponse.json()

        if (logicData.success) {
          setLogicQuestions(logicData.data)
        }

        if (creativeData.success) {
          setCreativeQuestions(creativeData.data)
        }
      } catch (err) {
        console.error('獲取題目失敗:', err)
        setError(err instanceof Error ? err.message : '獲取題目失敗')
      } finally {
        setIsLoading(false)
      }
    }

    fetchQuestions()
  }, [])

  const handleFileSelect = (event: React.ChangeEvent<HTMLInputElement>) => {
    const file = event.target.files?.[0]
    if (file) {
      if (
        file.type === "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" ||
        file.type === "application/vnd.ms-excel" ||
        file.name.endsWith(".xlsx") ||
        file.name.endsWith(".xls")
      ) {
        setSelectedFile(file)
        setImportResult(null)
      } else {
        setImportResult({
          success: false,
          message: "請選擇 Excel 檔案 (.xlsx 或 .xls)",
        })
      }
    }
  }

  const handleImport = async () => {
    if (!selectedFile) {
      setImportResult({
        success: false,
        message: "請先選擇要匯入的 Excel 檔案",
      })
      return
    }

    setIsImporting(true)

    try {
      const formData = new FormData()
      formData.append("file", selectedFile)
      formData.append("type", importType)

      const response = await fetch("/api/questions/import", {
        method: "POST",
        body: formData,
      })

      const result = await response.json()
      setImportResult(result)

      if (result.success) {
        setSelectedFile(null)
        // 重置檔案輸入
        const fileInput = document.getElementById("file-input") as HTMLInputElement
        if (fileInput) fileInput.value = ""
        
        // 重新載入題目資料
        const fetchQuestions = async () => {
          try {
            const [logicResponse, creativeResponse] = await Promise.all([
              fetch('/api/questions/logic'),
              fetch('/api/questions/creative')
            ])

            if (logicResponse.ok) {
              const logicData = await logicResponse.json()
              if (logicData.success) {
                setLogicQuestions(logicData.data)
              }
            }

            if (creativeResponse.ok) {
              const creativeData = await creativeResponse.json()
              if (creativeData.success) {
                setCreativeQuestions(creativeData.data)
              }
            }
          } catch (err) {
            console.error('重新載入題目失敗:', err)
          }
        }

        fetchQuestions()
      }
    } catch (error) {
      setImportResult({
        success: false,
        message: "匯入失敗，請檢查檔案格式是否正確",
        errors: [error instanceof Error ? error.message : "未知錯誤"],
      })
    } finally {
      setIsImporting(false)
    }
  }

  const downloadTemplate = async (type: "logic" | "creative") => {
    try {
      const response = await fetch(`/api/questions/export?type=${type}`)
      
      if (!response.ok) {
        throw new Error('下載失敗')
      }

      const result = await response.json()
      
      if (!result.success) {
        throw new Error(result.message || '下載失敗')
      }

      // 解碼 Base64 資料，保留 UTF-8 BOM
      const binaryString = atob(result.data)
      const bytes = new Uint8Array(binaryString.length)
      for (let i = 0; i < binaryString.length; i++) {
        bytes[i] = binaryString.charCodeAt(i)
      }
      
      // 創建 Blob，保留原始字節資料
      const blob = new Blob([bytes], { 
        type: 'text/csv;charset=utf-8'
      })
      
      const url = window.URL.createObjectURL(blob)
      const link = document.createElement('a')
      link.href = url
      link.download = result.filename
      document.body.appendChild(link)
      link.click()
      document.body.removeChild(link)
      window.URL.revokeObjectURL(url)
    } catch (error) {
      console.error("下載範本失敗:", error)
      setImportResult({
        success: false,
        message: "下載範本失敗，請稍後再試",
      })
    }
  }

  return (
    <div className="min-h-screen bg-background">
      {/* Header */}
      <header className="border-b bg-card/50 backdrop-blur-sm">
        <div className="container mx-auto px-4 py-4">
          <div className="flex items-center gap-4">
            <Button variant="ghost" size="sm" asChild>
              <Link href="/dashboard">
                <ArrowLeft className="w-4 h-4 mr-2" />
                <span className="hidden sm:inline">返回儀表板</span>
              </Link>
            </Button>
            <div>
              <h1 className="text-xl font-bold text-foreground">題目管理</h1>
              <p className="text-sm text-muted-foreground">管理測試題目和匯入新題目</p>
            </div>
          </div>
        </div>
      </header>

