import React, { useState, useCallback, useMemo } from 'react';
import { Card, Button, Badge, Select, DatePicker, Input, Modal, Table } from '../../ui';
import { productionService, type ProductionScheduleEntry, ProductionBatchStatus } from '../../../api';
import type { ProductionSchedule as ProductionScheduleType, ProductionBatch, EquipmentReservation, StaffAssignment } from '../../../types/production.types';

interface ProductionScheduleProps {
  className?: string;
  onBatchSelected?: (batch: ProductionBatch) => void;
  onScheduleUpdate?: (schedule: ProductionScheduleEntry) => void;
}

interface TimeSlot {
  time: string;
  capacity: number;
  utilized: number;
  available: number;
  batches: ProductionScheduleEntry[];
}

interface CapacityResource {
  id: string;
  name: string;
  type: 'oven' | 'mixer' | 'staff';
  capacity: number;
  slots: TimeSlot[];
}

const PRODUCT_TYPE_COLORS = {
  pan: 'bg-[var(--color-warning)]/10 border-[var(--color-warning)]/20 text-[var(--color-warning)]',
  bolleria: 'bg-[var(--color-primary)]/10 border-[var(--color-primary)]/20 text-[var(--color-primary)]',
  reposteria: 'bg-[var(--color-error)]/10 border-[var(--color-error)]/20 text-[var(--color-error)]',
  especial: 'bg-[var(--color-info)]/10 border-[var(--color-info)]/20 text-[var(--color-info)]',
};

const STATUS_COLORS = {
  [ProductionBatchStatus.PLANNED]: 'bg-[var(--color-info)]/10 text-[var(--color-info)]',
  [ProductionBatchStatus.IN_PROGRESS]: 'bg-[var(--color-warning)]/10 text-[var(--color-warning)]',
  [ProductionBatchStatus.COMPLETED]: 'bg-[var(--color-success)]/10 text-[var(--color-success)]',
  [ProductionBatchStatus.CANCELLED]: 'bg-[var(--color-error)]/10 text-[var(--color-error)]',
  [ProductionBatchStatus.ON_HOLD]: 'bg-[var(--bg-tertiary)] text-[var(--text-secondary)]',
};

export const ProductionSchedule: React.FC<ProductionScheduleProps> = ({
  className = '',
  onBatchSelected,
  onScheduleUpdate,
}) => {
  const [scheduleEntries, setScheduleEntries] = useState<ProductionScheduleEntry[]>([]);
  const [loading, setLoading] = useState(false);
  const [selectedDate, setSelectedDate] = useState<Date>(new Date());
  const [viewMode, setViewMode] = useState<'calendar' | 'timeline' | 'capacity'>('timeline');
  const [filterStatus, setFilterStatus] = useState<ProductionBatchStatus | 'all'>('all');
  const [filterProduct, setFilterProduct] = useState<string>('all');
  const [draggedBatch, setDraggedBatch] = useState<ProductionScheduleEntry | null>(null);
  const [isScheduleModalOpen, setIsScheduleModalOpen] = useState(false);
  const [selectedBatchForScheduling, setSelectedBatchForScheduling] = useState<ProductionBatch | null>(null);

  // Mock data for demonstration
  const mockCapacityResources: CapacityResource[] = [
    {
      id: 'horno-1',
      name: 'Horno Principal',
      type: 'oven',
      capacity: 4,
      slots: generateTimeSlots('06:00', '20:00', 2),
    },
    {
      id: 'horno-2',
      name: 'Horno Secundario',
      type: 'oven',
      capacity: 2,
      slots: generateTimeSlots('06:00', '18:00', 2),
    },
    {
      id: 'amasadora-1',
      name: 'Amasadora Industrial',
      type: 'mixer',
      capacity: 6,
      slots: generateTimeSlots('05:00', '21:00', 1),
    },
    {
      id: 'panadero-1',
      name: 'Equipo Panadería',
      type: 'staff',
      capacity: 8,
      slots: generateTimeSlots('06:00', '14:00', 1),
    },
  ];

