// Copyright (C) 2021 The Android Open Source Project
//
// 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 aidl

import (
	"android/soong/android"
	"android/soong/genrule"

	"path/filepath"
	"strings"

	"github.com/google/blueprint"
	"github.com/google/blueprint/pathtools"
	"github.com/google/blueprint/proptools"
)

var (
	aidlDirPrepareRule = pctx.StaticRule("aidlDirPrepareRule", blueprint.RuleParams{
		Command: `rm -rf "${outDir}" && mkdir -p "${outDir}" && ` +
			`touch ${out} # ${in}`,
		Description: "create ${out}",
	}, "outDir")

	aidlCppRule = pctx.StaticRule("aidlCppRule", blueprint.RuleParams{
		Command: `mkdir -p "${headerDir}" && ` +
			`${aidlCmd} --lang=${lang} ${optionalFlags} --structured --ninja -d ${out}.d ` +
			`-h ${headerDir} -o ${outDir} ${imports} ${in}`,
		Depfile:     "${out}.d",
		Deps:        blueprint.DepsGCC,
		CommandDeps: []string{"${aidlCmd}"},
		Description: "AIDL ${lang} ${in}",
	}, "imports", "lang", "headerDir", "outDir", "optionalFlags")

	aidlJavaRule = pctx.StaticRule("aidlJavaRule", blueprint.RuleParams{
		Command: `${aidlCmd} --lang=java ${optionalFlags} --structured --ninja -d ${out}.d ` +
			`-o ${outDir} ${imports} ${in}`,
		Depfile:     "${out}.d",
		Deps:        blueprint.DepsGCC,
		CommandDeps: []string{"${aidlCmd}"},
		Description: "AIDL Java ${in}",
	}, "imports", "outDir", "optionalFlags")

	aidlRustRule = pctx.StaticRule("aidlRustRule", blueprint.RuleParams{
		Command: `${aidlCmd} --lang=rust ${optionalFlags} --structured --ninja -d ${out}.d ` +
			`-o ${outDir} ${imports} ${in}`,
		Depfile:     "${out}.d",
		Deps:        blueprint.DepsGCC,
		CommandDeps: []string{"${aidlCmd}"},
		Description: "AIDL Rust ${in}",
	}, "imports", "outDir", "optionalFlags")
)

type aidlGenProperties struct {
	Srcs                  []string `android:"path"`
	AidlRoot              string   // base directory for the input aidl file
	IsToT                 bool
	ImportsWithoutVersion []string
	Stability             *string
	Lang                  string // target language [java|cpp|ndk|rust]
	BaseName              string
	GenLog                bool
	Version               string
	GenTrace              bool
	Unstable              *bool
	Visibility            []string
	Flags                 []string
}

type aidlGenRule struct {
	android.ModuleBase

	properties aidlGenProperties

	implicitInputs android.Paths
	importFlags    string

	// TODO(b/149952131): always have a hash file
	hashFile android.Path

	genOutDir     android.ModuleGenPath
	genHeaderDir  android.ModuleGenPath
	genHeaderDeps android.Paths
	genOutputs    android.WritablePaths
}

var _ android.SourceFileProducer = (*aidlGenRule)(nil)
var _ genrule.SourceFileGenerator = (*aidlGenRule)(nil)

func (g *aidlGenRule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
	srcs, imports := getPaths(ctx, g.properties.Srcs, g.properties.AidlRoot)

	if ctx.Failed() {
		return
	}

	genDirTimestamp := android.PathForModuleGen(ctx, "timestamp") // $out/gen/timestamp
	g.implicitInputs = append(g.implicitInputs, genDirTimestamp)

	importPaths, implicits := getImportsFromDeps(ctx, g.properties.IsToT)
	imports = append(imports, importPaths...)

	g.importFlags = strings.Join(wrap("-I", imports, ""), " ")

	g.genOutDir = android.PathForModuleGen(ctx)
	g.genHeaderDir = android.PathForModuleGen(ctx, "include")
	for _, src := range srcs {
		outFile, headers := g.generateBuildActionsForSingleAidl(ctx, src)
		g.genOutputs = append(g.genOutputs, outFile)
		g.genHeaderDeps = append(g.genHeaderDeps, headers...)
	}

	// This is to clean genOutDir before generating any file
	ctx.Build(pctx, android.BuildParams{
		Rule:      aidlDirPrepareRule,
		Implicits: implicits,
		Inputs:    srcs,
		Output:    genDirTimestamp,
		Args: map[string]string{
			"outDir": g.genOutDir.String(),
		},
	})

