/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you 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.
 */

import org.apache.tools.ant.taskdefs.condition.Os
import org.elasticsearch.gradle.LoggedExec
import org.elasticsearch.gradle.Version
import org.elasticsearch.gradle.VersionCollection

import java.nio.charset.StandardCharsets

import static org.elasticsearch.gradle.BuildPlugin.getJavaHome

/**
 *  We want to be able to do BWC tests for unreleased versions without relying on and waiting for snapshots.
 *  For this we need to check out and build the unreleased versions.
 *  Since These depend on the current version, we can't name the Gradle projects statically, and don't know what the
 *  unreleased versions are when Gradle projects are set up, so we use "build-unreleased-version-*" as placeholders
 *  and configure them to build various versions here.
 */
bwcVersions.forPreviousUnreleased { VersionCollection.UnreleasedVersionInfo unreleasedVersion -> project("${project.path}:${unreleasedVersion.gradleProjectName}") {
    Version bwcVersion = unreleasedVersion.version
    String bwcBranch = unreleasedVersion.branch
    apply plugin: 'distribution'
    // Not published so no need to assemble
    assemble.enabled = false

    File checkoutDir = file("${buildDir}/bwc/checkout-${bwcBranch}")

    final String remote = System.getProperty("tests.bwc.remote", "elastic")

    boolean gitFetchLatest
    final String gitFetchLatestProperty = System.getProperty("tests.bwc.git_fetch_latest", "true")
    if ("true".equals(gitFetchLatestProperty)) {
        gitFetchLatest = true
    } else if ("false".equals(gitFetchLatestProperty)) {
        gitFetchLatest = false
    } else {
        throw new GradleException("tests.bwc.git_fetch_latest must be [true] or [false] but was [" + gitFetchLatestProperty + "]")
    }

    task createClone(type: LoggedExec) {
        onlyIf { checkoutDir.exists() == false }
        commandLine = ['git', 'clone', rootDir, checkoutDir]
    }

    task findRemote(type: LoggedExec) {
        dependsOn createClone
        workingDir = checkoutDir
        commandLine = ['git', 'remote', '-v']
        ByteArrayOutputStream output = new ByteArrayOutputStream()
        standardOutput = output
        doLast {
            project.ext.remoteExists = false
            output.toString('UTF-8').eachLine {
                if (it.contains("${remote}\t")) {
                    project.ext.remoteExists = true
                }
            }
        }
    }

    task addRemote(type: LoggedExec) {
        dependsOn findRemote
        onlyIf { project.ext.remoteExists == false }
        workingDir = checkoutDir
        commandLine = ['git', 'remote', 'add', "${remote}", "https://github.com/${remote}/elasticsearch.git"]
    }

    task fetchLatest(type: LoggedExec) {
        onlyIf { project.gradle.startParameter.isOffline() == false && gitFetchLatest }
        dependsOn addRemote
        workingDir = checkoutDir
        commandLine = ['git', 'fetch', '--all']
    }

    String buildMetadataKey = "bwc_refspec_${project.path.substring(1)}"
    task checkoutBwcBranch(type: LoggedExec) {
        String refspec = System.getProperty("tests.bwc.refspec.${bwcBranch}", buildMetadata.get(buildMetadataKey, "${remote}/${bwcBranch}"))
        dependsOn fetchLatest
        workingDir = checkoutDir
        commandLine = ['git', 'checkout', refspec]
        doFirst {
            println "Checking out elasticsearch ${refspec} for branch ${bwcBranch}"
        }
    }

    File buildMetadataFile = project.file("build/${project.name}/build_metadata")
    task writeBuildMetadata(type: LoggedExec) {
        dependsOn checkoutBwcBranch
        workingDir = checkoutDir
        commandLine = ['git', 'rev-parse', 'HEAD']
        ignoreExitValue = true
        ByteArrayOutputStream output = new ByteArrayOutputStream()
        standardOutput = output
        doLast {
            if (execResult.exitValue != 0) {
                output.toString('UTF-8').eachLine { line -> logger.error(line) }
                execResult.assertNormalExitValue()
            }
            project.mkdir(buildMetadataFile.parent)
            String commit = output.toString('UTF-8')
            buildMetadataFile.setText("${buildMetadataKey}=${commit}", 'UTF-8')
            println "Checked out elasticsearch commit ${commit}"
        }
    }

    Map<String, File> artifactFiles = [:]
    List<String> projectDirs = []
    List<String> projects = ['deb', 'rpm']
    if (bwcVersion.onOrAfter('7.0.0')) {
      projects.addAll(['windows-zip', 'darwin-tar', 'linux-tar'])
    } else {
      projects.add('zip')
    }

