import React, { useState, useEffect } from 'react';
import { X, Calendar, Clock, FileText, UserCheck, AlertCircle } from 'lucide-react';
import { Employee, EmployeeVacation, EmployeeSickLeave, EmployeeAbsence, User, UserRole } from '../../types';
import { authFetch } from '../../services/apiClient';

export type AbsenceType = 'vacation' | 'sick_leave' | 'day_off' | 'absence' | 'late' | 'early_leave';

interface WorkCalendarModalProps {
  employee: Employee;
  onClose: () => void;
  onSave: () => void;
  type?: AbsenceType;
  currentUser?: User;
  /** Список сотрудников для подстановки имени руководителя */
  employees?: Employee[];
  /** Сотрудники, от имени которых можно оформить запись (для смены имени в шапке) */
  selectableEmployees?: Employee[];
  /** Вызов при смене сотрудника в шапке модалки */
  onEmployeeChange?: (employee: Employee) => void;
}

export const WorkCalendarModal: React.FC<WorkCalendarModalProps> = ({ 
  employee, 
  onClose, 
  onSave,
  type: initialType,
  currentUser,
  employees = [],
  selectableEmployees,
  onEmployeeChange,
}) => {
  const [absenceType, setAbsenceType] = useState<AbsenceType>(initialType || 'vacation');
  const [startDate, setStartDate] = useState('');
  const [endDate, setEndDate] = useState('');
  const [startTime, setStartTime] = useState('');
  const [endTime, setEndTime] = useState('');
  const [reason, setReason] = useState('');
  const [notes, setNotes] = useState('');
  const [requiresApproval, setRequiresApproval] = useState(true);
  const [approverSignature, setApproverSignature] = useState('');
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');

  const [vacationType, setVacationType] = useState<'annual' | 'unpaid' | 'study' | 'maternity' | 'other'>('annual');
  const [sickLeaveNumber, setSickLeaveNumber] = useState('');
  const [diagnosis, setDiagnosis] = useState('');
  const [medicalInstitution, setMedicalInstitution] = useState('');
  /** Предварительная дата выхода с больничного */
  const [expectedReturnDate, setExpectedReturnDate] = useState('');
  /** Флаг: пользователь вручную менял дату окончания отпуска (не перезаписывать +14) */
  const [vacationEndManuallyChanged, setVacationEndManuallyChanged] = useState(false);

  const absenceTypeLabels: Record<AbsenceType, { label: string; icon: React.ReactNode; color: string }> = {
    vacation: { label: 'Отпуск', icon: '🏖️', color: 'bg-blue-50 text-blue-600 border-blue-200' },
    sick_leave: { label: 'Больничный', icon: '🏥', color: 'bg-red-50 text-red-600 border-red-200' },
    day_off: { label: 'Отгул', icon: '📅', color: 'bg-amber-50 text-amber-600 border-amber-200' },
    absence: { label: 'Прогул', icon: '⚠️', color: 'bg-orange-50 text-orange-600 border-orange-200' },
    late: { label: 'Опоздание', icon: '⏰', color: 'bg-purple-50 text-purple-600 border-purple-200' },
    early_leave: { label: 'Ранний уход', icon: '🚪', color: 'bg-indigo-50 text-indigo-600 border-indigo-200' },
  };

  const vacationTypeLabels: Record<string, string> = {
    annual: 'Ежегодный',
    unpaid: 'Без сохранения зарплаты',
    study: 'Учебный',
    maternity: 'Декретный',
    other: 'Другой',
  };

  const isSelf = currentUser && employee && currentUser.id === employee.id;
  /** Типы, которые сотрудник не может оформить себе: только руководитель или HR подчинённым */
  const onlyManagerOrHrTypes: AbsenceType[] = ['absence', 'late', 'early_leave'];
  const allowedTypes = (Object.keys(absenceTypeLabels) as AbsenceType[]).filter(
    (t) => !isSelf || !onlyManagerOrHrTypes.includes(t)
  );

  // Руководитель для согласования подтягивается автоматически; если руководителя нет — автовыбор HR
  useEffect(() => {
    if (!employee) return;
    if (employee.managerId && employees?.length) {
      const manager = employees.find((e) => e.id === employee.managerId);
      if (manager?.name) {
        setApproverSignature(manager.name);
        return;
      }
    }
    setApproverSignature('HR');
  }, [employee?.id, employee?.managerId, employees]);

