import fs from "node:fs/promises";
import fsSync from "node:fs";
import path from "node:path";
import { once } from "node:events";
import {
  FileBlob,
  SpreadsheetFile,
  Workbook,
} from "@oai/artifact-tool";

const root =
  "/Users/lingniu/project/ai-coding/lingniu-vehicle-ingest";
const workDir = path.join(root, "outputs/g7-mileage-history-20260724");
const dailyDir = path.join(workDir, "raw/daily");
const statisticDir = path.join(workDir, "raw/statistic");
const mergedDir = path.join(workDir, "merged");
const outputXlsx = path.join(
  mergedDir,
  "G7车辆每日里程及里程统计_20220101-20260720.xlsx",
);
const importCsv = path.join(
  mergedDir,
  "G7车辆每日里程_20220101-20260720.csv",
);
const manifestPath = path.join(mergedDir, "manifest.json");
const priorMappingCsv = path.join(
  root,
  "outputs/g7-mileage-import-20260716/import_rows.csv",
);

await fs.mkdir(mergedDir, { recursive: true });

const months = buildMonths();
const dailyFilesByTaskId = await sortedXlsxFiles(dailyDir);
// 2022-02 was the one-file validation task. The remaining formal queue then
// started with 2022-01 and continued from 2022-03, so swap the first two task IDs
// back into natural month order.
const dailyFiles = [
  dailyFilesByTaskId[1],
  dailyFilesByTaskId[0],
  ...dailyFilesByTaskId.slice(2),
];
const statisticFiles = await sortedXlsxFiles(statisticDir);
assert(dailyFiles.length === months.length, `日报文件应为 ${months.length}，实际 ${dailyFiles.length}`);
assert(
  statisticFiles.length === months.length,
  `里程统计文件应为 ${months.length}，实际 ${statisticFiles.length}`,
);

const vehicles = new Map();
const dateOrder = [];
const dateSource = new Map();
const monthlyDailyTotals = new Map();
const dailyBatchManifest = [];
let dailyPositiveCells = 0;
let dailyZeroCells = 0;
let dailyTotalKm = 0;
let dailyTotalMismatchRows = 0;
let dailyCompletenessNoteRows = 0;

for (let monthIndex = 0; monthIndex < months.length; monthIndex += 1) {
  const month = months[monthIndex];
  const file = dailyFiles[monthIndex];
  const values = await readFirstSheetValues(file);
  const headers = values[0] ?? [];
  const runtimeIndex = headers.indexOf("运行时长");
  assert(runtimeIndex > 3, `${path.basename(file)} 缺少运行时长列`);
  const dateColumnCount = runtimeIndex - 3;
  assert(
    dateColumnCount === month.dayCount,
    `${path.basename(file)} 日期列应为 ${month.dayCount}，实际 ${dateColumnCount}`,
  );

  const monthDates = [];
  for (let day = 1; day <= month.dayCount; day += 1) {
    const date = `${month.year}-${pad(month.month)}-${pad(day)}`;
    monthDates.push(date);
    dateOrder.push(date);
    dateSource.set(date, path.basename(file));
  }

  let batchTotal = 0;
  let batchPositive = 0;
  let batchZero = 0;
  let batchMismatch = 0;
  let batchNotes = 0;
  const seenPlates = new Set();
  for (let rowIndex = 1; rowIndex < values.length; rowIndex += 1) {
    const row = values[rowIndex] ?? [];
    const plate = cleanText(row[0]);
    if (!plate) continue;
    assert(!seenPlates.has(plate), `${path.basename(file)} 存在重复车牌 ${plate}`);
    seenPlates.add(plate);
    const organization = cleanText(row[1]);
    const statedTotal = numberValue(row[2]);
    const dailyValues = row.slice(3, runtimeIndex).map(numberValue);
    const calculatedTotal = dailyValues.reduce((sum, value) => sum + value, 0);
    if (Math.abs(statedTotal - calculatedTotal) > 0.011) {
      dailyTotalMismatchRows += 1;
      batchMismatch += 1;
    }
    const note = cleanText(row[runtimeIndex + 1]);
    if (note) {
      dailyCompletenessNoteRows += 1;
      batchNotes += 1;
    }

