package core

import (
	"strconv"
	"strings"
	"unicode/utf8"

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

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

		if strings.HasPrefix(digits, "0x") {
			number, err := strconv.ParseInt(digits[2:], 16, 64)
			return int(number), err
		}

		if strings.HasPrefix(digits, "0o") {
			number, err := strconv.ParseInt(digits[2:], 8, 64)
			return int(number), err
		}

		if strings.HasPrefix(digits, "0b") {
			number, err := strconv.ParseInt(digits[2:], 2, 64)
			return int(number), err
		}

		number, err := strconv.Atoi(digits)
		return number, err

	case token.Rune:
		r := t.Bytes(f.File.Bytes)
		r = String(r)

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

		number, size := utf8.DecodeRune(r)

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

		return int(number), nil
	}

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