	// This is to trigger genrule alone
	ctx.Build(pctx, android.BuildParams{
		Rule:   android.Phony,
		Output: android.PathForModuleOut(ctx, "timestamp"), // $out/timestamp
		Inputs: g.genOutputs.Paths(),
	})
}

func (g *aidlGenRule) generateBuildActionsForSingleAidl(ctx android.ModuleContext, src android.Path) (android.WritablePath, android.Paths) {
	baseDir := getBaseDir(ctx, src, android.PathForModuleSrc(ctx, g.properties.AidlRoot))

	var ext string
	if g.properties.Lang == langJava {
		ext = "java"
	} else if g.properties.Lang == langRust {
		ext = "rs"
	} else {
		ext = "cpp"
	}
	relPath, _ := filepath.Rel(baseDir, src.String())
	outFile := android.PathForModuleGen(ctx, pathtools.ReplaceExtension(relPath, ext))
	implicits := g.implicitInputs

	optionalFlags := append([]string{}, g.properties.Flags...)
	if g.properties.Version != "" {
		optionalFlags = append(optionalFlags, "--version "+g.properties.Version)

		hash := "notfrozen"
		if !strings.HasPrefix(baseDir, ctx.Config().BuildDir()) {
			hashFile := android.ExistentPathForSource(ctx, baseDir, ".hash")
			if hashFile.Valid() {
				hash = "$$(read -r <" + hashFile.Path().String() + " hash extra; printf '%s' \"$$hash\")"
				implicits = append(implicits, hashFile.Path())

				g.hashFile = hashFile.Path()
			}
		}
		optionalFlags = append(optionalFlags, "--hash "+hash)
	}
	if g.properties.GenTrace {
		optionalFlags = append(optionalFlags, "-t")
	}
	if g.properties.Stability != nil {
		optionalFlags = append(optionalFlags, "--stability", *g.properties.Stability)
	}

	var headers android.WritablePaths
	if g.properties.Lang == langJava {
		ctx.Build(pctx, android.BuildParams{
			Rule:      aidlJavaRule,
			Input:     src,
			Implicits: implicits,
			Output:    outFile,
			Args: map[string]string{
				"imports":       g.importFlags,
				"outDir":        g.genOutDir.String(),
				"optionalFlags": strings.Join(optionalFlags, " "),
			},
		})
	} else if g.properties.Lang == langRust {
		ctx.Build(pctx, android.BuildParams{
			Rule:      aidlRustRule,
			Input:     src,
			Implicits: implicits,
			Output:    outFile,
			Args: map[string]string{
				"imports":       g.importFlags,
				"outDir":        g.genOutDir.String(),
				"optionalFlags": strings.Join(optionalFlags, " "),
			},
		})
	} else {
		typeName := strings.TrimSuffix(filepath.Base(relPath), ".aidl")
		packagePath := filepath.Dir(relPath)
		baseName := typeName
		// TODO(b/111362593): aidl_to_cpp_common.cpp uses heuristics to figure out if
		//   an interface name has a leading I. Those same heuristics have been
		//   moved here.
		if len(baseName) >= 2 && baseName[0] == 'I' &&
			strings.ToUpper(baseName)[1] == baseName[1] {
			baseName = strings.TrimPrefix(typeName, "I")
		}

		prefix := ""
		if g.properties.Lang == langNdk || g.properties.Lang == langNdkPlatform {
			prefix = "aidl"
		}

		headers = append(headers, g.genHeaderDir.Join(ctx, prefix, packagePath,
			typeName+".h"))
		headers = append(headers, g.genHeaderDir.Join(ctx, prefix, packagePath,
			"Bp"+baseName+".h"))
		headers = append(headers, g.genHeaderDir.Join(ctx, prefix, packagePath,
			"Bn"+baseName+".h"))

		if g.properties.GenLog {
			optionalFlags = append(optionalFlags, "--log")
		}

		aidlLang := g.properties.Lang
		if aidlLang == langNdkPlatform {
			aidlLang = "ndk"
		}

		ctx.Build(pctx, android.BuildParams{
			Rule:            aidlCppRule,
			Input:           src,
			Implicits:       implicits,
			Output:          outFile,
			ImplicitOutputs: headers,
			Args: map[string]string{
				"imports":       g.importFlags,
				"lang":          aidlLang,
				"headerDir":     g.genHeaderDir.String(),
				"outDir":        g.genOutDir.String(),
				"optionalFlags": strings.Join(optionalFlags, " "),
			},
		})
	}

	return outFile, headers.Paths()
}

func (g *aidlGenRule) GeneratedSourceFiles() android.Paths {
	return g.genOutputs.Paths()
}

func (g *aidlGenRule) Srcs() android.Paths {
	return g.genOutputs.Paths()
}

func (g *aidlGenRule) GeneratedDeps() android.Paths {
	return g.genHeaderDeps
}

func (g *aidlGenRule) GeneratedHeaderDirs() android.Paths {
	return android.Paths{g.genHeaderDir}
}

func (g *aidlGenRule) DepsMutator(ctx android.BottomUpMutatorContext) {
	// original interface
	ctx.AddDependency(ctx.Module(), interfaceDep, g.properties.BaseName+aidlInterfaceSuffix)

	if !proptools.Bool(g.properties.Unstable) {
		// for checkapi timestamps
		ctx.AddDependency(ctx.Module(), apiDep, g.properties.BaseName+aidlApiSuffix)
	}

	// imported interfaces
	ctx.AddDependency(ctx.Module(), importInterfaceDep, wrap("", g.properties.ImportsWithoutVersion, aidlInterfaceSuffix)...)

	ctx.AddReverseDependency(ctx.Module(), nil, aidlMetadataSingletonName)
}

func aidlGenFactory() android.Module {
	g := &aidlGenRule{}
	g.AddProperties(&g.properties)
	android.InitAndroidModule(g)
	return g
}