    let vehicle = vehicles.get(plate);
    if (!vehicle) {
      vehicle = {
        plate,
        organization,
        values: new Map(),
      };
      vehicles.set(plate, vehicle);
    } else if (!vehicle.organization && organization) {
      vehicle.organization = organization;
    }

    for (let dayIndex = 0; dayIndex < dailyValues.length; dayIndex += 1) {
      const value = dailyValues[dayIndex];
      const date = monthDates[dayIndex];
      vehicle.values.set(date, value);
      batchTotal += value;
      dailyTotalKm += value;
      if (value > 0) {
        batchPositive += 1;
        dailyPositiveCells += 1;
      } else {
        batchZero += 1;
        dailyZeroCells += 1;
      }
    }
  }
  monthlyDailyTotals.set(month.key, round(batchTotal));
  dailyBatchManifest.push({
    type: "车辆里程日报",
    month: month.key,
    date_from: month.dateFrom,
    date_to: month.dateTo,
    file: path.basename(file),
    vehicle_rows: seenPlates.size,
    date_columns: month.dayCount,
    positive_cells: batchPositive,
    zero_cells: batchZero,
    total_km: round(batchTotal),
    total_mismatch_rows: batchMismatch,
    completeness_note_rows: batchNotes,
  });
}

assert(dateOrder.length === 1662, `日期列应为 1662，实际 ${dateOrder.length}`);
assert(new Set(dateOrder).size === dateOrder.length, "日报日期列存在重复");
assert(dateOrder[0] === "2022-01-01", `起始日期异常：${dateOrder[0]}`);
assert(dateOrder.at(-1) === "2026-07-20", `结束日期异常：${dateOrder.at(-1)}`);

const statisticRows = [];
const monthlyStatisticTotals = new Map();
const statisticBatchManifest = [];
for (let monthIndex = 0; monthIndex < months.length; monthIndex += 1) {
  const month = months[monthIndex];
  const file = statisticFiles[monthIndex];
  const values = await readFirstSheetValues(file);
  const headers = (values[0] ?? []).map(cleanText);
  const plateIndex = findHeader(headers, ["车牌号"]);
  const orgIndex = findHeader(headers, ["所属机构", "机构"]);
  const sourceOrgIndex = findHeader(headers, ["来源机构"]);
  const lengthIndex = findHeader(headers, ["车长(米)", "车长"]);
  const boxIndex = findHeader(headers, ["厢型"]);
  const runtimeIndex = findHeader(headers, ["运行时长"]);
  const mileageIndex = findHeader(headers, ["行驶里程(KM)", "行驶里程"]);
  assert(plateIndex >= 0, `${path.basename(file)} 缺少车牌号`);
  assert(mileageIndex >= 0, `${path.basename(file)} 缺少行驶里程`);

  let batchTotal = 0;
  let vehicleRows = 0;
  for (let rowIndex = 1; rowIndex < values.length; rowIndex += 1) {
    const row = values[rowIndex] ?? [];
    const plate = cleanText(row[plateIndex]);
    if (!plate) continue;
    const mileage = numberValue(row[mileageIndex]);
    batchTotal += mileage;
    vehicleRows += 1;
    statisticRows.push([
      month.key,
      plate,
      orgIndex >= 0 ? cleanText(row[orgIndex]) : "",
      sourceOrgIndex >= 0 ? cleanText(row[sourceOrgIndex]) : "",
      lengthIndex >= 0 ? row[lengthIndex] ?? "" : "",
      boxIndex >= 0 ? cleanText(row[boxIndex]) : "",
      runtimeIndex >= 0 ? cleanText(row[runtimeIndex]) : "",
      mileage,
      path.basename(file),
    ]);
  }
  monthlyStatisticTotals.set(month.key, round(batchTotal));
  statisticBatchManifest.push({
    type: "车辆里程统计",
    month: month.key,
    date_from: month.dateFrom,
    date_to: month.dateTo,
    file: path.basename(file),
    vehicle_rows: vehicleRows,
    total_km: round(batchTotal),
  });
}

