/*

 * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#pragma once

#include <AK/ByteString.h>

#include <AK/NonnullRefPtr.h>

#include <AK/RefCounted.h>

#include <AK/Types.h>

#include <AK/Utf16View.h>

#include <AK/Vector.h>

#include <LibJS/Runtime/Completion.h>

namespace JS {

namespace Detail {

class Utf16StringImpl : public RefCounted<Utf16StringImpl> {

public:

    ~Utf16StringImpl() = default;

    [[nodiscard]] static NonnullRefPtr<Utf16StringImpl> create();

    [[nodiscard]] static NonnullRefPtr<Utf16StringImpl> create(Utf16Data);

    [[nodiscard]] static NonnullRefPtr<Utf16StringImpl> create(StringView);

    [[nodiscard]] static NonnullRefPtr<Utf16StringImpl> create(Utf16View const&);

    Utf16Data const& string() const;

    Utf16View view() const;

    [[nodiscard]] u32 hash() const

    {

        if (!m_has_hash) {

            m_hash = compute_hash();

            m_has_hash = true;

        }

        return m_hash;

    }

    [[nodiscard]] bool operator==(Utf16StringImpl const& other) const { return string() == other.string(); }

private:

    Utf16StringImpl() = default;

    explicit Utf16StringImpl(Utf16Data string);

    [[nodiscard]] u32 compute_hash() const;

    mutable bool m_has_hash { false };

    mutable u32 m_hash { 0 };

    Utf16Data m_string;

};

}

class Utf16String {

public:

    [[nodiscard]] static Utf16String create();

    [[nodiscard]] static Utf16String create(Utf16Data);

    [[nodiscard]] static Utf16String create(StringView);

    [[nodiscard]] static Utf16String create(Utf16View const&);

    Utf16Data const& string() const;

    Utf16View view() const;

    Utf16View substring_view(size_t code_unit_offset, size_t code_unit_length) const;

    Utf16View substring_view(size_t code_unit_offset) const;

    [[nodiscard]] String to_utf8() const;

    [[nodiscard]] ByteString to_byte_string() const;

    u16 code_unit_at(size_t index) const;

    size_t length_in_code_units() const;

    bool is_empty() const;

    [[nodiscard]] u32 hash() const { return m_string->hash(); }

    [[nodiscard]] bool operator==(Utf16String const& other) const

    {

        if (m_string == other.m_string)

            return true;

        return *m_string == *other.m_string;

    }

private:

    explicit Utf16String(NonnullRefPtr<Detail::Utf16StringImpl>);

    NonnullRefPtr<Detail::Utf16StringImpl> m_string;

};

}

namespace AK {

template<>

struct Traits<JS::Utf16String> : public DefaultTraits<JS::Utf16String> {

    static unsigned hash(JS::Utf16String const& s) { return s.hash(); }

};

}