import ExcelJS from 'exceljs';

const resourceSpecs = {
  classes: {
    title: '班级台账', sheet: '班级',
    columns: [
      ['schoolCode', '学校代码*', 16, 'HZ01'], ['grade', '年级*', 14, '高三'],
      ['name', '班级名称*', 22, '高三（3）班'], ['status', '状态*', 12, '启用']
    ],
    validations: { status: ['启用', '停用'] }
  },
  class_admins: {
    title: '班级管理员台账', sheet: '班级管理员',
    columns: [
      ['schoolCode', '学校代码*', 16, 'HZ01'], ['className', '班级名称*', 22, '高三（1）班'],
      ['displayName', '管理员姓名*', 18, '张老师'], ['username', '登录账号*', 20, 'hz01_g301'],
      ['initialPassword', '初始密码（新建必填）', 24, 'ChangeMe123!'], ['status', '状态*', 12, '启用']
    ],
    validations: { status: ['启用', '停用'] }
  },
  account_quotas: {
    title: '批量报名号申领配额', sheet: '班级配额',
    columns: [['className', '班级名称*', 24, '高三（1）班'], ['count', '申领数量*', 16, 30]],
    numberColumns: ['count']
  },
  account_results: {
    title: '报名号下发清单', sheet: '账号结果',
    columns: [
      ['batchId', '批次编号', 30, ''], ['className', '班级', 22, ''],
      ['candidateNumber', '固定报名号', 26, ''], ['initialPassword', '初始密码', 22, '']
    ]
  },
  candidates: {
    title: '考生资料台账', sheet: '考生资料',
    columns: [
      ['candidateNumber', '报名号*', 26, '2026-HZ01-X-0001'], ['name', '姓名*', 16, '李明'],
      ['gender', '性别*', 10, '男'], ['idNumber', '证件号码*', 24, '320101200801011234'],
      ['phone', '手机号*', 18, '13800138000'], ['email', '邮箱', 24, 'student@example.com'],
      ['nativePlace', '籍贯', 18, '江苏海州'], ['address', '家庭住址', 32, '海州市清河区示例路 1 号'],
      ['className', '班级*', 22, '高三（1）班'], ['ethnicity', '民族', 12, '汉族'],
      ['birthDate', '出生日期', 16, '2008-01-01'], ['postalCode', '邮编', 14, '222000'],
      ['guardianName', '监护人', 16, '李家长'], ['guardianPhone', '监护人电话', 18, '13900139000']
    ],
    validations: { gender: ['男', '女'] }
  },
  centers: {
    title: '考点考场档案', sheet: '考点考场',
    columns: [
      ['schoolCode', '学校代码*', 14, 'HZ01'], ['centerCode', '考点代码*', 18, 'HZ01-C02'],
      ['centerName', '考点名称*', 24, '第一中学东区考点'], ['address', '详细地址*', 30, '海州市示例路 8 号'],
      ['managerName', '负责人', 16, '王老师'], ['managerPhone', '负责人手机', 18, '13800138000'],
      ['contact', '值班电话', 18, '0518-86020000'], ['emergencyPhone', '应急电话', 18, '0518-120'],
      ['gateOpenTime', '开放时间', 14, '07:00'], ['transport', '交通提示', 30, '东门入场'],
      ['centerStatus', '考点状态*', 14, '启用'], ['centerNotes', '考点备注', 26, ''],
      ['roomCode', '考场代码*', 16, '001'], ['roomName', '考场名称*', 22, '第 001 考场'],
      ['building', '楼栋*', 18, '教学楼 A'], ['floor', '楼层', 12, '1 层'],
      ['capacity', '容量*', 12, 30], ['seatPlan', '座位编排说明', 28, '按教室现场座次表编排'],
      ['roomType', '考场类型*', 16, '标准考场'], ['roomStatus', '考场状态*', 14, '启用'],
      ['roomNotes', '考场备注', 26, '']
    ],
    validations: { centerStatus: ['启用', '停用'], roomStatus: ['启用', '停用'], roomType: ['标准考场', '机考考场', '无障碍考场', '备用考场'] },
    numberColumns: ['capacity']
  },
  results: {
    title: '考试成绩台账', sheet: '成绩',
    columns: [
      ['candidateNumber', '报名号*', 26, '2026-HZ01-X-0001'], ['examCode', '考试代码*', 20, 'EX-2026-AUT'],
      ['subjectName', '科目*', 16, '语文'], ['score', '成绩*', 12, 120],
      ['grade', '等级', 12, 'A'], ['published', '发布状态*', 14, '发布']
    ],
    validations: { published: ['发布', '不发布'] },
    numberColumns: ['score']
  }
};

export function hasExcelResource(resource) {
  return Boolean(resourceSpecs[resource]);
}

function cellValue(cell) {
  const value = cell.value;
  if (value == null) return '';
  if (value instanceof Date) return value.toISOString().slice(0, 10);
  if (typeof value === 'object') {
    if ('text' in value) return String(value.text || '').trim();
    if ('result' in value) return String(value.result ?? '').trim();
  }
  return typeof value === 'number' ? value : String(value).trim();
}