  // Отпуск: конец по умолчанию +14 дней от начала, с возможностью изменить
  useEffect(() => {
    if (absenceType !== 'vacation' || !startDate || vacationEndManuallyChanged) return;
    const start = new Date(startDate);
    start.setDate(start.getDate() + 14);
    setEndDate(start.toISOString().split('T')[0]);
  }, [absenceType, startDate, vacationEndManuallyChanged]);

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    setError('');
    setLoading(true);

    try {
      // Валидация
      if (!startDate) {
        setError('Укажите дату начала');
        setLoading(false);
        return;
      }

      if (absenceType === 'vacation' || absenceType === 'day_off' || absenceType === 'absence') {
        if (!endDate) {
          setError('Укажите дату окончания');
          setLoading(false);
          return;
        }
        if (new Date(endDate) < new Date(startDate)) {
          setError('Дата окончания не может быть раньше даты начала');
          setLoading(false);
          return;
        }
      }
      if (absenceType === 'sick_leave' && endDate && new Date(endDate) < new Date(startDate)) {
        setError('Дата окончания не может быть раньше даты начала');
        setLoading(false);
        return;
      }

      if (absenceType === 'late' || absenceType === 'early_leave') {
        if (!startTime) {
          setError('Укажите время');
          setLoading(false);
          return;
        }
      }

      const apiBaseUrl = import.meta.env.VITE_API_BASE_URL;
      const baseUrl = (import.meta.env.DEV || !apiBaseUrl) ? '/api' : `${apiBaseUrl}`;

      let response: Response;

      if (absenceType === 'vacation') {
        // Создание отпуска
        const calculatedDays = Math.ceil((new Date(endDate) - new Date(startDate)) / (1000 * 60 * 60 * 24)) + 1;
        response = await authFetch(`${baseUrl}/employees/${employee.id}/vacations`, {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            startDate,
            endDate,
            daysCount: calculatedDays,
            vacationType,
            status: requiresApproval ? 'planned' : 'approved',
            requiresApproval,
            approvedBy: !requiresApproval ? 'Система' : undefined,
            approvedAt: !requiresApproval ? new Date().toISOString() : undefined,
            approvedSignature: !requiresApproval ? 'Автоматическое согласование' : approverSignature || undefined,
            notes,
            currentUserId: currentUser?.id,
            currentUserRole: currentUser?.role,
          }),
        });
      } else if (absenceType === 'sick_leave') {
        // Создание больничного
        const calculatedDays = endDate ? Math.ceil((new Date(endDate) - new Date(startDate)) / (1000 * 60 * 60 * 24)) + 1 : undefined;
        const sickLeaveUrl = `${baseUrl}/employees/${employee.id}/sick-leaves`;
        response = await authFetch(sickLeaveUrl, {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            startDate,
            endDate: endDate || null,
            expectedReturnDate: expectedReturnDate || null,
            daysCount: calculatedDays,
            sickLeaveNumber: sickLeaveNumber || null,
            diagnosis: diagnosis || null,
            medicalInstitution: medicalInstitution || null,
            status: 'active',
            requiresApproval,
            approvedBy: !requiresApproval ? 'Система' : undefined,
            approvedAt: !requiresApproval ? new Date().toISOString() : undefined,
            approvedSignature: !requiresApproval ? 'Автоматическое согласование' : approverSignature || undefined,
            notes,
            currentUserId: currentUser?.id,
            currentUserRole: currentUser?.role,
          }),
        });
      } else {
        // Создание отгула/прогула/опоздания/раннего ухода
        let calculatedDays = 1.0;
        if (endDate) {
          calculatedDays = Math.ceil((new Date(endDate) - new Date(startDate)) / (1000 * 60 * 60 * 24)) + 1;
        } else if (startTime && endTime) {
          // Для части дня рассчитываем долю дня
          const start = new Date(`2000-01-01T${startTime}`);
          const end = new Date(`2000-01-01T${endTime}`);
          const hours = (end.getTime() - start.getTime()) / (1000 * 60 * 60);
          calculatedDays = hours / 8; // Предполагаем 8-часовой рабочий день
        }

