/*
 * This file is part of the CCD_Capture project.
 * Copyright 2022 Edward V. Emelianov <edward.emelianoff@gmail.com>.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

// client-side functions
#include <stdatomic.h>
#include <math.h>  // isnan
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <usefull_macros.h>

#include "ccdfunc.h" // framerate
#include "client.h"
#include "cmdlnopts.h"
#ifdef IMAGEVIEW
#include "imageview.h"
#endif
#include "server.h" // for common commands names
#include "socket.h"

extern double answer_timeout;

static char sendbuf[BUFSIZ];
static char *lastfilename = NULL;
// send message and wait any answer
#define SENDMSG(...) do{DBG("SENDMSG"); snprintf(sendbuf, BUFSIZ-1, __VA_ARGS__); verbose(2, "\t> %s", sendbuf); cc_sendstrmessage(sock, sendbuf); while(getans(sock, NULL));} while(0)
// send message and wait answer starting with 'cmd'
#define SENDMSGW(cmd, ...) do{DBG("SENDMSGW"); snprintf(sendbuf, BUFSIZ-1, cmd __VA_ARGS__); verbose(2, "\t> %s", sendbuf); cc_sendstrmessage(sock, sendbuf);}while(!getans(sock, cmd))
// send command and wait for answer on it
#define SENDCMDW(cmd) do{DBG("SENDCMDW"); strncpy(sendbuf, cmd, BUFSIZ-1); verbose(2, "\t> %s", sendbuf); cc_sendstrmessage(sock, sendbuf);}while(!getans(sock, cmd))
static volatile atomic_int expstate = CAMERA_CAPTURE;
static int xm0,ym0,xm1,ym1; // max format
static int xc0,yc0,xc1,yc1; // current format

static volatile atomic_int grabno = 0;
static int oldgrabno = 0;
// IPC key for shared memory
static cc_IMG ima = {0}, *shmima = NULL; // ima - local storage, shmima - shm (if available)
static size_t imbufsz = 0; // image buffer for allocated `ima`
static uint8_t *imbuf = NULL;


// read message from queue or file descriptor
static char *readmsg(int fd){
    static cc_strbuff *buf = NULL;
    if(!buf) buf = cc_strbufnew(BUFSIZ, 256);
    int test(){
        size_t got = cc_getline(buf);
        if(got > 255){
            DBG("Client fd=%d gave buffer overflow", fd);
            LOGMSG("SERVER client fd=%d buffer overflow", fd);
        }else if(got){
            return TRUE;
        }
        return FALSE;
    }
    if(test()) return buf->string;
    if(1 == sl_canread(fd)){
        if(cc_read2buf(fd, buf)){
            if(test()) return buf->string;
        }else ERRX("Server disconnected");
    }
    return NULL;
}

#define CMP_ANS(cmd, ans)   strncmp(cmd, ans, sizeof(cmd)-1)
// parser of CCD server messages; return TRUE to exit from polling cycle of `getans` (if receive 'FAIL', 'OK' or 'BUSY')
static cc_hresult parseans(char *ans){
    if(!ans) return CC_RESULT_BADKEY;
    //TIMESTAMP("parseans() begin");
    //DBG("Parsing of '%s'", ans);
    if(0 == strcmp(cc_hresult2str(CC_RESULT_OK), ans)) return CC_RESULT_OK;
    for(cc_hresult res = CC_RESULT_BUSY; res < CC_RESULT_NUM; ++res){
        const char *resmsg = cc_hresult2str(res);
        if(0 == strcmp(resmsg, ans)){
            WARNX("Server answered: %s", resmsg);
            return res;
        }
    }
    char *val = cc_get_keyval(&ans); // now `ans` is a key and `val` its value
    if(0 == CMP_ANS(CC_CMD_EXPSTATE, ans)){
        int st = atoi(val);
        atomic_store(&expstate, st);
        DBG("Exposition state: %d", st);
        return CC_RESULT_OK;
    }else if(0 == CMP_ANS(CC_CMD_FRAMEMAX, ans)){
        sscanf(val, "%d,%d,%d,%d", &xm0, &ym0, &xm1, &ym1);
        DBG("Got maxformat: %d,%d,%d,%d", xm0, ym0, xm1, ym1);
        return CC_RESULT_OK;
    }else if(0 == CMP_ANS(CC_CMD_FRAMEFORMAT, ans)){
        sscanf(val, "%d,%d,%d,%d", &xc0, &yc0, &xc1, &yc1);
        DBG("Got current format: %d,%d,%d,%d", xc0, yc0, xc1, yc1);
        return CC_RESULT_OK;
    }
    //TIMESTAMP("parseans() end");
    return CC_RESULT_SILENCE; // echo of sent command or something else
}

