//
// OCCAM
//
// Copyright (c) 2017, SRI International
//
//  All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice, this
//   list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
//
// * Neither the name of SRI International nor the names of its contributors may
//   be used to endorse or promote products derived from this software without
//   specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//

package shared

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"path"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"
)

type parserResult struct {
	InputList        []string
	InputFiles       []string
	ObjectFiles      []string
	OutputFilename   string
	CompileArgs      []string
	LinkArgs         []string
	IsVerbose        bool
	IsDependencyOnly bool
	IsPreprocessOnly bool
	IsAssembleOnly   bool
	IsAssembly       bool
	IsCompileOnly    bool
	IsEmitLLVM       bool
	IsPrintOnly      bool
}

type flagInfo struct {
	arity   int
	handler func(string, []string)
}

func skipBitcodeGeneration(pr parserResult) bool {
	if LLVMConfigureOnly != "" {
		return true
	}
	if len(pr.InputFiles) == 0 ||
		pr.IsEmitLLVM ||
		pr.IsAssembly ||
		pr.IsAssembleOnly ||
		(pr.IsDependencyOnly && !pr.IsCompileOnly) ||
		pr.IsPreprocessOnly ||
		pr.IsPrintOnly {
		return true
	}
	return false

}

func parse(argList []string) parserResult {
	var pr = parserResult{}
	pr.InputList = argList

	var argsExactMatches = map[string]flagInfo{
		"-":  {0, pr.printOnlyCallback},
		"-o": {1, pr.outputFileCallback},
		"-c": {0, pr.compileOnlyCallback},
		"-E": {0, pr.preprocessOnlyCallback},
		"-S": {0, pr.assembleOnlyCallback},

		"--verbose": {0, pr.verboseFlagCallback},
		"--param":   {1, pr.defaultBinaryCallback},
		"-aux-info": {1, pr.defaultBinaryCallback},

		"--version": {0, pr.compileOnlyCallback},
		"-v":        {0, pr.compileOnlyCallback},

		"-w": {0, pr.compileOnlyCallback},
		"-W": {0, pr.compileOnlyCallback},

		"-emit-llvm": {0, pr.emitLLVMCallback},

		"-pipe":              {0, pr.compileUnaryCallback},
		"-undef":             {0, pr.compileUnaryCallback},
		"-nostdinc":          {0, pr.compileUnaryCallback},
		"-nostdinc++":        {0, pr.compileUnaryCallback},
		"-Qunused-arguments": {0, pr.compileUnaryCallback},
		"-no-integrated-as":  {0, pr.compileUnaryCallback},
		"-integrated-as":     {0, pr.compileUnaryCallback},

		"-pthread":     {0, pr.compileUnaryCallback},
		"-nostdlibinc": {0, pr.compileUnaryCallback},

		"-mno-omit-leaf-frame-pointer": {0, pr.compileUnaryCallback},
		"-maes":           {0, pr.compileUnaryCallback},
		"-mno-aes":        {0, pr.compileUnaryCallback},
		"-mavx":           {0, pr.compileUnaryCallback},
		"-mno-avx":        {0, pr.compileUnaryCallback},
		"-mavx2":          {0, pr.compileUnaryCallback},
		"-mno-avx2":       {0, pr.compileUnaryCallback},
		"-mcmodel=kernel": {0, pr.compileUnaryCallback},
		"-mno-red-zone":   {0, pr.compileUnaryCallback},
		"-mmmx":           {0, pr.compileUnaryCallback},
		"-mno-mmx":        {0, pr.compileUnaryCallback},
		"-msse":           {0, pr.compileUnaryCallback},
		"-mno-sse":        {0, pr.compileUnaryCallback},
		"-msse2":          {0, pr.compileUnaryCallback},
		"-mno-sse2":       {0, pr.compileUnaryCallback},
		"-msse3":          {0, pr.compileUnaryCallback},
		"-mno-sse3":       {0, pr.compileUnaryCallback},
		"-mssse3":         {0, pr.compileUnaryCallback},
		"-mno-ssse3":      {0, pr.compileUnaryCallback},
		"-msse4":          {0, pr.compileUnaryCallback},
		"-mno-sse4":       {0, pr.compileUnaryCallback},
		"-msse4.1":        {0, pr.compileUnaryCallback},
		"-mno-sse4.1":     {0, pr.compileUnaryCallback},
		"-msse4.2":        {0, pr.compileUnaryCallback},
		"-mno-sse4.2":     {0, pr.compileUnaryCallback},
		"-msoft-float":    {0, pr.compileUnaryCallback},
		"-m3dnow":         {0, pr.compileUnaryCallback},
		"-mno-3dnow":      {0, pr.compileUnaryCallback},
		"-m32":            {0, pr.compileUnaryCallback},
		"-m64":            {0, pr.compileUnaryCallback},
		"-mstackrealign":  {0, pr.compileUnaryCallback},

