import { useState, useRef } from 'react'
import { toast } from 'sonner'
import { Sparkles, Loader2, Download, TrendingUp } from 'lucide-react'
import ReactMarkdown from 'react-markdown'
import remarkGfm from 'remark-gfm'
import rehypeRaw from 'rehype-raw'
import { Document, Packer, Paragraph, HeadingLevel, TextRun, Table, TableRow, TableCell, WidthType, BorderStyle, AlignmentType } from 'docx'
import { saveAs } from 'file-saver'
import { useAuthStore } from '../../store/authStore'
import Card from '../../components/ui/Card'
import Button from '../../components/ui/Button'



/** 解析 markdown 内联格式（**bold** 和 `code`）为 TextRun 数组 */
function parseInlineBold(text: string): TextRun[] {
  const runs: TextRun[] = []
  const regex = /(\*\*(.+?)\*\*|`(.+?)`)/g
  let lastIndex = 0
  let match
  while ((match = regex.exec(text)) !== null) {
    if (match.index > lastIndex) {
      runs.push(new TextRun({ text: text.slice(lastIndex, match.index) }))
    }
    if (match[2]) {
      runs.push(new TextRun({ text: match[2], bold: true }))
    } else if (match[3]) {
      runs.push(new TextRun({ text: match[3], font: 'Courier New', size: 20 }))
    }
    lastIndex = regex.lastIndex
  }
  if (lastIndex < text.length) {
    runs.push(new TextRun({ text: text.slice(lastIndex) }))
  }
  return runs.length ? runs : [new TextRun({ text })]
}

/** 导出 Markdown 文本为 Word 文档 */
async function exportMarkdownToWord(markdown: string, fileName: string) {
  const lines = markdown.split('\n')
  const children: (Paragraph | Table)[] = []
  let i = 0

  while (i < lines.length) {
    const line = lines[i]
    if (!line.trim()) { i++; continue }
    if (line.includes('|') && i + 1 < lines.length && lines[i + 1].includes('---')) {
      const headerCells = line.split('|').map(c => c.trim()).filter(Boolean)
      i += 2
      const rows: TableRow[] = []
      rows.push(new TableRow({
        children: headerCells.map(text => new TableCell({
          children: [new Paragraph({ children: [new TextRun({ text, bold: true })] })],
          shading: { fill: 'F3F4F6' },
        })),
      }))
      while (i < lines.length && lines[i].includes('|') && lines[i].trim()) {
        const cells = lines[i].split('|').map(c => c.trim()).filter(Boolean)
        rows.push(new TableRow({
          children: cells.map(text => new TableCell({
            children: [new Paragraph({ children: [new TextRun({ text })] })],
          })),
        }))
        i++
      }
      children.push(new Table({ rows, width: { size: 100, type: WidthType.PERCENTAGE } }))
      continue
    }
    if (line.startsWith('### ')) {
      children.push(new Paragraph({ heading: HeadingLevel.HEADING_3, children: [new TextRun({ text: line.slice(4), bold: true })] }))
    } else if (line.startsWith('## ')) {
      children.push(new Paragraph({ heading: HeadingLevel.HEADING_2, children: [new TextRun({ text: line.slice(3), bold: true })] }))
    } else if (line.startsWith('# ')) {
      children.push(new Paragraph({ heading: HeadingLevel.HEADING_1, children: [new TextRun({ text: line.slice(2), bold: true })] }))
    } else if (line.startsWith('> ')) {
      children.push(new Paragraph({ children: [new TextRun({ text: line.slice(2), italics: true })], indent: { left: 720 } }))
    } else if (line.startsWith('- ') || line.startsWith('* ')) {
      children.push(new Paragraph({ children: parseInlineBold(line.slice(2)), bullet: { level: 0 } }))
    } else if (/^\d+\.\s/.test(line)) {
      children.push(new Paragraph({ children: parseInlineBold(line.replace(/^\d+\.\s/, '')), numbering: { reference: 'default-numbering', level: 0 } }))
    } else if (line === '---' || line === '***') {
      children.push(new Paragraph({ children: [], border: { bottom: { style: BorderStyle.SINGLE, size: 6, color: 'E5E7EB' } } }))
    } else {
      children.push(new Paragraph({ children: parseInlineBold(line) }))
    }
    i++
  }

  const doc = new Document({
    numbering: { config: [{ reference: 'default-numbering', levels: [{ level: 0, format: 'decimal', text: '%1.', alignment: AlignmentType.START }] }] },
    sections: [{ children }],
  })
  const blob = await Packer.toBlob(doc)
  saveAs(blob, fileName)
}

// 通用 AI 历史记录 hook

// 通用历史记录栏组件

export function HRReportTab() {
  const [result, setResult] = useState('')
  const [loading, setLoading] = useState(false)
  const abortRef = useRef<AbortController | null>(null)

  const handleGenerate = async () => {
    if (loading) return
    abortRef.current?.abort()
    const controller = new AbortController()
    abortRef.current = controller

    setLoading(true)
    setResult('')

    try {
      const token = useAuthStore.getState().accessToken
      const url = import.meta.env.DEV
        ? `http://localhost:3000/api/v1/ai/hr-report-stream`
        : `/api/v1/ai/hr-report-stream`

