import type { VehicleProfileSyncItem } from '../../api/types';

const headers = ['vin', 'modelName', 'vehicleType', 'companyName', 'operationStatus', 'accessProvider', 'firstAccessAt', 'runtimeSeconds'] as const;
const allowedStatuses = new Set(['', 'unknown', 'active', 'inactive', 'maintenance', 'retired']);

export const vehicleProfileSyncCSVHeader = headers.join(',');

export function parseVehicleProfileSyncCSV(text: string): VehicleProfileSyncItem[] {
  const rows = parseCSVRows(text.replace(/^\uFEFF/, ''));
  if (rows.length < 2) throw new Error('CSV 至少需要表头和一行车辆数据');
  const actualHeaders = rows[0].map((value) => value.trim());
  if (actualHeaders.length !== headers.length || actualHeaders.some((value, index) => value !== headers[index])) {
    throw new Error(`CSV 表头必须为：${vehicleProfileSyncCSVHeader}`);
  }
  const dataRows = rows.slice(1).filter((row) => row.some((value) => value.trim() !== ''));
  if (dataRows.length === 0 || dataRows.length > 500) throw new Error('单个 CSV 必须包含 1 至 500 辆车');
  const seen = new Set<string>();
  return dataRows.map((row, index) => {
    const line = index + 2;
    if (row.length !== headers.length) throw new Error(`CSV 第 ${line} 行列数不正确`);
    const [rawVIN, modelName, vehicleType, companyName, rawStatus, accessProvider, firstAccessAt, rawRuntime] = row.map((value) => value.trim());
    const vin = rawVIN.toUpperCase();
    if (!vin || vin.length > 32) throw new Error(`CSV 第 ${line} 行 VIN 无效`);
    if (seen.has(vin)) throw new Error(`CSV 第 ${line} 行 VIN 重复：${vin}`);
    seen.add(vin);
    const operationStatus = rawStatus.toLowerCase();
    if (!allowedStatuses.has(operationStatus)) throw new Error(`CSV 第 ${line} 行运营状态无效`);
    const runtimeSeconds = rawRuntime === '' ? null : Number(rawRuntime);
    if (runtimeSeconds !== null && (!Number.isSafeInteger(runtimeSeconds) || runtimeSeconds < 0)) throw new Error(`CSV 第 ${line} 行累计运行秒数无效`);
    return {
      vin, modelName, vehicleType, companyName,
      operationStatus: (operationStatus || 'unknown') as VehicleProfileSyncItem['operationStatus'],
      accessProvider, firstAccessAt, runtimeSeconds
    };
  });
}

function parseCSVRows(text: string): string[][] {
  const rows: string[][] = [];
  let row: string[] = [];
  let field = '';
  let quoted = false;
  let closedQuote = false;
  for (let index = 0; index < text.length; index += 1) {
    const char = text[index];
    if (quoted) {
      if (char === '"') {
        if (text[index + 1] === '"') { field += '"'; index += 1; } else { quoted = false; closedQuote = true; }
      } else {
        field += char;
      }
      continue;
    }
    if (closedQuote && char !== ',' && char !== '\n' && char !== '\r') throw new Error('CSV 引号结束后存在无效字符');
    if (char === '"') {
      if (field !== '') throw new Error('CSV 引号格式无效');
      quoted = true;
    } else if (char === ',') {
      row.push(field); field = ''; closedQuote = false;
    } else if (char === '\n' || char === '\r') {
      if (char === '\r' && text[index + 1] === '\n') index += 1;
      row.push(field); rows.push(row); row = []; field = ''; closedQuote = false;
    } else {
      field += char;
    }
  }
  if (quoted) throw new Error('CSV 存在未闭合的引号');
  if (field !== '' || row.length > 0) { row.push(field); rows.push(row); }
  return rows;
}