		"-A": {1, pr.compileBinaryCallback},
		"-D": {1, pr.compileBinaryCallback},
		"-U": {1, pr.compileBinaryCallback},

		"-M":   {0, pr.dependencyOnlyCallback},
		"-MM":  {0, pr.dependencyOnlyCallback},
		"-MF":  {1, pr.dependencyBinaryCallback},
		"-MG":  {0, pr.dependencyOnlyCallback},
		"-MP":  {0, pr.dependencyOnlyCallback},
		"-MT":  {1, pr.dependencyBinaryCallback},
		"-MQ":  {1, pr.dependencyBinaryCallback},
		"-MD":  {0, pr.dependencyOnlyCallback},
		"-MMD": {0, pr.dependencyOnlyCallback},

		"-I":                 {1, pr.compileBinaryCallback},
		"-idirafter":         {1, pr.compileBinaryCallback},
		"-include":           {1, pr.compileBinaryCallback},
		"-imacros":           {1, pr.compileBinaryCallback},
		"-iprefix":           {1, pr.compileBinaryCallback},
		"-iwithprefix":       {1, pr.compileBinaryCallback},
		"-iwithprefixbefore": {1, pr.compileBinaryCallback},
		"-isystem":           {1, pr.compileBinaryCallback},
		"-isysroot":          {1, pr.compileBinaryCallback},
		"-iquote":            {1, pr.compileBinaryCallback},
		"-imultilib":         {1, pr.compileBinaryCallback},

		"-ansi":     {0, pr.compileUnaryCallback},
		"-pedantic": {0, pr.compileUnaryCallback},
		"-x":        {1, pr.compileBinaryCallback},

		"-g":                 {0, pr.compileUnaryCallback},
		"-g0":                {0, pr.compileUnaryCallback},
		"-ggdb":              {0, pr.compileUnaryCallback},
		"-ggdb3":             {0, pr.compileUnaryCallback},
		"-gdwarf-2":          {0, pr.compileUnaryCallback},
		"-gdwarf-3":          {0, pr.compileUnaryCallback},
		"-gline-tables-only": {0, pr.compileUnaryCallback},

		"-p":  {0, pr.compileUnaryCallback},
		"-pg": {0, pr.compileUnaryCallback},

		"-O":     {0, pr.compileUnaryCallback},
		"-O0":    {0, pr.compileUnaryCallback},
		"-O1":    {0, pr.compileUnaryCallback},
		"-O2":    {0, pr.compileUnaryCallback},
		"-O3":    {0, pr.compileUnaryCallback},
		"-Os":    {0, pr.compileUnaryCallback},
		"-Ofast": {0, pr.compileUnaryCallback},
		"-Og":    {0, pr.compileUnaryCallback},

		"-Xclang":        {1, pr.compileBinaryCallback},
		"-Xpreprocessor": {1, pr.defaultBinaryCallback},
		"-Xassembler":    {1, pr.defaultBinaryCallback},
		"-Xlinker":       {1, pr.defaultBinaryCallback},

		"-l": {1, pr.linkBinaryCallback},
		"-L": {1, pr.linkBinaryCallback},
		"-T": {1, pr.linkBinaryCallback},
		"-u": {1, pr.linkBinaryCallback},

