#include <cstring>
#include <algorithm>
#include "RawCircleBuff.h"

#ifndef SCF_MAX_LIMITED_BUFF_SIZE
#define SCF_MAX_LIMITED_BUFF_SIZE (32 * 1024 * 1024)  // 32MB
#endif

CircleBuff::CircleBuff()
{
    m_TotalSize = 0;
    m_UsedSize = 0;
    m_BasePos = 0;
    m_HeadPos = 0;
    m_Limit = SCF_MAX_LIMITED_BUFF_SIZE;
    m_pBuff = NULL;
    pthread_mutex_init(&m_Mutex, NULL);
}

CircleBuff::~CircleBuff()
{
    if (m_pBuff) {
        delete[] m_pBuff;
    }
    pthread_mutex_destroy(&m_Mutex);
}

void CircleBuff::Lock() {
    pthread_mutex_lock(&m_Mutex);
}

void CircleBuff::Unlock() {
    pthread_mutex_unlock(&m_Mutex);
}

void CircleBuff::SetBuffMaxLimit(uint32_t limit)
{
    Lock();
    m_Limit = limit;
    Unlock();
}

bool CircleBuff::ReSetBuffSize(uint32_t Size)
{
    Lock();
    if (m_pBuff && m_TotalSize > Size) {
        Unlock();
        return true;
    }

    if (Size > m_Limit) {
        Unlock();
        return false;
    }

    char* pOldBuff = m_pBuff;
    MsgQueue<Packet_CB> OldPacketQue;

    m_pBuff = new char[Size];
    if (m_pBuff != NULL) {
        uint32_t OldTotalSize = m_TotalSize;
        m_TotalSize = Size;
        m_UsedSize = 0;
        m_BasePos = 0;
        m_HeadPos = 0;

        if (pOldBuff) {
            Packet_CB pcb;
            while (m_PacketQue.DeQueue(pcb)) {
                OldPacketQue.InQueue(pcb);
            }

            while (OldPacketQue.DeQueue(pcb)) {
                uint32_t copied = 0;
                uint32_t offset = m_BasePos;
                if ((pcb.m_Offset + pcb.m_PacketSize) > OldTotalSize) {
                    copied += PushBlock(&pOldBuff[pcb.m_Offset], OldTotalSize - pcb.m_Offset);
                    copied += PushBlock(&pOldBuff[0], pcb.m_PacketSize - (OldTotalSize - pcb.m_Offset));
                }
                else {
                    copied += PushBlock(&pOldBuff[pcb.m_Offset], pcb.m_PacketSize);
                }
                Packet_CB packet(offset, pcb.m_PacketSize);
                m_PacketQue.InQueue(packet);
            }
            delete[] pOldBuff;
        }
        Unlock();
        return true;
    }

    m_TotalSize = 0;
    Unlock();
    return false;
}

uint32_t CircleBuff::PushBlock(const char* pContext, uint32_t Size)
{
    if (m_TotalSize < Size + m_UsedSize) {
        return 0;
    }

    uint32_t copied = 0;
    uint32_t offset = m_HeadPos;

    if (m_HeadPos >= m_BasePos) {
        copied = std::min(m_TotalSize - m_HeadPos, Size);
        memcpy(&m_pBuff[m_HeadPos], pContext, copied);
        if (copied == Size) {
            m_HeadPos += copied;
            if (m_HeadPos == m_TotalSize) {
                m_HeadPos = 0;
            }
        }
        else {
            memcpy(&m_pBuff[0], &pContext[copied], Size - copied);
            m_HeadPos = Size - copied;
        }
    }
    else {
        memcpy(&m_pBuff[m_HeadPos], pContext, Size);
        m_HeadPos += Size;
    }

    m_UsedSize += Size;
    return Size;
}

uint32_t CircleBuff::Push(const char* pContext, uint32_t Size)
{
    if (Size == 0) {
        return 0;
    }

    Lock();
    uint32_t offset = m_HeadPos;
    uint32_t copied = PushBlock(pContext, Size);

    if (copied == 0) {
        uint32_t newSize = m_TotalSize + std::max(Size + 4096, 1024 * 1024u);
        if (newSize > m_Limit) newSize = m_Limit;
        if (newSize <= m_TotalSize || !ReSetBuffSize(newSize)) {
            Unlock();
            return 0;
        }
        copied = PushBlock(pContext, Size);
    }

    if (copied == Size) {
        Packet_CB packet(offset, Size);
        m_PacketQue.InQueue(packet);
    }
    Unlock();
    return copied;
}

int CircleBuff::Pop(char* pContext, uint32_t ContextSize)
{
    uint32_t size = 0;
    Packet_CB pack;

    Lock();
    if (m_PacketQue.DeQueue(pack)) {
        if (ContextSize < pack.m_PacketSize) {
            m_PacketQue.InQueue(pack);
            Unlock();
            return LOW_REQUEST_SIZE;
        }

        uint32_t copied = std::min(m_TotalSize - pack.m_Offset, pack.m_PacketSize);
        memcpy(pContext, &m_pBuff[pack.m_Offset], copied);
        m_BasePos += copied;
        if (m_BasePos == m_TotalSize) {
            m_BasePos = 0;
        }

        if (copied < pack.m_PacketSize) {
            memcpy(&pContext[copied], &m_pBuff[0], pack.m_PacketSize - copied);
            m_BasePos = pack.m_PacketSize - copied;
        }

        m_UsedSize -= pack.m_PacketSize;
        size = pack.m_PacketSize;
    }
    Unlock();
    return size;
}

uint32_t CircleBuff::GetPacketCount()
{
    return m_PacketQue.size();
}

uint32_t CircleBuff::GetFrontPacketSize()
{
    uint32_t size = 0;
    Lock();
    if (m_PacketQue.size() > 0) {
        Packet_CB pack = m_PacketQue.front();
        size = pack.m_PacketSize;
    }
    Unlock();
    return size;
}