/*
 * Copyright 2009 the original author or authors.
 *
 * 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 org.gradle.api.internal.artifacts.ivyservice;

import org.gradle.api.artifacts.Dependency;
import org.gradle.api.artifacts.LenientConfiguration;
import org.gradle.api.artifacts.ModuleVersionIdentifier;
import org.gradle.api.artifacts.ResolveException;
import org.gradle.api.artifacts.ResolvedArtifact;
import org.gradle.api.artifacts.ResolvedConfiguration;
import org.gradle.api.artifacts.ResolvedDependency;
import org.gradle.api.artifacts.UnresolvedDependency;
import org.gradle.api.artifacts.component.ComponentIdentifier;
import org.gradle.api.artifacts.result.ResolutionResult;
import org.gradle.api.internal.artifacts.ConfigurationResolver;
import org.gradle.api.internal.artifacts.DefaultModuleVersionIdentifier;
import org.gradle.api.internal.artifacts.Module;
import org.gradle.api.internal.artifacts.ResolverResults;
import org.gradle.api.internal.artifacts.component.ComponentIdentifierFactory;
import org.gradle.api.internal.artifacts.configurations.ConfigurationInternal;
import org.gradle.api.internal.artifacts.ivyservice.resolveengine.projectresult.DefaultResolvedLocalComponentsResultBuilder;
import org.gradle.api.internal.artifacts.ivyservice.resolveengine.projectresult.ResolvedLocalComponentsResult;
import org.gradle.api.internal.artifacts.ivyservice.resolveengine.result.DefaultResolutionResultBuilder;
import org.gradle.api.specs.Spec;

import java.io.File;
import java.util.Collections;
import java.util.Set;

public class ShortCircuitEmptyConfigurationResolver implements ConfigurationResolver {
    private final ConfigurationResolver delegate;
    private final ComponentIdentifierFactory componentIdentifierFactory;

    public ShortCircuitEmptyConfigurationResolver(ConfigurationResolver delegate, ComponentIdentifierFactory componentIdentifierFactory) {
        this.delegate = delegate;
        this.componentIdentifierFactory = componentIdentifierFactory;
    }

    @Override
    public void resolve(ConfigurationInternal configuration, ResolverResults results) throws ResolveException {
        if (configuration.getAllDependencies().isEmpty()) {
            Module module = configuration.getModule();
            ModuleVersionIdentifier id = DefaultModuleVersionIdentifier.newId(module);
            ComponentIdentifier componentIdentifier = componentIdentifierFactory.createComponentIdentifier(module);
            ResolutionResult emptyResult = new DefaultResolutionResultBuilder().start(id, componentIdentifier).complete();
            ResolvedLocalComponentsResult emptyProjectResult = new DefaultResolvedLocalComponentsResultBuilder(false).complete();
            results.resolved(emptyResult, emptyProjectResult);
        } else {
            delegate.resolve(configuration, results);
        }
    }

    @Override
    public void resolveArtifacts(ConfigurationInternal configuration, ResolverResults results) throws ResolveException {
        if (configuration.getAllDependencies().isEmpty()) {
            results.withResolvedConfiguration(new EmptyResolvedConfiguration());
        } else {
            delegate.resolveArtifacts(configuration, results);
        }
    }

    private static class EmptyResolvedConfiguration implements ResolvedConfiguration {

        public boolean hasError() {
            return false;
        }

        public LenientConfiguration getLenientConfiguration() {
            return new LenientConfiguration() {
                public Set<ResolvedDependency> getFirstLevelModuleDependencies(Spec<? super Dependency> dependencySpec) {
                    return Collections.emptySet();
                }

                public Set<UnresolvedDependency> getUnresolvedModuleDependencies() {
                    return Collections.emptySet();
                }

                public Set<File> getFiles(Spec<? super Dependency> dependencySpec) {
                    return Collections.emptySet();
                }

                public Set<ResolvedArtifact> getArtifacts(Spec<? super Dependency> dependencySpec) {
                    return Collections.emptySet();
                }
            };
        }

        public void rethrowFailure() throws ResolveException {
        }

        public Set<File> getFiles(Spec<? super Dependency> dependencySpec) {
            return Collections.emptySet();
        }

        public Set<ResolvedDependency> getFirstLevelModuleDependencies() {
            return Collections.emptySet();
        }

        public Set<ResolvedDependency> getFirstLevelModuleDependencies(Spec<? super Dependency> dependencySpec) throws ResolveException {
            return Collections.emptySet();
        }

        public Set<ResolvedArtifact> getResolvedArtifacts() {
            return Collections.emptySet();
        }
    }
}
