import fs from 'fs';

const experiment = {
    start_date: "2026-01-18",
    end_date: null,
    asins: ["LINE:LEGENDS"],
    marketplace: "ES"
};

const salesData = [
    { year: 2026, week: 7, asin: "B0CHW338VR", line: "LEGENDS", unitsTotal: 4, salesTotal: 24.40, marketplace: "ES" },
    { year: 2026, week: 7, asin: "B0CHW338VR", line: "LEGENDS", unitsTotal: 4, salesTotal: 24.40, marketplace: "GB" }
];

const getExperimentAsins = (experimentAsins, salesData) => {
  const explicitAsins = new Set();
  const lines = new Set();

  (experimentAsins || []).forEach(a => {
    const val = (a || '').trim().toUpperCase();
    if (val.startsWith('LINE:')) {
      lines.add(val.substring(5).trim());
    } else if (val) {
      explicitAsins.add(val);
    }
  });

  const asinSet = new Set(explicitAsins);
  if (lines.size > 0 && salesData) {
    salesData.forEach(r => {
      const line = (r.line || '').trim().toUpperCase();
      if (line && lines.has(line)) {
        if (r.asin) asinSet.add(r.asin.toUpperCase());
      }
    });
  }

  return asinSet;
};

const parseLocalDate = (dateStr) => {
    if (!dateStr) return new Date();
    const [y, m, d] = dateStr.split('T')[0].split('-');
    return new Date(Number(y), Number(m) - 1, Number(d));
};


const calculate = (experiment, salesData) => {
  const startDate = parseLocalDate(experiment.start_date);
  const endDate = experiment.end_date ? parseLocalDate(experiment.end_date) : new Date();

  console.log('Parsed start date:', startDate);
  console.log('Parsed end date:', endDate);

  const durationMs = endDate.getTime() - startDate.getTime();
  const baselineStart = new Date(startDate.getTime() - durationMs);
  const baselineEnd = startDate;

  console.log('Parsed baseline start:', baselineStart);
  console.log('Parsed baseline end:', baselineEnd);

  const asinSet = getExperimentAsins(experiment.asins, salesData);
  console.log('Resolved ASINs:', Array.from(asinSet));

  const baselineData = salesData.filter(r => {
    const recordDate = new Date(r.year, 0, 1 + (r.week - 1) * 7);
    const inRange = recordDate >= baselineStart && recordDate < baselineEnd;
    const isAsin = asinSet.has(r.asin.toUpperCase());
    return isAsin && inRange && (experiment.marketplace === 'All' || r.marketplace === experiment.marketplace);
  });

  const experimentData = salesData.filter(r => {
    const recordDate = new Date(r.year, 0, 1 + (r.week - 1) * 7);
    const inRange = recordDate >= startDate && recordDate <= endDate;
    const isAsin = asinSet.has(r.asin.toUpperCase());
    return isAsin && inRange && (experiment.marketplace === 'All' || r.marketplace === experiment.marketplace);
  });

  console.log('Baseline records matched:', baselineData.length);
  console.log('Experiment records matched:', experimentData.length);
};

calculate(experiment, salesData);