  function generateTimeSlots(startTime: string, endTime: string, intervalHours: number): TimeSlot[] {
    const slots: TimeSlot[] = [];
    const start = new Date(`2024-01-01 ${startTime}`);
    const end = new Date(`2024-01-01 ${endTime}`);
    
    while (start < end) {
      const timeStr = start.toLocaleTimeString('es-ES', { hour: '2-digit', minute: '2-digit' });
      slots.push({
        time: timeStr,
        capacity: 100,
        utilized: Math.floor(Math.random() * 80),
        available: 100 - Math.floor(Math.random() * 80),
        batches: [],
      });
      start.setHours(start.getHours() + intervalHours);
    }
    
    return slots;
  }

  const loadSchedule = useCallback(async () => {
    setLoading(true);
    try {
      const response = await productionService.getProductionSchedule({
        start_date: selectedDate.toISOString().split('T')[0],
        end_date: selectedDate.toISOString().split('T')[0],
      });
      
      if (response.success) {
        setScheduleEntries(response.data || []);
      }
    } catch (error) {
      console.error('Error loading schedule:', error);
    } finally {
      setLoading(false);
    }
  }, [selectedDate]);

  const filteredEntries = useMemo(() => {
    return scheduleEntries.filter(entry => {
      if (filterStatus !== 'all' && entry.batch?.status !== filterStatus) {
        return false;
      }
      if (filterProduct !== 'all' && entry.batch?.recipe?.category !== filterProduct) {
        return false;
      }
      return true;
    });
  }, [scheduleEntries, filterStatus, filterProduct]);

  const handleDragStart = (e: React.DragEvent, entry: ProductionScheduleEntry) => {
    setDraggedBatch(entry);
    e.dataTransfer.effectAllowed = 'move';
  };

  const handleDragOver = (e: React.DragEvent) => {
    e.preventDefault();
    e.dataTransfer.dropEffect = 'move';
  };

  const handleDrop = async (e: React.DragEvent, newTime: string) => {
    e.preventDefault();
    
    if (!draggedBatch) return;

    try {
      const response = await productionService.updateScheduleEntry(draggedBatch.id, {
        scheduled_start_time: newTime,
        scheduled_end_time: calculateEndTime(newTime, draggedBatch.estimated_duration_minutes),
      });

      if (response.success && onScheduleUpdate) {
        onScheduleUpdate(response.data);
        await loadSchedule();
      }
    } catch (error) {
      console.error('Error updating schedule:', error);
    } finally {
      setDraggedBatch(null);
    }
  };

  const calculateEndTime = (startTime: string, durationMinutes: number): string => {
    const start = new Date(`2024-01-01 ${startTime}`);
    start.setMinutes(start.getMinutes() + durationMinutes);
    return start.toLocaleTimeString('es-ES', { hour: '2-digit', minute: '2-digit' });
  };

  const handleScheduleBatch = async (scheduleData: {
    batch_id: string;
    scheduled_date: string;
    scheduled_start_time: string;
    scheduled_end_time: string;
    equipment_reservations?: string[];
    staff_assignments?: string[];
  }) => {
    try {
      const response = await productionService.scheduleProductionBatch(scheduleData);
      
      if (response.success && onScheduleUpdate) {
        onScheduleUpdate(response.data);
        await loadSchedule();
        setIsScheduleModalOpen(false);
        setSelectedBatchForScheduling(null);
      }
    } catch (error) {
      console.error('Error scheduling batch:', error);
    }
  };

  const getProductTypeColor = (category?: string) => {
    return PRODUCT_TYPE_COLORS[category as keyof typeof PRODUCT_TYPE_COLORS] || 'bg-[var(--bg-tertiary)] border-[var(--border-secondary)] text-[var(--text-secondary)]';
  };

  const getStatusColor = (status?: ProductionBatchStatus) => {
    return STATUS_COLORS[status as keyof typeof STATUS_COLORS] || 'bg-[var(--bg-tertiary)] text-[var(--text-secondary)]';
  };

