/*
 * Copyright 2003-2016 JetBrains s.r.o.
 *
 * 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 jetbrains.mps.generator.impl.template;

import jetbrains.mps.generator.impl.GenerationFailureException;
import jetbrains.mps.generator.impl.query.CallArgumentQuery;
import jetbrains.mps.generator.impl.query.IfMacroCondition;
import jetbrains.mps.generator.impl.query.InlineSwitchCaseCondition;
import jetbrains.mps.generator.impl.query.InsertMacroQuery;
import jetbrains.mps.generator.impl.query.MapNodeQuery;
import jetbrains.mps.generator.impl.query.MapPostProcessor;
import jetbrains.mps.generator.impl.query.PropertyValueQuery;
import jetbrains.mps.generator.impl.query.ReferenceTargetQuery;
import jetbrains.mps.generator.impl.query.SourceNodeQuery;
import jetbrains.mps.generator.impl.query.SourceNodesQuery;
import jetbrains.mps.generator.impl.query.VariableValueQuery;
import jetbrains.mps.generator.template.IfMacroContext;
import jetbrains.mps.generator.template.InlineSwitchCaseContext;
import jetbrains.mps.generator.template.InsertMacroContext;
import jetbrains.mps.generator.template.MapSrcMacroContext;
import jetbrains.mps.generator.template.MapSrcMacroPostProcContext;
import jetbrains.mps.generator.template.PropertyMacroContext;
import jetbrains.mps.generator.template.ReferenceMacroContext;
import jetbrains.mps.generator.template.SourceSubstituteMacroNodeContext;
import jetbrains.mps.generator.template.SourceSubstituteMacroNodesContext;
import jetbrains.mps.generator.template.TemplateArgumentContext;
import jetbrains.mps.generator.template.TemplateVarContext;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.mps.openapi.model.SNode;

import java.util.Collection;

/**
 * This is not an attempt to make new and nice replacement for QueryExecutionContext, rather an attempt to fix
 * shortcomings arising when using it. Hence it's very similar to the QEC.
 *
 * This is an indirection mechanism to invoke queries, suitable if there's need to perform extra activities (like tracing/model access recording)
 * in addition to query execution. Note, this might change once we encapsulate all queries into objects. Then, factory for these query object may
 * augment them with proper extra tasks as needed, without need to have this indirection mediator. Meanwhile, however, we keep this and slowly
 * migrate methods of QEC here, with proper/better API.
 * IMPORTANT: One real benefit of using indirection mechanism of this class is handling of user-code exceptions. While for reflective calls we can do that in
 * query implementations from {@code ReflectiveQueryProvider}, we can't expect generated non-reflective queries to execute without a RuntimeException
 * always. This indirection allows us to keep this handling in a single place (and report e.g. with dedicated GFE subclass). Besides,
 * we can provide 'straightforward' QE implementation that doesn't do additional try/catch for templates from deployed generators to speed-up
 * things a bit (if/when we are pretty confident our generators work good)
 *
 * Note, with extra layer of RT objects as Rules, for a query that is associated with a Rule, it's not always straightforward whether
 * generator implementation shall run it directly through <code>QueryExecutor</code> or shall delegate to Rule implementation instead
 * (which, in turn, would either use QueryExecutor (for interpreted), or invoke code directly (for generated templates)). Consider
 * <code>TemplateWeavingRule</code> and its contextNode and anchorNode queries. Generator implementation may invoke these directly with
 * QueryExecutor or delegate to rule. In former case, the role of TWR itself becomes uncertain, in latter, the question "why don't we do
 * the same for other queries" is raised, and there's yet no good answer to this one.
 *
 * @author Artem Tikhomirov
 */
public interface QueryExecutor {
  @NotNull
  Collection<SNode> evaluate(@NotNull SourceNodesQuery query, @NotNull SourceSubstituteMacroNodesContext context) throws GenerationFailureException;
  @Nullable
  SNode evaluate(@NotNull SourceNodeQuery query, @NotNull SourceSubstituteMacroNodeContext context) throws GenerationFailureException;
  @Nullable
  Object evaluate(@NotNull PropertyValueQuery query, @NotNull PropertyMacroContext context) throws GenerationFailureException;
  boolean evaluate(@NotNull IfMacroCondition condition, @NotNull IfMacroContext context) throws GenerationFailureException;
  boolean evaluate(@NotNull InlineSwitchCaseCondition condition, @NotNull InlineSwitchCaseContext context) throws GenerationFailureException;
  @Nullable
  Object evaluate(@NotNull ReferenceTargetQuery query, @NotNull ReferenceMacroContext context) throws GenerationFailureException;
  @Nullable
  Object evaluate(@NotNull CallArgumentQuery query, @NotNull TemplateArgumentContext context) throws GenerationFailureException;
  @Nullable
  Object evaluate(@NotNull VariableValueQuery query, @NotNull TemplateVarContext context) throws GenerationFailureException;
  @Nullable
  SNode evaluate(@NotNull InsertMacroQuery query, @NotNull InsertMacroContext context) throws GenerationFailureException;
  @Nullable
  SNode evaluate(@NotNull MapNodeQuery query, @NotNull MapSrcMacroContext context) throws GenerationFailureException;
  void execute(@NotNull MapPostProcessor codeBlock, @NotNull MapSrcMacroPostProcContext context) throws GenerationFailureException;
}
