// Copyright 2014 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 bootstrap

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"runtime"
	"runtime/debug"
	"runtime/pprof"
	"runtime/trace"

	"github.com/google/blueprint"
	"github.com/google/blueprint/deptools"
)

type Args struct {
	OutFile                  string
	GlobFile                 string
	DepFile                  string
	DocFile                  string
	Cpuprofile               string
	Memprofile               string
	TraceFile                string
	RunGoTests               bool
	UseValidations           bool
	NoGC                     bool
	EmptyNinjaFile           bool
	BuildDir                 string
	ModuleListFile           string
	NinjaBuildDir            string
	TopFile                  string
	GeneratingPrimaryBuilder bool
}

var (
	cmdline   Args
	absSrcDir string
)

func CmdlineOutFile() string {
	return cmdline.OutFile
}

// Returns the build dir as parsed from the command line. This is necessary
// because even though these flags are defined here, soong_build accesses them.
// The plan is to move these flags to soong_build.
func CmdlineBuildDir() string {
	return cmdline.BuildDir
}

// Returns the module list file as parsed from the command line. This is necessary
// because even though these flags are defined here, soong_build accesses them.
// The plan is to move these flags to soong_build.
func CmdlineModuleListFile() string {
	return cmdline.ModuleListFile
}

func init() {
	flag.StringVar(&cmdline.OutFile, "o", "build.ninja", "the Ninja file to output")
	flag.StringVar(&cmdline.GlobFile, "globFile", "build-globs.ninja", "the Ninja file of globs to output")
	flag.StringVar(&cmdline.BuildDir, "b", ".", "the build output directory")
	flag.StringVar(&cmdline.NinjaBuildDir, "n", "", "the ninja builddir directory")
	flag.StringVar(&cmdline.DepFile, "d", "", "the dependency file to output")
	flag.StringVar(&cmdline.DocFile, "docs", "", "build documentation file to output")
	flag.StringVar(&cmdline.Cpuprofile, "cpuprofile", "", "write cpu profile to file")
	flag.StringVar(&cmdline.TraceFile, "trace", "", "write trace to file")
	flag.StringVar(&cmdline.Memprofile, "memprofile", "", "write memory profile to file")
	flag.BoolVar(&cmdline.NoGC, "nogc", false, "turn off GC for debugging")
	flag.BoolVar(&cmdline.RunGoTests, "t", false, "build and run go tests during bootstrap")
	flag.BoolVar(&cmdline.UseValidations, "use-validations", false, "use validations to depend on go tests")
	flag.StringVar(&cmdline.ModuleListFile, "l", "", "file that lists filepaths to parse")
	flag.BoolVar(&cmdline.EmptyNinjaFile, "empty-ninja-file", false, "write out a 0-byte ninja file")
}

func Main(ctx *blueprint.Context, config interface{}, generatingPrimaryBuilder bool, extraNinjaFileDeps ...string) {
	if !flag.Parsed() {
		flag.Parse()
	}

	if flag.NArg() != 1 {
		fatalf("no Blueprints file specified")
	}

	cmdline.TopFile = flag.Arg(0)
	cmdline.GeneratingPrimaryBuilder = generatingPrimaryBuilder
	RunBlueprint(cmdline, ctx, config, extraNinjaFileDeps...)
}

func RunBlueprint(args Args, ctx *blueprint.Context, config interface{}, extraNinjaFileDeps ...string) {
	runtime.GOMAXPROCS(runtime.NumCPU())

	if args.NoGC {
		debug.SetGCPercent(-1)
	}

	absSrcDir = ctx.SrcDir()

	if args.Cpuprofile != "" {
		f, err := os.Create(absolutePath(args.Cpuprofile))
		if err != nil {
			fatalf("error opening cpuprofile: %s", err)
		}
		pprof.StartCPUProfile(f)
		defer f.Close()
		defer pprof.StopCPUProfile()
	}

	if args.TraceFile != "" {
		f, err := os.Create(absolutePath(args.TraceFile))
		if err != nil {
			fatalf("error opening trace: %s", err)
		}
		trace.Start(f)
		defer f.Close()
		defer trace.Stop()
	}

	srcDir := filepath.Dir(args.TopFile)

	if args.ModuleListFile != "" {
		ctx.SetModuleListFile(args.ModuleListFile)
		extraNinjaFileDeps = append(extraNinjaFileDeps, args.ModuleListFile)
	} else {
		fatalf("-l <moduleListFile> is required and must be nonempty")
	}
	filesToParse, err := ctx.ListModulePaths(srcDir)
	if err != nil {
		fatalf("could not enumerate files: %v\n", err.Error())
	}

	buildDir := args.BuildDir

	stage := StageMain
	if args.GeneratingPrimaryBuilder {
		stage = StagePrimary
	}

	bootstrapConfig := &Config{
		stage: stage,

		topLevelBlueprintsFile: args.TopFile,
		emptyNinjaFile:         args.EmptyNinjaFile,
		runGoTests:             args.RunGoTests,
		useValidations:         args.UseValidations,
		moduleListFile:         args.ModuleListFile,
	}