  const renderTimelineView = () => (
    <div className="space-y-4">
      <div className="flex gap-4 items-center mb-6">
        <DatePicker
          selected={selectedDate}
          onChange={(date) => setSelectedDate(date || new Date())}
          dateFormat="dd/MM/yyyy"
          className="w-40"
        />
        <Select
          value={filterStatus}
          onChange={(e) => setFilterStatus(e.target.value as ProductionBatchStatus | 'all')}
          className="w-40"
        >
          <option value="all">Todos los estados</option>
          <option value={ProductionBatchStatus.PLANNED}>Planificado</option>
          <option value={ProductionBatchStatus.IN_PROGRESS}>En progreso</option>
          <option value={ProductionBatchStatus.COMPLETED}>Completado</option>
        </Select>
        <Select
          value={filterProduct}
          onChange={(e) => setFilterProduct(e.target.value)}
          className="w-40"
        >
          <option value="all">Todos los productos</option>
          <option value="pan">Pan</option>
          <option value="bolleria">Bollería</option>
          <option value="reposteria">Repostería</option>
        </Select>
      </div>

      <div className="bg-white rounded-lg border">
        <div className="grid grid-cols-25 gap-1 p-4 bg-[var(--bg-secondary)] text-xs font-medium text-[var(--text-tertiary)] border-b">
          <div className="col-span-3">Producto</div>
          {Array.from({ length: 22 }, (_, i) => (
            <div key={i} className="text-center">
              {String(i + 3).padStart(2, '0')}:00
            </div>
          ))}
        </div>

        <div className="divide-y">
          {filteredEntries.map((entry) => (
            <div
              key={entry.id}
              className="grid grid-cols-25 gap-1 p-2 hover:bg-[var(--bg-secondary)]"
            >
              <div className="col-span-3 flex items-center space-x-2">
                <div className="flex flex-col">
                  <span className="font-medium text-sm">{entry.batch?.recipe?.name}</span>
                  <Badge className={`text-xs ${getStatusColor(entry.batch?.status)}`}>
                    {entry.batch?.status === ProductionBatchStatus.PLANNED && 'Planificado'}
                    {entry.batch?.status === ProductionBatchStatus.IN_PROGRESS && 'En progreso'}
                    {entry.batch?.status === ProductionBatchStatus.COMPLETED && 'Completado'}
                  </Badge>
                </div>
              </div>

              {Array.from({ length: 22 }, (_, hourIndex) => {
                const hour = hourIndex + 3;
                const hourStr = `${String(hour).padStart(2, '0')}:00`;
                const startHour = parseInt(entry.scheduled_start_time.split(':')[0]);
                const endHour = parseInt(entry.scheduled_end_time.split(':')[0]);
                
                const isInRange = hour >= startHour && hour < endHour;
                const isStart = hour === startHour;
                
                return (
                  <div
                    key={hourIndex}
                    className={`h-12 border border-[var(--border-primary)] ${isInRange ? getProductTypeColor(entry.batch?.recipe?.category) : ''}`}
                    onDragOver={handleDragOver}
                    onDrop={(e) => handleDrop(e, hourStr)}
                  >
                    {isStart && (
                      <div
                        className={`h-full w-full rounded px-1 py-1 cursor-move ${getProductTypeColor(entry.batch?.recipe?.category)} border-l-4 border-blue-500`}
                        draggable
                        onDragStart={(e) => handleDragStart(e, entry)}
                        onClick={() => onBatchSelected?.(entry.batch!)}
                      >
                        <div className="text-xs font-medium truncate">
                          {entry.batch?.recipe?.name}
                        </div>
                        <div className="text-xs text-[var(--text-secondary)]">
                          {entry.batch?.planned_quantity} uds
                        </div>
                      </div>
                    )}
                  </div>
                );
              })}
            </div>
          ))}
        </div>
      </div>
    </div>
  );

  const renderCapacityView = () => (
    <div className="space-y-6">
      <div className="flex gap-4 items-center mb-6">
        <DatePicker
          selected={selectedDate}
          onChange={(date) => setSelectedDate(date || new Date())}
          dateFormat="dd/MM/yyyy"
          className="w-40"
        />
      </div>