// read until timeout all messages from server; return FALSE if there was no messages from server
// if msg != NULL - wait for it in answer
static int getans(int sock, const char *msg){
    double t0 = sl_dtime();
    char *ans = NULL;
    double tmout = answer_timeout;
    if(msg) tmout *= 5.; // make first timeout larger for slow networks
    cc_hresult res = CC_RESULT_FAIL;
    while(sl_dtime() - t0 < tmout){
        ans = readmsg(sock);
        if(!ans) continue;
        // got answer -> make timeout less
        tmout = answer_timeout;
        t0 = sl_dtime();
        TIMESTAMP("Got from server: %s", ans);
        verbose(1, "\t%s", ans);
        DBG("1 msg-> %s, ans -> %s", msg, ans);
        res = parseans(ans);
        DBG("2 msg-> %s, ans -> %s; result: %d", msg, ans, res);
        if(res == CC_RESULT_SILENCE && msg){
            if(strncmp(ans, msg, strlen(msg))) continue;
            else res = CC_RESULT_OK;
        }
        DBG("Got answer -> break");
        break;
    }
    if(!ans) DBG("Got no answer from server");
    if(res == CC_RESULT_OK) return TRUE;
    return FALSE;
}

/**
 * @brief processData - process here some actions and make messages for server
 */
static void send_headers(int sock){
    if(GP->plugincmd){
        char **p = GP->plugincmd;
        green("Send custom plugin commands\n");
        while(p && *p){
            printf("\t%s\n", *p);
            SENDMSGW(CC_CMD_PLUGINCMD, "=%s", *p);
            ++p;
        }
        while(getans(sock, NULL));
    }
    if(GP->exptime > -DBL_EPSILON) SENDMSGW(CC_CMD_EXPOSITION, "=%g", GP->exptime);
    DBG("infty=%d", GP->infty);
    if(GP->infty > -1) SENDMSGW(CC_CMD_INFTY, "=%d", GP->infty);
    // common information
    SENDMSG(CC_CMD_INFO);
    // focuser
    if(GP->listdevices) SENDMSG(CC_CMD_FOCLIST);
    if(GP->focdevno > -1) SENDMSG(CC_CMD_FDEVNO "=%d", GP->focdevno);
    if(!isnan(GP->gotopos)){
        SENDMSGW(CC_CMD_FGOTO, "=%g", GP->gotopos);
    }
    // wheel
    if(GP->listdevices) SENDCMDW(CC_CMD_WLIST);
    if(GP->whldevno > -1) SENDMSGW(CC_CMD_WDEVNO, "=%d", GP->whldevno);
    if(GP->setwheel > -1) SENDMSGW(CC_CMD_WPOS, "=%d", GP->setwheel);
    DBG("nxt");
    // CCD/CMOS
    if(GP->X0 > INT_MIN || GP->Y0 > INT_MIN || GP->X1 > INT_MIN || GP->Y1 > INT_MIN){ // set format
        SENDCMDW(CC_CMD_FRAMEMAX);
        SENDCMDW(CC_CMD_FRAMEFORMAT);
        // default values
        if(GP->X0 == INT_MIN) GP->X0 = xc0;
        if(GP->X1 == INT_MIN) GP->X1 = xc1;
        if(GP->Y0 == INT_MIN) GP->Y0 = yc0;
        if(GP->Y1 == INT_MIN) GP->Y1 = yc1;
        // limiting values
        if(GP->X0 < 0) GP->X0 = xm0;