const mapping = await readPriorMapping(priorMappingCsv);
const sortedVehicles = [...vehicles.values()].sort((a, b) =>
  a.plate.localeCompare(b.plate, "zh-CN"),
);
const mappedVehicles = sortedVehicles.filter((vehicle) => mapping.has(vehicle.plate));
const unmappedVehicles = sortedVehicles.filter((vehicle) => !mapping.has(vehicle.plate));

await writeImportCsv(importCsv, sortedVehicles, dateOrder);

const workbook = Workbook.create();
const summarySheet = workbook.worksheets.add("汇总");
const positiveDailySheet = workbook.worksheets.add("每日里程非零");
const statisticSheet = workbook.worksheets.add("G7里程统计");
const mappingSheet = workbook.worksheets.add("车辆映射");
const batchSheet = workbook.worksheets.add("导出批次");

buildSummarySheet(summarySheet);
await buildPositiveDailySheet(positiveDailySheet);
await buildStatisticSheet(statisticSheet);
await buildMappingSheet(mappingSheet);
await buildBatchSheet(batchSheet);

const summaryInspect = await workbook.inspect({
  kind: "table",
  sheetId: "汇总",
  range: "A1:F25",
  include: "values,formulas",
  maxChars: 12000,
  tableMaxRows: 25,
  tableMaxCols: 6,
});
const dailyInspect = await workbook.inspect({
  kind: "table",
  sheetId: "每日里程非零",
  range: "A1:D12",
  include: "values,formulas",
  maxChars: 12000,
  tableMaxRows: 12,
  tableMaxCols: 4,
});
const formulaErrors = await workbook.inspect({
  kind: "match",
  searchTerm: "#REF!|#DIV/0!|#VALUE!|#NAME\\?|#N/A",
  options: { useRegex: true, maxResults: 300 },
  summary: "final formula error scan",
});
assert(!formulaErrors.ndjson.includes('"match"'), "工作簿存在公式错误");

const summaryPreview = await workbook.render({
  sheetName: "汇总",
  range: "A1:F25",
  scale: 1.5,
  format: "png",
});
await fs.writeFile(
  path.join(mergedDir, "summary-preview.png"),
  new Uint8Array(await summaryPreview.arrayBuffer()),
);
const dailyPreview = await workbook.render({
  sheetName: "每日里程非零",
  range: "A1:D12",
  scale: 1.2,
  format: "png",
});
await fs.writeFile(
  path.join(mergedDir, "daily-preview.png"),
  new Uint8Array(await dailyPreview.arrayBuffer()),
);

try {
  const output = await SpreadsheetFile.exportXlsx(workbook);
  await output.save(outputXlsx);
} catch (error) {
  console.error(
    JSON.stringify(
      {
        stage: "export_xlsx",
        name: error?.name,
        message: error?.message,
        stack: String(error?.stack ?? "")
          .split("\n")
          .filter((line) => !line.includes("artifact_tool.mjs:3121"))
          .slice(0, 12),
      },
      null,
      2,
    ),
  );
  process.exit(1);
}

const monthlyReconciliation = months.map((month) => {
  const dailyKm = monthlyDailyTotals.get(month.key) ?? 0;
  const statisticKm = monthlyStatisticTotals.get(month.key) ?? 0;
  return {
    month: month.key,
    daily_km: dailyKm,
    statistic_km: statisticKm,
    difference_km: round(dailyKm - statisticKm),
  };
});
const manifest = {
  generated_at: new Date().toISOString(),
  range: {
    date_from: dateOrder[0],
    date_to: dateOrder.at(-1),
    days: dateOrder.length,
    months: months.length,
  },
  files: {
    daily_raw: dailyFiles.map((file) => path.basename(file)),
    statistic_raw: statisticFiles.map((file) => path.basename(file)),
    workbook: path.basename(outputXlsx),
    import_csv: path.basename(importCsv),
  },
  vehicle_count: sortedVehicles.length,
  mapped_vehicle_count: mappedVehicles.length,
  unmapped_vehicle_count: unmappedVehicles.length,
  vehicle_day_rows: sortedVehicles.length * dateOrder.length,
  mapped_vehicle_day_rows: mappedVehicles.length * dateOrder.length,
  positive_cells: dailyPositiveCells,
  zero_cells: dailyZeroCells,
  daily_total_km: round(dailyTotalKm),
  daily_total_mismatch_rows: dailyTotalMismatchRows,
  completeness_note_rows: dailyCompletenessNoteRows,
  monthly_reconciliation: monthlyReconciliation,
  daily_batches: dailyBatchManifest,
  statistic_batches: statisticBatchManifest,
  verification: {
    summary_inspect: summaryInspect.ndjson,
    daily_inspect: dailyInspect.ndjson,
    formula_errors: formulaErrors.ndjson,
  },
};
await fs.writeFile(manifestPath, `${JSON.stringify(manifest, null, 2)}\n`, "utf8");

