// Copyright 2020 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 android

import (
	"fmt"
	"os"
	"strings"

	"github.com/google/blueprint"
)

// The Bazel QueryView singleton is responsible for generating the Ninja actions
// for calling the soong_build primary builder in the main build.ninja file.
func init() {
	RegisterSingletonType("bazel_queryview", BazelQueryViewSingleton)
}

// BazelQueryViewSingleton is the singleton responsible for registering the
// soong_build build statement that will convert the Soong module graph after
// applying *all* mutators, enabing the feature to query the final state of the
// Soong graph. This mode is meant for querying the build graph state, and not meant
// for generating BUILD files to be checked in.
func BazelQueryViewSingleton() Singleton {
	return &bazelQueryViewSingleton{}
}

// BazelConverterSingleton is the singleton responsible for registering the soong_build
// build statement that will convert the Soong module graph by applying an alternate
// pipeline of mutators, with the goal of reaching semantic equivalence between the original
// Blueprint and final BUILD files. Using this mode, the goal is to be able to
// build with these BUILD files directly in the source tree.
func BazelConverterSingleton() Singleton {
	return &bazelConverterSingleton{}
}

type bazelQueryViewSingleton struct{}
type bazelConverterSingleton struct{}

func generateBuildActionsForBazelConversion(ctx SingletonContext, converterMode bool) {
	name := "queryview"
	descriptionTemplate := "[EXPERIMENTAL, PRE-PRODUCTION] Creating the Bazel QueryView workspace with %s at $outDir"

	// Create a build and rule statement, using the Bazel QueryView's WORKSPACE
	// file as the output file marker.
	var deps Paths
	moduleListFilePath := pathForBuildToolDep(ctx, ctx.Config().moduleListFile)
	deps = append(deps, moduleListFilePath)
	deps = append(deps, pathForBuildToolDep(ctx, ctx.Config().ProductVariablesFileName))

	bazelQueryViewDirectory := PathForOutput(ctx, name)
	bazelQueryViewWorkspaceFile := bazelQueryViewDirectory.Join(ctx, "WORKSPACE")
	primaryBuilder := primaryBuilderPath(ctx)
	bazelQueryView := ctx.Rule(pctx, "bazelQueryView",
		blueprint.RuleParams{
			Command: fmt.Sprintf(
				`rm -rf "${outDir}/"* && `+
					`mkdir -p "${outDir}" && `+
					`echo WORKSPACE: $$(cat "%s") > "${outDir}/.queryview-depfile.d" && `+
					`BUILDER="%s" && `+
					`echo BUILDER=$$BUILDER && `+
					`cd "$$(dirname "$$BUILDER")" && `+
					`echo PWD=$$PWD && `+
					`ABSBUILDER="$$PWD/$$(basename "$$BUILDER")" && `+
					`echo ABSBUILDER=$$ABSBUILDER && `+
					`cd / && `+
					`env -i "$$ABSBUILDER" --bazel_queryview_dir "${outDir}" "%s"`,
				moduleListFilePath.String(), // Use the contents of Android.bp.list as the depfile.
				primaryBuilder.String(),
				strings.Join(os.Args[1:], "\" \""),
			),
			CommandDeps: []string{primaryBuilder.String()},
			Description: fmt.Sprintf(
				descriptionTemplate,
				primaryBuilder.Base()),
			Deps:    blueprint.DepsGCC,
			Depfile: "${outDir}/.queryview-depfile.d",
		},
		"outDir")

	ctx.Build(pctx, BuildParams{
		Rule:   bazelQueryView,
		Output: bazelQueryViewWorkspaceFile,
		Inputs: deps,
		Args: map[string]string{
			"outDir": bazelQueryViewDirectory.String(),
		},
	})

	// Add a phony target for generating the workspace
	ctx.Phony(name, bazelQueryViewWorkspaceFile)
}

func (c *bazelQueryViewSingleton) GenerateBuildActions(ctx SingletonContext) {
	generateBuildActionsForBazelConversion(ctx, false)
}

func (c *bazelConverterSingleton) GenerateBuildActions(ctx SingletonContext) {
	generateBuildActionsForBazelConversion(ctx, true)
}