        else if(GP->X0 > xm1-1) GP->X0 = xm1-1;
        if(GP->Y0 < 0) GP->Y0 = ym0;
        else if(GP->Y0 > ym1-1) GP->Y0 = ym1-1;
        if(GP->X1 < GP->X0+1 || GP->X1 > xm1) GP->X1 = xm1;
        if(GP->Y1 < GP->Y0+1 || GP->Y1 > ym1) GP->Y1 = ym1;
        DBG("set format: (%d,%d)x(%d,%d)", GP->X0,GP->X1,GP->Y0,GP->Y1);
        SENDMSGW(CC_CMD_FRAMEFORMAT, "=%d,%d,%d,%d", GP->X0, GP->Y0, GP->X1, GP->Y1);
    }
    if(GP->cancelexpose) SENDMSGW(CC_CMD_EXPSTATE, "=%d", CAMERA_IDLE);
    if(GP->listdevices) SENDCMDW(CC_CMD_CAMLIST);
    if(GP->camdevno > -1) SENDMSGW(CC_CMD_CAMDEVNO, "=%d", GP->camdevno);
    if(GP->hbin) SENDMSGW(CC_CMD_HBIN, "=%d", GP->hbin);
    if(GP->vbin) SENDMSGW(CC_CMD_VBIN, "=%d", GP->vbin);
    if(!isnan(GP->temperature)) SENDMSGW(CC_CMD_CAMTEMPER, "=%g", GP->temperature);
    if(GP->shtr_cmd > -1) SENDMSGW(CC_CMD_SHUTTER, "=%d", GP->shtr_cmd);
    if(GP->confio > -1) SENDMSGW(CC_CMD_CONFIO, "=%d", GP->confio);
    if(GP->setio > -1) SENDMSGW(CC_CMD_IO, "=%d", GP->setio);\
    if(!isnan(GP->gain)) SENDMSGW(CC_CMD_GAIN, "=%g", GP->gain);
    if(!isnan(GP->brightness)) SENDMSGW(CC_CMD_BRIGHTNESS, "=%g", GP->brightness);
    if(GP->nflushes > 0) SENDMSGW(CC_CMD_NFLUSHES, "=%d", GP->nflushes);
    if(GP->exptime > -DBL_EPSILON){ // exposition and reading control: only if start of exposition
        if(GP->_8bit) SENDMSGW(CC_CMD_8BIT, "=1");
        else SENDMSGW(CC_CMD_8BIT, "=0");
        if(GP->fast) SENDMSGW(CC_CMD_FASTSPD, "=1");
        else SENDMSGW(CC_CMD_FASTSPD, "=0");
        if(GP->dark) SENDMSGW(CC_CMD_DARK, "=1");
        else SENDMSGW(CC_CMD_DARK, "=0");
    }
    // FITS header keywords:
#define CHKHDR(x, cmd)   do{if(x) SENDMSG(cmd "=%s", x);}while(0)
    CHKHDR(GP->author, CC_CMD_AUTHOR);
    CHKHDR(GP->instrument, CC_CMD_INSTRUMENT);
    CHKHDR(GP->observers, CC_CMD_OBSERVER);
    CHKHDR(GP->objname, CC_CMD_OBJECT);
    CHKHDR(GP->prog_id, CC_CMD_PROGRAM);
    CHKHDR(GP->objtype, CC_CMD_OBJTYPE);
#undef CHKHDR
}

/**
 * @brief readNbytes - read `N` bytes from descriptor `fd` into buffer *buf
 * @return false if failed
 */
static int readNbytes(int fd, size_t N, uint8_t *buf){
    size_t got = 0, need = N;
    double t0 = sl_dtime();
    while(sl_dtime() - t0 < CC_CLIENT_TIMEOUT /*&& sl_canread(fd)*/ && need){
        t0 = sl_dtime();
        ssize_t rd = read(fd, buf + got, need);
        if(rd <= 0){
            if(errno == EAGAIN || errno == EWOULDBLOCK) continue;
            WARNX("Server disconnected");
            signals(1);
        }
        got += rd; need -= rd;
    }
    if(need) return FALSE; // didn't got whole packet
    return TRUE;
}