console.log(
  JSON.stringify(
    {
      outputXlsx,
      importCsv,
      manifestPath,
      vehicleCount: sortedVehicles.length,
      mappedVehicleCount: mappedVehicles.length,
      unmappedVehicleCount: unmappedVehicles.length,
      dateCount: dateOrder.length,
      vehicleDayRows: sortedVehicles.length * dateOrder.length,
      mappedVehicleDayRows: mappedVehicles.length * dateOrder.length,
      positiveCells: dailyPositiveCells,
      zeroCells: dailyZeroCells,
      totalKm: round(dailyTotalKm),
      monthlyDifferenceCount: monthlyReconciliation.filter(
        (row) => Math.abs(row.difference_km) > 0.02,
      ).length,
    },
    null,
    2,
  ),
);

function buildSummarySheet(sheet) {
  sheet.showGridLines = false;
  sheet.getRange("A1:F1").merge();
  sheet.getRange("A1").values = [["G7 车辆里程全量导出汇总"]];
  sheet.getRange("A1:F1").format = {
    fill: "#0F766E",
    font: { bold: true, color: "#FFFFFF", size: 16 },
    horizontalAlignment: "center",
    verticalAlignment: "center",
  };
  sheet.getRange("A1:F1").format.rowHeight = 30;

  const metrics = [
    ["指标", "值", "说明"],
    ["统计起始日期", new Date(`${dateOrder[0]}T00:00:00+08:00`), "G7 日报"],
    ["统计结束日期", new Date(`${dateOrder.at(-1)}T00:00:00+08:00`), "含当日"],
    ["自然日数", dateOrder.length, "连续日期"],
    ["日报导出批次", dailyFiles.length, "每月 1 份"],
    ["里程统计导出批次", statisticFiles.length, "每月 1 份"],
    ["G7 车辆数", sortedVehicles.length, "当前导出车辆列表"],
    ["已映射 VIN 车辆数", mappedVehicles.length, "沿用现有车辆映射"],
    ["未映射车辆数", unmappedVehicles.length, "不进入正式导入"],
    ["映射覆盖率", null, "已映射 / G7 车辆数"],
    ["车辆-日期单元格", sortedVehicles.length * dateOrder.length, "包含 0 km"],
    ["可导入车辆-日期行", mappedVehicles.length * dateOrder.length, "包含 0 km"],
    ["正里程单元格", dailyPositiveCells, "> 0 km"],
    ["0 km 单元格", dailyZeroCells, "按用户确认保留"],
    ["日报累计里程(km)", round(dailyTotalKm), "55 份日报求和"],
    ["日报合计不一致车辆月", dailyTotalMismatchRows, "日报“行驶里程”与逐日求和"],
    ["完整度说明非空车辆月", dailyCompletenessNoteRows, "来自 G7 日报"],
  ];
  sheet.getRangeByIndexes(2, 0, metrics.length, 3).values = metrics;
  sheet.getRange("A3:C3").format = headerFormat();
  sheet.getRange("B4:B5").format.numberFormat = "yyyy-mm-dd";
  sheet.getRange("B6:B19").format.numberFormat = "#,##0.00";
  sheet.getRange("B12").formulas = [["=IFERROR(B10/B9,0)"]];
  sheet.getRange("B12").format.numberFormat = "0.0%";
  sheet.getRange("A4:A19").format.font = { bold: true, color: "#134E4A" };
  sheet.getRange("A3:C19").format.borders = {
    preset: "inside",
    style: "thin",
    color: "#D1D5DB",
  };

