// Copyright (c) 2009 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

package org.chromium.sdk.internal.protocolparser.dynamicimpl;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.List;

import org.chromium.sdk.internal.protocolparser.JsonProtocolModelParseException;

import org.chromium.sdk.internal.protocolparser.JsonProtocolParseException;

import org.chromium.sdk.internal.protocolparser.JsonSubtypeCondition;

import org.chromium.sdk.internal.protocolparser.JsonSubtypeConditionBoolValue;

import org.chromium.sdk.internal.protocolparser.JsonSubtypeConditionCustom;

import org.chromium.sdk.internal.protocolparser.JsonValueCondition;

/**

 * An interface to field conditions logic. Some conditions are simple and never need parsed

 * values, others are more fine-grained and require quick parser before making actual checks.

 */

abstract class FieldConditionLogic {

  private final boolean logicRequiresQuickParser;

  FieldConditionLogic(boolean logicRequiresQuickParser) {

    this.logicRequiresQuickParser = logicRequiresQuickParser;

  }

  boolean requiresQuickParser() {

    return logicRequiresQuickParser;

  }

  /**

   * @param hasValue whether field exists in JSON object (however its value may be null)

   * @param quickParser parser that may be used if {@link #requiresQuickParser()} is true

   */

  abstract boolean checkValue(boolean hasValue, Object unparsedValue, QuickParser<?> quickParser)

      throws JsonProtocolParseException;

  /**

   * Constructor function that creates field condition logic from method annotations.

   */

  static FieldConditionLogic readLogic(Method m) throws JsonProtocolModelParseException {

    List<FieldConditionLogic> results = new ArrayList<FieldConditionLogic>(1);

    JsonSubtypeConditionBoolValue boolValueAnn =

        m.getAnnotation(JsonSubtypeConditionBoolValue.class);

    if (boolValueAnn != null) {

      final Boolean required = boolValueAnn.value();

      results.add(new FieldConditionLogic(true) {

        @Override

        boolean checkValue(boolean hasValue, Object unparsedValue, QuickParser<?> parser)

            throws JsonProtocolParseException {

          return hasValue && required == parser.parseValueQuick(unparsedValue);

        }

      });

    }

    JsonSubtypeConditionCustom customAnn = m.getAnnotation(JsonSubtypeConditionCustom.class);

    if (customAnn != null) {

      final CustomConditionWrapper<?> constraint =

          CustomConditionWrapper.create(customAnn.condition());

      results.add(new FieldConditionLogic(true) {

        @Override

        boolean checkValue(boolean hasValue, Object unparsedValue, QuickParser<?> parser)

            throws JsonProtocolParseException {

          return hasValue && constraint.checkValue(parser.parseValueQuick(unparsedValue));

        }

      });

    }

    JsonSubtypeCondition conditionAnn = m.getAnnotation(JsonSubtypeCondition.class);

    if (conditionAnn != null) {

      int savedResSize = results.size();

      if (conditionAnn.fieldIsAbsent()) {

        results.add(new FieldConditionLogic(false) {

          @Override

          boolean checkValue(boolean hasValue, Object unparsedValue, QuickParser<?> parser) {

            return !hasValue;

          }

        });

      }

      if (conditionAnn.valueIsNull()) {

        results.add(new FieldConditionLogic(false) {

          @Override

          boolean checkValue(boolean hasValue, Object unparsedValue, QuickParser<?> parser) {

            return hasValue && unparsedValue != null;

          }

        });

      }

      if (savedResSize == results.size()) {

        results.add(new FieldConditionLogic(false) {

          @Override

          boolean checkValue(boolean hasValue, Object unparsedValue, QuickParser<?> parser) {

            return hasValue;

          }

        });

      }

    }

    if (results.size() == 0) {

      return null;

    }

    if (results.size() > 1) {

      throw new JsonProtocolModelParseException("Too many constraints for field getter " + m);

    }

    return results.get(0);

  }

  private static class CustomConditionWrapper<T> {

    static <T, CL extends JsonValueCondition<T>> CustomConditionWrapper<T> create(

        Class<CL> constraintClass) {

      return new CustomConditionWrapper<T>(constraintClass);

    }

    private final JsonValueCondition<? super T> constraint;

    private CustomConditionWrapper(Class<? extends JsonValueCondition<? super T>> constraintClass) {

      try {

        constraint = constraintClass.newInstance();

      } catch (InstantiationException e) {

        throw new RuntimeException(e);

      } catch (IllegalAccessException e) {

        throw new RuntimeException(e);

      }

    }

    boolean checkValue(Object parsedValue) {

      return constraint.conforms((T)parsedValue);

    }

  }

}