package main

import "go/constant"

type Node interface {
	Pos() Pos
	SetPos(Pos)
	aNode()
}

type node struct {
	pos Pos
}

func (n *node) Pos() Pos       { return n.pos }
func (n *node) SetPos(pos Pos) { n.pos = pos }
func (*node) aNode()           {}

type File struct {
	Pragma    Pragma
	PkgName   *Name
	DeclList  []Decl
	EOF       Pos
	GoVersion string
	node
}

type (
	Decl interface {
		Node
		aDecl()
	}

	ImportDecl struct {
		Group        *Group
		Pragma       Pragma
		LocalPkgName *Name
		Path         *BasicLit
		decl
	}

	ConstDecl struct {
		Group    *Group
		Pragma   Pragma
		NameList []*Name
		Type     Expr
		Values   Expr
		decl
	}

	TypeDecl struct {
		Group      *Group
		Pragma     Pragma
		Name       *Name
		TParamList []*Field
		Alias      bool
		Type       Expr
		decl
	}

	VarDecl struct {
		Group    *Group
		Pragma   Pragma
		NameList []*Name
		Type     Expr
		Values   Expr
		decl
	}

	FuncDecl struct {
		Pragma     Pragma
		Recv       *Field
		Name       *Name
		TParamList []*Field
		Type       *FuncType
		Body       *BlockStmt
		decl
	}
)

type decl struct{ node }

func (*decl) aDecl() {}

type Group struct {
	_ int
}

func NewName(pos Pos, value string) *Name {
	n := &Name{}
	n.pos = pos
	n.Value = value
	return n
}

type (
	Expr interface {
		Node
		typeInfo
		aExpr()
	}

	BadExpr struct {
		expr
	}

	Name struct {
		Value string
		expr
	}

	BasicLit struct {
		Value string
		Kind  LitKind
		Bad   bool
		expr
	}

	CompositeLit struct {
		Type     Expr
		ElemList []Expr
		NKeys    int
		Rbrace   Pos
		expr
	}

	KeyValueExpr struct {
		Key, Value Expr
		expr
	}

	FuncLit struct {
		Type *FuncType
		Body *BlockStmt
		expr
	}

	ParenExpr struct {
		X Expr
		expr
	}

	SelectorExpr struct {
		X   Expr
		Sel *Name
		expr
	}

	IndexExpr struct {
		X     Expr
		Index Expr
		expr
	}

	SliceExpr struct {
		X     Expr
		Index [3]Expr
		Full  bool
		expr
	}

	AssertExpr struct {
		X    Expr
		Type Expr
		expr
	}

	TypeSwitchGuard struct {
		Lhs *Name
		X   Expr
		expr
	}

	Operation struct {
		Op   Operator
		X, Y Expr
		expr
	}

	CallExpr struct {
		Fun     Expr
		ArgList []Expr
		HasDots bool
		expr
	}

	ListExpr struct {
		ElemList []Expr
		expr
	}

	ArrayType struct {
		Len  Expr
		Elem Expr
		expr
	}

	SliceType struct {
		Elem Expr
		expr
	}

	DotsType struct {
		Elem Expr
		expr
	}

	StructType struct {
		FieldList []*Field
		TagList   []*BasicLit
		expr
	}

	Field struct {
		Name *Name
		Type Expr
		node
	}

	InterfaceType struct {
		MethodList []*Field
		expr
	}

	FuncType struct {
		ParamList  []*Field
		ResultList []*Field
		expr
	}

	MapType struct {
		Key, Value Expr
		expr
	}

	ChanType struct {
		Dir  ChanDir
		Elem Expr
		expr
	}
)

type Type interface {
	Underlying() Type
	String() string
}

type typeInfo interface {
	SetTypeInfo(TypeAndValue)
	GetTypeInfo() TypeAndValue
}