      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
        {mockCapacityResources.map((resource) => (
          <Card key={resource.id} className="p-4">
            <div className="flex items-center justify-between mb-4">
              <div>
                <h3 className="font-semibold text-lg">{resource.name}</h3>
                <p className="text-sm text-[var(--text-secondary)]">
                  {resource.type === 'oven' && 'Horno'}
                  {resource.type === 'mixer' && 'Amasadora'}
                  {resource.type === 'staff' && 'Personal'}
                  - Capacidad: {resource.capacity}
                </p>
              </div>
              <Badge className="bg-[var(--color-info)]/10 text-[var(--color-info)]">
                {Math.round(resource.slots.reduce((acc, slot) => acc + slot.utilized, 0) / resource.slots.length)}% utilizado
              </Badge>
            </div>

            <div className="space-y-2">
              {resource.slots.slice(0, 8).map((slot, index) => (
                <div key={index} className="flex items-center gap-3">
                  <span className="text-sm font-mono w-16">{slot.time}</span>
                  <div className="flex-1 h-6 bg-[var(--bg-quaternary)] rounded-full overflow-hidden">
                    <div
                      className={`h-full ${
                        slot.utilized > 80 
                          ? 'bg-[var(--color-error)]' 
                          : slot.utilized > 60 
                            ? 'bg-yellow-500' 
                            : 'bg-[var(--color-success)]'
                      }`}
                      style={{ width: `${slot.utilized}%` }}
                    />
                  </div>
                  <span className="text-sm text-[var(--text-secondary)] w-12">
                    {slot.utilized}%
                  </span>
                </div>
              ))}
            </div>

            <Button
              variant="outline"
              size="sm"
              className="mt-4 w-full"
              onClick={() => {
                // Open detailed capacity view
                console.log('Open detailed view for', resource.name);
              }}
            >
              Ver detalles completos
            </Button>
          </Card>
        ))}
      </div>
    </div>
  );

  const renderCalendarView = () => (
    <div className="bg-white rounded-lg border p-4">
      <div className="grid grid-cols-7 gap-4 mb-4">
        {['Lun', 'Mar', 'Mié', 'Jue', 'Vie', 'Sáb', 'Dom'].map((day) => (
          <div key={day} className="text-center font-semibold text-[var(--text-secondary)] py-2">
            {day}
          </div>
        ))}
      </div>

      <div className="grid grid-cols-7 gap-4">
        {Array.from({ length: 35 }, (_, i) => {
          const date = new Date(selectedDate);
          date.setDate(date.getDate() - date.getDay() + i);
          const dayEntries = filteredEntries.filter(entry => 
            new Date(entry.scheduled_date).toDateString() === date.toDateString()
          );

          return (
            <div
              key={i}
              className={`min-h-24 p-2 border rounded-lg ${
                date.toDateString() === selectedDate.toDateString() 
                  ? 'bg-[var(--color-info)]/5 border-[var(--color-info)]/20' 
                  : 'bg-[var(--bg-secondary)] border-[var(--border-primary)]'
              }`}
            >
              <div className="text-sm font-medium mb-1">{date.getDate()}</div>
              <div className="space-y-1">
                {dayEntries.slice(0, 3).map((entry) => (
                  <div
                    key={entry.id}
                    className={`text-xs p-1 rounded cursor-pointer ${getProductTypeColor(entry.batch?.recipe?.category)}`}
                    onClick={() => onBatchSelected?.(entry.batch!)}
                  >
                    {entry.batch?.recipe?.name}
                  </div>
                ))}
                {dayEntries.length > 3 && (
                  <div className="text-xs text-[var(--text-tertiary)]">
                    +{dayEntries.length - 3} más
                  </div>
                )}
              </div>
            </div>
          );
        })}
      </div>
    </div>
  );

  return (
    <div className={`space-y-6 ${className}`}>
      <div className="flex justify-between items-center">
        <div>
          <h2 className="text-2xl font-bold text-[var(--text-primary)]">Programación de Producción</h2>
          <p className="text-[var(--text-secondary)]">Gestiona y programa la producción diaria de la panadería</p>
        </div>

