/*
 * Copyright (c) 2024 The GoPlus Authors (goplus.org). 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 ssa

import (
	"go/constant"
	"go/types"

	"github.com/goplus/llvm"
	"golang.org/x/tools/go/types/typeutil"
)

// -----------------------------------------------------------------------------

// InitFlags is a set of flags for initializing the LLVM library.
type InitFlags int

const (
	InitNativeTarget InitFlags = 1 << iota
	InitAllTargets
	InitAllTargetInfos
	InitAllTargetMCs

	InitNativeAsmPrinter
	InitAllAsmPrinters

	InitAllAsmParsers

	InitNative = InitNativeTarget | InitNativeAsmPrinter
	InitAll    = InitAllTargets | InitAllAsmParsers | InitAllAsmPrinters | InitAllTargetInfos | InitAllTargetMCs
)

// Initialize initializes the LLVM library.
func Initialize(flags InitFlags) {
	if flags&InitAllTargetInfos != 0 {
		llvm.InitializeAllTargetInfos()
	}
	if flags&InitAllTargets != 0 {
		llvm.InitializeAllTargets()
	}
	if flags&InitAllTargetMCs != 0 {
		llvm.InitializeAllTargetMCs()
	}
	if flags&InitAllAsmParsers != 0 {
		llvm.InitializeAllAsmParsers()
	}
	if flags&InitAllAsmPrinters != 0 {
		llvm.InitializeAllAsmPrinters()
	}
	if flags&InitNativeTarget != 0 {
		llvm.InitializeNativeTarget()
	}
	if flags&InitNativeAsmPrinter != 0 {
		llvm.InitializeNativeAsmPrinter()
	}
}

// -----------------------------------------------------------------------------

type aProgram struct {
	ctx  llvm.Context
	typs typeutil.Map

	target *Target
	td     llvm.TargetData
	// tm  llvm.TargetMachine

	intType   llvm.Type
	int1Type  llvm.Type
	int8Type  llvm.Type
	int16Type llvm.Type
	int32Type llvm.Type
	int64Type llvm.Type
	voidType  llvm.Type
	voidPtrTy llvm.Type

	voidTy Type
	boolTy Type
	intTy  Type
	f64Ty  Type
}

// A Program presents a program.
type Program = *aProgram

// NewProgram creates a new program.
func NewProgram(target *Target) Program {
	if target == nil {
		target = &Target{}
	}
	ctx := llvm.NewContext()
	ctx.Finalize()
	td := llvm.NewTargetData("") // TODO(xsw): target config
	return &aProgram{ctx: ctx, target: target, td: td}
}

// NewPackage creates a new package.
func (p Program) NewPackage(name, pkgPath string) Package {
	mod := p.ctx.NewModule(pkgPath)
	mod.Finalize()
	return &aPackage{mod, p}
}

// Void returns void type.
func (p Program) Void() Type {
	if p.voidTy == nil {
		p.voidTy = &aType{p.tyVoid(), types.Typ[types.Invalid], vkInvalid}
	}
	return p.voidTy
}

// Bool returns bool type.
func (p Program) Bool() Type {
	if p.boolTy == nil {
		p.boolTy = p.llvmType(types.Typ[types.Bool])
	}
	return p.boolTy
}

// Int returns int type.
func (p Program) Int() Type {
	if p.intTy == nil {
		p.intTy = p.llvmType(types.Typ[types.Int])
	}
	return p.intTy
}

// Float64 returns float64 type.
func (p Program) Float64() Type {
	if p.f64Ty == nil {
		p.f64Ty = p.llvmType(types.Typ[types.Float64])
	}
	return p.f64Ty
}

// -----------------------------------------------------------------------------

// A Package is a single analyzed Go package containing Members for
// all package-level functions, variables, constants and types it
// declares.  These may be accessed directly via Members, or via the
// type-specific accessor methods Func, Type, Var and Const.
//
// Members also contains entries for "init" (the synthetic package
// initializer) and "init#%d", the nth declared init function,
// and unspecified other things too.
type aPackage struct {
	mod  llvm.Module
	prog Program
}

type Package = *aPackage

func (p Package) NewConst(name string, val constant.Value) NamedConst {
	return &aNamedConst{}
}

// NewVar creates a new global variable.
func (p Package) NewVar(name string, typ types.Type) Global {
	t := p.prog.llvmType(typ)
	gbl := llvm.AddGlobal(p.mod, t.ll, name)
	return &aGlobal{Expr{gbl, t}}
}

// NewFunc creates a new function.
func (p Package) NewFunc(name string, sig *types.Signature) Function {
	t := p.prog.llvmSignature(sig)
	fn := llvm.AddFunction(p.mod, name, t.ll)
	return newFunction(fn, t, p.prog)
}

// String returns a string representation of the package.
func (p Package) String() string {
	return p.mod.String()
}

/*
type CodeGenFileType = llvm.CodeGenFileType

const (
	AssemblyFile = llvm.AssemblyFile
	ObjectFile   = llvm.ObjectFile
)

func (p *Package) CodeGen(ft CodeGenFileType) (ret []byte, err error) {
	buf, err := p.prog.targetMachine().EmitToMemoryBuffer(p.mod, ft)
	if err != nil {
		return
	}
	ret = buf.Bytes()
	buf.Dispose()
	return
}

func (p *Package) Bitcode() []byte {
	buf := llvm.WriteBitcodeToMemoryBuffer(p.mod)
	ret := buf.Bytes()
	buf.Dispose()
	return ret
}

func (p *Package) WriteTo(w io.Writer) (int64, error) {
	n, err := w.Write(p.Bitcode())
	return int64(n), err
}

func (p *Package) WriteFile(file string) (err error) {
	f, err := os.Create(file)
	if err != nil {
		return
	}
	defer f.Close()
	return llvm.WriteBitcodeToFile(p.mod, f)
}
*/

// -----------------------------------------------------------------------------