import type { TacheRecord } from '@/types/collections';

/** Parse PocketBase `date` (YYYY-MM-DD) en date locale minuit. */
export function parsePbDateOnly(raw?: string | null): Date | null {
  if (!raw) return null;
  const m = /^(\d{4})-(\d{2})-(\d{2})/.exec(raw.trim());
  if (!m) return null;
  return new Date(Number(m[1]), Number(m[2]) - 1, Number(m[3]));
}

export function startOfLocalDay(d: Date): Date {
  return new Date(d.getFullYear(), d.getMonth(), d.getDate());
}

export function addDays(d: Date, n: number): Date {
  const x = new Date(d);
  x.setDate(x.getDate() + n);
  return x;
}

export function formatPbDateOnly(d: Date): string {
  const y = d.getFullYear();
  const m = String(d.getMonth() + 1).padStart(2, '0');
  const day = String(d.getDate()).padStart(2, '0');
  return `${y}-${m}-${day}`;
}

export function isTaskActive(statut?: string): boolean {
  return statut !== 'fait' && statut !== 'annule';
}

export type AgendaPartition = {
  overdue: TacheRecord[];
  today: TacheRecord[];
  week: TacheRecord[];
  nodate: TacheRecord[];
};

/** Tâches actives : en retard, aujourd’hui, dans les 7 jours (excl. aujourd’hui), sans date. */
export function partitionTachesForAgenda(taches: TacheRecord[]): AgendaPartition {
  const now = new Date();
  const startToday = startOfLocalDay(now);
  const startTomorrow = addDays(startToday, 1);
  const endWeek = addDays(startToday, 7);

  const overdue: TacheRecord[] = [];
  const today: TacheRecord[] = [];
  const week: TacheRecord[] = [];
  const nodate: TacheRecord[] = [];

  for (const t of taches) {
    if (!isTaskActive(t.statut)) continue;
    const d = parsePbDateOnly(t.date_echeance);
    if (!d) {
      nodate.push(t);
      continue;
    }
    if (d < startToday) overdue.push(t);
    else if (d < startTomorrow) today.push(t);
    else if (d < endWeek) week.push(t);
  }

  const byDue = (a: TacheRecord, b: TacheRecord) => {
    const da = parsePbDateOnly(a.date_echeance)?.getTime() ?? 0;
    const db = parsePbDateOnly(b.date_echeance)?.getTime() ?? 0;
    return da - db;
  };
  overdue.sort(byDue);
  today.sort(byDue);
  week.sort(byDue);
  return { overdue, today, week, nodate };
}