        <div className="flex gap-2">
          <div className="flex bg-[var(--bg-tertiary)] rounded-lg p-1">
            <Button
              variant={viewMode === 'calendar' ? 'primary' : 'ghost'}
              size="sm"
              onClick={() => setViewMode('calendar')}
              className="px-3"
            >
              Calendario
            </Button>
            <Button
              variant={viewMode === 'timeline' ? 'primary' : 'ghost'}
              size="sm"
              onClick={() => setViewMode('timeline')}
              className="px-3"
            >
              Línea de tiempo
            </Button>
            <Button
              variant={viewMode === 'capacity' ? 'primary' : 'ghost'}
              size="sm"
              onClick={() => setViewMode('capacity')}
              className="px-3"
            >
              Capacidad
            </Button>
          </div>

          <Button
            variant="primary"
            onClick={() => setIsScheduleModalOpen(true)}
          >
            Nueva programación
          </Button>
        </div>
      </div>

      {loading ? (
        <div className="flex justify-center items-center h-64">
          <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-blue-600"></div>
        </div>
      ) : (
        <>
          {viewMode === 'calendar' && renderCalendarView()}
          {viewMode === 'timeline' && renderTimelineView()}
          {viewMode === 'capacity' && renderCapacityView()}
        </>
      )}

      {/* Schedule Creation Modal */}
      <Modal
        isOpen={isScheduleModalOpen}
        onClose={() => {
          setIsScheduleModalOpen(false);
          setSelectedBatchForScheduling(null);
        }}
        title="Programar Lote de Producción"
      >
        <div className="space-y-4">
          <Select className="w-full">
            <option value="">Seleccionar lote...</option>
            <option value="batch-1">Lote #001 - Pan de Molde (100 uds)</option>
            <option value="batch-2">Lote #002 - Croissants (50 uds)</option>
            <option value="batch-3">Lote #003 - Tarta de Chocolate (5 uds)</option>
          </Select>

          <div className="grid grid-cols-2 gap-4">
            <DatePicker
              selected={selectedDate}
              onChange={(date) => setSelectedDate(date || new Date())}
              dateFormat="dd/MM/yyyy"
            />
            <Input
              type="time"
              placeholder="Hora de inicio"
              defaultValue="06:00"
            />
          </div>

          <div className="grid grid-cols-2 gap-4">
            <Input
              type="number"
              placeholder="Duración (horas)"
              defaultValue="4"
            />
            <Select>
              <option value="">Asignar horno...</option>
              <option value="horno-1">Horno Principal</option>
              <option value="horno-2">Horno Secundario</option>
            </Select>
          </div>

          <Select>
            <option value="">Asignar personal...</option>
            <option value="panadero-1">Equipo Panadería - Turno Mañana</option>
            <option value="panadero-2">Equipo Panadería - Turno Tarde</option>
          </Select>

          <div className="flex justify-end gap-2 pt-4">
            <Button
              variant="outline"
              onClick={() => setIsScheduleModalOpen(false)}
            >
              Cancelar
            </Button>
            <Button
              variant="primary"
              onClick={() => {
                // Handle schedule creation
                setIsScheduleModalOpen(false);
              }}
            >
              Programar lote
            </Button>
          </div>
        </div>
      </Modal>

      {/* Legend */}
      <Card className="p-4">
        <h3 className="font-semibold mb-3">Leyenda de productos</h3>
        <div className="flex flex-wrap gap-4">
          <div className="flex items-center gap-2">
            <div className="w-4 h-4 bg-[var(--color-warning)]/10 border border-[var(--color-warning)]/20 rounded"></div>
            <span className="text-sm">Pan</span>
          </div>
          <div className="flex items-center gap-2">
            <div className="w-4 h-4 bg-[var(--color-primary)]/10 border border-[var(--color-primary)]/20 rounded"></div>
            <span className="text-sm">Bollería</span>
          </div>
          <div className="flex items-center gap-2">
            <div className="w-4 h-4 bg-pink-100 border border-pink-300 rounded"></div>
            <span className="text-sm">Repostería</span>
          </div>
          <div className="flex items-center gap-2">
            <div className="w-4 h-4 bg-purple-100 border border-purple-300 rounded"></div>
            <span className="text-sm">Especial</span>
          </div>
        </div>
      </Card>
    </div>
  );
};

export default ProductionSchedule;