/**
 * @brief getimage - read image from shared memory or socket
 * @param askheader == TRUE for storing FITS-header
 * @return FALSE if failed to catch image
 */
static int getimage(int askheader){
    FNAME();
    int imsock = -1, shmlocked = FALSE, ret = FALSE;
    static double oldtimestamp = -1.;
    TIMESTAMP("Get image sizes");
    if(shmima){ // read image from shared memory
        double t0 = sl_dtime();
        while(sl_dtime() - t0 < MUTEX_LOCK_TMOUT){
            if(client_lock_shm(shmima)){
                shmlocked = TRUE;
                break;
            }
            usleep(100);
        }
        if(!shmlocked){
            WARNX("Can't lock shared memory");
            return FALSE;
        }
        memcpy(&ima, shmima, sizeof(cc_IMG));
    }else{ // get image by socket
        imsock = cc_open_socket(FALSE, GP->imageport, TRUE);
        if(imsock < 0) ERRX("getimage(): can't open image transport socket");
        // get image size
        if(!readNbytes(imsock, sizeof(cc_IMG), (uint8_t*)&ima)){
            WARNX("Can't read image header");
            goto eofg;
        }
    }
    if(ima.bytelen < 1){
        WARNX("Wrong image size");
        goto eofg;
    }
    DBG("bytelen=%zd, w=%d, h=%d; bitpix=%d", ima.bytelen, ima.w, ima.h, ima.bitpix);
    // realloc memory if needed
    if(imbufsz < ima.bytelen){
        size_t newsz = 1024 * (1 + ima.bytelen / 1024);
        DBG("Reallocate memory from %zd to %zd", imbufsz, newsz);
        imbufsz = newsz;
        imbuf = realloc(imbuf, imbufsz);
    }
    ima.data = imbuf; // renew this value each time after getting `ima` from server
    TIMESTAMP("Start of data read");
    if(shmima){
        uint8_t *datastart = (uint8_t*)shmima + sizeof(cc_IMG);
        memcpy(imbuf, datastart, ima.bytelen);
        TIMESTAMP("Got by shared memory");
        if(!askheader){
            unlock_shm(shmima);
            shmlocked = FALSE;
        }
        ret = TRUE;
    }else{
        if(!readNbytes(imsock, ima.bytelen, imbuf)){
            WARNX("Can't read image data");
            goto eofg;
        }
        ret = TRUE;
        TIMESTAMP("Got by socket");
    }
    DBG("timestamps new-old=%g; imno: %zd", ima.timestamp - oldtimestamp, ima.imnumber);
    if(ima.timestamp != oldtimestamp){ // test if image is really new
        oldtimestamp = ima.timestamp;
        atomic_store(&grabno, ima.imnumber);
        TIMESTAMP("Got image #%zd", ima.imnumber);
        if(askheader){ // read FITS-header for later saving
            if(shmima){
                size_t rsz = FLEN_CARD * ima.headerstrings;
                memcpy(ima.fitsheader, shmima->fitsheader, rsz);
            }else{
                uint8_t card[FLEN_CARD];
                for(size_t i = 0; i < ima.headerstrings; ++i){
                    if(!readNbytes(imsock, FLEN_CARD, card)){
                        WARNX("Can't read full header, got %zd records from %zd", i, ima.headerstrings);
                        break;
                    }
                    memcpy(&ima.fitsheader[i], card, FLEN_CARD);
                }
            }
            if(GP->addhdr){ // add records from client-side files
                char **nxtfile = GP->addhdr;
                while(*nxtfile){
                    cc_kwfromfile(&ima, *(nxtfile++));
                }
            }
        }else ima.headerstrings = 0;
    }else WARNX("Still got old image");
eofg:
    if(imsock != -1) close(imsock);
    if(shmlocked) unlock_shm(shmima);
    return ret;
}

