package object

import (
	"fmt"
	"strings"
	"unicode/utf8"
)

type String struct {
	Value string
}

func (s String) Len() int {
	return utf8.RuneCountInString(s.Value)
}

func (s String) Bool() bool {
	return s.Value != ""
}

func (s String) Type() Type {
	return StringType
}

func (s String) Inspect() string {
	return fmt.Sprintf("%#v", s.Value)
}

func (s String) Clone() Object {
	return String{Value: s.Value}
}

func (s String) String() string {
	return s.Value
}

func (s String) Add(other Object) (Object, error) {
	if !AssertTypes(other, StringType) {
		return nil, NewBinaryOpError(s, other, "+")
	}
	return String{s.Value + other.(String).Value}, nil
}

func (s String) Mul(other Object) (Object, error) {
	if !AssertTypes(other, IntegerType) {
		return nil, NewBinaryOpError(s, other, "*")
	}
	return String{strings.Repeat(s.Value, int(other.(Integer).Value))}, nil
}

func (s String) Get(index Object) (Object, error) {
	if !AssertTypes(index, IntegerType) {
		return nil, fmt.Errorf("invalid type for string index, expected Integer got %s", index.Type())
	}

	i := int(index.(Integer).Value)
	if i < 0 || i >= len(s.Value) {
		return String{}, nil
	}

	return String{string(s.Value[i])}, nil
}

func (s String) Compare(other Object) int {
	if obj, ok := other.(String); ok {
		switch {
		case s.Value < obj.Value:
			return -1
		case s.Value > obj.Value:
			return 1
		default:
			return 0
		}
	}
	return 1
}