/*
 * 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.
 */

#ifndef FUD_FIXED_VECTOR_HPP
#define FUD_FIXED_VECTOR_HPP

#include "fud_assert.hpp"
#include "fud_config.hpp"
#include "fud_option.hpp"
#include "fud_span.hpp"

#include <cstddef>

namespace fud {

template <typename T, size_t Size>
class FixedVector {
    static_assert(Size > 0);
    using ValueType = T;

  private:
    T m_data[Size]; // NOLINT(cppcoreguidelines-avoid-c-arrays)
    size_t m_length;

  public:
    [[nodiscard]] constexpr size_t size() const
    {
        return Size;
    }

    constexpr T* data() noexcept
    {
        return m_data;
    }

    constexpr const T* data() const noexcept
    {
        return m_data;
    }

    constexpr T* begin() noexcept
    {
        return m_data;
    }

    constexpr const T* begin() const noexcept
    {
        return m_data;
    }

    constexpr T* end() noexcept
    {
        return m_data + Size;
    }

    constexpr const T* end() const noexcept
    {
        return m_data + Size;
    }

    constexpr T& operator[](size_t index)
    {
        if constexpr (fudBoundsChecking) {
            fudAssert(m_data != nullptr);
            fudAssert(index < m_length);
        }
        return m_data[index];
    }

    constexpr const T& operator[](size_t index) const
    {
        if constexpr (fudBoundsChecking) {
            fudAssert(m_data != nullptr);
            fudAssert(index < m_length);
        }
        return m_data[index];
    }

    constexpr bool operator==(const FixedVector<T, Size>&) const noexcept = default;

    constexpr auto operator<=>(const FixedVector<T, Size>& other) const noexcept = default;

    Span<T, Size> span()
    {
        return Span<T, Size>{data(), Size};
    }

    FudStatus resize(size_t count)
    {
        if (count == m_length) {
            return FudStatus::Success;
        }

        if (count < m_length) {
            m_length = count;
            return FudStatus::Success;
        }

        for (size_t index = m_length; index < count; ++index) {
            m_data = std::move(T());
        }

        m_length = count;
        return FudStatus::Success;
    }

    FudStatus clear()
    {
        m_length = 0;
        return FudStatus::Success;
    }

    constexpr Option<T&> front()
    {
        if (m_length > 0) {
            return m_data[0];
        }
        return NullOpt;
    }

    constexpr Option<const T&> front() const
    {
        if (m_length > 0) {
            return m_data[0];
        }
        return NullOpt;
    }

    constexpr Option<T&> back()
    {
        if (m_length > 0) {
            return m_data[m_length - 1];
        }
        return NullOpt;
    }

    constexpr Option<const T&> back() const
    {
        if (m_length > 0) {
            return m_data[m_length - 1];
        }
        return NullOpt;
    }

    FudStatus pushBack(const T& value)
    {
        if (m_length == Size) {
            return FudStatus::Full;
        }

        m_data[m_length] = value;
        m_length++;
        return FudStatus::Success;
    }

    FudStatus pushBack(T&& value)
    {
        if (m_length == Size) {
            return FudStatus::Full;
        }

        m_data[m_length] = std::move(value);
        m_length++;
        return FudStatus::Success;
    }

    Result<T, FudStatus> popBack()
    {
        if (m_data == nullptr) {
            return FudStatus::ObjectInvalid;
        }
        if (m_length == 0) {
            return FudStatus::Empty;
        }
        auto result{std::move(m_data[m_length - 1])};
        m_length--;
        return result;
    }

    FudStatus eraseBack()
    {
        if (m_data == nullptr) {
            return FudStatus::ObjectInvalid;
        }
        if (m_length == 0) {
            return FudStatus::Empty;
        }
        m_length--;
        return FudStatus::Success;
    }

    FudStatus insert(size_t index, const T& value)
    {
        if (index > m_length) {
            return FudStatus::IndexInvalid;
        }
        if (index == m_length) {
            return pushBack(value);
        }
        if (m_length == Size) {
            return FudStatus::Full;
        }

        m_data[m_length] = std::move(m_data[m_length - 1]);

        for (size_t backIndex = m_length - 1; backIndex > index; --backIndex) {
            m_data[backIndex] = std::move(m_data[backIndex - 1]);
        }
        m_data[index] = value;
        m_length++;
        return FudStatus::Success;
    }

    FudStatus insert(size_t index, T&& value)
    {
        if (index > m_length) {
            return FudStatus::IndexInvalid;
        }
        if (index == m_length) {
            return pushBack(std::move(value));
        }
        if (m_length == Size) {
            return FudStatus::Full;
        }

        m_data[m_length] = std::move(m_data[m_length - 1]);

        for (size_t backIndex = m_length - 1; backIndex > index; --backIndex) {
            m_data[backIndex] = std::move(m_data[backIndex - 1]);
        }
        m_data[index] = std::move(value);
        m_length++;
        return FudStatus::Success;
    }

    FudStatus erase(size_t index)
    {
        if (index >= m_length) {
            return FudStatus::IndexInvalid;
        }

        for (size_t fwdIndex = index; fwdIndex + 1 < m_length; fwdIndex++) {
            m_data[fwdIndex] = std::move(m_data[fwdIndex + 1]);
        }

        m_length--;
        return FudStatus::Success;
    }

  private:
    FudStatus cleanup() noexcept
    {
        auto status = clear();

        m_length = 0;
        return status;
    }
};

} // namespace fud

#endif