#include "core.h"
#include "tr.h"
#include "tm.h"

#define ACK_RATE            8
#define ACK_MASK_FIRST      ((ecp_ack_t)1 << (ECP_SIZE_ACKB - 1))

static ssize_t msg_store(ECPConnection *conn, ecp_seq_t seq, unsigned char *msg, size_t msg_size, ECP2Buffer *b) {
    ECPRBRecv *buf = conn->rbuf.recv;
    unsigned char flags = ECP_RBUF_FLAG_IN_RBUF;
    unsigned char mtype;
    ssize_t rv;
    int _rv;

    _rv = ecp_msg_get_type(msg, msg_size, &mtype);
    if (_rv) return _rv;

    mtype &= ECP_MTYPE_MASK;
    if (mtype < ECP_MAX_MTYPE_SYS) flags |= ECP_RBUF_FLAG_SYS;

#ifdef ECP_WITH_MSGQ
    if (buf->flags & ECP_RBUF_FLAG_MSGQ) {
        ecp_seq_t seq_offset;
        int _rv = ECP_OK;

        pthread_mutex_lock(&buf->msgq.mutex);
        seq_offset = seq - buf->msgq.seq_start;
        if (seq_offset >= buf->rbuf.msg_size) _rv = ECP_ERR_RBUF_FULL;
        pthread_mutex_unlock(&buf->msgq.mutex);

        if (_rv) return _rv;
    }
#endif

    rv = _ecp_rbuf_msg_store(&buf->rbuf, seq, -1, msg, msg_size, ECP_RBUF_FLAG_IN_RBUF | ECP_RBUF_FLAG_IN_MSGQ, flags);
    if (rv < 0) return rv;

    if (ECP_SEQ_LT(buf->rbuf.seq_max, seq)) buf->rbuf.seq_max = seq;
    if (flags & ECP_RBUF_FLAG_SYS) ecp_conn_handle_msg(conn, seq, msg, msg_size, b);

    return rv;
}

static void msg_flush(ECPConnection *conn, ECP2Buffer *b) {
    ECPRBRecv *buf = conn->rbuf.recv;

#ifdef ECP_WITH_MSGQ
    if (buf->flags & ECP_RBUF_FLAG_MSGQ) pthread_mutex_lock(&buf->msgq.mutex);
#endif

    ecp_seq_t msg_cnt = buf->rbuf.seq_max - buf->rbuf.seq_start + 1;
    ecp_seq_t seq_next = buf->rbuf.seq_start;
    ecp_seq_t i = 0;
    unsigned int idx = buf->rbuf.msg_start;

    if (buf->timer_pts) {
        ecp_timer_pop(conn, ECP_MTYPE_RBFLUSH_PTS);
        buf->timer_pts = 0;
    }

    for (i=0; i<msg_cnt; i++) {
        if (buf->rbuf.msg[idx].flags & ECP_RBUF_FLAG_IN_RBUF) {
            if (buf->rbuf.msg[idx].flags & ECP_RBUF_FLAG_SYS) {
                buf->rbuf.msg[idx].flags &= ~ECP_RBUF_FLAG_SYS;
            } else {
                ecp_pts_t msg_pts;
                ecp_seq_t seq = buf->rbuf.seq_start + i;
                unsigned char frag_tot;
                unsigned char frag_cnt;
                uint16_t frag_size;
                int rv;

                rv = ecp_msg_get_frag(buf->rbuf.msg[idx].msg, buf->rbuf.msg[idx].size, &frag_cnt, &frag_tot, &frag_size);
                if (!rv && (frag_cnt != 0) && (seq != seq_next)) {
                    ecp_seq_t seq_fend = seq + (ecp_seq_t)(frag_tot - frag_cnt - 1);

                    if (ECP_SEQ_LT(buf->rbuf.seq_max, seq_fend) || (buf->hole_max && ((ecp_seq_t)(buf->rbuf.seq_max - seq_fend) <= buf->hole_max))) {
                        ecp_seq_t seq_fbeg = seq - frag_cnt;
                        ecp_seq_t seq_offset = ECP_SEQ_LT(seq_next, seq_fbeg) ? seq - seq_fbeg : seq - seq_next;

