// Copyright 2017 Google Inc. 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 java

import (
	"fmt"
	"io"
	"strings"

	"github.com/google/blueprint"

	"android/soong/android"
)

// OpenJDK 9 introduces the concept of "system modules", which replace the bootclasspath.  This
// file will produce the rules necessary to convert each unique set of bootclasspath jars into
// system modules in a runtime image using the jmod and jlink tools.

func init() {
	android.RegisterModuleType("java_system_modules", SystemModulesFactory)

	pctx.SourcePathVariable("moduleInfoJavaPath", "build/soong/scripts/jars-to-module-info-java.sh")
}

var (
	jarsTosystemModules = pctx.AndroidStaticRule("jarsTosystemModules", blueprint.RuleParams{
		Command: `rm -rf ${outDir} ${workDir} && mkdir -p ${workDir}/jmod && ` +
			`${moduleInfoJavaPath} ${moduleName} $in > ${workDir}/module-info.java && ` +
			`${config.JavacCmd} --system=none --patch-module=java.base=${classpath} ${workDir}/module-info.java && ` +
			`${config.SoongZipCmd} -jar -o ${workDir}/classes.jar -C ${workDir} -f ${workDir}/module-info.class && ` +
			`${config.MergeZipsCmd} -j ${workDir}/module.jar ${workDir}/classes.jar $in && ` +
			`${config.JmodCmd} create --module-version 9 --target-platform android ` +
			`  --class-path ${workDir}/module.jar ${workDir}/jmod/${moduleName}.jmod && ` +
			`${config.JlinkCmd} --module-path ${workDir}/jmod --add-modules ${moduleName} --output ${outDir} && ` +
			`cp ${config.JrtFsJar} ${outDir}/lib/`,
		CommandDeps: []string{
			"${moduleInfoJavaPath}",
			"${config.JavacCmd}",
			"${config.SoongZipCmd}",
			"${config.MergeZipsCmd}",
			"${config.JmodCmd}",
			"${config.JlinkCmd}",
			"${config.JrtFsJar}",
		},
	},
		"moduleName", "classpath", "outDir", "workDir")
)

func TransformJarsToSystemModules(ctx android.ModuleContext, moduleName string, jars android.Paths) android.WritablePath {
	outDir := android.PathForModuleOut(ctx, "system")
	workDir := android.PathForModuleOut(ctx, "modules")
	outputFile := android.PathForModuleOut(ctx, "system/lib/modules")
	outputs := android.WritablePaths{
		outputFile,
		android.PathForModuleOut(ctx, "system/lib/jrt-fs.jar"),
		android.PathForModuleOut(ctx, "system/release"),
	}

	ctx.Build(pctx, android.BuildParams{
		Rule:        jarsTosystemModules,
		Description: "system modules",
		Outputs:     outputs,
		Inputs:      jars,
		Args: map[string]string{
			"moduleName": moduleName,
			"classpath":  strings.Join(jars.Strings(), ":"),
			"workDir":    workDir.String(),
			"outDir":     outDir.String(),
		},
	})

	return outputFile
}

func SystemModulesFactory() android.Module {
	module := &SystemModules{}
	module.AddProperties(&module.properties)
	android.InitAndroidArchModule(module, android.HostAndDeviceSupported, android.MultilibCommon)
	return module
}

type SystemModules struct {
	android.ModuleBase

	properties SystemModulesProperties

	outputFile android.Path
}

type SystemModulesProperties struct {
	// List of java library modules that should be included in the system modules
	Libs []string

	// List of prebuilt jars that should be included in the system modules
	Jars []string

	// Sdk version that should be included in the system modules
	Sdk_version *string
}

func (system *SystemModules) GenerateAndroidBuildActions(ctx android.ModuleContext) {
	var jars android.Paths

	ctx.VisitDirectDeps(func(module android.Module) {
		if ctx.OtherModuleDependencyTag(module) == libTag {
			dep, _ := module.(Dependency)
			jars = append(jars, dep.HeaderJars()...)
		}
	})

	jars = append(jars, android.PathsForModuleSrc(ctx, system.properties.Jars)...)

	if ctx.AConfig().TargetOpenJDK9() {
		system.outputFile = TransformJarsToSystemModules(ctx, "java.base", jars)
	}
}

func (system *SystemModules) DepsMutator(ctx android.BottomUpMutatorContext) {
	ctx.AddDependency(ctx.Module(), libTag, system.properties.Libs...)
}

func (system *SystemModules) AndroidMk() android.AndroidMkData {
	return android.AndroidMkData{
		Custom: func(w io.Writer, name, prefix, moduleDir string, data android.AndroidMkData) {
			if system.outputFile != nil {
				makevar := "SOONG_SYSTEM_MODULES_" + name
				fmt.Fprintln(w)
				fmt.Fprintln(w, makevar, ":=", system.outputFile.String())
				fmt.Fprintln(w, ".KATI_READONLY", ":=", makevar)
				fmt.Fprintln(w, name+":", "$("+makevar+")")
			}
		},
	}
}