#include "WebSocket.h"
#include "Group.h"
#include "Hub.h"

namespace uWS {

/*
 * Frames and sends a WebSocket message.
 *
 * Hints: Consider using any of the prepare function if any of their
 * use cases match what you are trying to achieve (pub/sub, broadcast)
 *
 * Thread safe
 *
 */
template <bool isServer>
void WebSocket<isServer>::send(const char *message, size_t length, OpCode opCode, void(*callback)(WebSocket<isServer> *webSocket, void *data, bool cancelled, void *reserved), void *callbackData) {

#ifdef UWS_THREADSAFE
    std::lock_guard<std::recursive_mutex> lockGuard(*nodeData->asyncMutex);
    if (isClosed()) {
        if (callback) {
            callback(this, callbackData, true, nullptr);
        }
        return;
    }
#endif

    const int HEADER_LENGTH = WebSocketProtocol<!isServer, WebSocket<!isServer>>::LONG_MESSAGE_HEADER;

    struct TransformData {
        OpCode opCode;
    } transformData = {opCode};

    struct WebSocketTransformer {
        static size_t estimate(const char *data, size_t length) {
            return length + HEADER_LENGTH;
        }

        static size_t transform(const char *src, char *dst, size_t length, TransformData transformData) {
            return WebSocketProtocol<isServer, WebSocket<isServer>>::formatMessage(dst, src, length, transformData.opCode, length, false);
        }
    };

    sendTransformed<WebSocketTransformer>((char *) message, length, (void(*)(void *, void *, bool, void *)) callback, callbackData, transformData);
}

/*
 * Prepares a single message for use with sendPrepared.
 *
 * Hints: Useful in cases where you need to send the same message to many
 * recipients. Do not use when only sending one message.
 *
 * Thread safe
 *
 */
template <bool isServer>
typename WebSocket<isServer>::PreparedMessage *WebSocket<isServer>::prepareMessage(char *data, size_t length, OpCode opCode, bool compressed, void(*callback)(WebSocket<isServer> *webSocket, void *data, bool cancelled, void *reserved)) {
    PreparedMessage *preparedMessage = new PreparedMessage;
    preparedMessage->buffer = new char[length + 10];
    preparedMessage->length = WebSocketProtocol<isServer, WebSocket<isServer>>::formatMessage(preparedMessage->buffer, data, length, opCode, length, compressed);
    preparedMessage->references = 1;
    preparedMessage->callback = (void(*)(void *, void *, bool, void *)) callback;
    return preparedMessage;
}

/*
 * Prepares a batch of messages to send as one single TCP packet / syscall.
 *
 * Hints: Useful when doing pub/sub-like broadcasts where many recipients should receive many
 * messages. Do not use if only sending one message.
 *
 * Thread safe
 *
 */
template <bool isServer>
typename WebSocket<isServer>::PreparedMessage *WebSocket<isServer>::prepareMessageBatch(std::vector<std::string> &messages, std::vector<int> &excludedMessages, OpCode opCode, bool compressed, void (*callback)(WebSocket<isServer> *, void *, bool, void *))
{
    // should be sent in!
    size_t batchLength = 0;
    for (size_t i = 0; i < messages.size(); i++) {
        batchLength += messages[i].length();
    }

    PreparedMessage *preparedMessage = new PreparedMessage;
    preparedMessage->buffer = new char[batchLength + 10 * messages.size()];

    int offset = 0;
    for (size_t i = 0; i < messages.size(); i++) {
        offset += WebSocketProtocol<isServer, WebSocket<isServer>>::formatMessage(preparedMessage->buffer + offset, messages[i].data(), messages[i].length(), opCode, messages[i].length(), compressed);
    }
    preparedMessage->length = offset;
    preparedMessage->references = 1;
    preparedMessage->callback = (void(*)(void *, void *, bool, void *)) callback;
    return preparedMessage;
}

