'use client';

/* EngagementRecentMeetings — phase 08 (D-18..D-21).
 * Purpose: Collapsible list of up to 10 recent Teams meetings. Tap-to-expand
 *          reveals matched time entries and attendee list. Local Set<string>
 *          state tracks expanded IDs — period changes do not reset expansion (D-20). */

import { useState } from 'react';
import { Card, CardContent } from '@/components/ui/card';
import { Collapsible, CollapsibleContent, CollapsibleTrigger } from '@/components/ui/collapsible';
import { useUserTimezone, formatInUserTimezone } from '@/lib/hooks/use-user-timezone';

export interface RecentMeeting {
  subject: string | null;
  startTime: string;
  durationMinutes: number | null;
  attendeeCount: number;
  clientAttendeeCount: number;
  hasClientAttendees: boolean;
  clientCompanies: string[];
  participantNames: string[];
  matchedEntries: Array<{
    hours_worked: number;
    billable: boolean | null;
    notes: string | null;
    title: string | null;
    company_name: string | null;
    start_date_time: string | null;
    end_date_time: string | null;
  }>;
}

export interface EngagementRecentMeetingsProps {
  meetings: RecentMeeting[];
}

export function EngagementRecentMeetings({ meetings }: EngagementRecentMeetingsProps) {
  const tz = useUserTimezone();
  const [expandedIds, setExpandedIds] = useState<Set<string>>(new Set());

  const toggle = (id: string) => {
    setExpandedIds((prev) => {
      const next = new Set(prev);
      if (next.has(id)) next.delete(id);
      else next.add(id);
      return next;
    });
  };

  // ID derivation: caller doesn't pass an explicit id, so derive a stable string per row.
  const idFor = (m: RecentMeeting, i: number) =>
    `${m.startTime}|${m.subject ?? ''}|${i}`;

  // Format a duration in minutes as "Hh Mm" / "Mm" — used in the collapsed summary
  const fmtDuration = (mins: number | null): string => {
    if (mins === null || mins === undefined || !Number.isFinite(mins) || mins <= 0) return '';
    const h = Math.floor(mins / 60);
    const m = Math.round(mins % 60);
    if (h > 0 && m > 0) return `${h}h ${m}m`;
    if (h > 0) return `${h}h`;
    return `${m}m`;
  };

  return (
    <Card className="py-0 shadow-none">
      <CardContent className="px-4 py-4">
        <h3 className="text-sm font-semibold text-foreground mb-3">Recent meetings</h3>
        {meetings.length === 0 ? (
          <p className="text-sm text-muted-foreground py-2">No meetings recorded</p>
        ) : (
          <ul className="space-y-1">
            {meetings.slice(0, 10).map((meeting, i) => {
              const id = idFor(meeting, i);
              const open = expandedIds.has(id);
              const subjectLabel = meeting.subject ?? '(no subject)';
              const startLabel = formatInUserTimezone(meeting.startTime, tz, {
                month: 'short', day: 'numeric', hour: 'numeric', minute: '2-digit',
              });
              const durationLabel = fmtDuration(meeting.durationMinutes);
              const attendeeLabel = meeting.attendeeCount > 0
                ? `${meeting.attendeeCount} attendee${meeting.attendeeCount === 1 ? '' : 's'}`
                : '';

              const visibleParticipants = meeting.participantNames.slice(0, 5);
              const moreCount = Math.max(0, meeting.participantNames.length - 5);

              return (
                <li key={id}>
                  <Collapsible open={open} onOpenChange={() => toggle(id)}>
                    <CollapsibleTrigger asChild>
                      <button
                        type="button"
                        className="w-full text-left flex items-center justify-between gap-2 min-h-[44px] py-2"
                      >
                        <span className="flex-1 min-w-0 flex flex-col">
                          <span className="text-sm font-medium truncate">{subjectLabel}</span>
                          <span className="text-xs text-muted-foreground tabular-nums">
                            {startLabel}
                            {durationLabel ? ` · ${durationLabel}` : ''}
                            {attendeeLabel ? ` · ${attendeeLabel}` : ''}
                          </span>
                        </span>
                      </button>
                    </CollapsibleTrigger>
                    <CollapsibleContent className="text-sm text-muted-foreground pb-3 pl-2 space-y-2">
                      {meeting.matchedEntries.length > 0 && (
                        <div>
                          <p className="font-medium text-foreground mb-1">Matched time entries:</p>
                          <ul className="space-y-1">
                            {meeting.matchedEntries.map((te, j) => (
                              <li key={j} className="flex flex-wrap gap-x-2">
                                <span className="text-foreground tabular-nums">{Number(te.hours_worked).toFixed(1)}h</span>
                                {te.company_name && <span>· {te.company_name}</span>}
                                {te.notes && <span className="truncate">· {te.notes.split('\n')[0]?.slice(0, 80) ?? ''}</span>}
                              </li>
                            ))}
                          </ul>
                        </div>
                      )}
                      {visibleParticipants.length > 0 && (
                        <p>
                          <span className="font-medium text-foreground">Attendees:</span>{' '}
                          {visibleParticipants.join(', ')}
                          {moreCount > 0 ? ` and ${moreCount} more` : ''}
                        </p>
                      )}
                      {durationLabel && (
                        <p>
                          <span className="font-medium text-foreground">Duration:</span> {durationLabel}
                        </p>
                      )}
                    </CollapsibleContent>
                  </Collapsible>
                </li>
              );
            })}
          </ul>
        )}
      </CardContent>
    </Card>
  );
}