#include <pthread.h>
#include <unistd.h>
#include <string.h>

#include <mgba/core/serialize.h>
#include <mgba/core/core.h>
#include <mgba-util/vfs.h>

#include <msgba/packet.h>
#include <msgba/packet/save_request.h>
#include <msgba/packet/save_response.h>
#include <msgba/core_controller.h>

bool
msPacketSaveRequestGet(const struct msPacket *packet, int clientFd, struct msClientConnectionData *const data) {
    bool result = false;
    struct msPacketSaveRequest *self = NULL;
    uint64_t identifier = 0;
    FILE *fp = fmemopen(packet->rawData, packet->size, "r");
    if (1 != fread(&identifier, sizeof identifier, 1, fp)) {
        goto return_ms_packet_save_request_get;
    }
    identifier = be64toh(identifier);
    self = malloc(sizeof *self);
    self->identifier = identifier;
    result = true;
return_ms_packet_save_request_get:
    fclose(fp);
    if (!result) {
        return false;
    }
    return msPacketSaveRequestHandle(packet, self, data);
}

struct msPacketSaveRequestData {
    uint64_t identifier;
};

static struct msPacketSaveRequestData *
msPacketSaveRequestDataNew(uint64_t identifier) {
    struct msPacketSaveRequestData *self = malloc(sizeof *self);
    self->identifier = identifier;
    return self;
}

void
msPacketSaveRequestDestroy(struct msPacketSaveRequest **self) {
    free(*self);
    *self = NULL;
}

void
msPacketSaveRequestDataDestroy(struct msPacketSaveRequestData **self) {
    free(*self);
    *self = NULL;
}

static void
shrinkOrNullSaveRequestsDataArray(struct msClientConnectionData *data) {
    size_t requestsLen = data->saveRequestsLen;
    struct msPacketSaveRequestData **requests = data->saveRequests;
    for (size_t i = 1; i < requestsLen; i++) {
        requests[i-1] = requests[i];
    }
    requestsLen--;
    data->saveRequestsLen = requestsLen;
    if (!requestsLen) {
        free(data->saveRequests);
        data->saveRequests = NULL;
        return;
    }
    data->saveRequests = realloc(requests, sizeof *requests * requestsLen); 
}

static unsigned char *
vFileToBytes(struct VFile *file, size_t *len) {
    unsigned char *result = NULL;
    const ssize_t bufferLen = 120;
    ssize_t readLen = 0;
    unsigned char buffer[bufferLen];
    if (!len) {
        goto return_vfile_to_bytes;    
    }
    *len = 0;
    file->seek(file, 0, SEEK_SET);
    while ((readLen = file->read(file, buffer, bufferLen)) && readLen) {
        *len += readLen; 
        size_t size = sizeof *result * *len;
        result = realloc(result, size);
        // memcpy_s not available in linux.
        memcpy(&result[*len - readLen], buffer, readLen); // NOLINT
    }
return_vfile_to_bytes:
    return result;
}

static void
msPacketSaveRequestSendResponse(struct mCoreThread *threadContext) {
    struct msClientConnectionData *data = (struct msClientConnectionData *) threadContext->userData;
    struct msPacketSaveRequestData **requests = data->saveRequests;
    size_t requestsLen;
    struct msPacketSaveRequestData *request = NULL;
    struct VFile *saveState = NULL;
    size_t saveLen = 0;
    unsigned char *save = NULL;
    struct msPacketSaveResponse *response = NULL;
    size_t rawDataLen = 0;
    unsigned char *rawData = NULL;
    struct msPacket *packet = NULL;
    pthread_mutex_lock(data->mutexSaveRequests);
    requestsLen = data->saveRequestsLen;
    if (!requestsLen) {
        printf("Somehow the queue of saveRequests got exhausted, this should not happen.\n");
        goto unlock_ms_packet_save_request_send_response;
    }
    struct msCoreController *coreController = data->coreController;
    struct mCore *core = coreController->threadContext.core;
    request = requests[0];
    shrinkOrNullSaveRequestsDataArray(data);
unlock_ms_packet_save_request_send_response:
    pthread_mutex_unlock(data->mutexSaveRequests);
    if (!requestsLen) {
        return;
    }
    saveState = VFileMemChunk (NULL, 0);
    mCoreSaveStateNamed(core, saveState, SAVESTATE_ALL);
    save = vFileToBytes(saveState, &saveLen);
    response = msPacketSaveResponseNew(request->identifier, saveLen, save);
    rawData = msPacketSaveResponseSerialize(response, &rawDataLen);
    if (!rawData) {
        goto return_ms_packet_save_request_send_response;
    }
    packet = msPacketNew(PACKET_SEND_SAVE_RESPONSE, rawDataLen, rawData);
    msPacketSend(packet, data);

return_ms_packet_save_request_send_response:
    if (!packet && rawData) {
        free(rawData);
    }
    if (response) {
        msPacketSaveResponseDestroy(&response);
    }
    if (request) {
        msPacketSaveRequestDataDestroy(&request);
    }
    if (packet) {
        msPacketDestroy(&packet);
    }
}

bool
msPacketSaveRequestHandle(const struct msPacket *packet, struct msPacketSaveRequest *self, struct msClientConnectionData *const data) {
    bool result = false;
    struct msCoreController *coreController = data->coreController;
    size_t saveRequestsLen = 0;
    if (!coreController) {
        goto return_ms_packet_save_request_handle;
    }

    pthread_mutex_lock(data->mutexSaveRequests);
    data->saveRequestsLen++;
    saveRequestsLen = data->saveRequestsLen;

    // W: Suspicious usage of 'sizeof(A*)'; pointer to aggregate by clang-tidy.
    data->saveRequests = realloc(data->saveRequests,  sizeof *data->saveRequests * saveRequestsLen);
    data->saveRequests[data->saveRequestsLen - 1] = msPacketSaveRequestDataNew(self->identifier);
    pthread_mutex_unlock(data->mutexSaveRequests);

    mCoreThreadRunFunction(&coreController->threadContext, &msPacketSaveRequestSendResponse);
    result = true;
return_ms_packet_save_request_handle:
    msPacketSaveRequestDestroy(&self);
    return result;
}