package core

import (
	"strconv"
	"unicode/utf8"

	"git.akyoto.dev/cli/q/src/build/errors"
	"git.akyoto.dev/cli/q/src/build/token"
)

// Number tries to convert the token into a numeric value.
func (f *Function) Number(t token.Token) (int, byte, error) {
	switch t.Kind {
	case token.Number:
		number, err := strconv.Atoi(t.Text(f.File.Bytes))
		return number, 8, err

	case token.Rune:
		r := t.Bytes(f.File.Bytes)
		r = r[1 : len(r)-1]

		if len(r) == 0 {
			return 0, 0, errors.New(errors.InvalidRune, f.File, t.Position+1)
		}

		number, size := utf8.DecodeRune(r)

		if len(r) > size {
			return 0, 0, errors.New(errors.InvalidRune, f.File, t.Position+1)
		}

		return int(number), byte(size), nil
	}

	return 0, 0, errors.New(errors.InvalidNumber, f.File, t.Position)
}