  sheet.getRange("E3:H3").values = [["月份", "日报合计(km)", "里程统计合计(km)", "差异(km)"]];
  sheet.getRange("E3:H3").format = headerFormat();
  const monthlyRows = months.map((month) => [
    month.key,
    monthlyDailyTotals.get(month.key) ?? 0,
    monthlyStatisticTotals.get(month.key) ?? 0,
    null,
  ]);
  sheet.getRangeByIndexes(3, 4, monthlyRows.length, 4).values = monthlyRows;
  sheet.getRange("H4").formulas = [["=F4-G4"]];
  sheet.getRange(`H4:H${3 + monthlyRows.length}`).fillDown();
  sheet.getRange(`F4:H${3 + monthlyRows.length}`).format.numberFormat = "#,##0.00";
  sheet.getRange(`E3:H${3 + monthlyRows.length}`).format.borders = {
    preset: "inside",
    style: "thin",
    color: "#E5E7EB",
  };

  sheet.freezePanes.freezeRows(3);
  sheet.getRange("A21:C23").merge();
  sheet.getRange("A21").values = [[
    "Excel 的“每日里程非零”工作表列出全部正里程记录；未出现的车辆×日期组合按用户确认均为 0 km。含全部 0 km 的逐行明细保存在同目录 CSV：G7车辆每日里程_20220101-20260720.csv。",
  ]];
  sheet.getRange("A21:C23").format = {
    fill: "#ECFDF5",
    font: { color: "#065F46", italic: true },
    wrapText: true,
    verticalAlignment: "center",
  };
  sheet.getRange(`A1:H${3 + monthlyRows.length}`).format.font = { name: "Aptos", size: 10 };
  sheet.getRange(`A1:A${3 + monthlyRows.length}`).format.columnWidth = 24;
  sheet.getRange(`B1:B${3 + monthlyRows.length}`).format.columnWidth = 18;
  sheet.getRange(`C1:C${3 + monthlyRows.length}`).format.columnWidth = 30;
  sheet.getRange(`D1:D${3 + monthlyRows.length}`).format.columnWidth = 3;
  sheet.getRange(`E1:E${3 + monthlyRows.length}`).format.columnWidth = 12;
  sheet.getRange(`F1:H${3 + monthlyRows.length}`).format.columnWidth = 18;
}

async function buildPositiveDailySheet(sheet) {
  sheet.showGridLines = false;
  const headers = ["日期", "车牌号", "机构", "每日里程(km)"];
  sheet.getRange("A1:D1").values = [headers];
  sheet.getRange("A1:D1").format = headerFormat();
  const rows = [];
  for (const vehicle of sortedVehicles) {
    for (const date of dateOrder) {
      const mileage = vehicle.values.get(date) ?? 0;
      if (mileage <= 0) continue;
      rows.push([
        new Date(`${date}T00:00:00+08:00`),
        vehicle.plate,
        vehicle.organization,
        mileage,
      ]);
    }
  }
  const chunkSize = 1000;
  for (let start = 0; start < rows.length; start += chunkSize) {
    const chunk = rows.slice(start, start + chunkSize);
    sheet.getRangeByIndexes(start + 1, 0, chunk.length, headers.length).values = chunk;
  }
  sheet.getRange(`A2:A${rows.length + 1}`).format.numberFormat = "yyyy-mm-dd";
  sheet.getRange(`D2:D${rows.length + 1}`).format.numberFormat = "#,##0.00";
  sheet.freezePanes.freezeRows(1);
  [14, 16, 30, 18].forEach((width, index) => {
    sheet.getRangeByIndexes(0, index, rows.length + 1, 1).format.columnWidth = width;
  });
}

