'use client';

import type { AppointmentColumnProvider, AppointmentRecord } from '@/types/appointment';
import { formatHourLabel } from '@/lib/appointmentTime';
import { purposeStyle } from '@/components/ui/appointments/appointmentPurposeStyles';

const HOUR_PX = 40;
const HOURS = Array.from({ length: 24 }, (_, i) => i);

function layoutBlock(apt: AppointmentRecord, day: Date): { top: string; height: string } | null {
  const dayStart = new Date(day.getFullYear(), day.getMonth(), day.getDate(), 0, 0, 0, 0);
  const dayEnd = new Date(day.getFullYear(), day.getMonth(), day.getDate() + 1, 0, 0, 0, 0);
  const start = new Date(apt.startAt);
  const end = new Date(apt.endAt);
  const ms = dayEnd.getTime() - dayStart.getTime();
  const clipStart = Math.max(start.getTime(), dayStart.getTime());
  const clipEnd = Math.min(end.getTime(), dayEnd.getTime());
  if (clipEnd <= clipStart) {
    return null;
  }
  const top = ((clipStart - dayStart.getTime()) / ms) * 100;
  const height = ((clipEnd - clipStart) / ms) * 100;
  return { top: `${top}%`, height: `${height}%` };
}

function appointmentDurationMinutes(apt: AppointmentRecord): number {
  const start = new Date(apt.startAt).getTime();
  const end = new Date(apt.endAt).getTime();
  return Math.max(0, Math.round((end - start) / 60_000));
}

interface AppointmentScheduleGridProps {
  day: Date;
  providers: AppointmentColumnProvider[];
  appointments: AppointmentRecord[];
  canBook: boolean;
  onSlotClick: (hour: number, providerUserId: string, providerName: string) => void;
  onAppointmentClick?: (appointment: AppointmentRecord) => void;
}

export function AppointmentScheduleGrid({
  day,
  providers,
  appointments,
  canBook,
  onSlotClick,
  onAppointmentClick,
}: AppointmentScheduleGridProps) {
  const gridHeight = HOURS.length * HOUR_PX;

  if (providers.length === 0) {
    return (
      <div className="surface-card p-6 text-sm text-text-muted">
        No providers available. Add staff with treatment edit access to see columns here.
      </div>
    );
  }

  return (
    <div className="surface-card overflow-x-auto">
      <div className="min-w-[640px]">
        <div className="flex border-b border-border">
          <div className="w-14 flex-shrink-0" />
          {providers.map((p) => (
            <div
              key={p.userId}
              className="flex-1 min-w-[130px] text-center text-sm font-medium text-text-primary py-2.5 px-1 border-l border-border"
            >
              {p.name}
            </div>
          ))}
        </div>

        <div className="flex">
          <div className="w-14 flex-shrink-0 border-r border-border bg-background-secondary/40">
            {HOURS.map((h) => (
              <div
                key={h}
                className="text-[11px] text-text-muted flex items-start justify-end pr-1.5 pt-0.5 border-b border-border/50"
                style={{ height: HOUR_PX }}
              >
                {formatHourLabel(h)}
              </div>
            ))}
          </div>

          <div className="flex-1 flex min-w-0">
            {providers.map((p) => (
              <div
                key={p.userId}
                className="flex-1 min-w-[130px] border-l border-border relative"
                style={{ height: gridHeight }}
              >
                {HOURS.map((h) => {
                  const slotDisabled = !canBook;
                  return (
                    <button
                      key={h}
                      type="button"
                      disabled={slotDisabled}
                      title={
                        slotDisabled ? 'You cannot create appointments' : `Book ${formatHourLabel(h)}`
                      }
                      className={`absolute left-0 right-0 border-b border-border/50 transition-colors ${
                        slotDisabled
                          ? 'cursor-not-allowed opacity-50'
                          : 'hover:bg-primary/8 cursor-pointer'
                      }`}
                      style={{ top: h * HOUR_PX, height: HOUR_PX }}
                      onClick={() => onSlotClick(h, p.userId, p.name)}
                    />
                  );
                })}

                {appointments
                  .filter((a) => a.providerUserId === p.userId)
                  .map((apt) => {
                    const pos = layoutBlock(apt, day);
                    if (!pos) {
                      return null;
                    }
                    const durationMin = appointmentDurationMinutes(apt);
                    return (
                      <button
                        type="button"
                        key={apt.id}
                        onClick={() => onAppointmentClick?.(apt)}
                        className={`absolute left-0.5 right-0.5 min-h-0 overflow-hidden rounded-[var(--radius-sm)] border pointer-events-auto z-10 flex flex-col justify-start px-1.5 py-0.5 text-left ${purposeStyle(apt.purpose)} focus:outline-none focus-visible:ring-2 focus-visible:ring-primary/35`}
                        style={{ top: pos.top, height: pos.height }}
                      >
                        <p className="text-[11px] font-medium leading-tight truncate pointer-events-none">
                          {apt.patient.firstName} {apt.patient.lastName}
                        </p>
                        {durationMin >= 30 && apt.patient.phone && (
                          <p className="text-[10px] opacity-90 truncate pointer-events-none">
                            {apt.patient.phone}
                          </p>
                        )}
                      </button>
                    );
                  })}
              </div>
            ))}
          </div>
        </div>
      </div>
    </div>
  );
}