/**
 * 查询结果导出工具
 * 支持 CSV、JSON、Excel 格式
 */

import { escapeHtml } from '@/utils/fileUtils'

/**
 * 导出为 CSV
 */
export function exportToCSV(data, columns = [], filename = 'query-result.csv') {
  if (!data || !Array.isArray(data) || data.length === 0) {
    console.warn('No data to export')
    return false
  }

  try {
    // 自动检测列名
    let headers = columns
    if (headers.length === 0) {
      headers = Object.keys(data[0])
    }

    // 构建 CSV 内容
    const rows = []

    // 表头
    rows.push(headers.join(','))

    // 数据行
    data.forEach(row => {
      const values = headers.map(header => {
        const value = row[header]
        // 处理 null/undefined
        if (value === null || value === undefined) return ''
        // 处理包含逗号或引号的值
        const strValue = String(value)
        if (strValue.includes(',') || strValue.includes('"') || strValue.includes('\n')) {
          return `"${strValue.replace(/"/g, '""')}"`
        }
        return strValue
      })
      rows.push(values.join(','))
    })

    // 添加 BOM 使 Excel 正确识别 UTF-8
    const BOM = '\uFEFF'
    const csvContent = BOM + rows.join('\n')

    // 创建下载
    downloadFile(csvContent, filename, 'text/csv;charset=utf-8')
    return true
  } catch (e) {
    console.error('Failed to export CSV:', e)
    return false
  }
}

/**
 * 导出为 JSON
 */
export function exportToJSON(data, filename = 'query-result.json', pretty = true) {
  if (!data || !Array.isArray(data)) {
    console.warn('No data to export')
    return false
  }

  try {
    const jsonContent = pretty
      ? JSON.stringify(data, null, 2)
      : JSON.stringify(data)

    downloadFile(jsonContent, filename, 'application/json;charset=utf-8')
    return true
  } catch (e) {
    console.error('Failed to export JSON:', e)
    return false
  }
}

/**
 * 导出为 Markdown 表格
 */
export function exportToMarkdown(data, columns = [], filename = 'query-result.md') {
  if (!data || !Array.isArray(data) || data.length === 0) {
    console.warn('No data to export')
    return false
  }

  try {
    // 自动检测列名
    let headers = columns
    if (headers.length === 0) {
      headers = Object.keys(data[0])
    }

    // 构建 Markdown 表格
    const rows = []

    // 表头
    rows.push('| ' + headers.join(' | ') + ' |')
    rows.push('| ' + headers.map(() => '---').join(' | ') + ' |')

    // 数据行
    data.forEach(row => {
      const values = headers.map(header => {
        const value = row[header]
        if (value === null || value === undefined) return ''
        // 转义管道符
        return String(value).replace(/\|/g, '\\|')
      })
      rows.push('| ' + values.join(' | ') + ' |')
    })

    const mdContent = rows.join('\n')
    downloadFile(mdContent, filename, 'text/markdown;charset=utf-8')
    return true
  } catch (e) {
    console.error('Failed to export Markdown:', e)
    return false
  }
}

/**
 * 导出为 Excel (HTML 表格格式)
 */
export function exportToExcel(data, columns = [], filename = 'query-result.xls') {
  if (!data || !Array.isArray(data) || data.length === 0) {
    console.warn('No data to export')
    return false
  }

  try {
    // 自动检测列名
    let headers = columns
    if (headers.length === 0) {
      headers = Object.keys(data[0])
    }

    // 构建 HTML 表格
    let html = '<table>\n'

    // 表头
    html += '  <thead>\n    <tr>\n'
    headers.forEach(header => {
      html += `      <th><b>${escapeHtml(header)}</b></th>\n`
    })
    html += '    </tr>\n  </thead>\n'

    // 表体
    html += '  <tbody>\n'
    data.forEach(row => {
      html += '    <tr>\n'
      headers.forEach(header => {
        const value = row[header]
        const displayValue = value === null || value === undefined ? '' : String(value)
        html += `      <td>${escapeHtml(displayValue)}</td>\n`
      })
      html += '    </tr>\n'
    })
    html += '  </tbody>\n'

    html += '</table>'

    downloadFile(html, filename, 'application/vnd.ms-excel;charset=utf-8')
    return true
  } catch (e) {
    console.error('Failed to export Excel:', e)
    return false
  }
}

/**
 * 下载文件
 */
function downloadFile(content, filename, mimeType) {
  const blob = new Blob([content], { type: mimeType })
  const url = URL.createObjectURL(blob)
  const link = document.createElement('a')
  link.href = url
  link.download = filename
  document.body.appendChild(link)
  link.click()
  document.body.removeChild(link)
  URL.revokeObjectURL(url)
}

/**
 * 复制到剪贴板
 */
export async function copyToClipboard(data, format = 'json') {
  if (!data) return false

  try {
    let content = ''

    switch (format) {
      case 'json':
        content = JSON.stringify(data, null, 2)
        break
      case 'csv':
        if (data.length === 0) return false
        const headers = Object.keys(data[0])
        content = headers.join(',') + '\n'
        data.forEach(row => {
          content += headers.map(h => row[h] ?? '').join(',') + '\n'
        })
        break
      default:
        content = String(data)
    }

    await navigator.clipboard.writeText(content)
    return true
  } catch (e) {
    console.error('Failed to copy to clipboard:', e)
    return false
  }
}