async function buildStatisticSheet(sheet) {
  sheet.showGridLines = false;
  const headers = [
    "月份",
    "车牌号",
    "所属机构",
    "来源机构",
    "车长(米)",
    "厢型",
    "运行时长",
    "行驶里程(KM)",
    "来源文件",
  ];
  sheet.getRange("A1:I1").values = [headers];
  sheet.getRange("A1:I1").format = headerFormat();
  const chunkSize = 1000;
  for (let start = 0; start < statisticRows.length; start += chunkSize) {
    const chunk = statisticRows.slice(start, start + chunkSize);
    sheet.getRangeByIndexes(start + 1, 0, chunk.length, headers.length).values = chunk;
  }
  sheet.getRange(`E2:E${statisticRows.length + 1}`).format.numberFormat = "0.0";
  sheet.getRange(`H2:H${statisticRows.length + 1}`).format.numberFormat = "#,##0.00";
  sheet.freezePanes.freezeRows(1);
  const widths = [12, 16, 28, 28, 12, 16, 18, 18, 34];
  widths.forEach((width, index) => {
    sheet.getRangeByIndexes(0, index, statisticRows.length + 1, 1).format.columnWidth = width;
  });
}

async function buildMappingSheet(sheet) {
  sheet.showGridLines = false;
  const headers = ["车牌号", "机构", "VIN", "终端号", "映射状态", "期间里程(km)", "正里程天数", "0 km天数"];
  sheet.getRange("A1:H1").values = [headers];
  sheet.getRange("A1:H1").format = headerFormat();
  const rows = sortedVehicles.map((vehicle) => {
    const mapped = mapping.get(vehicle.plate);
    const allValues = dateOrder.map((date) => vehicle.values.get(date) ?? 0);
    const positiveDays = allValues.filter((value) => value > 0).length;
    return [
      vehicle.plate,
      vehicle.organization,
      mapped?.vin ?? "",
      mapped?.phone ?? "",
      mapped ? "已映射" : "未映射",
      round(allValues.reduce((sum, value) => sum + value, 0)),
      positiveDays,
      dateOrder.length - positiveDays,
    ];
  });
  sheet.getRangeByIndexes(1, 0, rows.length, headers.length).values = rows;
  sheet.getRange(`F2:F${rows.length + 1}`).format.numberFormat = "#,##0.00";
  sheet.getRange(`E2:E${rows.length + 1}`).conditionalFormats.add("containsText", {
    text: "未映射",
    format: { fill: "#FEE2E2", font: { color: "#991B1B", bold: true } },
  });
  sheet.freezePanes.freezeRows(1);
  [16, 30, 22, 18, 14, 18, 14, 14].forEach((width, index) => {
    sheet.getRangeByIndexes(0, index, rows.length + 1, 1).format.columnWidth = width;
  });
}

async function buildBatchSheet(sheet) {
  sheet.showGridLines = false;
  const headers = [
    "类型",
    "月份",
    "开始日期",
    "结束日期",
    "来源文件",
    "车辆数",
    "日期列数",
    "正里程单元格",
    "0 km 单元格",
    "合计里程(km)",
  ];
  sheet.getRange("A1:J1").values = [headers];
  sheet.getRange("A1:J1").format = headerFormat();
  const rows = [
    ...dailyBatchManifest.map((batch) => [
      batch.type,
      batch.month,
      new Date(`${batch.date_from}T00:00:00+08:00`),
      new Date(`${batch.date_to}T00:00:00+08:00`),
      batch.file,
      batch.vehicle_rows,
      batch.date_columns,
      batch.positive_cells,
      batch.zero_cells,
      batch.total_km,
    ]),
    ...statisticBatchManifest.map((batch) => [
      batch.type,
      batch.month,
      new Date(`${batch.date_from}T00:00:00+08:00`),
      new Date(`${batch.date_to}T00:00:00+08:00`),
      batch.file,
      batch.vehicle_rows,
      "",
      "",
      "",
      batch.total_km,
    ]),
  ];
  sheet.getRangeByIndexes(1, 0, rows.length, headers.length).values = rows;
  sheet.getRange(`C2:D${rows.length + 1}`).format.numberFormat = "yyyy-mm-dd";
  sheet.getRange(`F2:J${rows.length + 1}`).format.numberFormat = "#,##0.00";
  sheet.freezePanes.freezeRows(1);
  [18, 12, 14, 14, 36, 12, 12, 18, 18, 18].forEach((width, index) => {
    sheet.getRangeByIndexes(0, index, rows.length + 1, 1).format.columnWidth = width;
  });
}

