const EMPTY_BAR_COLOR = '#E5E7EB';
const DATA_BAR_COLOR = '#3B82F6';
const CURRENT_BAR_COLOR = '#10B981';

export const toLocalIsoDate = (value) => {
  const year = value.getFullYear();
  const month = String(value.getMonth() + 1).padStart(2, '0');
  const day = String(value.getDate()).padStart(2, '0');
  return `${year}-${month}-${day}`;
};

const labelTextStyle = (shiftX) => ({
  fontSize: 10,
  color: '#6B7280',
  width: 40,
  textAlign: 'center',
  shiftX,
});

const formatYearLabel = (label) => (
  label?.length === 4 ? `${label.slice(2)}년` : (label || '')
);

export const formatHourlyChartData = (hourlyData, selectedDate, now = new Date()) => {
  const byHour = new Map(hourlyData.map((item) => [item.hour, item]));
  const isToday = toLocalIsoDate(now) === toLocalIsoDate(selectedDate);

  return Array.from({ length: 25 }, (_, hour) => {
    if (hour === 24) {
      return { value: 0, label: '24시', frontColor: 'transparent' };
    }

    const item = byHour.get(hour) || {};
    const hasData = item.has_data || item.current_kw > 0;
    const isCurrentHour = isToday && hour === now.getHours();

    return {
      value: item.current_kw || 0,
      label: hour % 2 === 0 ? `${hour}시` : '',
      frontColor: isCurrentHour
        ? CURRENT_BAR_COLOR
        : (hasData ? DATA_BAR_COLOR : EMPTY_BAR_COLOR),
    };
  });
};

export const formatPeriodChartData = (period, rawData, selectedDate) => {
  const year = selectedDate.getFullYear();
  const month = selectedDate.getMonth() + 1;
  const dataMap = new Map(rawData.map((item) => [item.label, item.value || 0]));

  if (period === 'day') {
    const lastDay = new Date(year, month, 0).getDate();
    return Array.from({ length: lastDay }, (_, index) => {
      const day = index + 1;
      const key = `${year}-${String(month).padStart(2, '0')}-${String(day).padStart(2, '0')}`;
      const value = dataMap.get(key) || 0;
      return {
        value,
        label: day === 1 || day % 5 === 0 ? `${day}` : '',
        labelTextStyle: labelTextStyle(-10),
        frontColor: value > 0 ? DATA_BAR_COLOR : EMPTY_BAR_COLOR,
      };
    });
  }

  if (period === 'month') {
    return Array.from({ length: 12 }, (_, index) => {
      const itemMonth = index + 1;
      const key = `${year}-${String(itemMonth).padStart(2, '0')}`;
      const value = dataMap.get(key) || 0;
      return {
        value,
        label: `${itemMonth}월`,
        labelTextStyle: labelTextStyle(-5),
        frontColor: value > 0 ? DATA_BAR_COLOR : EMPTY_BAR_COLOR,
      };
    });
  }

  return rawData.map((item) => ({
    value: item.value || 0,
    label: formatYearLabel(item.label),
    labelTextStyle: labelTextStyle(-10),
    frontColor: item.value > 0 ? DATA_BAR_COLOR : EMPTY_BAR_COLOR,
  }));
};