		"-e":     {1, pr.linkBinaryCallback},
		"-rpath": {1, pr.linkBinaryCallback},

		"-shared":        {0, pr.linkUnaryCallback},
		"-static":        {0, pr.linkUnaryCallback},
		"-pie":           {0, pr.linkUnaryCallback},
		"-nostdlib":      {0, pr.linkUnaryCallback},
		"-nodefaultlibs": {0, pr.linkUnaryCallback},
		"-rdynamic":      {0, pr.linkUnaryCallback},

		"-dynamiclib":            {0, pr.linkUnaryCallback},
		"-current_version":       {1, pr.linkBinaryCallback},
		"-compatibility_version": {1, pr.linkBinaryCallback},

		"-print-multi-directory":  {0, pr.compileUnaryCallback},
		"-print-multi-lib":        {0, pr.compileUnaryCallback},
		"-print-libgcc-file-name": {0, pr.compileUnaryCallback},

		"-fprofile-arcs": {0, pr.compileLinkUnaryCallback},
		"-coverage":      {0, pr.compileLinkUnaryCallback},
		"--coverage":     {0, pr.compileLinkUnaryCallback},

		"-Wl,-dead_strip": {0, pr.darwinWarningLinkUnaryCallback},
	}

	var argPatterns = map[string]flagInfo{
		`^.+\.(c|cc|cpp|C|cxx|i|s|S|bc)$`:       {0, pr.inputFileCallback},
		`^.+\.([fF](|[0-9][0-9]|or|OR|pp|PP))$`: {0, pr.inputFileCallback},
		`^.+\.(o|lo|So|so|po|a|dylib)$`:         {0, pr.objectFileCallback},
		`^.+\.dylib(\.\d)+$`:                    {0, pr.objectFileCallback},
		`^.+\.(So|so)(\.\d)+$`:                  {0, pr.objectFileCallback},
		`^-(l|L).+$`:                            {0, pr.linkUnaryCallback},
		`^-I.+$`:                                {0, pr.compileUnaryCallback},
		`^-D.+$`:                                {0, pr.compileUnaryCallback},
		`^-U.+$`:                                {0, pr.compileUnaryCallback},
		`^-Wl,.+$`:                              {0, pr.linkUnaryCallback},
		`^-W[^l].*$`:                            {0, pr.compileUnaryCallback},
		`^-f.+$`:                                {0, pr.compileUnaryCallback},
		`^-rtlib=.+$`:                           {0, pr.linkUnaryCallback},
		`^-std=.+$`:                             {0, pr.compileUnaryCallback},
		`^-stdlib=.+$`:                          {0, pr.compileLinkUnaryCallback},
		`^-mtune=.+$`:                           {0, pr.compileUnaryCallback},
		`^--sysroot=.+$`:                        {0, pr.compileUnaryCallback},
		`^-print-prog-name=.*$`:                 {0, pr.compileUnaryCallback},
		`^-print-file-name=.*$`:                 {0, pr.compileUnaryCallback},
	}

	for len(argList) > 0 {
		var elem = argList[0]

		// Try to match the flag exactly
		if fi, ok := argsExactMatches[elem]; ok {
			fi.handler(elem, argList[1:1+fi.arity])
			argList = argList[1+fi.arity:]
			// Else try to match a pattern
		} else {
			var listShift = 0
			for pattern, fi := range argPatterns {
				var regExp = regexp.MustCompile(pattern)
				if regExp.MatchString(elem) {
					fi.handler(elem, argList[1:1+fi.arity])
					listShift = fi.arity
					break
				}
			}
			argList = argList[1+listShift:]
		}

	}
	return pr
}

// Return the object and bc filenames that correspond to the i-th source file
func getArtifactNames(pr parserResult, srcFileIndex int, hidden bool) (objBase string, bcBase string) {
	if len(pr.InputFiles) == 1 && pr.IsCompileOnly && len(pr.OutputFilename) > 0 {
		objBase = pr.OutputFilename
		dir, baseName := path.Split(objBase)
		bcBaseName := fmt.Sprintf(".%s.bc", baseName)
		bcBase = path.Join(dir, bcBaseName)
	} else {
		srcFile := pr.InputFiles[srcFileIndex]
		var _, baseNameWithExt = path.Split(srcFile)
		var baseName = strings.TrimSuffix(baseNameWithExt, filepath.Ext(baseNameWithExt))
		bcBase = fmt.Sprintf(".%s.o.bc", baseName)
		if hidden {
			objBase = fmt.Sprintf(".%s.o", baseName)
		} else {
			objBase = fmt.Sprintf("%s.o", baseName)
		}
	}
	return
}

