package io.pry.gradle.offline_dependencies

import io.pry.gradle.offline_dependencies.maven.PomDependencyModelResolver
import io.pry.gradle.offline_dependencies.repackaged.org.apache.maven.model.Model
import io.pry.gradle.offline_dependencies.repackaged.org.apache.maven.model.building.*
import io.pry.gradle.offline_dependencies.repackaged.org.apache.maven.model.interpolation.StringSearchModelInterpolator
import io.pry.gradle.offline_dependencies.repackaged.org.apache.maven.model.path.DefaultPathTranslator
import io.pry.gradle.offline_dependencies.repackaged.org.apache.maven.model.path.DefaultUrlNormalizer
import io.pry.gradle.offline_dependencies.repackaged.org.apache.maven.model.validation.DefaultModelValidator
import org.gradle.api.DefaultTask
import org.gradle.api.artifacts.Configuration
import org.gradle.api.artifacts.Dependency
import org.gradle.api.artifacts.ExternalModuleDependency
import org.gradle.api.artifacts.UnknownConfigurationException
import org.gradle.api.artifacts.component.ComponentIdentifier
import org.gradle.api.artifacts.component.ModuleComponentIdentifier
import org.gradle.api.artifacts.result.UnresolvedArtifactResult
import org.gradle.api.internal.artifacts.DefaultModuleIdentifier
import org.gradle.api.tasks.Input
import org.gradle.api.tasks.TaskAction
import org.gradle.internal.component.external.model.DefaultModuleComponentIdentifier
import org.gradle.ivy.IvyDescriptorArtifact
import org.gradle.ivy.IvyModule
import org.gradle.jvm.JvmLibrary
import org.gradle.language.base.artifact.SourcesArtifact
import org.gradle.language.java.artifact.JavadocArtifact
import org.gradle.maven.MavenModule
import org.gradle.maven.MavenPomArtifact
import org.gradle.util.GFileUtils

import static io.pry.gradle.offline_dependencies.Utils.addToMultimap

class UpdateOfflineRepositoryTask extends DefaultTask {

    def EMPTY_DEPENDENCIES_ARRAY = new Dependency[0]

    @Input
    GString root
    @Input
    Set<String> configurationNames
    @Input
    Set<String> buildscriptConfigurationNames
    @Input
    boolean includeSources
    @Input
    boolean includeJavadocs
    @Input
    boolean includePoms
    @Input
    boolean includeIvyXmls
    @Input
    boolean includeBuildscriptDependencies

    @TaskAction
    void run() {
        withRepositoryFiles { repositoryFiles ->
            // copy collected files to destination directory
            repositoryFiles.each { id, files ->
                def directory = moduleDirectory(id)
                GFileUtils.mkdirs(directory)
                files.each { File file -> GFileUtils.copyFile(file, new File(directory, file.name)) }
            }
        }
    }

    // configurations
    private Set<Configuration> getConfigurations() {
        Set<Configuration> configurations = []

        if (this.getConfigurationNames()) {
            def configurationNames = this.getConfigurationNames()

            logger.trace("Trying to resolve the following project configurations: '${configurationNames.join(",")}'")

            configurationNames.each { name ->
                try {
                    configurations.add(project.configurations.getByName(name))
                } catch (UnknownConfigurationException e) {
                    logger.warn("Unable to resolve project configuration with name '${name}'")
                }
            }
        } else {
            logger.trace("No project configurations specified, defaulting to all configurations")
            configurations.addAll(project.configurations)
        }

        if (this.getIncludeBuildscriptDependencies()) {
            if (this.getBuildscriptConfigurationNames()) {
                def configurationNames = this.getBuildscriptConfigurationNames()

                logger.trace("Trying to resolve the following buildscript configurations: '${configurationNames.join(",")}'")

                configurationNames.each { name ->
                    try {
                        configurations.add(project.buildscript.configurations.getByName(name))
                    } catch (UnknownConfigurationException e) {
                        logger.warn("Unable to resolve buildscript configuration with name '${name}'")
                    }
                }
            } else {
                logger.trace("No buildscript configurations specified, defaulting to all configurations")
                configurations.addAll(project.buildscript.configurations)
            }
        } else {
            logger.trace("Skipping buildscript configurations")
        }

