import React from 'react';
import { MONTHS, addDays, formatDuration, fromIso, mondayOf, todayIso, weekdayIndex } from '../../lib/format';
import { useGrow } from '../../lib/hooks';
import { BudgetBar, Card } from '../ui/controls';
import type { TimeEntry } from '../../types';

/** Jahresansicht: Monatskacheln mit Soll/Ist und eine Heatmap aller Tage. */
export const YearView: React.FC<{ year: string; entries: TimeEntry[]; weeklyTarget: number; onOpenMonth: (month: string) => void }> = ({
  year,
  entries,
  weeklyTarget,
  onOpenMonth,
}) => {
  const today = todayIso();
  const perDay = new Map<string, number>();
  for (const e of entries) perDay.set(e.entry_date, (perDay.get(e.entry_date) || 0) + e.minutes);
  const grown = useGrow(year);

  const months = MONTHS.map((name, i) => {
    const key = `${year}-${String(i + 1).padStart(2, '0')}`;
    const list = entries.filter((e) => e.entry_date.startsWith(key));
    const minutes = list.reduce((s, e) => s + e.minutes, 0);
    const billable = list.filter((e) => e.billable).reduce((s, e) => s + e.minutes, 0);
    let workdays = 0;
    for (let d = `${key}-01`; d.startsWith(key); d = addDays(d, 1)) {
      if (d > today) break;
      if (weekdayIndex(d) < 5) workdays++;
    }
    const target = (weeklyTarget / 5) * workdays * 60;
    return { key, name, minutes, billable, target };
  });
  const max = Math.max(1, ...months.map((m) => m.minutes));

  // Heatmap: Wochen als Spalten, Mo-So als Zeilen.
  const first = mondayOf(`${year}-01-01`);
  const weeks: string[][] = [];
  for (let d = first; d <= `${year}-12-31`; d = addDays(d, 7)) {
    weeks.push(Array.from({ length: 7 }, (_, i) => addDays(d, i)));
  }
  const level = (minutes: number) => (minutes === 0 ? 0 : minutes < 180 ? 1 : minutes < 360 ? 2 : minutes < 480 ? 3 : 4);
  const LEVELS = ['var(--color-ink-100)', 'var(--color-brand-200)', 'var(--color-brand-300)', 'var(--color-brand-500)', 'var(--color-brand-700)'];

  return (
    <div className="space-y-4">
      <Card className="animate-rise overflow-x-auto p-4">
        <p className="mb-3 text-[11px] font-extrabold uppercase tracking-[0.14em] text-ink-400">Buchungsdichte {year}</p>
        <div className="flex gap-[3px]" style={{ minWidth: weeks.length * 14 }}>
          {weeks.map((week, w) => (
            <div key={week[0]} className="flex flex-col gap-[3px]">
              {week.map((date) => {
                const minutes = perDay.get(date) || 0;
                const out = !date.startsWith(year);
                return (
                  <span
                    key={date}
                    title={`${fromIso(date).toLocaleDateString('de-DE')}: ${formatDuration(minutes)} h`}
                    className="h-[11px] w-[11px] rounded-[3px] transition-opacity duration-500"
                    style={{ background: out ? 'transparent' : LEVELS[level(minutes)], opacity: grown ? 1 : 0, transitionDelay: `${w * 8}ms` }}
                  />
                );
              })}
            </div>
          ))}
        </div>
        <div className="mt-3 flex items-center justify-end gap-1 text-[10px] font-bold text-ink-400">
          weniger
          {LEVELS.map((c) => (
            <span key={c} className="h-[11px] w-[11px] rounded-[3px]" style={{ background: c }} />
          ))}
          mehr
        </div>
      </Card>

      <div className="grid grid-cols-2 gap-3 sm:grid-cols-3 lg:grid-cols-4 xl:grid-cols-6">
        {months.map((m, i) => (
          <button
            key={m.key}
            onClick={() => onOpenMonth(m.key)}
            className="animate-rise rounded-2xl border border-ink-200 bg-surface p-4 text-left shadow-card transition hover:-translate-y-0.5 hover:border-brand-300 hover:shadow-lift"
            style={{ '--i': i } as React.CSSProperties}
          >
            <p className={`text-xs font-extrabold uppercase tracking-wider ${m.key === today.slice(0, 7) ? 'text-brand-600' : 'text-ink-400'}`}>{m.name}</p>
            <p className="tabular mt-1 text-2xl font-extrabold text-ink-900">{formatDuration(m.minutes)}</p>
            <div className="mt-3 flex h-12 items-end gap-1">
              <div className="flex-1 rounded-t-md bg-brand-500 transition-[height] duration-700" style={{ height: grown ? `${(m.billable / max) * 100}%` : 0 }} title="billable" />
              <div className="flex-1 rounded-t-md bg-brand-200 transition-[height] duration-700" style={{ height: grown ? `${((m.minutes - m.billable) / max) * 100}%` : 0 }} title="non-billable" />
            </div>
            <BudgetBar className="mt-3" height="h-1.5" percent={m.target ? (m.minutes / m.target) * 100 : null} goal />
            <p className="tabular mt-1 text-[10px] font-bold text-ink-400">Soll {m.target ? formatDuration(m.target) : '–'} h</p>
          </button>
        ))}
      </div>
    </div>
  );
};