      <div className="container mx-auto px-4 py-8">
        <div className="max-w-6xl mx-auto space-y-8">
          {/* Import Section */}
          <Card className="border-2 border-primary/20">
            <CardHeader>
              <CardTitle className="flex items-center gap-2">
                <Upload className="w-5 h-5 text-primary" />
                Excel 檔案匯入
              </CardTitle>
              <CardDescription>上傳 Excel 檔案來批量匯入測試題目。支援邏輯思維測試和創意能力測試題目。</CardDescription>
            </CardHeader>
            <CardContent className="space-y-6">
              {/* File Upload */}
              <div className="space-y-4">
                <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                  <div className="space-y-2">
                    <Label htmlFor="file-input">選擇 Excel 檔案</Label>
                    <Input
                      id="file-input"
                      type="file"
                      accept=".xlsx,.xls"
                      onChange={handleFileSelect}
                      className="cursor-pointer"
                    />
                  </div>
                  <div className="space-y-2">
                    <Label>題目類型</Label>
                    <Select value={importType} onValueChange={(value: "logic" | "creative") => setImportType(value)}>
                      <SelectTrigger>
                        <SelectValue />
                      </SelectTrigger>
                      <SelectContent>
                        <SelectItem value="logic">邏輯思維測試</SelectItem>
                        <SelectItem value="creative">創意能力測試</SelectItem>
                      </SelectContent>
                    </Select>
                  </div>
                </div>

                {selectedFile && (
                  <div className="flex items-center gap-2 p-3 bg-blue-50 rounded-lg border border-blue-200">
                    <FileSpreadsheet className="w-4 h-4 text-blue-600" />
                    <span className="text-sm text-blue-800">已選擇：{selectedFile.name}</span>
                  </div>
                )}

                <div className="flex gap-3">
                  <Button onClick={handleImport} disabled={!selectedFile || isImporting} className="flex-1">
                    {isImporting ? (
                      <>
                        <div className="w-4 h-4 border-2 border-white border-t-transparent rounded-full animate-spin mr-2" />
                        匯入中...
                      </>
                    ) : (
                      <>
                        <Upload className="w-4 h-4 mr-2" />
                        開始匯入
                      </>
                    )}
                  </Button>
                </div>
              </div>

              {/* Import Result */}
              {importResult && (
                <Alert variant={importResult.success ? "default" : "destructive"}>
                  {importResult.success ? <CheckCircle className="h-4 w-4" /> : <AlertCircle className="h-4 w-4" />}
                  <AlertDescription>
                    {importResult.message}
                    {importResult.errors && (
                      <ul className="mt-2 list-disc list-inside">
                        {importResult.errors.map((error, index) => (
                          <li key={index} className="text-sm">
                            {error}
                          </li>
                        ))}
                      </ul>
                    )}
                  </AlertDescription>
                </Alert>
              )}

              {/* Template Download */}
              <div className="border-t pt-4">
                <div className="flex items-center gap-2 mb-3">
                  <Info className="w-4 h-4 text-blue-500" />
                  <span className="text-sm font-medium">下載範本檔案</span>
                </div>
                <div className="flex gap-3">
                  <Button variant="outline" onClick={() => downloadTemplate("logic")} className="flex-1">
                    <Download className="w-4 h-4 mr-2" />
                    邏輯思維範本
                  </Button>
                  <Button variant="outline" onClick={() => downloadTemplate("creative")} className="flex-1">
                    <Download className="w-4 h-4 mr-2" />
                    創意能力範本
                  </Button>
                </div>
              </div>
            </CardContent>
          </Card>

