import type ExcelJS from 'exceljs'

const XLSX_MIME_TYPE = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'

type PerformanceSurveyExportCell = {
  score?: number | null
  surveyCount?: number | null
  positionGroupCode?: string | null
}

type PerformanceSurveyExportRow = {
  month: string
  employee: {
    displayName?: string | null
    jobNumber?: string | null
    departmentName?: string | null
    positionLevel?: string | null
    levelType?: string | null
  }
  cells?: Record<string, PerformanceSurveyExportCell | null | undefined>
}

export type PerformanceSurveyDashboardExportData = {
  month: string
  filters?: { positionGroupCode?: string | null }
  selectedPositionGroup?: { code?: string | null; name?: string | null } | null
  positionGroups?: Array<{ code: string; name: string }>
  templates: Array<{
    code: string
    name?: string | null
    fullName?: string | null
    maxTotal?: number | null
  }>
  public: { rows: PerformanceSurveyExportRow[] }
}

type WritableFileHandle = {
  createWritable: () => Promise<{
    write: (data: Blob) => Promise<void>
    close: () => Promise<void>
  }>
}

export type PerformanceSurveyExportDestination =
  | { kind: 'file-system'; handle: WritableFileHandle }
  | { kind: 'download' }
  | { kind: 'cancelled' }

function safeText(value: unknown, fallback = '-') {
  const normalized = String(value ?? '').trim()
  return normalized || fallback
}

export function sanitizePerformanceSurveyExportFileName(value: string) {
  const normalized = value
    .replace(/[\\/:*?"<>|]/g, '_')
    .replace(/\s+/g, ' ')
    .trim()
  return `${normalized || '考核调研公共看板'}.xlsx`
}

function getTemplateName(template: PerformanceSurveyDashboardExportData['templates'][number]) {
  return safeText(template.fullName || template.name, template.code)
}

function getRowPositionName(
  data: PerformanceSurveyDashboardExportData,
  row: PerformanceSurveyExportRow,
) {
  if (data.selectedPositionGroup?.name) return data.selectedPositionGroup.name

  const positionNameByCode = new Map(
    (data.positionGroups || []).map((group) => [group.code, group.name]),
  )
  const names = Array.from(new Set(
    Object.values(row.cells || {})
      .map((cell) => cell?.positionGroupCode ? positionNameByCode.get(cell.positionGroupCode) : null)
      .filter((name): name is string => Boolean(name)),
  ))
  return names.length > 0 ? names.join('、') : '全部岗位'
}

export function buildPerformanceSurveyExportTable(data: PerformanceSurveyDashboardExportData) {
  const fixedHeaders = ['序号', '岗位', '考核月份', '姓名', '工号', '组织', '职级']
  const scoreHeaders = data.templates.map((template) => {
    const maxTotal = Number(template.maxTotal)
    return Number.isFinite(maxTotal) && maxTotal > 0
      ? `${getTemplateName(template)}（满分${maxTotal}）`
      : getTemplateName(template)
  })

  const rows = data.public.rows.map((row, index) => {
    const values: Array<string | number> = [
      index + 1,
      getRowPositionName(data, row),
      safeText(row.month || data.month),
      safeText(row.employee.displayName),
      safeText(row.employee.jobNumber),
      safeText(row.employee.departmentName),
      safeText(row.employee.positionLevel || row.employee.levelType),
    ]

    for (const template of data.templates) {
      const cell = row.cells?.[template.code]
      const score = Number(cell?.score)
      if (cell?.score !== null && cell?.score !== undefined && Number.isFinite(score)) {
        values.push(score)
      } else if (Number(cell?.surveyCount || 0) > 0) {
        values.push('待评分')
      } else {
        values.push('-')
      }
    }
    return values
  })

  return { headers: [...fixedHeaders, ...scoreHeaders], rows }
}

export async function buildPerformanceSurveyDashboardWorkbook(
  data: PerformanceSurveyDashboardExportData,
) {
  const excelJsModule = await import('exceljs')
  const ExcelJS = excelJsModule.default
  const workbook = new ExcelJS.Workbook()
  workbook.creator = '考核调研'
  workbook.created = new Date()

  const selectedPositionName = data.selectedPositionGroup?.name
    || (data.filters?.positionGroupCode === 'all' ? '全部岗位' : '考核岗位')
  const sheetName = `${safeText(data.month)}_${selectedPositionName}`.slice(0, 31)
  const worksheet = workbook.addWorksheet(sheetName)
  const table = buildPerformanceSurveyExportTable(data)
  const lastColumn = Math.max(table.headers.length, 1)

  worksheet.mergeCells(1, 1, 1, lastColumn)
  const titleCell = worksheet.getCell(1, 1)
  titleCell.value = `${safeText(data.month)} · ${selectedPositionName}考核调研得分`
  titleCell.font = { bold: true, color: { argb: 'FFFFFFFF' }, size: 16 }
  titleCell.fill = { type: 'pattern', pattern: 'solid', fgColor: { argb: 'FF1F2937' } }
  titleCell.alignment = { vertical: 'middle', horizontal: 'left' }
  worksheet.getRow(1).height = 30