void client(int sock){
    if(GP->restart){
        SENDCMDW(CC_CMD_RESTART);
        return;
    }
    TIMEINIT();
    send_headers(sock);
    TIMESTAMP("Got headers");
    double t0 = sl_dtime(), tw = t0;
    int Nremain = 0, nframe = 1;
    // if client gives filename/prefix or Nframes, make exposition
    if((GP->outfile && *GP->outfile) || (GP->outfileprefix && *GP->outfileprefix) || GP->nframes > 0){
        Nremain = GP->nframes;
        if(Nremain < 1) Nremain = 1;
        else GP->waitexpend = TRUE; // N>1 - wait for exp ends
        SENDMSGW(CC_CMD_EXPSTATE, "=%d", CAMERA_CAPTURE);
    }else{
        int cntr = 0;
        while(sl_dtime() - t0 < CC_WAIT_TIMEOUT && cntr < 3)
            if(!getans(sock, NULL)) ++cntr;
        DBG("RETURN: no more data");
        return;
    }
    double timeout = GP->waitexpend ? CC_CLIENT_TIMEOUT : CC_WAIT_TIMEOUT;
    verbose(1, "Exposing frame 1...");
    if(GP->waitexpend){
        atomic_store(&expstate, CAMERA_CAPTURE); // could be changed earlier
        verbose(2, "Wait for exposition end");
    }
    while(sl_dtime() - t0 < timeout){
        if(GP->waitexpend && sl_dtime() - tw > CC_WAIT_TIMEOUT){
            SENDCMDW(CC_CMD_TREMAIN); // get remained time
            tw = sl_dtime();
            sprintf(sendbuf, "%s", CC_CMD_EXPSTATE);
            cc_sendstrmessage(sock, sendbuf);
        }
        if(getans(sock, NULL)){ // got next portion of data
            DBG("server message");
            t0 = sl_dtime();
            int curst = atomic_load(&expstate);
            if(curst == CAMERA_ERROR){
                WARNX(_("Can't make exposition"));
                if(Nremain > 1){
                    verbose(1, "Exposing frame %d...", nframe);
                    SENDMSGW(CC_CMD_EXPSTATE, "=%d", CAMERA_CAPTURE);
                }
                continue;
            }
            //if(expstate != CAMERA_CAPTURE){
            if(curst == CAMERA_FRAMERDY){
                atomic_store(&expstate, CAMERA_IDLE);
                if(Nremain > 1){
                    verbose(1, "Exposing frame %d...", nframe+1);
                    SENDMSGW(CC_CMD_EXPSTATE, "=%d", CAMERA_CAPTURE);
                }
                verbose(2, "Frame ready, try to grab");
                int failed = TRUE;
                if(!getimage(TRUE)){
                    WARNX("Can't get next image");
                }else{
                    if(saveFITS(&ima, &lastfilename)){
                        --Nremain;
                        ++nframe;
                        failed = FALSE;
                    }
                }
                if(failed && Nremain == 1){ // last image -> should re-expose
                    verbose(1, "Exposing frame %d...", nframe);
                    SENDMSGW(CC_CMD_EXPSTATE, "=%d", CAMERA_CAPTURE);
                }
                if(Nremain > 0){
                    if(GP->pause_len > 0){
                        double delta, time1 = sl_dtime() + GP->pause_len;
                        while(1){
                            SENDCMDW(CC_CMD_CAMTEMPER);
                            if((delta = time1 - sl_dtime()) < __FLT_EPSILON__) break;
                            if(delta > 1.) verbose(1, _("%d seconds till pause ends\n"), (int)delta);
                            if(delta > 6.) sleep(5);
                            else if(delta > 1.) sleep((int)delta);
                            else usleep((int)(delta*1e6 + 1));
                        }
                    }
                }else{
                    GP->waitexpend = 0;
                    DBG("All images saved -> exit");
                    break;
                }
            }
        }
    }
    if(GP->waitexpend) WARNX(_("Server timeout"));
}