          {/* Current Questions */}
          <Card>
            <CardHeader>
              <CardTitle>現有題目管理</CardTitle>
              <CardDescription>查看和管理系統中的測試題目</CardDescription>
            </CardHeader>
            <CardContent>
              <Tabs value={activeTab} onValueChange={setActiveTab}>
                <TabsList className="grid w-full grid-cols-2">
                  <TabsTrigger value="logic" className="flex items-center gap-2">
                    <Brain className="w-4 h-4" />
                    邏輯思維 ({logicQuestions.length})
                  </TabsTrigger>
                  <TabsTrigger value="creative" className="flex items-center gap-2">
                    <Lightbulb className="w-4 h-4" />
                    創意能力 ({creativeQuestions.length})
                  </TabsTrigger>
                </TabsList>

                <TabsContent value="logic" className="space-y-4">
                  <div className="flex justify-between items-center">
                    <h3 className="text-lg font-semibold">邏輯思維測試題目</h3>
                    <Badge variant="outline">{logicQuestions.length} 道題目</Badge>
                  </div>

                  {isLoading ? (
                    <div className="flex items-center justify-center py-8">
                      <Loader2 className="w-6 h-6 animate-spin mr-2" />
                      <span>載入題目中...</span>
                    </div>
                  ) : error ? (
                    <Alert variant="destructive">
                      <AlertCircle className="h-4 w-4" />
                      <AlertDescription>{error}</AlertDescription>
                    </Alert>
                  ) : (
                    <Table>
                      <TableHeader>
                        <TableRow>
                          <TableHead>題目ID</TableHead>
                          <TableHead>題目內容</TableHead>
                          <TableHead>選項數量</TableHead>
                          <TableHead>正確答案</TableHead>
                        </TableRow>
                      </TableHeader>
                      <TableBody>
                        {currentLogicQuestions.map((question) => (
                          <TableRow key={question.id}>
                            <TableCell className="font-medium">{question.id}</TableCell>
                            <TableCell className="max-w-md truncate">{question.question}</TableCell>
                            <TableCell>
                              {question.option_e ? 5 : 4}
                            </TableCell>
                            <TableCell>
                              <Badge className="bg-green-500 text-white">{question.correct_answer}</Badge>
                            </TableCell>
                          </TableRow>
                        ))}
                      </TableBody>
                    </Table>
                  )}

                  {/* 邏輯題目分頁控制 */}
                  {!isLoading && !error && logicQuestions.length > itemsPerPage && (
                    <div className="flex flex-col sm:flex-row items-center justify-between mt-6 gap-4">
                      <div className="text-sm text-muted-foreground text-center sm:text-left">
                        顯示第 {logicStartIndex + 1} - {Math.min(logicEndIndex, logicQuestions.length)} 筆，共 {logicQuestions.length} 筆
                      </div>
                      
                      {/* Desktop Pagination */}
                      <div className="hidden sm:flex items-center space-x-2">
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handleLogicPreviousPage}
                          disabled={currentLogicPage === 1}
                        >
                          <ChevronLeft className="h-4 w-4" />
                          上一頁
                        </Button>
                        
                        <div className="flex items-center space-x-1">
                          {Array.from({ length: totalLogicPages }, (_, i) => i + 1).map((page) => (
                            <Button
                              key={page}
                              variant={currentLogicPage === page ? "default" : "outline"}
                              size="sm"
                              onClick={() => handleLogicPageChange(page)}
                              className="w-8 h-8 p-0"
                            >
                              {page}
                            </Button>
                          ))}
                        </div>
                        
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handleLogicNextPage}
                          disabled={currentLogicPage === totalLogicPages}
                        >
                          下一頁
                          <ChevronRight className="h-4 w-4" />
                        </Button>
                      </div>

                      {/* Mobile Pagination */}
                      <div className="flex sm:hidden items-center space-x-2 w-full justify-center">
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handleLogicPreviousPage}
                          disabled={currentLogicPage === 1}
                          className="flex-1 max-w-[80px]"
                        >
                          <ChevronLeft className="h-4 w-4 mr-1" />
                          上一頁
                        </Button>
                        