  worksheet.mergeCells(2, 1, 2, lastColumn)
  const summaryCell = worksheet.getCell(2, 1)
  summaryCell.value = `岗位：${selectedPositionName}    月份：${safeText(data.month)}    人员：${data.public.rows.length} 人    考核项：${data.templates.length} 项`
  summaryCell.font = { color: { argb: 'FF475467' }, size: 10 }
  summaryCell.fill = { type: 'pattern', pattern: 'solid', fgColor: { argb: 'FFF4F6F8' } }
  summaryCell.alignment = { vertical: 'middle', horizontal: 'left' }
  worksheet.getRow(2).height = 24

  worksheet.addRow([])
  const headerRow = worksheet.addRow(table.headers)
  headerRow.height = 34
  headerRow.font = { bold: true, color: { argb: 'FF1F2937' }, size: 10 }
  headerRow.fill = { type: 'pattern', pattern: 'solid', fgColor: { argb: 'FFDCE8F8' } }
  headerRow.alignment = { vertical: 'middle', horizontal: 'center', wrapText: true }

  for (const values of table.rows) {
    const row = worksheet.addRow(values)
    row.height = 26
    row.alignment = { vertical: 'middle', horizontal: 'center', wrapText: true }
    row.eachCell((cell, columnNumber) => {
      if (columnNumber >= 8 && typeof cell.value === 'number') cell.numFmt = '0.##'
    })
  }

  worksheet.columns = table.headers.map((header, index) => ({
    width: index === 0
      ? 8
      : index === 1
        ? 18
        : index === 2
          ? 13
          : index === 3
            ? 14
            : index === 4
              ? 16
              : index === 5
                ? 22
                : index === 6
                  ? 12
                  : Math.min(Math.max(header.length * 1.2, 18), 30),
  }))
  worksheet.views = [{ state: 'frozen', xSplit: 7, ySplit: 4 }]
  worksheet.autoFilter = { from: { row: 4, column: 1 }, to: { row: 4, column: lastColumn } }

  const border: Partial<ExcelJS.Borders> = {
    top: { style: 'thin', color: { argb: 'FFD0D5DD' } },
    left: { style: 'thin', color: { argb: 'FFD0D5DD' } },
    bottom: { style: 'thin', color: { argb: 'FFD0D5DD' } },
    right: { style: 'thin', color: { argb: 'FFD0D5DD' } },
  }
  for (let rowNumber = 4; rowNumber <= worksheet.rowCount; rowNumber += 1) {
    worksheet.getRow(rowNumber).eachCell({ includeEmpty: true }, (cell) => {
      cell.border = border
    })
  }

  return workbook
}

export async function choosePerformanceSurveyExportDestination(
  suggestedName: string,
): Promise<PerformanceSurveyExportDestination> {
  if (typeof window === 'undefined') return { kind: 'download' }
  const picker = (window as unknown as {
    showSaveFilePicker?: (options: unknown) => Promise<WritableFileHandle>
  }).showSaveFilePicker

  if (!picker) return { kind: 'download' }

  try {
    const handle = await picker.call(window, {
      suggestedName,
      types: [{
        description: 'WPS/Excel 工作簿',
        accept: { [XLSX_MIME_TYPE]: ['.xlsx'] },
      }],
      excludeAcceptAllOption: true,
    })
    return { kind: 'file-system', handle }
  } catch (error) {
    if (error instanceof DOMException && error.name === 'AbortError') return { kind: 'cancelled' }
    throw error
  }
}

export async function savePerformanceSurveyDashboardWorkbook(
  data: PerformanceSurveyDashboardExportData,
  fileName: string,
  destination: PerformanceSurveyExportDestination,
) {
  if (destination.kind === 'cancelled') return
  const workbook = await buildPerformanceSurveyDashboardWorkbook(data)
  const buffer = await workbook.xlsx.writeBuffer()
  const blob = new Blob([buffer], { type: XLSX_MIME_TYPE })

  if (destination.kind === 'file-system') {
    const writable = await destination.handle.createWritable()
    await writable.write(blob)
    await writable.close()
    return
  }

  if (
    typeof document === 'undefined'
    || typeof URL === 'undefined'
    || typeof URL.createObjectURL !== 'function'
  ) {
    throw new Error('当前浏览器无法创建下载文件，请更换 Chrome 或 Edge 后重试。')
  }

  const objectUrl = URL.createObjectURL(blob)
  const anchor = document.createElement('a')
  anchor.href = objectUrl
  anchor.download = fileName
  anchor.rel = 'noopener'
  anchor.style.display = 'none'
  document.body.appendChild(anchor)

  try {
    anchor.click()
  } finally {
    anchor.remove()
    window.setTimeout(() => URL.revokeObjectURL(objectUrl), 0)
  }
}