/*
 * 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_STRING_HPP
#define FUD_STRING_HPP

#include "fud_utf8.hpp"

#include <climits>
#include <cstddef>

static_assert(CHAR_BIT == 8);

namespace fud {

constexpr size_t SSO_BUF_LENGTH = 15;
constexpr size_t SSO_BUF_SIZE = SSO_BUF_LENGTH + 1;

class String {
  public:
    String() = default;
    explicit String(const utf8* cString);
    explicit String(const char* cString);
    String(const String& rhs);
    String(String&& rhs);
    ~String();

    String& operator=(const String& rhs);
    String& operator=(String&& rhs);

    [[nodiscard]] constexpr size_t length() const
    {
        return m_length;
    }

    [[nodiscard]] constexpr bool empty() const
    {
        return m_length == 0;
    }

    [[nodiscard]] constexpr size_t size() const
    {
        return m_length + 1;
    }

    [[nodiscard]] constexpr size_t capacity() const
    {
        return m_capacity - 1;
    }

    /** \brier The underlying data, guaranteed to have c string representation. */
    [[nodiscard]] constexpr const utf8* data() const
    {
        return isLarge() ? m_data : m_buffer.data();
    }

    /** \brier The underlying data as an explicit c string. */
    [[nodiscard]] inline const char* c_str() const
    {
        return isLarge() ? reinterpret_cast<const char*>(m_data) : reinterpret_cast<const char*>(m_buffer.data());
    }

    /** \brier The underlying data, guaranteed to have c string representation. */
    [[nodiscard]] constexpr utf8* data()
    {
        return isLarge() ? m_data : m_buffer.data();
    }

    /** \brier The underlying data as an explicit c string. */
    [[nodiscard]] inline char* c_str()
    {
        return isLarge() ? reinterpret_cast<char*>(m_data) : reinterpret_cast<char*>(m_buffer.data());
    }

    [[nodiscard]] bool nullTerminated() const;

    [[nodiscard]] bool valid() const;

    [[nodiscard]] bool utf8Valid() const;

    [[nodiscard]] FudStatus nullTerminate();

    [[nodiscard]] std::optional<utf8> back();

    [[nodiscard]] constexpr size_t remainingLength() const
    {
        if (m_length >= m_capacity) {
            return 0;
        }

        return m_capacity - 1U - m_length;
    }

    [[nodiscard]] FudStatus pushBack(char letter);

    [[nodiscard]] FudStatus pushBack(utf8 letter);

    [[nodiscard]] FudStatus pushBack(const FudUtf8& letter);

    std::optional<utf8> pop();

    [[nodiscard]] FudStatus catenate(StringView source);

    [[nodiscard]] String append(const String& rhs) const;

  private:
    using BufType = Array<utf8, SSO_BUF_SIZE>;
    union {
        BufType m_buffer{BufType::constFill(0)};
        utf8* m_data;
    };
    size_t m_length{0};
    size_t m_capacity{SSO_BUF_SIZE};

    [[nodiscard]] constexpr bool isLarge() const
    {
        return m_capacity > SSO_BUF_SIZE;
    }
};

class StringView {
  public:
    constexpr StringView() noexcept : m_length(0), m_data{nullptr}
    {
    }

    constexpr StringView(size_t strLen, const utf8* strData) : m_length(strLen), m_data{strData}
    {
    }

    StringView(size_t strLen, const char* strData) :
        m_length(strLen),                              // line break
        m_data{reinterpret_cast<const utf8*>(strData)} // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
    {
    }

    explicit constexpr StringView(const StringView& view) noexcept = default;

    explicit constexpr StringView(const String& fudString) noexcept : StringView(fudString.length(), fudString.data())
    {
    }

    [[nodiscard]] constexpr size_t length() const
    {
        return m_length;
    }

    [[nodiscard]] constexpr const utf8* data() const
    {
        return m_data;
    }

    [[nodiscard]] bool nullTerminated() const;

    [[nodiscard]] bool utf8Valid() const;

    Result<size_t, FudStatus> skipWhitespace();

    Result<size_t, FudStatus> trimWhitespace();

    FudStatus toUint8(uint8_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toUint16(uint16_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toUint32(uint32_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toUint64(uint64_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toInt8(int8_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toInt16(int16_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toInt32(int32_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toInt64(int64_t& number, uint8_t specifiedRadix, size_t& strLen) const;

    FudStatus toFloat(float& number, size_t& strLen) const;

    FudStatus toDouble(double& number, size_t& strLen) const;

  private:
    size_t m_length;
    const utf8* m_data;
};

FudStatus skipWhitespace(StringView& view, size_t& skipIndex);

ssize_t cStringLength(const char* str);

ssize_t cStringLength(const char* str, size_t maxLength);

} // namespace fud

#endif