                        <div className="flex items-center space-x-1 px-2">
                          {(() => {
                            const maxVisiblePages = 3
                            const startPage = Math.max(1, currentLogicPage - 1)
                            const endPage = Math.min(totalLogicPages, startPage + maxVisiblePages - 1)
                            const pages = []
                            
                            // 如果不在第一頁，顯示第一頁和省略號
                            if (startPage > 1) {
                              pages.push(
                                <Button
                                  key={1}
                                  variant="outline"
                                  size="sm"
                                  onClick={() => handleLogicPageChange(1)}
                                  className="w-8 h-8 p-0"
                                >
                                  1
                                </Button>
                              )
                              if (startPage > 2) {
                                pages.push(
                                  <span key="ellipsis1" className="text-muted-foreground px-1">
                                    ...
                                  </span>
                                )
                              }
                            }
                            
                            // 顯示當前頁附近的頁碼
                            for (let i = startPage; i <= endPage; i++) {
                              pages.push(
                                <Button
                                  key={i}
                                  variant={currentLogicPage === i ? "default" : "outline"}
                                  size="sm"
                                  onClick={() => handleLogicPageChange(i)}
                                  className="w-8 h-8 p-0"
                                >
                                  {i}
                                </Button>
                              )
                            }
                            
                            // 如果不在最後一頁，顯示省略號和最後一頁
                            if (endPage < totalLogicPages) {
                              if (endPage < totalLogicPages - 1) {
                                pages.push(
                                  <span key="ellipsis2" className="text-muted-foreground px-1">
                                    ...
                                  </span>
                                )
                              }
                              pages.push(
                                <Button
                                  key={totalLogicPages}
                                  variant="outline"
                                  size="sm"
                                  onClick={() => handleLogicPageChange(totalLogicPages)}
                                  className="w-8 h-8 p-0"
                                >
                                  {totalLogicPages}
                                </Button>
                              )
                            }
                            
                            return pages
                          })()}
                        </div>
                        
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handleLogicNextPage}
                          disabled={currentLogicPage === totalLogicPages}
                          className="flex-1 max-w-[80px]"
                        >
                          下一頁
                          <ChevronRight className="h-4 w-4 ml-1" />
                        </Button>
                      </div>
                    </div>
                  )}
                </TabsContent>

                <TabsContent value="creative" className="space-y-4">
                  <div className="flex justify-between items-center">
                    <h3 className="text-lg font-semibold">創意能力測試題目</h3>
                    <Badge variant="outline">{creativeQuestions.length} 道題目</Badge>
                  </div>

                  {isLoading ? (
                    <div className="flex items-center justify-center py-8">
                      <Loader2 className="w-6 h-6 animate-spin mr-2" />
                      <span>載入題目中...</span>
                    </div>
                  ) : error ? (
                    <Alert variant="destructive">
                      <AlertCircle className="h-4 w-4" />
                      <AlertDescription>{error}</AlertDescription>
                    </Alert>
                  ) : (
                    <Table>
                      <TableHeader>
                        <TableRow>
                          <TableHead>題目ID</TableHead>
                          <TableHead>陳述內容</TableHead>
                          <TableHead>類別</TableHead>
                          <TableHead>反向計分</TableHead>
                        </TableRow>
                      </TableHeader>
                      <TableBody>
                        {currentCreativeQuestions.map((question) => (
                          <TableRow key={question.id}>
                            <TableCell className="font-medium">{question.id}</TableCell>
                            <TableCell className="max-w-md truncate">{question.statement}</TableCell>
                            <TableCell>
                              <Badge variant="secondary">{question.category}</Badge>
                            </TableCell>
                            <TableCell>
                              {question.is_reverse ? (
                                <Badge className="bg-orange-500 text-white">是</Badge>
                              ) : (
                                <Badge variant="outline">否</Badge>
                              )}
                            </TableCell>
                          </TableRow>
                        ))}
                      </TableBody>
                    </Table>
                  )}