/*
 * Sends a prepared message.
 *
 * Hints: Used to improve broadcasting and similar use cases where the same
 * message is sent to multiple recipients. Do not used if only sending one message
 * in total.
 *
 * Warning: Modifies passed PreparedMessage and is thus not thread safe. Other
 * data is also modified and it makes sense to not make this function thread-safe
 * since it is a central part in broadcasting and other high-perf code paths.
 *
 */
template <bool isServer>
void WebSocket<isServer>::sendPrepared(typename WebSocket<isServer>::PreparedMessage *preparedMessage, void *callbackData) {
    // todo: see if this can be made a transformer instead
    preparedMessage->references++;
    void (*callback)(void *webSocket, void *userData, bool cancelled, void *reserved) = [](void *webSocket, void *userData, bool cancelled, void *reserved) {
        PreparedMessage *preparedMessage = (PreparedMessage *) userData;
        bool lastReference = !--preparedMessage->references;

        if (preparedMessage->callback) {
            preparedMessage->callback(webSocket, reserved, cancelled, (void *) lastReference);
        }

        if (lastReference) {
            delete [] preparedMessage->buffer;
            delete preparedMessage;
        }
    };

    // candidate for fixed size pool allocator
    int memoryLength = sizeof(Queue::Message);
    int memoryIndex = nodeData->getMemoryBlockIndex(memoryLength);

    Queue::Message *messagePtr = (Queue::Message *) nodeData->getSmallMemoryBlock(memoryIndex);
    messagePtr->data = preparedMessage->buffer;
    messagePtr->length = preparedMessage->length;

    bool wasTransferred;
    if (write(messagePtr, wasTransferred)) {
        if (!wasTransferred) {
            nodeData->freeSmallMemoryBlock((char *) messagePtr, memoryIndex);
            if (callback) {
                callback(this, preparedMessage, false, callbackData);
            }
        } else {
            messagePtr->callback = callback;
            messagePtr->callbackData = preparedMessage;
            messagePtr->reserved = callbackData;
        }
    } else {
        nodeData->freeSmallMemoryBlock((char *) messagePtr, memoryIndex);
        if (callback) {
            callback(this, preparedMessage, true, callbackData);
        }
    }
}

/*
 * Decrements the reference count of passed PreparedMessage. On zero references
 * the memory will be deleted.
 *
 * Hints: Used together with prepareMessage, prepareMessageBatch and similar calls.
 *
 * Warning: Will modify passed PrepareMessage and is thus not thread safe by itself.
 *
 */
template <bool isServer>
void WebSocket<isServer>::finalizeMessage(typename WebSocket<isServer>::PreparedMessage *preparedMessage) {
    if (!--preparedMessage->references) {
        delete [] preparedMessage->buffer;
        delete preparedMessage;
    }
}

template <bool isServer>
uS::Socket *WebSocket<isServer>::onData(uS::Socket *s, char *data, size_t length) {
    WebSocket<isServer> *webSocket = static_cast<WebSocket<isServer> *>(s);

    webSocket->hasOutstandingPong = false;
    if (!webSocket->isShuttingDown()) {
        webSocket->cork(true);
        WebSocketProtocol<isServer, WebSocket<isServer>>::consume(data, length, webSocket);
        if (!webSocket->isClosed()) {
            webSocket->cork(false);
        }
    }

    return webSocket;
}

/*
 * Immediately terminates this WebSocket. Will call onDisconnection of its Group.
 *
 * Hints: Close code will be 1006 and message will be empty.
 *
 */
template <bool isServer>
void WebSocket<isServer>::terminate() {

#ifdef UWS_THREADSAFE
    std::lock_guard<std::recursive_mutex> lockGuard(*nodeData->asyncMutex);
    if (isClosed()) {
        return;
    }
#endif

