/*
 * Copyright 2018 The Bazel Authors. All rights reserved.
 *
 * 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 io.bazel.kotlin.builder.tasks.jvm

import com.google.devtools.build.lib.view.proto.Deps
import io.bazel.kotlin.builder.toolchain.CompilationException
import io.bazel.kotlin.builder.toolchain.CompilationStatusException
import io.bazel.kotlin.builder.toolchain.KotlinToolchain
import io.bazel.kotlin.builder.utils.joinedClasspath
import io.bazel.kotlin.builder.utils.resolveVerified
import io.bazel.kotlin.builder.utils.rootCause
import io.bazel.kotlin.model.JvmCompilationTask
import java.io.ByteArrayOutputStream
import java.io.FileOutputStream
import java.io.PrintWriter
import java.nio.file.Files
import java.nio.file.Paths
import javax.inject.Inject
import javax.inject.Singleton

@Singleton
internal class JDepsGenerator @Inject constructor(
    toolchain: KotlinToolchain,
    private val invoker: KotlinToolchain.JDepsInvoker
) {
    private val isKotlinImplicit = JdepsParser.pathSuffixMatchingPredicate(
        toolchain.kotlinHome.resolveVerified("lib").toPath(), *toolchain.kotlinStandardLibraries.toTypedArray()
    )

    fun generateJDeps(command: JvmCompilationTask) {
        val jdepsContent =
            if (command.inputs.classpathList.isEmpty()) {
                Deps.Dependencies.newBuilder().let {
                    it.ruleLabel = command.info.label
                    it.build()
                }
            } else {
                ByteArrayOutputStream().use { out ->
                    PrintWriter(out).use { writer ->
                        val joinedClasspath = command.inputs.joinedClasspath
                        val res = invoker.run(
                            arrayOf(
                                "-cp", joinedClasspath,
                                command.outputs.jdeps
                            ),
                            writer
                        )
                        out.toByteArray().inputStream().bufferedReader().readLines().let {
                            if (res != 0) {
                                throw CompilationStatusException("could not run jdeps tool", res, it)
                            }
                            try {
                                JdepsParser.parse(
                                    command.info.label,
                                    command.outputs.jdeps,
                                    command.inputs.classpathList,
                                    it,
                                    isKotlinImplicit
                                )
                            } catch (e: Exception) {
                                throw CompilationException("error reading or parsing jdeps file", e.rootCause)
                            }
                        }
                    }
                }
            }
        Paths.get(command.outputs.jdeps).also {
            Files.deleteIfExists(it)
            FileOutputStream(Files.createFile(it).toFile()).use(jdepsContent::writeTo)
        }
    }
}