// Copyright (c) Vitaliy Filippov, 2019+
// License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)

#include "messenger.h"

void osd_messenger_t::outbox_push(osd_op_t *cur_op)
{
    assert(cur_op->peer_fd);
    osd_client_t *cl = clients.at(cur_op->peer_fd);
    if (cur_op->op_type == OSD_OP_OUT)
    {
        clock_gettime(CLOCK_REALTIME, &cur_op->tv_begin);
    }
    else
    {
        // Check that operation actually belongs to this client
        bool found = false;
        for (auto it = cl->received_ops.begin(); it != cl->received_ops.end(); it++)
        {
            if (*it == cur_op)
            {
                found = true;
                cl->received_ops.erase(it, it+1);
                break;
            }
        }
        if (!found)
        {
            delete cur_op;
            return;
        }
    }
    cl->outbox.push_back(cur_op);
    if (!ringloop)
    {
        while (cl->write_op || cl->outbox.size())
        {
            try_send(cl);
        }
    }
    else if (cl->write_op || cl->outbox.size() > 1 || !try_send(cl))
    {
        if (cl->write_state == 0)
        {
            cl->write_state = CL_WRITE_READY;
            write_ready_clients.push_back(cur_op->peer_fd);
        }
        ringloop->wakeup();
    }
}

bool osd_messenger_t::try_send(osd_client_t *cl)
{
    int peer_fd = cl->peer_fd;
    if (!cl->write_op)
    {
        // pick next command
        cl->write_op = cl->outbox.front();
        cl->outbox.pop_front();
        cl->write_state = CL_WRITE_REPLY;
        if (cl->write_op->op_type == OSD_OP_IN)
        {
            // Measure execution latency
            timespec tv_end;
            clock_gettime(CLOCK_REALTIME, &tv_end);
            stats.op_stat_count[cl->write_op->req.hdr.opcode]++;
            if (!stats.op_stat_count[cl->write_op->req.hdr.opcode])
            {
                stats.op_stat_count[cl->write_op->req.hdr.opcode]++;
                stats.op_stat_sum[cl->write_op->req.hdr.opcode] = 0;
                stats.op_stat_bytes[cl->write_op->req.hdr.opcode] = 0;
            }
            stats.op_stat_sum[cl->write_op->req.hdr.opcode] += (
                (tv_end.tv_sec - cl->write_op->tv_begin.tv_sec)*1000000 +
                (tv_end.tv_nsec - cl->write_op->tv_begin.tv_nsec)/1000
            );
            if (cl->write_op->req.hdr.opcode == OSD_OP_READ ||
                cl->write_op->req.hdr.opcode == OSD_OP_WRITE)
            {
                stats.op_stat_bytes[cl->write_op->req.hdr.opcode] += cl->write_op->req.rw.len;
            }
            else if (cl->write_op->req.hdr.opcode == OSD_OP_SEC_READ ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE)
            {
                stats.op_stat_bytes[cl->write_op->req.hdr.opcode] += cl->write_op->req.sec_rw.len;
            }
            cl->send_list.push_back(cl->write_op->reply.buf, OSD_PACKET_SIZE);
            if (cl->write_op->req.hdr.opcode == OSD_OP_READ ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_READ ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_LIST ||
                cl->write_op->req.hdr.opcode == OSD_OP_SHOW_CONFIG)
            {
                cl->send_list.append(cl->write_op->iov);
            }
        }
        else
        {
            cl->send_list.push_back(cl->write_op->req.buf, OSD_PACKET_SIZE);
            if (cl->write_op->req.hdr.opcode == OSD_OP_WRITE ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_STABILIZE ||
                cl->write_op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK)
            {
                cl->send_list.append(cl->write_op->iov);
            }
        }
    }
    cl->write_msg.msg_iov = cl->send_list.get_iovec();
    cl->write_msg.msg_iovlen = cl->send_list.get_size();
    cl->refs++;
    if (ringloop && !use_sync_send_recv)
    {
        io_uring_sqe* sqe = ringloop->get_sqe();
        if (!sqe)
        {
            return false;
        }
        ring_data_t* data = ((ring_data_t*)sqe->user_data);
        data->callback = [this, cl](ring_data_t *data) { handle_send(data->res, cl); };
        my_uring_prep_sendmsg(sqe, peer_fd, &cl->write_msg, 0);
    }
    else
    {
        int result = sendmsg(peer_fd, &cl->write_msg, MSG_NOSIGNAL);
        if (result < 0)
        {
            result = -errno;
        }
        handle_send(result, cl);
    }
    return true;
}

void osd_messenger_t::send_replies()
{
    for (int i = 0; i < write_ready_clients.size(); i++)
    {
        int peer_fd = write_ready_clients[i];
        if (!try_send(clients[peer_fd]))
        {
            write_ready_clients.erase(write_ready_clients.begin(), write_ready_clients.begin() + i);
            return;
        }
    }
    write_ready_clients.clear();
}

void osd_messenger_t::handle_send(int result, osd_client_t *cl)
{
    cl->refs--;
    if (cl->peer_state == PEER_STOPPED)
    {
        if (!cl->refs)
        {
            delete cl;
        }
        return;
    }
    if (result < 0 && result != -EAGAIN)
    {
        // this is a client socket, so don't panic. just disconnect it
        printf("Client %d socket write error: %d (%s). Disconnecting client\n", cl->peer_fd, -result, strerror(-result));
        stop_client(cl->peer_fd);
        return;
    }
    if (result >= 0)
    {
        cl->send_list.eat(result);
        if (cl->send_list.done >= cl->send_list.count)
        {
            // Done
            cl->send_list.reset();
            if (cl->write_op->op_type == OSD_OP_IN)
            {
                delete cl->write_op;
            }
            else
            {
                cl->sent_ops[cl->write_op->req.hdr.id] = cl->write_op;
            }
            cl->write_op = NULL;
            cl->write_state = cl->outbox.size() > 0 ? CL_WRITE_READY : 0;
        }
    }
    if (cl->write_state != 0)
    {
        write_ready_clients.push_back(cl->peer_fd);
    }
}