                        i -= seq_offset;
                        idx = ECP_RBUF_IDX_MASK(idx - seq_offset, buf->rbuf.msg_size);
                        break;
                    }
                }

                rv = ecp_msg_get_pts(buf->rbuf.msg[idx].msg, buf->rbuf.msg[idx].size, &msg_pts);
                if (!rv) {
                    ecp_pts_t now = ecp_tm_abstime_ms(0);
                    if (ECP_PTS_LT(now, msg_pts)) {
                        ECPTimerItem ti;
                        ecp_seq_t seq_offset = seq - seq_next;

                        rv = ecp_timer_item_init(&ti, conn, ECP_MTYPE_RBFLUSH_PTS, 0, msg_pts - now);
                        if (!rv) rv = ecp_timer_push(&ti);
                        if (!rv) buf->timer_pts = 1;

                        i -= seq_offset;
                        idx = ECP_RBUF_IDX_MASK(idx - seq_offset, buf->rbuf.msg_size);
                        break;
                    }
                }

                seq_next = seq + 1;
#ifdef ECP_WITH_MSGQ
                if (buf->flags & ECP_RBUF_FLAG_MSGQ) {
                    unsigned char mtype;

                    rv = ecp_msg_get_type(buf->rbuf.msg[idx].msg, buf->rbuf.msg[idx].size, &mtype);
                    if (!rv) rv = ecp_conn_msgq_push(conn, seq, mtype);
                    if (rv) break;

                    buf->rbuf.msg[idx].flags |= ECP_RBUF_FLAG_IN_MSGQ;
                } else

#endif
                    ecp_conn_handle_msg(conn, seq, buf->rbuf.msg[idx].msg, buf->rbuf.msg[idx].size, b);
            }
            buf->rbuf.msg[idx].flags &= ~ECP_RBUF_FLAG_IN_RBUF;
        } else {
            if (buf->flags & ECP_RBUF_FLAG_RELIABLE) break;
            if (buf->hole_max) {
                ecp_seq_t seq = buf->rbuf.seq_start + i;
                ecp_seq_t seq_offset = buf->rbuf.seq_max - seq;
                if (seq_offset <= buf->hole_max) break;
            }
        }
        idx = ECP_RBUF_IDX_MASK(idx + 1, buf->rbuf.msg_size);
    }
    buf->rbuf.seq_start += i;
    buf->rbuf.msg_start = idx;

#ifdef ECP_WITH_MSGQ
    if (buf->flags & ECP_RBUF_FLAG_MSGQ) pthread_mutex_unlock(&buf->msgq.mutex);
#endif

}

static int ack_send(ECPConnection *conn) {
    ECPRBRecv *buf = conn->rbuf.recv;
    ECPBuffer packet;
    ECPBuffer payload;
    unsigned char pkt_buf[ECP_SIZE_PKT_BUF(sizeof(ecp_seq_t) + sizeof(ecp_ack_t), ECP_MTYPE_RBACK, conn)];
    unsigned char pld_buf[ECP_SIZE_PLD_BUF(sizeof(ecp_seq_t) + sizeof(ecp_ack_t), ECP_MTYPE_RBACK, conn)];
    unsigned char *_buf;
    ssize_t rv;

    packet.buffer = pkt_buf;
    packet.size = ECP_SIZE_PKT_BUF(sizeof(ecp_seq_t) + sizeof(ecp_ack_t), ECP_MTYPE_RBACK, conn);
    payload.buffer = pld_buf;
    payload.size = ECP_SIZE_PLD_BUF(sizeof(ecp_seq_t) + sizeof(ecp_ack_t), ECP_MTYPE_RBACK, conn);

    ecp_pld_set_type(payload.buffer, payload.size, ECP_MTYPE_RBACK);
    _buf = ecp_pld_get_buf(payload.buffer, payload.size);
    _buf[0] = (buf->seq_ack & 0xFF000000) >> 24;
    _buf[1] = (buf->seq_ack & 0x00FF0000) >> 16;
    _buf[2] = (buf->seq_ack & 0x0000FF00) >> 8;
    _buf[3] = (buf->seq_ack & 0x000000FF);
    _buf[4] = (buf->ack_map & 0xFF000000) >> 24;
    _buf[5] = (buf->ack_map & 0x00FF0000) >> 16;
    _buf[6] = (buf->ack_map & 0x0000FF00) >> 8;
    _buf[7] = (buf->ack_map & 0x000000FF);