#ifdef IMAGEVIEW
static int controlfd = -1; // control socket FD
void init_grab_sock(int sock){
    if(sock < 0) ERRX("Can't run without command socket");
    controlfd = sock;
    send_headers(sock);
    if(!GP->forceimsock && !shmima){ // init shm buffer if user don't ask to work through image socket
        shmima = cc_getshm(GP->shmkey, 0); // try to init client shm
    }
}

// grab image for active viewer
static void *grabnext(void _U_ *arg){
    FNAME();
    if(controlfd < 0) return NULL;
    int sock = controlfd;
    while(1){
        if(!getWin()) exit(1);
        TIMESTAMP("End of cycle, start new");
        atomic_store(&expstate, CAMERA_CAPTURE);
        TIMEINIT();
        SENDMSGW(CC_CMD_EXPSTATE, "=%d", CAMERA_CAPTURE); // start capture
        double timeout = GP->exptime + CC_CLIENT_TIMEOUT, t0 = sl_dtime();
        useconds_t sleept = 500000; // 0.5s
        if(GP->exptime < 0.5){
            sleept = (useconds_t)(GP->exptime * 500000.);
            if(sleept < 1000) sleept = 1000;
        }
//        double exptime = GP->exptime;
        TIMESTAMP("Wait for exposition ends (%g s)", timeout);
        while(sl_dtime() - t0 < timeout){
            usleep(sleept);
       //     getans(sock, NULL);
            //TIMESTAMP("EXPSTATE ===> %d", expstate);
            if(atomic_load(&expstate) != CAMERA_CAPTURE) break;
            if(sl_dtime() - t0 < GP->exptime + 0.5) sleept = 1000;
        }
        if(sl_dtime() - t0 >= timeout || atomic_load(&expstate) != CAMERA_FRAMERDY){
            WARNX("Image wasn't received");
            continue;
        }
        TIMESTAMP("Frame ready");
        getimage(FALSE);
    }
    return NULL;
}

// passive waiting for next image
static void *waitimage(void _U_ *arg){
    FNAME();
    if(controlfd < 0) return NULL;
    int sock = controlfd;
    while(1){
        if(!getWin()) exit(1);
        getans(sock, NULL);
        if(atomic_load(&expstate) != CAMERA_FRAMERDY){
            usleep(1000);
            continue;
        }
        TIMESTAMP("End of cycle, start new");
        TIMEINIT();
        getimage(FALSE);
        atomic_store(&expstate, CAMERA_IDLE);
    }
    return NULL;
}

// try to capture images for viewer
int sockcaptured(cc_IMG **imgptr){
    //TIMESTAMP("sockcaptured() start");
    if(!imgptr) return FALSE;
    static pthread_t grabthread = 0;
    if(controlfd < 0) return FALSE;
    if(imgptr == (void*)-1){ // kill `grabnext`
        DBG("Wait for grabbing thread");
        if(grabthread){
            pthread_cancel(grabthread);
            pthread_join(grabthread, NULL);
            grabthread = 0;
        }
        DBG("OK");
        return FALSE;
    }
    if(!grabthread || pthread_kill(grabthread, 0)){ // start new grab
        if(GP->viewer){
            TIMEINIT();
            DBG("\n\n\nStart new waiting");
            if(pthread_create(&grabthread, NULL, &waitimage, NULL)){
                WARN("Can't create waiting thread");
                grabthread = 0;
           }
        }else{
            TIMEINIT();
            DBG("\n\n\nStart new grab");
            if(pthread_create(&grabthread, NULL, &grabnext, NULL)){
                WARN("Can't create grabbing thread");
                grabthread = 0;
           }
        }
    }else{ // grab in process
        int curno = atomic_load(&grabno);
        if(curno != oldgrabno){ // image is ready
            TIMESTAMP("Image #%d ready", curno);
            if(*imgptr && (*imgptr != &ima)) free(*imgptr);
            *imgptr = &ima;
            oldgrabno = curno;
            framerate();
            //TIMESTAMP("sockcaptured() end, return TRUE");
            return TRUE;
        }
    }
    //TIMESTAMP("sockcaptured() end, return FALSE");
    return FALSE;
}
// IMAGEVIEW
#endif