async function readFirstSheetValues(file) {
  const input = await FileBlob.load(file);
  const workbook = await SpreadsheetFile.importXlsx(input);
  const sheet = workbook.worksheets.getItemAt(0);
  const usedRange = sheet.getUsedRange(true);
  return usedRange?.values ?? [];
}

async function sortedXlsxFiles(directory) {
  const names = (await fs.readdir(directory))
    .filter((name) => name.endsWith(".xlsx"))
    .sort((a, b) => extractTaskId(a) - extractTaskId(b));
  return names.map((name) => path.join(directory, name));
}

function extractTaskId(file) {
  const match = path.basename(file).match(/-(\d+)\.xlsx$/);
  assert(match, `无法从文件名解析任务号：${file}`);
  return Number(match[1]);
}

function buildMonths() {
  const result = [];
  for (let year = 2022, month = 1; year < 2026 || (year === 2026 && month <= 7); ) {
    const naturalLastDay = new Date(Date.UTC(year, month, 0)).getUTCDate();
    const lastDay = year === 2026 && month === 7 ? 20 : naturalLastDay;
    result.push({
      key: `${year}-${pad(month)}`,
      year,
      month,
      dayCount: lastDay,
      dateFrom: `${year}-${pad(month)}-01`,
      dateTo: `${year}-${pad(month)}-${pad(lastDay)}`,
    });
    month += 1;
    if (month === 13) {
      year += 1;
      month = 1;
    }
  }
  return result;
}

async function readPriorMapping(csvPath) {
  const text = await fs.readFile(csvPath, "utf8");
  const lines = text.replace(/^\uFEFF/, "").split(/\r?\n/);
  const result = new Map();
  for (const line of lines.slice(1)) {
    if (!line) continue;
    const columns = parseCsvLine(line);
    const [vin, plate, phone] = columns;
    if (!vin || !plate) continue;
    const current = result.get(plate);
    if (current && current.vin !== vin) {
      result.delete(plate);
      continue;
    }
    result.set(plate, { vin, phone: phone ?? "" });
  }
  return result;
}

async function writeImportCsv(file, vehicleRows, dates) {
  const stream = fsSync.createWriteStream(file, { encoding: "utf8" });
  stream.write("\uFEFFplate,date,daily_mileage_km\n");
  for (const vehicle of vehicleRows) {
    for (const date of dates) {
      const value = vehicle.values.get(date) ?? 0;
      if (!stream.write(`${csvCell(vehicle.plate)},${date},${numberText(value)}\n`)) {
        await once(stream, "drain");
      }
    }
  }
  stream.end();
  await once(stream, "finish");
}

function headerFormat() {
  return {
    fill: "#0F766E",
    font: { bold: true, color: "#FFFFFF" },
    horizontalAlignment: "center",
    verticalAlignment: "center",
    wrapText: true,
    borders: { preset: "outside", style: "thin", color: "#115E59" },
  };
}

function findHeader(headers, names) {
  return headers.findIndex((header) => names.includes(header));
}

function parseCsvLine(line) {
  const result = [];
  let value = "";
  let quoted = false;
  for (let index = 0; index < line.length; index += 1) {
    const char = line[index];
    if (quoted) {
      if (char === '"' && line[index + 1] === '"') {
        value += '"';
        index += 1;
      } else if (char === '"') {
        quoted = false;
      } else {
        value += char;
      }
    } else if (char === '"') {
      quoted = true;
    } else if (char === ",") {
      result.push(value);
      value = "";
    } else {
      value += char;
    }
  }
  result.push(value);
  return result;
}

function csvCell(value) {
  const text = cleanText(value);
  return /[",\r\n]/.test(text) ? `"${text.replaceAll('"', '""')}"` : text;
}

function cleanText(value) {
  return value === null || value === undefined ? "" : String(value).trim();
}

function numberValue(value) {
  const number = Number(value);
  return Number.isFinite(number) ? number : 0;
}

function numberText(value) {
  return String(round(value));
}

function round(value) {
  return Math.round((value + Number.EPSILON) * 100) / 100;
}

function pad(value) {
  return String(value).padStart(2, "0");
}

function assert(condition, message) {
  if (!condition) throw new Error(message);
}