                  {/* 創意題目分頁控制 */}
                  {!isLoading && !error && creativeQuestions.length > itemsPerPage && (
                    <div className="flex flex-col sm:flex-row items-center justify-between mt-6 gap-4">
                      <div className="text-sm text-muted-foreground text-center sm:text-left">
                        顯示第 {startIndex + 1} - {Math.min(endIndex, creativeQuestions.length)} 筆，共 {creativeQuestions.length} 筆
                      </div>
                      
                      {/* Desktop Pagination */}
                      <div className="hidden sm:flex items-center space-x-2">
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handlePreviousPage}
                          disabled={currentPage === 1}
                        >
                          <ChevronLeft className="h-4 w-4" />
                          上一頁
                        </Button>
                        
                        <div className="flex items-center space-x-1">
                          {Array.from({ length: totalPages }, (_, i) => i + 1).map((page) => (
                            <Button
                              key={page}
                              variant={currentPage === page ? "default" : "outline"}
                              size="sm"
                              onClick={() => handlePageChange(page)}
                              className="w-8 h-8 p-0"
                            >
                              {page}
                            </Button>
                          ))}
                        </div>
                        
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handleNextPage}
                          disabled={currentPage === totalPages}
                        >
                          下一頁
                          <ChevronRight className="h-4 w-4" />
                        </Button>
                      </div>

                      {/* Mobile Pagination */}
                      <div className="flex sm:hidden items-center space-x-2 w-full justify-center">
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handlePreviousPage}
                          disabled={currentPage === 1}
                          className="flex-1 max-w-[80px]"
                        >
                          <ChevronLeft className="h-4 w-4 mr-1" />
                          上一頁
                        </Button>
                        
                        <div className="flex items-center space-x-1 px-2">
                          {(() => {
                            const maxVisiblePages = 3
                            const startPage = Math.max(1, currentPage - 1)
                            const endPage = Math.min(totalPages, startPage + maxVisiblePages - 1)
                            const pages = []
                            
                            // 如果不在第一頁，顯示第一頁和省略號
                            if (startPage > 1) {
                              pages.push(
                                <Button
                                  key={1}
                                  variant="outline"
                                  size="sm"
                                  onClick={() => handlePageChange(1)}
                                  className="w-8 h-8 p-0"
                                >
                                  1
                                </Button>
                              )
                              if (startPage > 2) {
                                pages.push(
                                  <span key="ellipsis1" className="text-muted-foreground px-1">
                                    ...
                                  </span>
                                )
                              }
                            }
                            
                            // 顯示當前頁附近的頁碼
                            for (let i = startPage; i <= endPage; i++) {
                              pages.push(
                                <Button
                                  key={i}
                                  variant={currentPage === i ? "default" : "outline"}
                                  size="sm"
                                  onClick={() => handlePageChange(i)}
                                  className="w-8 h-8 p-0"
                                >
                                  {i}
                                </Button>
                              )
                            }
                            
                            // 如果不在最後一頁，顯示省略號和最後一頁
                            if (endPage < totalPages) {
                              if (endPage < totalPages - 1) {
                                pages.push(
                                  <span key="ellipsis2" className="text-muted-foreground px-1">
                                    ...
                                  </span>
                                )
                              }
                              pages.push(
                                <Button
                                  key={totalPages}
                                  variant="outline"
                                  size="sm"
                                  onClick={() => handlePageChange(totalPages)}
                                  className="w-8 h-8 p-0"
                                >
                                  {totalPages}
                                </Button>
                              )
                            }
                            
                            return pages
                          })()}
                        </div>
                        
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={handleNextPage}
                          disabled={currentPage === totalPages}
                          className="flex-1 max-w-[80px]"
                        >
                          下一頁
                          <ChevronRight className="h-4 w-4 ml-1" />
                        </Button>
                      </div>
                    </div>
                  )}
                </TabsContent>
              </Tabs>
            </CardContent>
          </Card>
        </div>
      </div>
    </div>
  )
}