        if (!configurations) {
            logger.warn('No configurations found. There are no dependencies to resolve.')
        }

        return configurations
    }

    // collect everything
    private Map<ModuleComponentIdentifier, Set<File>> collectRepositoryFiles(Set<Configuration> configurations) {
        Set<ModuleComponentIdentifier> componentIds = []
        Map<ModuleComponentIdentifier, Set<File>> repositoryFiles = [:]

        for (configuration in configurations) {
            for (dependency in configuration.allDependencies) {
                if (dependency instanceof ExternalModuleDependency) {

                    // create a detached configuration for each dependency to get all declared versions of a dependency.
                    // resolution would fetch only the newest otherwise.
                    //
                    // see:
                    // * http://stackoverflow.com/questions/29374885/multiple-version-of-dependencies-in-gradle
                    // * https://discuss.gradle.org/t/how-to-get-multiple-versions-of-the-same-library/7400
                    def cfg = project.configurations.detachedConfiguration([dependency].toArray(EMPTY_DEPENDENCIES_ARRAY))

                    cfg.resolvedConfiguration.resolvedArtifacts.forEach({ artifact ->
                        def componentId = DefaultModuleComponentIdentifier.newId(DefaultModuleIdentifier.newId(artifact.moduleVersion.id.group, artifact.moduleVersion.id.name), artifact.moduleVersion.id.version)

                        componentIds.add(componentId)
                        logger.trace("Adding artifact for component'{}' (location '{}')", componentId, artifact.file)
                        addToMultimap(repositoryFiles, componentId, artifact.file)
                    });
                }
            }
        }
        // collect sources and javadocs
        if (this.getIncludeSources() || this.getIncludeJavadocs()) {
            def jvmArtifacts = project.dependencies.createArtifactResolutionQuery()
                    .forComponents(componentIds)
                    .withArtifacts(JvmLibrary, SourcesArtifact, JavadocArtifact)
                    .execute()

            for (component in jvmArtifacts.resolvedComponents) {
                if (this.getIncludeSources()) {
                    def sources = component.getArtifacts(SourcesArtifact)
                    if (!sources?.empty) {
                        sources*.file.each { File source ->
                            logger.trace("Adding sources for component'{}' (location '{}')", component.id, source)
                            addToMultimap(repositoryFiles, component.id, source)
                        }
                    }
                }

                if (this.getIncludeJavadocs()) {
                    def javadocs = component.getArtifacts(JavadocArtifact)
                    if (!javadocs?.empty) {
                        javadocs*.file.each { File javadoc ->
                            logger.trace("Adding javadocs for component'{}' (location '{}')", component.id, javadoc)
                            addToMultimap(repositoryFiles, component.id, javadoc)
                        }
                    }
                }
            }
        }

        // collect maven poms (for immediate component ids and parents)
        if (this.getIncludePoms()) {
            collectPoms(componentIds, repositoryFiles)
        }

        // collect ivy xml files
        if (this.getIncludeIvyXmls()) {
            collectIvyXmls(componentIds, repositoryFiles)
        }

        return repositoryFiles
    }

    // adds pom artifacts and their parents for the givens component ids
    private void collectPoms(Set<ComponentIdentifier> componentIds, Map<ComponentIdentifier, Set<File>> repositoryFiles) {
        logger.trace("Collecting pom files")

        def mavenArtifacts = project.dependencies.createArtifactResolutionQuery()
                .forComponents(componentIds)
                .withArtifacts(MavenModule, MavenPomArtifact)
                .execute()

        def pomModelResolver = new PomDependencyModelResolver(project)

        for (component in mavenArtifacts.resolvedComponents) {
            def poms = component.getArtifacts(MavenPomArtifact)
            if (poms?.empty) {
                continue
            }

            def pomArtifact = poms.first()

            if (pomArtifact instanceof UnresolvedArtifactResult) {
                logger.error("Resolver was unable to resolve artifact '{}'", pomArtifact.id, pomArtifact.getFailure())
                continue
            }

