import fs from 'node:fs/promises';
import path from 'node:path';

const sourcePath = path.resolve('data/brk/rawData/brk_holdings_1988_1997_export.csv');
const outputPath = path.resolve('data/brk/brk_holdings.csv');

const COMPANY_NAMES = [
  ['american express|美国运通', '美国运通（American Express）'],
  ['coca-cola|可口可乐', '可口可乐（Coca-Cola）'],
  ['disney|迪士尼', '华特迪士尼（Walt Disney）'],
  ['freddie mac|房地美|联邦住', '房地美（Freddie Mac）'],
  ['gillette|吉列', '吉列（Gillette）'],
  ['travelers|旅行家', '旅行家集团（Travelers Group）'],
  ['washington post|华盛顿邮报', '华盛顿邮报（Washington Post）'],
  ['wells fargo|富国银行', '富国银行（Wells Fargo）'],
  ['capital cities|大都会', '大都会/ABC（Capital Cities/ABC）'],
  ['geico|盖可', '盖可保险（GEICO）'],
  ['gannett|甘尼特', '甘尼特（Gannett）'],
  ['pnc', 'PNC 银行（PNC Bank）'],
  ['general dynamics|通用动力', '通用动力（General Dynamics）'],
  ['guinness|健力士', '健力士（Guinness）'],
  ["mcdonald|麦当劳", '麦当劳（McDonald\'s）'],
].map(([pattern, name]) => ({ pattern: new RegExp(pattern, 'i'), name }));

function parseCSV(text) {
  const rows = [];
  let row = [];
  let value = '';
  let quoted = false;

  for (let i = 0; i < text.length; i += 1) {
    const char = text[i];
    if (char === '"') {
      if (quoted && text[i + 1] === '"') {
        value += '"';
        i += 1;
      } else {
        quoted = !quoted;
      }
    } else if (char === ',' && !quoted) {
      row.push(value.trim());
      value = '';
    } else if ((char === '\n' || char === '\r') && !quoted) {
      if (char === '\r' && text[i + 1] === '\n') i += 1;
      row.push(value.trim());
      rows.push(row);
      row = [];
      value = '';
    } else {
      value += char;
    }
  }
  if (value || row.length) rows.push([...row, value.trim()]);
  return rows;
}

function canonicalName(value) {
  return COMPANY_NAMES.find(({ pattern }) => pattern.test(value))?.name || value.trim();
}

function parseShares(value) {
  const digits = value.replace(/[^\d]/g, '');
  return digits ? Number(digits) : NaN;
}

const rows = parseCSV(await fs.readFile(sourcePath, 'utf8'));
const holdings = [];

for (let index = 0; index < rows.length; index += 1) {
  const dateMatch = rows[index][0]?.match(/^(\d{4})\/12\/31$/);
  if (!dateMatch) continue;

  const year = Number(dateMatch[1]);
  const header = rows[index + 1] || [];
  const sharesFirst = /股(份)?数量|股数|持股数量/.test(header[0] || '');
  const companyIndex = sharesFirst ? 1 : 0;
  const sharesIndex = sharesFirst ? 0 : 1;

  for (let rowIndex = index + 2; rowIndex < rows.length; rowIndex += 1) {
    const record = rows[rowIndex];
    if (!record.some(Boolean)) break;
    if (/^\d{4}\/12\/31$/.test(record[0] || '')) break;
    const company = record[companyIndex];
    const shares = parseShares(record[sharesIndex] || '');
    if (!company || !Number.isFinite(shares)) continue;
    holdings.push({ year, company: canonicalName(company), shares });
  }
}

holdings.sort((a, b) => a.year - b.year || a.company.localeCompare(b.company, 'zh-CN'));
const lines = ['year,company,shares', ...holdings.map((row) => `${row.year},${row.company},${row.shares}`)];
await fs.mkdir(path.dirname(outputPath), { recursive: true });
await fs.writeFile(outputPath, `${lines.join('\n')}\n`, 'utf8');

console.log(`Normalized ${holdings.length} holdings across ${new Set(holdings.map((row) => row.year)).size} years.`);