import type { DateQuickPick } from './types';

export type DateRangeMode = DateQuickPick | 'custom';

export interface DateRangeValue {
  start: string;
  end: string;
}

const LABELS: Record<DateQuickPick, string> = {
  thisWeek: '本周',
  thisMonth: '本月',
  last15: '近 15 天',
};

function fmtYmd(date: Date): string {
  return `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, '0')}-${String(date.getDate()).padStart(2, '0')}`;
}

function addDays(date: Date, days: number): Date {
  const next = new Date(date);
  next.setDate(next.getDate() + days);
  return next;
}

export function getQuickDateRange(pick: DateQuickPick, now = new Date()): DateRangeValue {
  const today = new Date(now);
  today.setHours(0, 0, 0, 0);
  if (pick === 'thisWeek') {
    const day = today.getDay() || 7;
    return { start: fmtYmd(addDays(today, -(day - 1))), end: fmtYmd(today) };
  }
  if (pick === 'thisMonth') {
    return { start: fmtYmd(new Date(today.getFullYear(), today.getMonth(), 1)), end: fmtYmd(today) };
  }
  return { start: fmtYmd(addDays(today, -14)), end: fmtYmd(today) };
}

export function normalizeDateRange(start: string, end: string): DateRangeValue {
  return start <= end ? { start, end } : { start: end, end: start };
}

export function inferDateRangeMode(start: string, end: string, now = new Date()): DateRangeMode {
  const range = normalizeDateRange(start, end);
  const match = QUICK_DATE_OPTIONS.find(({ id }) => {
    const quickRange = getQuickDateRange(id, now);
    return quickRange.start === range.start && quickRange.end === range.end;
  });
  return match?.id ?? 'custom';
}

export function dateRangeModeLabel(mode: DateRangeMode): string {
  return mode === 'custom' ? '自定义区间' : LABELS[mode];
}

export const QUICK_DATE_OPTIONS = (Object.keys(LABELS) as DateQuickPick[]).map(id => ({
  id,
  label: LABELS[id],
}));