/*
 * libfud
 * Copyright 2024 Dominick Allen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "fud_string_convert.hpp"

namespace fud::impl {

FudStatus checkPlusSigned(StringView& view, size_t& skipIndex)
{
    auto isPlusSigned = view.data()[0] == '+';
    if (isPlusSigned && view.length() == 1) {
        return FudStatus::ArgumentInvalid;
    }
    if (isPlusSigned) {
        view.advanceUnsafe();
        skipIndex++;
    }
    return FudStatus::Success;
}

Result<bool, FudStatus> checkNegative(StringView& view, size_t& skipIndex)
{
    bool isNegative = view.data()[0] == '-';
    if (isNegative && view.length() == 1) {
        return FudError{FudStatus::ArgumentInvalid};
    }
    if (isNegative) {
        skipIndex += 1;
        view.advanceUnsafe();
    }
    return Okay<bool>{isNegative};
}

Result<Radix, FudStatus> determineRadix(StringView input, size_t& index)
{
    if (input.length() < 1) {
        return FudError{FudStatus::ArgumentInvalid};
    }

    if (input.length() == 1 && input.data()[0] == '0') {
        return Okay<Radix>{Radix::Octal};
    }

    if (input.length() == 1) {
        return Okay<Radix>{Radix::Decimal};
    }

    if (input.data()[0] == '0' && (input.data()[1] == 'x' || input.data()[1] == 'X')) {
        index += 2;
        return Okay<Radix>{Radix::Hexadecimal};
    }

    if (input.data()[0] == '0') {
        auto nextChar = input.data()[1];
        auto nextVal = AsciiLookup[nextChar];
        if (nextVal >= 0 && nextVal < static_cast<uint8_t>(Radix::Octal)) {
            return Okay<Radix>{Radix::Octal};
        }
        if (nextVal >= static_cast<uint8_t>(Radix::Octal)) {
            return FudError{FudStatus::ArgumentInvalid};
        }
    }

    return Okay<Radix>{Radix::Decimal};
}

Result<uint8_t, FudStatus> getRadix(StringView& view, size_t& skipIndex, Option<uint8_t> specifiedRadixOption)
{
    using RetType = Result<uint8_t, FudStatus>;
    if (specifiedRadixOption.isNone()) {
        size_t radixIndex = 0;
        auto status = determineRadix(view, radixIndex);
        if (status.isOkay()) {
            skipIndex += radixIndex;
            view.advanceUnsafe(radixIndex);
            return RetType::okay(static_cast<uint8_t>(status.takeOkay()));
        }
        return RetType::error(status);
    }

    auto radix = specifiedRadixOption.value();
    if (radix == static_cast<uint8_t>(Radix::Hexadecimal) && view.length() > 2 &&
        (view.data()[1] == 'x' || view.data()[1] == 'X')) {
        skipIndex += 2;
        view.advanceUnsafe(2);
    } else if (radix == static_cast<uint8_t>(Radix::Binary) && view.length() > 2 && view.data()[1] == 'b') {
        skipIndex += 2;
        view.advanceUnsafe(2);
    } else if (radix == static_cast<uint8_t>(Radix::Octal) && view.length() > 2 && view.data()[1] == '0') {
        skipIndex += 2;
        view.advanceUnsafe(2);
    }

    return RetType::okay(radix);
}

} // namespace fud::impl