'use client';

import { useEffect, useState } from 'react';
import { X } from 'lucide-react';
import { Button } from '@/components/ui/common/Button';
import { Dropdown } from '@/components/ui/common/Dropdown';
import { APPOINTMENT_PURPOSES, type AppointmentPurpose } from '@/types/appointment';
import { APPOINTMENT_PURPOSE_LABEL } from '@/components/ui/appointments/appointmentPurposeStyles';
import type { Patient } from '@/types/patient';
import {
  combineLocalDateAndTime,
  formatTimeForInput,
  isSameLocalCalendarDay,
} from '@/lib/appointmentTime';

interface AppointmentBookingModalProps {
  open: boolean;
  scheduleDate: Date;
  patient: Patient | undefined;
  providerUserId: string | null;
  providerName: string;
  initialHour: number;
  onClose: () => void;
  onSubmit: (payload: {
    patientId: string;
    providerUserId: string;
    startAt: string;
    endAt: string;
    purpose: AppointmentPurpose;
  }) => Promise<void>;
  loading?: boolean;
}

export function AppointmentBookingModal({
  open,
  scheduleDate,
  patient,
  providerUserId,
  providerName,
  initialHour,
  onClose,
  onSubmit,
  loading = false,
}: AppointmentBookingModalProps) {
  const [startTime, setStartTime] = useState('09:00');
  const [endTime, setEndTime] = useState('10:00');
  const [purpose, setPurpose] = useState<AppointmentPurpose>('consultation');
  const [error, setError] = useState('');

  useEffect(() => {
    if (!open) {
      return;
    }
    const start = new Date(
      scheduleDate.getFullYear(),
      scheduleDate.getMonth(),
      scheduleDate.getDate(),
      initialHour,
      0,
      0,
      0,
    );
    const end = new Date(
      scheduleDate.getFullYear(),
      scheduleDate.getMonth(),
      scheduleDate.getDate(),
      initialHour < 23 ? initialHour + 1 : 23,
      initialHour < 23 ? 0 : 59,
      0,
      0,
    );
    setStartTime(formatTimeForInput(start));
    setEndTime(formatTimeForInput(end));
    setPurpose('consultation');
    setError('');
  }, [open, scheduleDate, initialHour]);

  if (!open || !providerUserId) {
    return null;
  }

  const inputClass =
    'w-full rounded-[var(--radius-md)] border border-border bg-background-secondary/90 text-text-primary px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-primary/35';

  async function handleSubmit() {
    setError('');
    if (!providerUserId) {
      return;
    }
    if (!patient) {
      setError('Select a patient first.');
      return;
    }

    const startAt = combineLocalDateAndTime(scheduleDate, startTime);
    const endAt = combineLocalDateAndTime(scheduleDate, endTime);

    if (endAt <= startAt) {
      setError('End time must be after start time.');
      return;
    }

    const now = new Date();
    if (isSameLocalCalendarDay(scheduleDate, now) && startAt.getTime() < now.getTime()) {
      setError('Cannot schedule in the past.');
      return;
    }

    await onSubmit({
      patientId: patient.id,
      providerUserId,
      startAt: startAt.toISOString(),
      endAt: endAt.toISOString(),
      purpose,
    });
  }

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/55">
      <div
        className="surface-card w-full max-w-md p-5 space-y-4 shadow-xl"
        role="dialog"
        aria-modal="true"
        aria-labelledby="appointment-modal-title"
      >
        <div className="flex items-start justify-between gap-2">
          <h2 id="appointment-modal-title" className="text-lg font-semibold text-text-primary pr-2">
            New appointment
          </h2>
          <button
            type="button"
            onClick={onClose}
            className="rounded-[var(--radius-sm)] p-1.5 text-text-muted hover:text-text-primary hover:bg-background-secondary/80 focus:outline-none focus:ring-2 focus:ring-primary/35"
            aria-label="Close"
          >
            <X className="h-5 w-5 icon-flat" />
          </button>
        </div>

        <p className="text-sm text-text-secondary">
          Provider: <span className="text-text-primary font-medium">{providerName}</span>
        </p>

        <div>
          <label className="block text-sm font-medium text-text-secondary mb-1">Patient</label>
          <p className="text-sm text-text-primary rounded-[var(--radius-md)] border border-border bg-background-secondary/60 px-3 py-2">
            {patient ? `${patient.firstName} ${patient.lastName}` : '—'}
          </p>
        </div>

        <div className="grid grid-cols-2 gap-3">
          <div>
            <label className="block text-sm font-medium text-text-secondary mb-1">Start</label>
            <input
              type="time"
              step={60}
              className={inputClass}
              value={startTime}
              onChange={(e) => setStartTime(e.target.value)}
            />
          </div>
          <div>
            <label className="block text-sm font-medium text-text-secondary mb-1">End</label>
            <input
              type="time"
              step={60}
              className={inputClass}
              value={endTime}
              onChange={(e) => setEndTime(e.target.value)}
            />
          </div>
        </div>

        <Dropdown
          label="Purpose"
          value={purpose}
          onChange={(e) => setPurpose(e.target.value as AppointmentPurpose)}
        >
          {APPOINTMENT_PURPOSES.map((p) => (
            <option key={p} value={p}>
              {APPOINTMENT_PURPOSE_LABEL[p]}
            </option>
          ))}
        </Dropdown>

        {error && <p className="text-sm text-red-400">{error}</p>}

        <div className="flex gap-2 justify-end">
          <Button type="button" variant="ghost" onClick={onClose} disabled={loading}>
            Cancel
          </Button>
          <Button type="button" variant="primary" onClick={() => void handleSubmit()} isLoading={loading}>
            Save
          </Button>
        </div>
      </div>
    </div>
  );
}