    rv = ecp_rbuf_pld_send(conn, &packet, &payload, ECP_SIZE_PLD(sizeof(ecp_seq_t) + sizeof(ecp_ack_t), ECP_MTYPE_RBACK), 0, 0);
    if (rv < 0) return rv;

    buf->ack_pkt = 0;
    buf->ack_do = 0;
    return ECP_OK;
}

static int ack_shift(ECPRBRecv *buf) {
    int do_ack = 0;
    int in_rbuf = 0;
    int idx;
    int i;

    if ((buf->flags & ECP_RBUF_FLAG_RELIABLE) && ((buf->ack_map & ACK_MASK_FIRST) == 0)) return 0;

    while (ECP_SEQ_LT(buf->seq_ack, buf->rbuf.seq_max)) {
        buf->seq_ack++;
        in_rbuf = ECP_SEQ_LT(buf->seq_ack, buf->rbuf.seq_start) ? 1 : buf->rbuf.msg[ECP_RBUF_IDX_MASK(buf->rbuf.msg_start + buf->seq_ack - buf->rbuf.seq_start, buf->rbuf.msg_size)].flags & ECP_RBUF_FLAG_IN_RBUF;

        if (in_rbuf && (buf->ack_map == ECP_ACK_FULL)) continue;

        buf->ack_map = buf->ack_map << 1;
        if (in_rbuf) {
            buf->ack_map |= 1;
        } else if (!do_ack && ECP_SEQ_LTE(buf->seq_ack, buf->rbuf.seq_max - 2 * buf->hole_max)) {
            do_ack = 1;
        }

        if ((buf->ack_map & ACK_MASK_FIRST) == 0) break;
    }

    if (!do_ack && (buf->seq_ack == buf->rbuf.seq_max) && ((buf->ack_map & buf->hole_mask_full) != buf->hole_mask_full)) {
        ecp_ack_t hole_mask = buf->ack_map;

        for (i=0; i<buf->hole_max-1; i++) {
            hole_mask = hole_mask >> 1;
            if ((hole_mask & buf->hole_mask_empty) == 0) {
                do_ack = 1;
                break;
            }
        }
    }

    return do_ack;
}

ssize_t ecp_rbuf_handle_flush(ECPConnection *conn, ecp_seq_t seq, unsigned char mtype, unsigned char *msg, ssize_t size, ECP2Buffer *b) {
    if (size < 0) return size;

    ECPRBRecv *buf = conn->rbuf.recv;
    if (buf == NULL) return ECP_ERR;

    ecp_tr_release(b->packet, 1);
    ack_send(conn);
    return 0;
}

ssize_t ecp_rbuf_handle_flush_pts(ECPConnection *conn, ecp_seq_t seq, unsigned char mtype, unsigned char *msg, ssize_t size, ECP2Buffer *b) {
    ECPRBRecv *buf = conn->rbuf.recv;
    if (buf == NULL) return ECP_ERR;

    buf->timer_pts = 0;
    msg_flush(conn, b);
    return 0;
}

int ecp_rbuf_recv_create(ECPConnection *conn, ECPRBRecv *buf, ECPRBMessage *msg, unsigned int msg_size) {
    int rv;

    memset(buf, 0, sizeof(ECPRBRecv));
    rv = _ecp_rbuf_init(&buf->rbuf, msg, msg_size);
    if (rv) return rv;

    buf->ack_map = ECP_ACK_FULL;
    buf->ack_rate = ACK_RATE;

#ifdef ECP_WITH_MSGQ
    rv = ecp_conn_msgq_create(&buf->msgq);
    if (rv) return rv;
#endif

    conn->rbuf.recv = buf;
    return ECP_OK;
}

void ecp_rbuf_recv_destroy(ECPConnection *conn) {
    ECPRBRecv *buf = conn->rbuf.recv;

    if (buf == NULL) return;
#ifdef ECP_WITH_MSGQ
    ecp_conn_msgq_destroy(&buf->msgq);
#endif

    conn->rbuf.recv = NULL;
}

int ecp_rbuf_recv_start(ECPConnection *conn, ecp_seq_t seq) {
    int rv;
    ECPRBRecv *buf = conn->rbuf.recv;

    if (buf == NULL) return ECP_ERR;

    seq--;
    buf->seq_ack = seq;
    rv = _ecp_rbuf_start(&buf->rbuf, seq);
    if (rv) return rv;