// Return a hash for the absolute object path
func getHashedPath(path string) string {
	inputBytes := []byte(path)
	hasher := sha256.New()
	//Hash interface claims this never returns an error
	hasher.Write(inputBytes)
	hash := hex.EncodeToString(hasher.Sum(nil))
	return hash
}

func (pr *parserResult) inputFileCallback(flag string, _ []string) {
	var regExp = regexp.MustCompile(`\.(s|S)$`)
	pr.InputFiles = append(pr.InputFiles, flag)
	if regExp.MatchString(flag) {
		pr.IsAssembly = true
	}
}

func (pr *parserResult) outputFileCallback(_ string, args []string) {
	pr.OutputFilename = args[0]
}

func (pr *parserResult) objectFileCallback(flag string, _ []string) {
	// FIXME: the object file is appended to ObjectFiles that
	// is used nowhere else in the code
	pr.ObjectFiles = append(pr.ObjectFiles, flag)
	// We append the object files to link args to handle the
	// -Wl,--start-group obj_1.o ... obj_n.o -Wl,--end-group case
	pr.LinkArgs = append(pr.LinkArgs, flag)
}

func (pr *parserResult) preprocessOnlyCallback(_ string, _ []string) {
	pr.IsPreprocessOnly = true
}

func (pr *parserResult) dependencyOnlyCallback(flag string, _ []string) {
	pr.IsDependencyOnly = true
	pr.CompileArgs = append(pr.CompileArgs, flag)
}

func (pr *parserResult) printOnlyCallback(flag string, _ []string) {
	pr.IsPrintOnly = true
}

func (pr *parserResult) assembleOnlyCallback(_ string, _ []string) {
	pr.IsAssembleOnly = true
}

func (pr *parserResult) verboseFlagCallback(_ string, _ []string) {
	pr.IsVerbose = true
}

func (pr *parserResult) compileOnlyCallback(_ string, _ []string) {
	pr.IsCompileOnly = true
}

func (pr *parserResult) emitLLVMCallback(_ string, _ []string) {
	pr.IsCompileOnly = true
	pr.IsEmitLLVM = true
}

func (pr *parserResult) linkUnaryCallback(flag string, _ []string) {
	pr.LinkArgs = append(pr.LinkArgs, flag)
}

func (pr *parserResult) compileUnaryCallback(flag string, _ []string) {
	pr.CompileArgs = append(pr.CompileArgs, flag)
}

func (pr *parserResult) darwinWarningLinkUnaryCallback(flag string, _ []string) {
	if runtime.GOOS == osDARWIN {
		fmt.Println("The flag", flag, "cannot be used with this tool.")
	} else {
		pr.LinkArgs = append(pr.LinkArgs, flag)
	}
}

func (pr *parserResult) defaultBinaryCallback(_ string, _ []string) {
	// Do nothing
}

func (pr *parserResult) dependencyBinaryCallback(flag string, args []string) {
	pr.CompileArgs = append(pr.CompileArgs, flag, args[0])
	pr.IsDependencyOnly = true
}

func (pr *parserResult) compileBinaryCallback(flag string, args []string) {
	pr.CompileArgs = append(pr.CompileArgs, flag, args[0])
}

func (pr *parserResult) linkBinaryCallback(flag string, args []string) {
	pr.LinkArgs = append(pr.LinkArgs, flag, args[0])
}

func (pr *parserResult) compileLinkUnaryCallback(flag string, _ []string) {
	pr.LinkArgs = append(pr.LinkArgs, flag)
	pr.CompileArgs = append(pr.CompileArgs, flag)
}