/****************************************************************************
 Copyright (c) 2020-2023 Xiamen Yaji Software Co., Ltd.

 http://www.cocos.com

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights to
 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 of the Software, and to permit persons to whom the Software is furnished to do so,
 subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 THE SOFTWARE.
****************************************************************************/

#pragma once

#include <cstring>
#include "StringHandle.h"
#include "base/Macros.h"
#include "base/memory/Memory.h"
#include "base/std/container/unordered_map.h"
#include "base/std/container/vector.h"
#include "base/std/hash/hash.h"
#include "threading/ReadWriteLock.h"

namespace cc {

template <bool ThreadSafe>
class StringPool final {
private:
    class StringHasher final {
    public:
        ccstd::hash_t operator()(const char *str) const noexcept {
            return ccstd::hash_range(str, str + strlen(str));
        }
    };

    class StringEqual final {
    public:
        bool operator()(const char *c1, const char *c2) const noexcept {
            return strcmp(c1, c2) == 0;
        }
    };

public:
    StringPool() = default;
    ~StringPool();
    StringPool(const StringPool &) = delete;
    StringPool(StringPool &&) = delete;
    StringPool &operator=(const StringPool &) = delete;
    StringPool &operator=(StringPool &&) = delete;

    StringHandle stringToHandle(const char *str) noexcept;
    char const *handleToString(const StringHandle &handle) const noexcept;
    StringHandle find(const char *str) const noexcept;

private:
    StringHandle doStringToHandle(const char *str) noexcept;
    char const *doHandleToString(const StringHandle &handle) const noexcept;
    StringHandle doFind(const char *str) const noexcept;

    ccstd::unordered_map<char const *, StringHandle, StringHasher, StringEqual> _stringToHandles{};
    ccstd::vector<char const *> _handleToStrings{};
    mutable ReadWriteLock _readWriteLock{};
};

using ThreadSafeStringPool = StringPool<true>;

template <bool ThreadSafe>
StringPool<ThreadSafe>::~StringPool() {
    for (char const *strCache : _handleToStrings) {
        delete[] strCache;
    }
}

template <bool ThreadSafe>
inline StringHandle StringPool<ThreadSafe>::stringToHandle(const char *str) noexcept {
    if (ThreadSafe) {
        return _readWriteLock.lockWrite([this, str]() {
            return doStringToHandle(str);
        });
    }
    return doStringToHandle(str);
}

template <bool ThreadSafe>
inline char const *StringPool<ThreadSafe>::handleToString(const StringHandle &handle) const noexcept {
    if (ThreadSafe) {
        return _readWriteLock.lockRead([this, handle]() {
            return doHandleToString(handle);
        });
    }
    return doHandleToString(handle);
}

template <bool ThreadSafe>
StringHandle StringPool<ThreadSafe>::find(const char *str) const noexcept {
    if (ThreadSafe) {
        return _readWriteLock.lockRead([this, str]() {
            return doFind(str);
        });
    }
    return doFind(str);
}

template <bool ThreadSafe>
inline StringHandle StringPool<ThreadSafe>::doStringToHandle(const char *str) noexcept {
    const auto it = _stringToHandles.find(str);

    if (it == _stringToHandles.end()) {
        size_t const strLength = strlen(str) + 1;
        char *const strCache = ccnew char[strLength];
        strcpy(strCache, str);
        StringHandle name(static_cast<StringHandle::IndexType>(_handleToStrings.size()), strCache);
        _handleToStrings.emplace_back(strCache);
        _stringToHandles.emplace(strCache, name);
        return name;
    }
    return it->second;
}

template <bool ThreadSafe>
inline const char *StringPool<ThreadSafe>::doHandleToString(const StringHandle &handle) const noexcept {
    CC_ASSERT(handle < _handleToStrings.size());
    return _handleToStrings[handle];
}

template <bool ThreadSafe>
StringHandle StringPool<ThreadSafe>::doFind(char const *str) const noexcept {
    auto const it = _stringToHandles.find(str);
    return it == _stringToHandles.end() ? StringHandle{} : it->second;
}

} // namespace cc