package main

import (
	"strconv"
)

type Lang_I8 int8
type Lang_I16 int16
type Lang_I32 int32
type Lang_I64 int64

type Lang_U8 uint8
type Lang_U16 uint16
type Lang_U32 uint32
type Lang_U64 uint64

type Lang_Bool bool

var PRIMITIVE_TYPE_NAMES = []string{"i8", "i16", "i32", "i64", "u8", "u16", "u32", "u64", "f32", "f64", "bool"}

type PrimitiveType uint32

const (
	Primitive_I8 PrimitiveType = iota
	Primitive_I16
	Primitive_I32
	Primitive_I64
	Primitive_U8
	Primitive_U16
	Primitive_U32
	Primitive_U64
	Primitive_F32
	Primitive_F64
	Primitive_Bool
)

const STRING_TYPE_NAME = "string"

var STRING_TYPE = Type{Type: Type_Named, Value: STRING_TYPE_NAME}

const InvalidValue = 0xEEEEEE // Magic value

type CompilerError struct {
	Position TokenPosition
	Message  string
}

func (e CompilerError) Error() string {
	return e.Message + " (at " + e.Position.SourceFile + ", index " + strconv.FormatUint(e.Position.Position, 10) + ")"
}

func isSignedInt(primitiveType PrimitiveType) bool {
	switch primitiveType {
	case Primitive_I8, Primitive_I16, Primitive_I32, Primitive_I64:
		return true
	default:
		return false
	}
}

func isUnsignedInt(primitiveType PrimitiveType) bool {
	switch primitiveType {
	case Primitive_U8, Primitive_U16, Primitive_U32, Primitive_U64:
		return true
	default:
		return false
	}
}

func isFloatingPoint(primitiveType PrimitiveType) bool {
	switch primitiveType {
	case Primitive_F32, Primitive_F64:
		return true
	default:
		return false
	}
}

func getBits(primitiveType PrimitiveType) int {
	switch primitiveType {
	case Primitive_I8, Primitive_U8:
		return 8
	case Primitive_I16, Primitive_U16:
		return 16
	case Primitive_I32, Primitive_U32, Primitive_F32:
		return 32
	case Primitive_I64, Primitive_U64, Primitive_F64:
		return 64
	default:
		panic("Passed an invalid type (" + strconv.FormatUint(uint64(primitiveType), 10) + ") to getBits()")
	}
}

func getPrimitiveTypeName(primitiveType PrimitiveType) string {
	return PRIMITIVE_TYPE_NAMES[primitiveType]
}

func getTypeName(theType Type) string {
	switch theType.Type {
	case Type_Primitive:
		return getPrimitiveTypeName(theType.Value.(PrimitiveType))
	case Type_Named:
		return theType.Value.(NamedType).TypeName
	case Type_Array:
		return getTypeName(theType.Value.(ArrayType).ElementType) + "[]"
	case Type_Tuple:
		name := "("

		for idx, member := range theType.Value.(TupleType).Types {
			name += getTypeName(member)
			if idx != len(theType.Value.(TupleType).Types)-1 {
				name += ", "
			}
		}

		name += ")"
		return name
	default:
		panic("type name not implemented")
	}
}

func (t Type) String() string {
	return getTypeName(t)
}

func (t PrimitiveType) String() string {
	return getPrimitiveTypeName(t)
}

func (t ExpressionType) String() string {
	return strconv.Itoa(int(t))
}

func getOperation(operator Operator) Operation {
	switch operator {
	case Operator_Greater:
		return Operation_Greater
	case Operator_Less:
		return Operation_Less
	case Operator_Plus, Operator_PlusEquals:
		return Operation_Add
	case Operator_Minus, Operator_MinusEquals:
		return Operation_Sub
	case Operator_Multiply, Operator_MultiplyEquals:
		return Operation_Mul
	case Operator_Divide, Operator_DivideEquals:
		return Operation_Div
	case Operator_Modulo, Operator_ModuloEquals:
		return Operation_Mod
	case Operator_EqualsEquals:
		return Operation_Equals
	case Operator_GreaterEquals:
		return Operation_GreaterEquals
	case Operator_LessEquals:
		return Operation_LessEquals
	case Operator_NotEquals:
		return Operation_NotEquals
	case Operator_Equals:
		return Operation_Nop
	default:
		return InvalidValue
	}
}

func getUnaryOperation(operator Operator) UnaryOperation {
	switch operator {
	case Operator_Minus:
		return UnaryOperation_Negate
	case Operator_Plus:
		return UnaryOperation_Nop
	case Operator_BitwiseNot:
		return UnaryOperation_BitwiseNot
	case Operator_Not:
		return UnaryOperation_LogicalNot
	default:
		return InvalidValue
	}
}

func isBooleanOperation(operation Operation) bool {
	switch operation {
	case Operation_Greater, Operation_Less, Operation_Equals, Operation_GreaterEquals, Operation_LessEquals, Operation_NotEquals:
		return true
	default:
		return false
	}
}

func isArithmeticOperation(operation Operation) bool {
	return !isBooleanOperation(operation)
}

func isValidLHS(expressionType ExpressionType) bool {
	switch expressionType {
	case Expression_ArrayAccess, Expression_VariableReference, Expression_RawMemoryReference:
		return true
	default:
		return false
	}
}