export async function parseWorkbook(resource, buffer) {
  const spec = resourceSpecs[resource];
  if (!spec) throw Object.assign(new Error('不支持的 Excel 数据类型'), { status: 404 });
  const workbook = new ExcelJS.Workbook();
  try {
    await workbook.xlsx.load(buffer);
  } catch {
    throw Object.assign(new Error('无法读取 Excel 文件，请使用系统下载的 .xlsx 模板'), { status: 400 });
  }
  const sheet = workbook.getWorksheet(spec.sheet) || workbook.worksheets[0];
  if (!sheet) throw Object.assign(new Error('Excel 文件中没有可读取的工作表'), { status: 400 });
  const headerMap = new Map();
  sheet.getRow(2).eachCell((cell, col) => headerMap.set(String(cell.value || '').replace(/\*/g, '').trim(), col));
  const missing = spec.columns.filter(([, label]) => !headerMap.has(label.replace(/\*/g, '').trim()));
  if (missing.length) throw Object.assign(new Error(`模板列不完整：缺少 ${missing.map(([, label]) => label).join('、')}`), { status: 400 });
  const rows = [];
  for (let rowNumber = 3; rowNumber <= sheet.rowCount; rowNumber += 1) {
    const row = sheet.getRow(rowNumber);
    const item = { __row: rowNumber };
    let populated = false;
    for (const [key, label] of spec.columns) {
      const value = cellValue(row.getCell(headerMap.get(label.replace(/\*/g, '').trim())));
      item[key] = value;
      if (value !== '') populated = true;
    }
    if (populated) rows.push(item);
  }
  if (!rows.length) throw Object.assign(new Error('Excel 中没有可导入的数据行'), { status: 400 });
  return rows;
}

export async function buildWorkbook(resource, rows = [], { template = false, subtitle = '' } = {}) {
  const spec = resourceSpecs[resource];
  if (!spec) throw Object.assign(new Error('不支持的 Excel 数据类型'), { status: 404 });
  const workbook = new ExcelJS.Workbook();
  workbook.creator = '衡准考试信息管理系统';
  workbook.created = new Date();
  const sheet = workbook.addWorksheet(spec.sheet, { views: [{ state: 'frozen', ySplit: 2, showGridLines: false }] });
  const lastColumn = spec.columns.length;
  sheet.columns = spec.columns.map(([key, , width]) => ({ key, width }));
  spec.columns.forEach(([key], index) => {
    sheet.getColumn(index + 1).numFmt = spec.numberColumns?.includes(key) ? '0' : '@';
  });
  sheet.mergeCells(1, 1, 1, lastColumn);
  const titleCell = sheet.getCell(1, 1);
  titleCell.value = subtitle ? `${spec.title}｜${subtitle}` : spec.title;
  titleCell.font = { name: '微软雅黑', size: 16, bold: true, color: { argb: 'FFFFFFFF' } };
  titleCell.fill = { type: 'pattern', pattern: 'solid', fgColor: { argb: 'FF173F60' } };
  titleCell.alignment = { vertical: 'middle', horizontal: 'left' };
  sheet.getRow(1).height = 34;
  const header = sheet.getRow(2);
  header.values = spec.columns.map(([, label]) => label);
  header.height = 25;
  header.font = { name: '微软雅黑', bold: true, color: { argb: 'FFFFFFFF' } };
  header.fill = { type: 'pattern', pattern: 'solid', fgColor: { argb: 'FF2C7080' } };
  header.alignment = { vertical: 'middle', horizontal: 'center' };
  const outputRows = rows.length ? rows : template ? [Object.fromEntries(spec.columns.map(([key, , , example]) => [key, example]))] : [];
  for (const item of outputRows) {
    const row = sheet.addRow(Object.fromEntries(spec.columns.map(([key]) => [key, item[key] ?? ''])));
    row.height = 23;
    row.font = { name: '微软雅黑', size: 10, color: { argb: 'FF243B4A' } };
    row.alignment = { vertical: 'middle' };
    row.eachCell(cell => {
      cell.border = { bottom: { style: 'hair', color: { argb: 'FFD8E2E7' } } };
    });
  }
  sheet.autoFilter = { from: { row: 2, column: 1 }, to: { row: Math.max(2, sheet.rowCount), column: lastColumn } };
  for (const [key, values] of Object.entries(spec.validations || {})) {
    const col = spec.columns.findIndex(([columnKey]) => columnKey === key) + 1;
    for (let row = 3; row <= Math.max(202, sheet.rowCount); row += 1) {
      sheet.getCell(row, col).dataValidation = { type: 'list', allowBlank: false, formulae: [`"${values.join(',')}"`] };
    }
  }
  const requiredColumns = spec.columns.map(([, label], index) => label.includes('*') ? index + 1 : 0).filter(Boolean);
  for (const col of requiredColumns) header.getCell(col).font = { name: '微软雅黑', bold: true, color: { argb: 'FFFFE7A3' } };
  return workbook.xlsx.writeBuffer();
}