        response = await authFetch(`${baseUrl}/employees/${employee.id}/absences`, {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            absenceType: absenceType === 'day_off' ? 'day_off' : absenceType === 'absence' ? 'absence' : absenceType === 'late' ? 'late' : 'early_leave',
            startDate,
            endDate: endDate || null,
            startTime: startTime || null,
            endTime: endTime || null,
            daysCount: calculatedDays,
            reason: reason || null,
            requiresApproval,
            status: requiresApproval ? 'pending' : 'approved',
            approvedBy: !requiresApproval ? 'Система' : undefined,
            approvedAt: !requiresApproval ? new Date().toISOString() : undefined,
            approvedSignature: !requiresApproval ? 'Автоматическое согласование' : approverSignature || undefined,
            notes: notes || null,
            currentUserId: currentUser?.id, // ID текущего пользователя для проверки прав
            currentUserRole: currentUser?.role, // Роль текущего пользователя для проверки прав
          }),
        });
      }

      if (response.ok) {
        onSave();
        onClose();
      } else {
        const errorData = await response.json();
        setError(errorData.error || 'Ошибка при создании записи');
      }
    } catch (err) {
      console.error('Error creating absence:', err);
      setError('Ошибка при создании записи');
    } finally {
      setLoading(false);
    }
  };

  const showDateRange = absenceType === 'vacation' || absenceType === 'sick_leave' || absenceType === 'day_off' || absenceType === 'absence';
  const showTimeFields = absenceType === 'late' || absenceType === 'early_leave';
  const showVacationFields = absenceType === 'vacation';
  const showSickLeaveFields = absenceType === 'sick_leave';

  return (
    <div 
      className="fixed inset-0 z-[100] flex items-center justify-center p-4 bg-black/50 backdrop-blur-sm animate-fade-in" 
      onClick={onClose}
    >
      <div 
        className="bg-white rounded-2xl w-full max-w-2xl max-h-[90vh] overflow-y-auto shadow-2xl animate-slide-up" 
        onClick={e => e.stopPropagation()}
      >
        {/* Header */}
        <div className="sticky top-0 bg-white border-b border-slate-200 p-6 rounded-t-2xl z-10">
          <div className="flex justify-between items-center">
            <div>
              <h3 className="text-xl font-bold text-slate-800">Рабочий календарь</h3>
              {selectableEmployees && selectableEmployees.length > 0 && onEmployeeChange ? (
                <select
                  value={employee.id}
                  onChange={(e) => {
                    const next = selectableEmployees.find((emp) => emp.id === e.target.value);
                    if (next) onEmployeeChange(next);
                  }}
                  className="mt-1 block text-sm text-slate-500 bg-transparent border-0 border-b border-transparent hover:border-slate-300 p-0 pr-5 -ml-0.5 cursor-pointer focus:ring-0 focus:outline-none focus:border-primary-500 hover:text-slate-700 font-normal appearance-none bg-no-repeat bg-[length:10px] bg-[right_0_top_55%]"
                  style={{ backgroundImage: 'url("data:image/svg+xml,%3Csvg xmlns=\'http://www.w3.org/2000/svg\' fill=\'none\' viewBox=\'0 0 24 24\' stroke=\'%2394a3b8\'%3E%3Cpath stroke-linecap=\'round\' stroke-linejoin=\'round\' stroke-width=\'2\' d=\'M19 9l-7 7-7-7\'%3E%3C/path%3E%3C/svg%3E")' }}
                >
                  {selectableEmployees.map((emp) => (
                    <option key={emp.id} value={emp.id}>
                      {emp.name}
                    </option>
                  ))}
                </select>
              ) : (
                <p className="text-sm text-slate-500 mt-1">{employee.name}</p>
              )}
            </div>
            <button 
              onClick={onClose} 
              className="p-2 hover:bg-slate-100 rounded-full transition-colors"
            >
              <X className="w-5 h-5 text-slate-500"/>
            </button>
          </div>
        </div>

        {/* Content */}
        <form onSubmit={handleSubmit} className="p-6 space-y-6">
          {error && (
            <div className="bg-red-50 border border-red-200 rounded-xl p-4 flex items-center gap-3">
              <AlertCircle className="w-5 h-5 text-red-600 flex-shrink-0"/>
              <p className="text-sm text-red-600">{error}</p>
            </div>
          )}

