return sequenceOf(directory)
    }

    private
    fun someClassesInDefaultPackage(): Sequence<Path> {
        val directory = projectDir.resolve("classes-default")

        DEFAULT_EXCLUDES_FOR_TEST.forEachIndexed { i, pkg ->
            touchFile(directory.resolve("$pkg/Foo$i.class"))
        }

        return sequenceOf(directory)
    }

    private

    val implementationClass: String
)


private
fun pluginExtensionsFrom(jars: Iterable<File>): Sequence<PluginExtension> =
    jars.asSequence().flatMap(::pluginExtensionsFrom)


private
fun pluginExtensionsFrom(file: File): Sequence<PluginExtension> =
    pluginEntriesFrom(file)
        .asSequence()
        .map { (id, implementationClass) ->
            val simpleId = id.substringAfter("org.gradle.")

        }

    private
    fun sourceNamesFromJar(jar: File): Sequence<String> =
        openJarFile(jar).run {
            entries().asSequence()
                .filter { it.name.isClassFilePath }
                .map { kotlinSourceNameOf(it.name) }
        }

    private
    fun sourceNamesFromDir(dir: File): Sequence<String> =
        dir.walkTopDown()
            .filter { it.name.isClassFilePath }

        isolatedClassLoaderFor(classpath).use { loader ->
            javaProjectBuilderFor(loader)
                .sequenceOfJavaSourcesFrom(sources)
                .flatMap { it.classes.asSequence().filter { it.isPublic } }
                .flatMap { it.methods.asSequence().filter { it.isPublic && it.parameterTypes.isNotEmpty() } }
                .map { method -> fullyQualifiedSignatureOf(method) to commaSeparatedParameterNamesOf(method) }

    }

    private
    fun groovyProjectAccessors(): String {
        val objectMethods = Any::class.java.declaredMethods.toList()
        return Project::class
            .memberFunctions
            .asSequence()
            .mapNotNull { it.javaMethod }
            .filterNot { objectMethods.contains(it) }
            .map { it.toGroovyScriptString() }
            .sorted()
            .joinToString(separator = "\n")

data class PluginEntry(val pluginId: String, val implementationClass: String)


fun pluginEntriesFrom(jar: File): List<PluginEntry> = try {
    JarFile(jar, false).use { jarFile ->
        jarFile.entries().asSequence().filter {
            isGradlePluginPropertiesFile(it)
        }.map { pluginEntry ->
            val pluginProperties = jarFile.getInputStream(pluginEntry).use { Properties().apply { load(it) } }

            }
        }
    }

    /**
     * @return the source file and it's source root
     */
    fun sourceFileAndSourceRootFor(sourceFilePath: String): Pair<File, File> =
        sourceRoots.asSequence()
            .map { it.resolve(sourceFilePath) to it }
            .firstOrNull { it.first.isFile }