import org.gradle.plugins.ide.eclipse.model.SourceFolder


def snowballVersion = '3.0.1'
def snowballArchiveName = "libstemmer_java-${snowballVersion}.tar.gz"
def snowballDistributionDirectoryName = "libstemmer_java-${snowballVersion}"
def snowballRootRelativePath = 'third-party/snowball'
def snowballSourceRelativePath = "${snowballRootRelativePath}/source"
def snowballJavaSourceRelativePath = "${snowballSourceRelativePath}/${snowballDistributionDirectoryName}/java"
def snowballGeneratedSourceRelativePath = 'generated/sources/snowball'
def snowballDownloadUrl = "https://snowballstem.org/dist/${snowballArchiveName}"
def snowballDownloadFile = layout.buildDirectory.file("${snowballRootRelativePath}/${snowballArchiveName}")
def snowballExtractDirectory = layout.buildDirectory.dir(snowballSourceRelativePath)
def snowballJavaSourceDirectory = layout.buildDirectory.dir(snowballJavaSourceRelativePath)
def snowballGeneratedSourceDirectory = layout.buildDirectory.dir(snowballGeneratedSourceRelativePath)
def snowballJavaSourceClasspathPath = provider {
    project.relativePath(snowballJavaSourceDirectory.get().asFile)
}
def snowballGeneratedSourceClasspathPath = provider {
    project.relativePath(snowballGeneratedSourceDirectory.get().asFile)
}
def transformSnowballSourceText = { final String sourceText ->
    String transformedText = sourceText

    transformedText = transformedText.replaceAll(/(?m)^\s*package\s+org\.tartarus\.snowball\.ext\s*;/,
            'package org.egothor.stemmer.benchmark.snowball.ext;')
    transformedText = transformedText.replaceAll(/(?m)^\s*package\s+org\.tartarus\.snowball\s*;/,
            'package org.egothor.stemmer.benchmark.snowball;')
    transformedText = transformedText.replace('org.tartarus.snowball.', 'org.egothor.stemmer.benchmark.snowball.')

    return transformedText
}
def copySnowballSourcesWithPackageIsolation = { final File sourceDirectory, final File targetDirectory ->
    final FileTree sourceFiles = fileTree(sourceDirectory).matching { include '**/*.java' }
    if (targetDirectory.exists()) {
        targetDirectory.deleteDir()
    }

    for (File sourceFile : sourceFiles.files) {
        final String relativePath = sourceDirectory.toPath().relativize(sourceFile.toPath()).toString()
        final File outputFile = new File(targetDirectory, relativePath)
        outputFile.parentFile.mkdirs()
        outputFile.text = transformSnowballSourceText(sourceFile.getText('UTF-8'))
    }
}

def snowballEclipseClasspathAttributes = [
        gradle_scope        : 'jmh',
        gradle_used_by_scope: 'jmh',
        test                : 'true'
]
def isAbsoluteClasspathPath = { String path ->
    path.startsWith('/') || path ==~ /^[A-Za-z]:[\\\/].*/
}

tasks.register('downloadSnowballJava') {
    group = 'build setup'
    description = 'Downloads the official Snowball Java source distribution for benchmark-only use.'

    outputs.file(snowballDownloadFile)

    doLast {
        File targetFile = snowballDownloadFile.get().asFile
        targetFile.parentFile.mkdirs()

        if (!targetFile.exists()) {
            new URL(snowballDownloadUrl).withInputStream { inputStream ->
                targetFile.withOutputStream { outputStream ->
                    outputStream << inputStream
                }
            }
        }
    }
}

tasks.register('extractSnowballJava', Copy) {
    group = 'build setup'
    description = 'Extracts the official Snowball Java source distribution.'

    dependsOn(tasks.named('downloadSnowballJava'))

    from(tarTree(resources.gzip(snowballDownloadFile)))
    into(snowballExtractDirectory)
}

tasks.register('generateIsolatedSnowballSources') {
    group = 'build setup'
    description = 'Copies Snowball source to benchmark-only package-isolated package paths.'

    dependsOn(tasks.named('extractSnowballJava'))

    inputs.dir(snowballJavaSourceDirectory)
    outputs.dir(snowballGeneratedSourceDirectory)

    doLast {
        copySnowballSourcesWithPackageIsolation(
                snowballJavaSourceDirectory.get().asFile,
                snowballGeneratedSourceDirectory.get().asFile
        )
    }
}

sourceSets {
    jmh {
        java {
            srcDir(snowballGeneratedSourceDirectory)
        }
    }
}

tasks.named('compileJmhJava') {
    dependsOn(tasks.named('generateIsolatedSnowballSources'))
}

eclipse {
    classpath {
        file {
            whenMerged { classpath ->
                String generatedSnowballPath = snowballJavaSourceClasspathPath.get()
                String generatedIsolatedSnowballPath = snowballGeneratedSourceClasspathPath.get()
                String modelSnowballPath = snowballJavaSourceRelativePath

                classpath.entries.removeAll { entry ->
                    entry.hasProperty('path') && (
                            entry.path == generatedSnowballPath ||
                            entry.path == generatedIsolatedSnowballPath ||
                            entry.path == modelSnowballPath ||
                            isAbsoluteClasspathPath(entry.path)
                    )
                }

                SourceFolder snowballEntry = new SourceFolder(generatedIsolatedSnowballPath, null)
                snowballEntry.output = 'bin/jmh'
                snowballEclipseClasspathAttributes.each { String name, String value ->
                    snowballEntry.entryAttributes[name] = value
                }

                classpath.entries.add(snowballEntry)
            }
        }
    }
}