    WebSocket<isServer>::onEnd(this);
}

/*
 * Transfers this WebSocket from its current Group to specified Group.
 *
 * Receiving Group has to have called listen(uWS::TRANSFERS) prior.
 *
 * Hints: Useful to implement subprotocols on the same thread and Loop
 * or to transfer WebSockets between threads at any point (dynamic load balancing).
 *
 * Warning: From the point of call to the point of onTransfer, this WebSocket
 * is invalid and cannot be used. What you put in is not guaranteed to be what you
 * get in onTransfer, the only guaranteed consistency is passed userData is the userData
 * of given WebSocket in onTransfer. Use setUserData and getUserData to identify the WebSocket.
 */
template <bool isServer>
void WebSocket<isServer>::transfer(Group<isServer> *group) {
    Group<isServer>::from(this)->removeWebSocket(this);
    if (group->loop == Group<isServer>::from(this)->loop) {
        // fast path
        this->nodeData = group;
        Group<isServer>::from(this)->addWebSocket(this);
        Group<isServer>::from(this)->transferHandler(this);
    } else {
        // slow path
        uS::Socket::transfer((uS::NodeData *) group, [](Poll *p) {
            WebSocket<isServer> *webSocket = (WebSocket<isServer> *) p;
            Group<isServer>::from(webSocket)->addWebSocket(webSocket);
            Group<isServer>::from(webSocket)->transferHandler(webSocket);
        });
    }
}

/*
 * Immediately calls onDisconnection of its Group and begins a passive
 * WebSocket closedown handshake in the background (might succeed or not,
 * we don't care).
 *
 * Hints: Close code and message will be what you pass yourself.
 *
 */
template <bool isServer>
void WebSocket<isServer>::close(int code, const char *message, size_t length) {

    // startTimeout is not thread safe

    static const int MAX_CLOSE_PAYLOAD = 123;
    length = std::min<size_t>(MAX_CLOSE_PAYLOAD, length);
    Group<isServer>::from(this)->removeWebSocket(this);
    Group<isServer>::from(this)->disconnectionHandler(this, code, (char *) message, length);
    setShuttingDown(true);

    // todo: using the shared timer in the group, we can skip creating a new timer per socket
    // only this line and the one in Hub::connect uses the timeout feature
    startTimeout<WebSocket<isServer>::onEnd>();

    char closePayload[MAX_CLOSE_PAYLOAD + 2];
    int closePayloadLength = WebSocketProtocol<isServer, WebSocket<isServer>>::formatClosePayload(closePayload, code, message, length);
    send(closePayload, closePayloadLength, OpCode::CLOSE, [](WebSocket<isServer> *p, void *data, bool cancelled, void *reserved) {
        if (!cancelled) {
            p->shutdown();
        }
    });
}

template <bool isServer>
void WebSocket<isServer>::onEnd(uS::Socket *s) {
    WebSocket<isServer> *webSocket = static_cast<WebSocket<isServer> *>(s);

    if (!webSocket->isShuttingDown()) {
        Group<isServer>::from(webSocket)->removeWebSocket(webSocket);
        Group<isServer>::from(webSocket)->disconnectionHandler(webSocket, 1006, nullptr, 0);
    } else {
        webSocket->cancelTimeout();
    }

    webSocket->template closeSocket<WebSocket<isServer>>();

    while (!webSocket->messageQueue.empty()) {
        Queue::Message *message = webSocket->messageQueue.front();
        if (message->callback) {
            message->callback(nullptr, message->callbackData, true, nullptr);
        }
        webSocket->messageQueue.pop();
    }

    webSocket->nodeData->clearPendingPollChanges(webSocket);
}

template <bool isServer>
bool WebSocket<isServer>::handleFragment(char *data, size_t length, unsigned int remainingBytes, int opCode, bool fin, WebSocketState<isServer> *webSocketState) {
    WebSocket<isServer> *webSocket = static_cast<WebSocket<isServer> *>(webSocketState);
    Group<isServer> *group = Group<isServer>::from(webSocket);

    if (opCode < 3) {
        if (!remainingBytes && fin && !webSocket->fragmentBuffer.length()) {
            if (webSocket->compressionStatus == WebSocket<isServer>::CompressionStatus::COMPRESSED_FRAME) {
                    webSocket->compressionStatus = WebSocket<isServer>::CompressionStatus::ENABLED;
                    data = group->hub->inflate(data, length, group->maxPayload);
                    if (!data) {
                        forceClose(webSocketState);
                        return true;
                    }
            }