    for (String projectName : projects) {
        String baseDir = "distribution"
        String classifier = ""
        String extension = projectName
        if (bwcVersion.onOrAfter('7.0.0') && (projectName.contains('zip') || projectName.contains('tar'))) {
          int index = projectName.indexOf('-')
          classifier = "-${projectName.substring(0, index)}-x86_64"
          extension = projectName.substring(index + 1)
          if (extension.equals('tar')) {
            extension += '.gz'
          }
        }
        if (bwcVersion.onOrAfter('7.0.0') && projectName.contains('deb')) {
          classifier = "-amd64"
        }
        if (bwcVersion.onOrAfter('7.0.0') && projectName.contains('rpm')) {
          classifier = "-x86_64"
        }
        if (bwcVersion.onOrAfter('6.3.0')) {
            baseDir += projectName.endsWith('zip') || projectName.endsWith('tar') ? '/archives' : '/packages'
            // add oss variant first
            projectDirs.add("${baseDir}/oss-${projectName}")
            artifactFiles.put("oss-" + projectName, file("${checkoutDir}/${baseDir}/oss-${projectName}/build/distributions/elasticsearch-oss-${bwcVersion}-SNAPSHOT${classifier}.${extension}"))
        }
        projectDirs.add("${baseDir}/${projectName}")
        artifactFiles.put(projectName,
                file("${checkoutDir}/${baseDir}/${projectName}/build/distributions/elasticsearch-${bwcVersion}-SNAPSHOT${classifier}.${extension}"))
    }
    
    Closure createRunBwcGradleTask = { name, extraConfig ->
        task "$name"(type: Exec) {
            dependsOn checkoutBwcBranch, writeBuildMetadata
            workingDir = checkoutDir
            doFirst {
                // Execution time so that the checkouts are available
                List<String> lines = file("${checkoutDir}/.ci/java-versions.properties").readLines()
                environment(
                        'JAVA_HOME',
                        getJavaHome(it, Integer.parseInt(
                                lines
                                        .findAll({ it.startsWith("ES_BUILD_JAVA=java") })
                                        .collect({ it.replace("ES_BUILD_JAVA=java", "").trim() })
                                        .join("!!")
                        ))
                )
                environment(
                        'RUNTIME_JAVA_HOME',
                        getJavaHome(it, Integer.parseInt(
                                lines
                                        .findAll({ it.startsWith("ES_RUNTIME_JAVA=java") })
                                        .collect({ it.replace("ES_RUNTIME_JAVA=java", "").trim() })
                                        .join("!!")
                        ))
                )
            }

            if (Os.isFamily(Os.FAMILY_WINDOWS)) {
                executable 'cmd'
                args '/C', 'call', new File(checkoutDir, 'gradlew').toString()
            } else {
                executable new File(checkoutDir, 'gradlew').toString()
            }
            if (gradle.startParameter.isOffline()) {
                args "--offline"
            }

            args "-Dbuild.snapshot=true"
            final LogLevel logLevel = gradle.startParameter.logLevel
            if ([LogLevel.QUIET, LogLevel.WARN, LogLevel.INFO, LogLevel.DEBUG].contains(logLevel)) {
                args "--${logLevel.name().toLowerCase(Locale.ENGLISH)}"
            }
            final String showStacktraceName = gradle.startParameter.showStacktrace.name()
            assert ["INTERNAL_EXCEPTIONS", "ALWAYS", "ALWAYS_FULL"].contains(showStacktraceName)
            if (showStacktraceName.equals("ALWAYS")) {
                args "--stacktrace"
            } else if (showStacktraceName.equals("ALWAYS_FULL")) {
                args "--full-stacktrace"
            }
            standardOutput = new IndentingOutputStream(System.out, bwcVersion)
            errorOutput = new IndentingOutputStream(System.err, bwcVersion)
            configure extraConfig
        }
    }

    createRunBwcGradleTask("buildBwcVersion") {
        for (String dir : projectDirs) {
            args ":${dir.replace('/', ':')}:assemble"
        }
        doLast {
            List missing = artifactFiles.values().grep { file ->
                false == file.exists()
            }
            if (false == missing.empty) {
                throw new InvalidUserDataException("Building ${bwcVersion} didn't generate expected files ${missing}")
            }
        }
    }

    createRunBwcGradleTask("resolveAllBwcDependencies") {
        args 'resolveAllDependencies'
    }

    resolveAllDependencies.dependsOn resolveAllBwcDependencies

    for (e in artifactFiles) {
        String projectName = e.key
        File artifactFile = e.value
        String artifactFileName = artifactFile.name
        String artifactName = artifactFileName.contains('oss') ? 'elasticsearch-oss' : 'elasticsearch'
        String suffix = artifactFile.toString()[-3..-1]
        int archIndex = artifactFileName.indexOf('x86_64')
        String classifier = ''
        if (archIndex != -1) {
            int osIndex = artifactFileName.lastIndexOf('-', archIndex - 2)
            classifier = "${artifactFileName.substring(osIndex + 1, archIndex - 1)}-x86_64"
        }
        configurations.create(projectName)
        artifacts {
            it.add(projectName, [file: artifactFile, name: artifactName, classifier: classifier, type: suffix, builtBy: buildBwcVersion])
        }
    }
    // make sure no dependencies were added to assemble; we want it to be a no-op
    assemble.dependsOn = []
}}

class IndentingOutputStream extends OutputStream {

    public final byte[] indent
    private final OutputStream delegate

    public IndentingOutputStream(OutputStream delegate, Object version) {
        this.delegate = delegate
        indent = " [${version}] ".getBytes(StandardCharsets.UTF_8)
    }

    @Override
    public void write(int b) {
        write([b] as int[], 0, 1)
    }

    public void write(int[] bytes, int offset, int length) {
        for (int i = 0; i < bytes.length; i++) {
            delegate.write(bytes[i])
            if (bytes[i] == '\n') {
                delegate.write(indent)
            }
        }
    }
}