#ifdef ECP_WITH_MSGQ
    if (buf->flags & ECP_RBUF_FLAG_MSGQ) {
        rv = ecp_conn_msgq_start(&buf->msgq, seq);
        if (rv) return rv;
    }
#endif

    return ECP_OK;
}

int ecp_rbuf_set_hole(ECPConnection *conn, unsigned short hole_max) {
    ECPRBRecv *buf = conn->rbuf.recv;

    buf->hole_max = hole_max;
    buf->hole_mask_full = ~(~((ecp_ack_t)1) << (hole_max * 2));
    buf->hole_mask_empty = ~(~((ecp_ack_t)1) << (hole_max + 1));

    return ECP_OK;
}

int ecp_rbuf_set_delay(ECPConnection *conn, ecp_pts_t delay) {
    ECPRBRecv *buf = conn->rbuf.recv;

    buf->deliver_delay = delay;

    return ECP_OK;
}

ssize_t ecp_rbuf_store(ECPConnection *conn, ecp_seq_t seq, unsigned char *msg, size_t msg_size, ECP2Buffer *b) {
    ECPRBRecv *buf = conn->rbuf.recv;
    ecp_seq_t ack_pkt = 0;
    ssize_t rv;
    int _rv;
    unsigned char mtype;

    _rv = ecp_msg_get_type(msg, msg_size, &mtype);
    if (_rv) return _rv;

    mtype &= ECP_MTYPE_MASK;
    if ((mtype == ECP_MTYPE_RBACK) || (mtype == ECP_MTYPE_RBFLUSH)) return ecp_conn_handle_msg(conn, seq, msg, msg_size, b);

    if (ECP_SEQ_LT(buf->rbuf.seq_max, seq)) {
        ack_pkt = seq - buf->rbuf.seq_max;
        buf->ack_pkt += ack_pkt;
        if (buf->ack_pkt > buf->ack_rate) buf->ack_do = 1;
    }
    if (ECP_SEQ_LTE(seq, buf->seq_ack)) {
        ecp_seq_t seq_offset = buf->seq_ack - seq;
        if (seq_offset < ECP_SIZE_ACKB) {
            ecp_ack_t ack_mask = ((ecp_ack_t)1 << seq_offset);

            if (ack_mask & buf->ack_map) return ECP_ERR_RBUF_DUP;

            buf->ack_map |= ack_mask;
            buf->ack_do = buf->ack_do || ack_shift(buf);

            rv = msg_store(conn, seq, msg, msg_size, b);
            if (rv < 0) return rv;
        } else {
            return ECP_ERR_RBUF_DUP;
        }
    } else {
        if ((buf->ack_map == ECP_ACK_FULL) && (seq == (ecp_seq_t)(buf->seq_ack + 1))) {
            if ((buf->flags & ECP_RBUF_FLAG_MSGQ) || buf->deliver_delay) {
                rv = msg_store(conn, seq, msg, msg_size, b);
                if (rv < 0) return rv;
            } else {
                ecp_conn_handle_msg(conn, seq, msg, msg_size, b);
                rv = msg_size;
                buf->rbuf.seq_max++;
                buf->rbuf.seq_start++;
                buf->rbuf.msg_start = ECP_RBUF_IDX_MASK(buf->rbuf.msg_start + 1, buf->rbuf.msg_size);
            }
            buf->seq_ack++;
        } else {
            rv = msg_store(conn, seq, msg, msg_size, b);
            if (rv < 0) return rv;

            buf->ack_do = buf->ack_do || ack_shift(buf);
        }
    }
    msg_flush(conn, b);
    if (!(mtype < ECP_MAX_MTYPE_SYS) && buf->ack_do) {
        int _rv;

        _rv = ack_send(conn);
        if (_rv) return _rv;
    }

    return rv;
}


ECPFragIter *ecp_rbuf_get_frag_iter(ECPConnection *conn) {
    if (conn->rbuf.recv) return conn->rbuf.recv->frag_iter;
    return NULL;
}