          {/* Тип пропуска (прогул/опоздание/ранний уход только для подчинённых — руководитель или HR) */}
          <div>
            <label className="block text-sm font-bold text-slate-700 mb-3">
              Тип пропуска
            </label>
            <div className="grid grid-cols-2 md:grid-cols-3 gap-3">
              {allowedTypes.map((type) => {
                const typeInfo = absenceTypeLabels[type];
                return (
                  <button
                    key={type}
                    type="button"
                    onClick={() => setAbsenceType(type)}
                    className={`p-4 rounded-xl border-2 transition-all text-left ${
                      absenceType === type
                        ? `${typeInfo.color} border-current`
                        : 'bg-slate-50 border-slate-200 text-slate-600 hover:border-slate-300'
                    }`}
                  >
                    <div className="text-2xl mb-1">{typeInfo.icon}</div>
                    <div className="text-xs font-bold uppercase tracking-wider">{typeInfo.label}</div>
                  </button>
                );
              })}
            </div>
          </div>

          {/* Тип отпуска (только для отпусков) */}
          {showVacationFields && (
            <div>
              <label className="block text-sm font-bold text-slate-700 mb-2">
                Тип отпуска
              </label>
              <select
                value={vacationType}
                onChange={(e) => setVacationType(e.target.value as any)}
                className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
              >
                {Object.entries(vacationTypeLabels).map(([value, label]) => (
                  <option key={value} value={value}>{label}</option>
                ))}
              </select>
            </div>
          )}

          {/* Даты */}
          {showDateRange && (
            <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
              <div>
                <label className="block text-sm font-bold text-slate-700 mb-2 flex items-center gap-2">
                  <Calendar className="w-4 h-4"/> Дата начала
                </label>
                <input
                  type="date"
                  value={startDate}
                  onChange={(e) => setStartDate(e.target.value)}
                  required
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                />
              </div>
              <div>
                <label className="block text-sm font-bold text-slate-700 mb-2 flex items-center gap-2">
                  <Calendar className="w-4 h-4"/> Дата окончания
                </label>
                <input
                  type="date"
                  value={endDate}
                  onChange={(e) => {
                    setEndDate(e.target.value);
                    if (absenceType === 'vacation') setVacationEndManuallyChanged(true);
                  }}
                  required={absenceType !== 'sick_leave'}
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                />
                {absenceType === 'vacation' && (
                  <p className="text-xs text-slate-500 mt-1">По умолчанию +14 дней от начала, можно изменить</p>
                )}
                {absenceType === 'sick_leave' && (
                  <p className="text-xs text-slate-500 mt-1">Заполняется при выходе с больничного</p>
                )}
              </div>
            </div>
          )}

          {/* Время (для опозданий и ранних уходов) */}
          {showTimeFields && (
            <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
              <div>
                <label className="block text-sm font-bold text-slate-700 mb-2 flex items-center gap-2">
                  <Calendar className="w-4 h-4"/> Дата
                </label>
                <input
                  type="date"
                  value={startDate}
                  onChange={(e) => setStartDate(e.target.value)}
                  required
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                />
              </div>
              <div>
                <label className="block text-sm font-bold text-slate-700 mb-2 flex items-center gap-2">
                  <Clock className="w-4 h-4"/> Время начала
                </label>
                <input
                  type="time"
                  value={startTime}
                  onChange={(e) => setStartTime(e.target.value)}
                  required
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                />
              </div>
              <div>
                <label className="block text-sm font-bold text-slate-700 mb-2 flex items-center gap-2">
                  <Clock className="w-4 h-4"/> Время окончания
                </label>
                <input
                  type="time"
                  value={endTime}
                  onChange={(e) => setEndTime(e.target.value)}
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                />
              </div>
            </div>
          )}

