/*

 * AboutOss is a utility library to retrieve and display

 * opensource licenses in Android applications.

 *

 * Copyright (C) 2023 by Frederic-Charles Barthelery.

 *

 * This file is part of AboutOss.

 *

 * AboutOss is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * AboutOss is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with AboutOss.  If not, see <http://www.gnu.org/licenses/>.

 */

package com.geekorum.build

import com.android.build.api.variant.ApplicationAndroidComponentsExtension

import com.android.build.api.variant.BuildConfigField

import com.android.build.api.variant.VariantOutputConfiguration.OutputType

import org.gradle.api.DefaultTask

import org.gradle.api.Project

import org.gradle.api.file.RegularFileProperty

import org.gradle.api.provider.Property

import org.gradle.api.tasks.Input

import org.gradle.api.tasks.OutputFile

import org.gradle.api.tasks.TaskAction

import org.gradle.configurationcache.extensions.capitalized

import org.gradle.kotlin.dsl.register

import org.gradle.process.ExecOperations

import java.io.ByteArrayOutputStream

import java.io.File

import javax.inject.Inject

internal fun ExecOperations.getGitSha1(projectDir: File): String? = runCommand("git rev-parse HEAD", workingDir = projectDir)?.trim()

internal fun ExecOperations.getHgSha1(projectDir: File): String? = runCommand("hg id --debug -i -r .", workingDir = projectDir)?.trim()

internal fun ExecOperations.getHgLocalRevisionNumber(projectDir: File): String? = runCommand("hg id -n -r .", workingDir = projectDir)?.trim()

private fun ExecOperations.getChangeSet(projectDir: File): String {

    val git = File(projectDir, ".git")

    val hg = File(projectDir, ".hg")

    return when {

        git.exists() -> "git:${getGitSha1(projectDir)}"

        hg.exists() -> "hg:${getHgSha1(projectDir)}"

        else -> "unknown"

    }

}

/**

 * Compute a version code following this format : MmmPBBB

 * M is major, mm is minor, P is patch

 * BBB is build version number from hg

 */

private fun ExecOperations.computeChangesetVersionCode(projectDir: File, major: Int = 0, minor: Int = 0, patch: Int = 0): Int {

    val base = (major * 1000000) + (minor * 10000) + (patch * 1000)

    return base + (getHgLocalRevisionNumber(projectDir)?.trim()?.toIntOrNull() ?: 0)

}

private fun ExecOperations.runCommand(

    command: String,

    workingDir: File = File(".")

): String? {

    val output = ByteArrayOutputStream()

    val result = exec {

        commandLine(command.split("\\s".toRegex()))

        setWorkingDir(workingDir)

        setStandardOutput(output)

        setErrorOutput(output)

    }

    result.rethrowFailure()

    return output.toString(Charsets.UTF_8)

}

abstract class VersionCodeTask : DefaultTask() {

    @get:OutputFile

    abstract val versionCodeOutputFile: RegularFileProperty

    @get:OutputFile

    abstract val changesetOutputFile: RegularFileProperty

    @get:Input

    abstract val repositoryDirectory: Property<String>

    @get:Input

    abstract val major: Property<Int>

    @get:Input

    abstract val minor: Property<Int>

    @get:Input

    abstract val patch: Property<Int>

    @get:Inject

    abstract val exec: ExecOperations

    @TaskAction

    fun computeVersionCode() {

        val projectDir = File(repositoryDirectory.get())

        val versionCode = exec.computeChangesetVersionCode(projectDir, major.getOrElse(0), minor.getOrElse(0), patch.getOrElse(0))

        versionCodeOutputFile.get().asFile.writeText("$versionCode")

    }

    @TaskAction

    fun computeChangeset() {

        val projectDir = File(repositoryDirectory.get())

        val changeset = exec.getChangeSet(projectDir)

        changesetOutputFile.get().asFile.writeText(changeset)

    }

}

/**

 * @param versionNameSuffix extra string to add to version name

 */

fun ApplicationAndroidComponentsExtension.configureVersionChangeset(project: Project, major: Int, minor: Int, patch: Int, versionNameSuffix: String = "") {

    // Note: Everything in there is incubating.

    // onVariantProperties registers an action that configures variant properties during

    // variant computation (which happens during afterEvaluate)

    onVariants {

        // Because app module can have multiple output when using mutli-APK, versionCode/Name

        // are only available on the variant output.

        // Here gather the output when we are in single mode (ie no multi-apk)

        val mainOutput = it.outputs.single { it.outputType == OutputType.SINGLE }

        // create version Code generating task

        val versionCodeTask = project.tasks.register<VersionCodeTask>("computeVersionCodeFor${it.name.capitalized()}") {

            this.major.set(major)

            this.minor.set(minor)

            this.patch.set(patch)

            repositoryDirectory.set(project.rootDir.absolutePath)

            versionCodeOutputFile.set(project.layout.buildDirectory.file("intermediates/versionCode.txt"))

            changesetOutputFile.set(project.layout.buildDirectory.file("intermediates/changeset.txt"))

        }

        // wire version code from the task output

        // map will create a lazy Provider that

        // 1. runs just before the consumer(s), ensuring that the producer (VersionCodeTask) has run

        //    and therefore the file is created.

        // 2. contains task dependency information so that the consumer(s) run after the producer.

        mainOutput.versionCode.set(versionCodeTask.map { it.versionCodeOutputFile.get().asFile.readText().toInt() })

        mainOutput.versionName.set("$major.$minor.$patch$versionNameSuffix")

        it.buildConfigFields.put("REPOSITORY_CHANGESET", versionCodeTask.map {

            BuildConfigField("String", "\"${it.changesetOutputFile.get().asFile.readText()}\"", "Repository changeset")

        })

    }

}