	ctx.RegisterBottomUpMutator("bootstrap_plugin_deps", pluginDeps)
	ctx.RegisterModuleType("bootstrap_go_package", newGoPackageModuleFactory(bootstrapConfig))
	ctx.RegisterModuleType("bootstrap_go_binary", newGoBinaryModuleFactory(bootstrapConfig, false))
	ctx.RegisterModuleType("blueprint_go_binary", newGoBinaryModuleFactory(bootstrapConfig, true))
	ctx.RegisterSingletonType("bootstrap", newSingletonFactory(bootstrapConfig))

	ctx.RegisterSingletonType("glob", globSingletonFactory(ctx))

	deps, errs := ctx.ParseFileList(filepath.Dir(bootstrapConfig.topLevelBlueprintsFile), filesToParse, config)
	if len(errs) > 0 {
		fatalErrors(errs)
	}

	// Add extra ninja file dependencies
	deps = append(deps, extraNinjaFileDeps...)

	extraDeps, errs := ctx.ResolveDependencies(config)
	if len(errs) > 0 {
		fatalErrors(errs)
	}
	deps = append(deps, extraDeps...)

	if args.DocFile != "" {
		err := writeDocs(ctx, config, absolutePath(args.DocFile))
		if err != nil {
			fatalErrors([]error{err})
		}
		return
	}

	if c, ok := config.(ConfigStopBefore); ok {
		if c.StopBefore() == StopBeforePrepareBuildActions {
			return
		}
	}

	extraDeps, errs = ctx.PrepareBuildActions(config)
	if len(errs) > 0 {
		fatalErrors(errs)
	}
	deps = append(deps, extraDeps...)

	if c, ok := config.(ConfigStopBefore); ok {
		if c.StopBefore() == StopBeforeWriteNinja {
			return
		}
	}

	const outFilePermissions = 0666
	var out io.StringWriter
	var f *os.File
	var buf *bufio.Writer

	if args.EmptyNinjaFile {
		if err := ioutil.WriteFile(absolutePath(args.OutFile), []byte(nil), outFilePermissions); err != nil {
			fatalf("error writing empty Ninja file: %s", err)
		}
	}

	if stage != StageMain || !args.EmptyNinjaFile {
		f, err = os.OpenFile(absolutePath(args.OutFile), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, outFilePermissions)
		if err != nil {
			fatalf("error opening Ninja file: %s", err)
		}
		buf = bufio.NewWriterSize(f, 16*1024*1024)
		out = buf
	} else {
		out = ioutil.Discard.(io.StringWriter)
	}

	if args.GlobFile != "" {
		buffer, errs := generateGlobNinjaFile(config, ctx.Globs)
		if len(errs) > 0 {
			fatalErrors(errs)
		}

		err = ioutil.WriteFile(absolutePath(args.GlobFile), buffer, outFilePermissions)
		if err != nil {
			fatalf("error writing %s: %s", args.GlobFile, err)
		}
	}

	if args.DepFile != "" {
		err := deptools.WriteDepFile(absolutePath(args.DepFile), args.OutFile, deps)
		if err != nil {
			fatalf("error writing depfile: %s", err)
		}
	}

	err = ctx.WriteBuildFile(out)
	if err != nil {
		fatalf("error writing Ninja file contents: %s", err)
	}

	if buf != nil {
		err = buf.Flush()
		if err != nil {
			fatalf("error flushing Ninja file contents: %s", err)
		}
	}

	if f != nil {
		err = f.Close()
		if err != nil {
			fatalf("error closing Ninja file: %s", err)
		}
	}

	if c, ok := config.(ConfigRemoveAbandonedFilesUnder); ok {
		under, except := c.RemoveAbandonedFilesUnder(buildDir)
		err := removeAbandonedFilesUnder(ctx, srcDir, buildDir, under, except)
		if err != nil {
			fatalf("error removing abandoned files: %s", err)
		}
	}

	if args.Memprofile != "" {
		f, err := os.Create(absolutePath(args.Memprofile))
		if err != nil {
			fatalf("error opening memprofile: %s", err)
		}
		defer f.Close()
		pprof.WriteHeapProfile(f)
	}
}

func fatalf(format string, args ...interface{}) {
	fmt.Printf(format, args...)
	fmt.Print("\n")
	os.Exit(1)
}

func fatalErrors(errs []error) {
	red := "\x1b[31m"
	unred := "\x1b[0m"

	for _, err := range errs {
		switch err := err.(type) {
		case *blueprint.BlueprintError,
			*blueprint.ModuleError,
			*blueprint.PropertyError:
			fmt.Printf("%serror:%s %s\n", red, unred, err.Error())
		default:
			fmt.Printf("%sinternal error:%s %s\n", red, unred, err)
		}
	}
	os.Exit(1)
}

func absolutePath(path string) string {
	if filepath.IsAbs(path) {
		return path
	}
	return filepath.Join(absSrcDir, path)
}