          {/* Дополнительные поля для больничных */}
          {showSickLeaveFields && (
            <div className="space-y-4">
              <div>
                <label className="block text-sm font-bold text-slate-700 mb-2 flex items-center gap-2">
                  <Calendar className="w-4 h-4"/> Предварительная дата выхода
                </label>
                <input
                  type="date"
                  value={expectedReturnDate}
                  onChange={(e) => setExpectedReturnDate(e.target.value)}
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                />
                <p className="text-xs text-slate-500 mt-1">При выходе нажмите «Выход с больничного» и укажите номер листа</p>
              </div>
              <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                <div>
                  <label className="block text-sm font-bold text-slate-700 mb-2">
                    Номер больничного листа
                  </label>
                  <input
                    type="text"
                    value={sickLeaveNumber}
                    onChange={(e) => setSickLeaveNumber(e.target.value)}
                    className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                    placeholder="Обязателен при выходе с больничного"
                  />
                </div>
                <div>
                  <label className="block text-sm font-bold text-slate-700 mb-2">
                    Медицинское учреждение
                  </label>
                  <input
                    type="text"
                    value={medicalInstitution}
                    onChange={(e) => setMedicalInstitution(e.target.value)}
                    className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                    placeholder="Необязательно"
                  />
                </div>
              </div>
              <div>
                <label className="block text-sm font-bold text-slate-700 mb-2">
                  Диагноз
                </label>
                <input
                  type="text"
                  value={diagnosis}
                  onChange={(e) => setDiagnosis(e.target.value)}
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                  placeholder="Необязательно"
                />
              </div>
            </div>
          )}

          {/* Причина (для отгулов и прогулов) */}
          {(absenceType === 'day_off' || absenceType === 'absence' || absenceType === 'late' || absenceType === 'early_leave') && (
            <div>
              <label className="block text-sm font-bold text-slate-700 mb-2">
                Причина
              </label>
              <textarea
                value={reason}
                onChange={(e) => setReason(e.target.value)}
                rows={3}
                className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent resize-none"
                placeholder="Укажите причину отсутствия"
              />
            </div>
          )}

          {/* Согласование */}
          <div className="bg-slate-50 rounded-xl p-4 border border-slate-200">
            <div className="flex items-center justify-between mb-4">
              <label className="flex items-center gap-2 text-sm font-bold text-slate-700">
                <UserCheck className="w-4 h-4"/> Требуется согласование с руководителем
              </label>
              <label className="relative inline-flex items-center cursor-pointer">
                <input
                  type="checkbox"
                  checked={requiresApproval}
                  onChange={(e) => setRequiresApproval(e.target.checked)}
                  className="sr-only peer"
                />
                <div className="w-11 h-6 bg-slate-300 peer-focus:outline-none peer-focus:ring-2 peer-focus:ring-primary-500 rounded-full peer peer-checked:after:translate-x-full peer-checked:after:border-white after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-white after:border-slate-300 after:border after:rounded-full after:h-5 after:w-5 after:transition-all peer-checked:bg-primary-600"></div>
              </label>
            </div>
            {requiresApproval && (
              <div className="mt-4">
                <label className="block text-sm font-bold text-slate-700 mb-2">
                  Подпись руководителя
                </label>
                <input
                  type="text"
                  value={approverSignature}
                  onChange={(e) => setApproverSignature(e.target.value)}
                  className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent"
                  placeholder="Введите ФИО руководителя для согласования"
                />
                <p className="text-xs text-slate-500 mt-1">
                  Руководитель должен будет подтвердить запись после создания
                </p>
              </div>
            )}
          </div>

          {/* Примечания */}
          <div>
            <label className="block text-sm font-bold text-slate-700 mb-2 flex items-center gap-2">
              <FileText className="w-4 h-4"/> Примечания
            </label>
            <textarea
              value={notes}
              onChange={(e) => setNotes(e.target.value)}
              rows={3}
              className="w-full px-4 py-3 rounded-xl border border-slate-200 bg-white text-slate-800 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent resize-none"
              placeholder="Дополнительная информация (необязательно)"
            />
          </div>

          {/* Кнопки */}
          <div className="flex gap-3 pt-4 border-t border-slate-200">
            <button
              type="button"
              onClick={onClose}
              className="flex-1 py-3 bg-slate-50 text-slate-700 rounded-xl text-sm font-bold hover:bg-slate-100 transition-colors"
            >
              Отмена
            </button>
            <button
              type="submit"
              disabled={loading}
              className="flex-1 py-3 bg-primary-600 text-white rounded-xl text-sm font-bold hover:bg-primary-700 transition-colors disabled:opacity-50 disabled:cursor-not-allowed shadow-lg shadow-primary-500/20"
            >
              {loading ? 'Создание...' : 'Создать'}
            </button>
          </div>
        </form>
      </div>
    </div>
  );
};