type TypeAndValue struct {
	Type  Type
	Value constant.Value
	exprFlags
}

type exprFlags uint16

func (f exprFlags) IsVoid() bool          { return f&1 != 0 }
func (f exprFlags) IsType() bool          { return f&2 != 0 }
func (f exprFlags) IsBuiltin() bool       { return f&4 != 0 }
func (f exprFlags) IsValue() bool         { return f&8 != 0 }
func (f exprFlags) IsNil() bool           { return f&16 != 0 }
func (f exprFlags) Addressable() bool     { return f&32 != 0 }
func (f exprFlags) Assignable() bool      { return f&64 != 0 }
func (f exprFlags) HasOk() bool           { return f&128 != 0 }
func (f exprFlags) IsRuntimeHelper() bool { return f&256 != 0 }

func (f *exprFlags) SetIsVoid()          { *f |= 1 }
func (f *exprFlags) SetIsType()          { *f |= 2 }
func (f *exprFlags) SetIsBuiltin()       { *f |= 4 }
func (f *exprFlags) SetIsValue()         { *f |= 8 }
func (f *exprFlags) SetIsNil()           { *f |= 16 }
func (f *exprFlags) SetAddressable()     { *f |= 32 }
func (f *exprFlags) SetAssignable()      { *f |= 64 }
func (f *exprFlags) SetHasOk()           { *f |= 128 }
func (f *exprFlags) SetIsRuntimeHelper() { *f |= 256 }

type typeAndValue struct {
	tv TypeAndValue
}

func (x *typeAndValue) SetTypeInfo(tv TypeAndValue) {
	x.tv = tv
}
func (x *typeAndValue) GetTypeInfo() TypeAndValue {
	return x.tv
}

type expr struct {
	node
	typeAndValue
}

func (*expr) aExpr() {}

type ChanDir uint

const (
	_ ChanDir = iota
	SendOnly
	RecvOnly
)

type (
	Stmt interface {
		Node
		aStmt()
	}

	SimpleStmt interface {
		Stmt
		aSimpleStmt()
	}

	EmptyStmt struct {
		simpleStmt
	}

	LabeledStmt struct {
		Label *Name
		Stmt  Stmt
		stmt
	}

	BlockStmt struct {
		List   []Stmt
		Rbrace Pos
		stmt
	}

	ExprStmt struct {
		X Expr
		simpleStmt
	}

	SendStmt struct {
		Chan, Value Expr
		simpleStmt
	}

	DeclStmt struct {
		DeclList []Decl
		stmt
	}

	AssignStmt struct {
		Op       Operator
		Lhs, Rhs Expr
		simpleStmt
	}

	BranchStmt struct {
		Tok    Token
		Label  *Name
		Target Stmt
		stmt
	}

	CallStmt struct {
		Tok     Token
		Call    Expr
		DeferAt Expr
		stmt
	}

	ReturnStmt struct {
		Results Expr
		stmt
	}

	IfStmt struct {
		Init SimpleStmt
		Cond Expr
		Then *BlockStmt
		Else Stmt
		stmt
	}

	ForStmt struct {
		Init SimpleStmt
		Cond Expr
		Post SimpleStmt
		Body *BlockStmt
		stmt
	}

	SwitchStmt struct {
		Init   SimpleStmt
		Tag    Expr
		Body   []*CaseClause
		Rbrace Pos
		stmt
	}

	SelectStmt struct {
		Body   []*CommClause
		Rbrace Pos
		stmt
	}
)

type (
	RangeClause struct {
		Lhs Expr
		Def bool
		X   Expr
		simpleStmt
	}

	CaseClause struct {
		Cases Expr
		Body  []Stmt
		Colon Pos
		node
	}

	CommClause struct {
		Comm  SimpleStmt
		Body  []Stmt
		Colon Pos
		node
	}
)

type stmt struct{ node }

func (stmt) aStmt() {}

type simpleStmt struct {
	stmt
}

func (simpleStmt) aSimpleStmt() {}

type CommentKind uint

const (
	Above CommentKind = iota
	Below
	Left
	Right
)

type Comment struct {
	Kind CommentKind
	Text string
	Next *Comment
}