            def pomFile = pomArtifact.file as File
            resolvePom(pomModelResolver, pomFile)

            logger.trace("Adding pom for component'{}' (location '{}')", component.id, pomFile)
            addToMultimap(repositoryFiles, component.id, pomFile)
        }

        pomModelResolver.componentCache().each { componentId, pomFile ->
            addToMultimap(repositoryFiles, componentId, pomFile)
        }
    }

    private Model resolvePom(PomDependencyModelResolver pomModelResolver, File pomFile) {
        def modelBuildingRequest = new DefaultModelBuildingRequest();
        modelBuildingRequest.setSystemProperties(System.getProperties())
        modelBuildingRequest.setModelSource(new FileModelSource(pomFile))
        modelBuildingRequest.setModelResolver(pomModelResolver)

        try {
            def modelBuilder = new DefaultModelBuilderFactory().newInstance()

            def modelInterpolator = new StringSearchModelInterpolator()
            modelInterpolator.setUrlNormalizer(new DefaultUrlNormalizer())
            modelInterpolator.setPathTranslator(new DefaultPathTranslator())

            modelBuilder.setModelInterpolator(modelInterpolator)
            modelBuilder.setModelValidator(new DefaultModelValidator())

            def result = modelBuilder.build(modelBuildingRequest)

            if (!result.problems.empty) {
                result.problems.each { this.logModelProblems(it) }
            }

            return result.effectiveModel
        } catch (ModelBuildingException e) {
            logger.error("${e.getMessage()}: ${e.problems}")
        }
    }

    protected void logModelProblems(ModelProblem problem) {
        def message = "$problem.modelId: $problem.message"

        switch (problem.severity) {
            case ModelProblem.Severity.WARNING:
                logger.info(message, problem.exception);
                break;

            case ModelProblem.Severity.ERROR:
            case ModelProblem.Severity.FATAL:
                logger.error(message, problem.exception);
                break;
        }
    }

    private void collectIvyXmls(Set<ComponentIdentifier> componentIds, Map<ComponentIdentifier, Set<File>> repositoryFiles) {
        logger.trace("Collecting ivy xml files")

        def ivyArtifacts = project.dependencies.createArtifactResolutionQuery()
                .forComponents(componentIds)
                .withArtifacts(IvyModule, IvyDescriptorArtifact)
                .execute()

        for (component in ivyArtifacts.resolvedComponents) {
            def ivyXmls = component.getArtifacts(IvyDescriptorArtifact)

            if (ivyXmls?.empty) {
                continue
            }

            def ivyXmlArtifact = ivyXmls.first()

            if (ivyXmlArtifact instanceof UnresolvedArtifactResult) {
                logger.error("Resolver was unable to resolve artifact '{}'", ivyXmlArtifact.id, ivyXmlArtifact.getFailure())
                continue
            }

            def ivyXml = ivyXmlArtifact.file as File
            logger.trace("Adding ivy artifact for component'{}' (location '{}')", component.id, ivyXml)
            addToMultimap(repositoryFiles, component.id, ivyXml)
        }
    }

    // Activate online repositories and collect dependencies.
    // Switch back to local repository afterwards.
    private def withRepositoryFiles(Closure<Map<ModuleComponentIdentifier, Set<File>>> callback) {
        def originalRepositories = project.repositories.collect()

        project.repositories.clear()

        OfflineDependenciesExtension extension =
                project.extensions.getByName(OfflineDependenciesPlugin.EXTENSION_NAME) as OfflineDependenciesExtension

        project.repositories.addAll(extension.repositoryHandler)

        def files = collectRepositoryFiles(getConfigurations())

        project.repositories.clear()
        project.repositories.addAll(originalRepositories)

        callback(files)
    }

    // Return the offline-repository target directory for the given component (naming follows maven conventions)
    protected File moduleDirectory(ModuleComponentIdentifier ci) {
        new File("${getRoot()}".toString(), "${ci.group.tokenize(".").join("/")}/${ci.module}/${ci.version}")
    }
}