            if (opCode == 1 && !WebSocketProtocol<isServer, WebSocket<isServer>>::isValidUtf8((unsigned char *) data, length)) {
                forceClose(webSocketState);
                return true;
            }

            group->messageHandler(webSocket, data, length, (OpCode) opCode);
            if (webSocket->isClosed() || webSocket->isShuttingDown()) {
                return true;
            }
        } else {
            webSocket->fragmentBuffer.append(data, length);
            if (!remainingBytes && fin) {
                length = webSocket->fragmentBuffer.length();
                if (webSocket->compressionStatus == WebSocket<isServer>::CompressionStatus::COMPRESSED_FRAME) {
                        webSocket->compressionStatus = WebSocket<isServer>::CompressionStatus::ENABLED;
                        webSocket->fragmentBuffer.append("....");
                        data = group->hub->inflate((char *) webSocket->fragmentBuffer.data(), length, group->maxPayload);
                        if (!data) {
                            forceClose(webSocketState);
                            return true;
                        }
                } else {
                    data = (char *) webSocket->fragmentBuffer.data();
                }

                if (opCode == 1 && !WebSocketProtocol<isServer, WebSocket<isServer>>::isValidUtf8((unsigned char *) data, length)) {
                    forceClose(webSocketState);
                    return true;
                }

                group->messageHandler(webSocket, data, length, (OpCode) opCode);
                if (webSocket->isClosed() || webSocket->isShuttingDown()) {
                    return true;
                }
                webSocket->fragmentBuffer.clear();
            }
        }
    } else {
        if (!remainingBytes && fin && !webSocket->controlTipLength) {
            if (opCode == CLOSE) {
                typename WebSocketProtocol<isServer, WebSocket<isServer>>::CloseFrame closeFrame = WebSocketProtocol<isServer, WebSocket<isServer>>::parseClosePayload(data, length);
                webSocket->close(closeFrame.code, closeFrame.message, closeFrame.length);
                return true;
            } else {
                if (opCode == PING) {
                    webSocket->send(data, length, (OpCode) OpCode::PONG);
                    group->pingHandler(webSocket, data, length);
                    if (webSocket->isClosed() || webSocket->isShuttingDown()) {
                        return true;
                    }
                } else if (opCode == PONG) {
                    group->pongHandler(webSocket, data, length);
                    if (webSocket->isClosed() || webSocket->isShuttingDown()) {
                        return true;
                    }
                }
            }
        } else {
            webSocket->fragmentBuffer.append(data, length);
            webSocket->controlTipLength += length;

            if (!remainingBytes && fin) {
                char *controlBuffer = (char *) webSocket->fragmentBuffer.data() + webSocket->fragmentBuffer.length() - webSocket->controlTipLength;
                if (opCode == CLOSE) {
                    typename WebSocketProtocol<isServer, WebSocket<isServer>>::CloseFrame closeFrame = WebSocketProtocol<isServer, WebSocket<isServer>>::parseClosePayload(controlBuffer, webSocket->controlTipLength);
                    webSocket->close(closeFrame.code, closeFrame.message, closeFrame.length);
                    return true;
                } else {
                    if (opCode == PING) {
                        webSocket->send(controlBuffer, webSocket->controlTipLength, (OpCode) OpCode::PONG);
                        group->pingHandler(webSocket, controlBuffer, webSocket->controlTipLength);
                        if (webSocket->isClosed() || webSocket->isShuttingDown()) {
                            return true;
                        }
                    } else if (opCode == PONG) {
                        group->pongHandler(webSocket, controlBuffer, webSocket->controlTipLength);
                        if (webSocket->isClosed() || webSocket->isShuttingDown()) {
                            return true;
                        }
                    }
                }

                webSocket->fragmentBuffer.resize(webSocket->fragmentBuffer.length() - webSocket->controlTipLength);
                webSocket->controlTipLength = 0;
            }
        }
    }

    return false;
}

template struct WebSocket<SERVER>;
template struct WebSocket<CLIENT>;

}