      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${token}`,
          'Content-Type': 'application/json',
        },
        signal: controller.signal,
      })

      if (!response.ok) {
        const errData = await response.json().catch(() => null)
        throw new Error(errData?.error?.message || '请求失败')
      }

      const reader = response.body?.getReader()
      const decoder = new TextDecoder()
      let accumulated = ''
      let buffer = ''

      if (reader) {
        while (true) {
          const { done, value } = await reader.read()
          if (done) break
          buffer += decoder.decode(value, { stream: true })
          const lines = buffer.split('\n')
          buffer = lines.pop() || ''
          for (const line of lines) {
            if (line.startsWith('data: ')) {
              const data = line.slice(6).trim()
              if (data === '[DONE]') continue
              try {
                const parsed = JSON.parse(data)
                if (parsed.delta) {
                  accumulated += parsed.delta
                  setResult(accumulated)
                }
                if (parsed.error) {
                  throw new Error(parsed.error)
                }
              } catch (parseErr: any) {
                if (parseErr instanceof SyntaxError) continue
                throw parseErr
              }
            }
          }
        }
        setResult(accumulated)
      }
    } catch (err: any) {
      if (err.name !== 'AbortError') {
        toast.error(err.message || '生成报告失败')
      }
    } finally {
      setLoading(false)
    }
  }

  const handleExport = async () => {
    if (!result) return
    try {
      await exportMarkdownToWord(result, `人力分析报告_${new Date().toISOString().slice(0, 10)}.docx`)
      toast.success('Word 文档已导出')
    } catch {
      toast.error('导出失败')
    }
  }

  return (
    <div className="space-y-3">
      <Card>
        <div className="flex items-center justify-between mb-3">
          <div>
            <h2 className="text-sm font-medium flex items-center gap-1.5">
              <TrendingUp className="w-4 h-4 text-primary" />
              AI 人力分析报告
            </h2>
            <p className="text-xs text-gray-500 mt-1">基于企业实际数据自动生成：人力概况、风险提示、成本分析、合规建议、改进方向</p>
          </div>
          <div className="flex items-center gap-2">
            {result && !loading && (
              <button
                onClick={handleExport}
                className="flex items-center gap-1 text-xs text-primary hover:text-primary/80 transition-colors"
              >
                <Download className="w-3.5 h-3.5" />
                导出 Word
              </button>
            )}
            <Button size="sm" onClick={handleGenerate} disabled={loading}>
              {loading ? (
                <><Loader2 className="w-4 h-4 mr-1 animate-spin" />生成中...</>
              ) : (
                <><Sparkles className="w-4 h-4 mr-1" />生成报告</>
              )}
            </Button>
          </div>
        </div>

        {!result && !loading && (
          <div className="text-center py-12 text-gray-400">
            <TrendingUp className="w-12 h-12 mx-auto mb-3 text-gray-300" />
            <p className="text-sm">点击"生成报告"，AI 将基于企业当前数据自动生成结构化人力分析报告</p>
          </div>
        )}

        {loading && !result && (
          <div className="text-center py-12">
            <Loader2 className="w-8 h-8 mx-auto mb-3 text-primary animate-spin" />
            <p className="text-sm text-gray-500">AI 正在分析企业数据并生成报告...</p>
          </div>
        )}

        {result && (
          <div className="prose prose-sm max-w-none
            prose-headings:text-gray-800 prose-headings:font-semibold
            prose-h1:text-lg prose-h1:border-b prose-h1:pb-2 prose-h1:border-gray-200
            prose-h2:text-base prose-h2:mt-4
            prose-h3:text-sm prose-h3:mt-3
            prose-p:text-gray-600 prose-p:leading-relaxed
            prose-li:text-gray-600 prose-li:leading-relaxed
            prose-strong:text-gray-800
            prose-code:text-pink-600 prose-code:bg-gray-100 prose-code:px-1.5 prose-code:py-0.5 prose-code:rounded prose-code:text-xs prose-code:before:content-none prose-code:after:content-none
            prose-pre:bg-gray-900 prose-pre:text-gray-100 prose-pre:rounded-lg prose-pre:p-3 prose-pre:my-3
            prose-blockquote:border-l-primary prose-blockquote:bg-primary/5 prose-blockquote:py-1 prose-blockquote:px-3 prose-blockquote:rounded-r prose-blockquote:not-italic
            prose-table:text-xs prose-table:border-collapse
            prose-th:bg-gray-50 prose-th:px-3 prose-th:py-1.5 prose-th:font-semibold prose-th:border prose-th:border-gray-200
            prose-td:px-3 prose-td:py-1.5 prose-td:border prose-td:border-gray-200
            prose-a:text-primary prose-a:no-underline hover:prose-a:underline
          ">
            <ReactMarkdown remarkPlugins={[remarkGfm]} rehypePlugins={[rehypeRaw]}>
              {result}
            </ReactMarkdown>
          </div>
        )}
      </Card>
    </div>
  )
}