/*
 * Copyright 2014 Effektif GmbH.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.effektif.workflow.impl.data.types;

import static java.awt.SystemColor.text;

import com.effektif.workflow.api.Configuration;
import com.effektif.workflow.api.types.DataType;
import com.effektif.workflow.api.types.ListType;
import com.effektif.workflow.impl.data.AbstractDataType;
import com.effektif.workflow.impl.data.DataTypeImpl;
import com.effektif.workflow.impl.data.DataTypeService;
import com.effektif.workflow.impl.data.TypedValueImpl;
import com.effektif.workflow.impl.template.Hints;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;


/**
 * @author Tom Baeyens
 */
public class ListTypeImpl extends AbstractDataType<ListType> {
  
  public DataTypeImpl elementType;
  
  public ListTypeImpl() {
    this(new ListType());
  }
  
  public ListTypeImpl(DataTypeImpl elementType) {
    this(new ListType(elementType.serialize()));
    this.elementType = elementType;
  }
  
  public ListTypeImpl(ListType listType) {
    super(listType);
  }
  
  @Override
  public String validateInternalValue(Object internalValue) {
    if (!(internalValue instanceof Collection)) {
      return "Value is not a list";
    }
    Iterator iterator = ((Collection)internalValue).iterator();
    int index = 0;
    while (iterator.hasNext()) {
      Object element = iterator.next();
      if (element!=null) {
        String elementErrorMessage = elementType.validateInternalValue(element);
        if (elementErrorMessage!=null) {
          return "Element "+index+" in list is invalid: "+element;
        }
      }
      index++;
    }
    return null;
  }

  @Override
  public void setConfiguration(Configuration configuration) {
    super.setConfiguration(configuration);
    DataType elementType = type.getElementType();
    if (elementType!=null) {
      DataTypeService dataTypeService = configuration.get(DataTypeService.class);
      this.elementType = dataTypeService.createDataType(elementType);
    }
  }

  @Override
  public boolean isStatic() {
    return false;
  }

  @Override
  public TypedValueImpl dereference(Object value, String field) {
    List<Object> fieldValues = null;
    if (value instanceof List) {
      List<Object> values = (List<Object>) value;
      fieldValues = new ArrayList<>(); 
      for (Object elementValue: values) {
        TypedValueImpl elementFieldValue = elementType.dereference(elementValue, field);
        if (elementFieldValue != null) {
          fieldValues.add(elementFieldValue.value);
        }
      }
    }
    return new TypedValueImpl(this, fieldValues);
  }

  @Override
  public String convertInternalToText(Object value, Hints hints) {
    if (value==null) {
      return "";
    }
    if (value instanceof List) {
      List<Object> list = (List<Object>) value;
      if (list.isEmpty()) {
        return "";
      }
      else {
        StringBuilder text = new StringBuilder();
        // Add blank lines before and after the list to separate it from mark-up around the list variable expression.
        text.append("\n");
        list.forEach(element -> text.append("\n* ").append(elementType.convertInternalToText(element, hints)));
        text.append("\n\n");
        return text.toString();
      }
    }
    return value.toString();
  }
}