//
// ZoneMinder Stream Class Implementation, $Date$, $Revision$
// Copyright (C) 2001-2008 Philip Coombes
//
// 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 2
// 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, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//

#include "zm_stream.h"

#include "zm_box.h"
#include "zm_monitor.h"
#include "zm_signal.h"

#include <cmath>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <unistd.h>

constexpr Seconds StreamBase::MAX_STREAM_DELAY;
constexpr Milliseconds StreamBase::MAX_SLEEP;

StreamBase::~StreamBase() {
  delete vid_stream;
  delete[] temp_img_buffer;
  closeComms();
}

bool StreamBase::loadMonitor(int p_monitor_id) {
  monitor_id = p_monitor_id;

  if ( !(monitor or (monitor = Monitor::Load(monitor_id, false, Monitor::QUERY))) ) {
    Error("Unable to load monitor id %d for streaming", monitor_id);
    return false;
  }

  if (monitor->Capturing() == Monitor::CAPTURING_NONE) {
    Info("Monitor %d has capturing == NONE. Will not be able to connect to it.", monitor_id);
    return false;
  }

  // Hold monitor_mutex during disconnect/connect to prevent the command
  // processor thread from accessing shared memory while it is remapped.
  std::lock_guard<std::mutex> lck(monitor_mutex);

  if (monitor->isConnected()) {
    monitor->disconnect();
  }

  if (!monitor->connect()) {
    Info("Unable to connect to monitor id %d for streaming", monitor_id);
    monitor->disconnect();
    // If we couldn't connect, it might be due to size mismatch in shm. Need to reload
    if ( !(monitor = Monitor::Load(monitor_id, false, Monitor::QUERY)))
      Error("Unable to reload monitor id %d for streaming", monitor_id);
    return false;
  }

  return true;
}

bool StreamBase::checkInitialised() {
  if (!monitor) {
    Error("Cannot stream, not initialised");
    return false;
  }
  if (monitor->Capturing() == Monitor::CAPTURING_NONE) {
    Info("Monitor %d has capturing == NONE. Will not be able to connect to it.", monitor_id);
    return false;
  }
  if (!monitor->ShmValid()) {
    Debug(1, "Monitor shm is not connected");
    return false;
  }
  if ((monitor->GetType() == Monitor::FFMPEG) and (monitor->Decoding() == Monitor::DECODING_NONE) ) {
    Debug(1, "Monitor is not decoding.");
    return false;
  }
  return true;
}

void StreamBase::updateFrameRate(double fps) {
  if ( (fps < 0) || !fps || std::isinf(fps) ) {
    Debug(1, "Zero or negative fps %f in updateFrameRate. Setting frame_mod=1 and effective_fps=0.0", fps);
    effective_fps = 0.0;
    base_fps = 0.0;
    return;
  }

  // Snapshot once so the loop below cannot see maxfps change underneath it.
  const double max_fps = maxfps.load();
  const int rate = replay_rate.load();

  base_fps = fps;
  effective_fps = (base_fps*abs(rate))/ZM_RATE_BASE;
  frame_mod = 1;
  Debug(3, "FPS:%.2f, MaxFPS:%.2f, BaseFPS:%.2f, EffectiveFPS:%.2f, FrameMod:%d, replay_rate(%d)",
        fps, max_fps, base_fps, effective_fps, frame_mod, rate);
  if (max_fps > 0.0) {
    // Min frame repeat?
    // We want to keep the frame skip easy... problem is ... if effective = 31 and max = 30 then we end up with 15.5 fps.
    while ( (int)effective_fps > (int)max_fps ) {
      effective_fps /= 2.0;
      frame_mod *= 2;
      Debug(3, "Changing fps to be < max %.2f EffectiveFPS:%.2f, FrameMod:%d",
            max_fps, effective_fps, frame_mod);
    }
  }
} // void StreamBase::updateFrameRate(double fps)

void StreamBase::checkCommandQueue() {
  while (!zm_terminate) {
    // Update modified time of the socket .lock file so that we can tell which ones are stale.
    if (now - last_comm_update > Hours(1)) {
      touch(sock_path_lock);
      last_comm_update = now;
    }

    if (sd >= 0) {
      CmdMsg msg;
      memset(&msg, 0, sizeof(msg));
      int nbytes = recvfrom(sd, &msg, sizeof(msg), 0, /*MSG_DONTWAIT*/ 0, 0);
      if (nbytes < 0) {
        if (errno != EAGAIN) {
          Error("recvfrom(), errno = %d, error = %s", errno, strerror(errno));
        }
      } else {
        Debug(2, "Message length is (%d)", nbytes);
        processCommand(&msg);
        got_command = true;
      }
    } else if (connkey) {
      Warning("No sd in checkCommandQueue, comms not open for connkey %06d?", connkey);
    } else {
      // Perfectly valid if only getting a snapshot
      Debug(1, "No sd in checkCommandQueue, comms not open.");
    }
  } // end while !zm_terminate
}  // end void StreamBase::checkCommandQueue()

int StreamBase::preScaleDimensions(int base_width, int base_height, int &width, int &height) const {
  // Any zoom crops before scaling and needs the full resolution to crop out of.
  if (zoom.load() != ZM_SCALE_BASE) return 0;

  const int cur_scale = scale.load();
  if (cur_scale == ZM_SCALE_BASE) return 0;

  const int scaled_width = (base_width * cur_scale) / ZM_SCALE_BASE;
  const int scaled_height = (base_height * cur_scale) / ZM_SCALE_BASE;
  // CMD_SCALE stores whatever the client sent, so 0 gets here. Image::Scale
  // refuses a zero factor, but converting straight to 0x0 would instead put a
  // negative av_image_get_buffer_size result into an unsigned size and allocate
  // on it, so leave anything degenerate to the path that already rejects it.
  if ((scaled_width <= 0) or (scaled_height <= 0)) return 0;

  width = scaled_width;
  height = scaled_height;
  return cur_scale;
}

Image *StreamBase::prepareImage(Image *image, int pre_scaled_by) {
  if (pre_scaled_by) {
    // The caller produced the image at exactly the size to send, folding the
    // scale into a colour conversion it had to do anyway. Send it untouched.
    //
    // The command thread can change scale or zoom between the caller reading
    // them and this call, in which case this one frame goes out at the scale it
    // was built for and without any new zoom, and the next frame is built from
    // the new values. Scaling here instead would apply the scale a second time
    // (a 50% frame of a 640px source would go out at 160px, not 320px), and
    // cropping here would do it in the reduced image's coordinates and leave
    // last_crop in the wrong units for every later frame. refs #3681
    Debug(3, "Sending pre-scaled %dx%d, scale %d", image->Width(), image->Height(), pre_scaled_by);
    last_scale = pre_scaled_by;
    last_zoom = ZM_SCALE_BASE;
    return image;
  }

  /* zooming should happen before scaling to preserve quality
   * scale is relative to base dimensions, and represents the rough ratio between desired view size and base dimensions
   */
  bool image_copied = false;

  // Snapshot the pan/zoom/scale state once. The command thread can change any
  // of these at any point, and the crop below is derived from all three
  // together, so re-reading them mid-calculation could mix a new zoom with an
  // old click position and produce a crop that matches neither.
  const int cur_zoom = zoom.load();
  const int cur_scale = scale.load();
  const unsigned short cur_x = x.load();
  const unsigned short cur_y = y.load();

  if (cur_zoom != 100) {
    int base_image_width = image->Width(),
        base_image_height = image->Height(),
        disp_image_width = image->Width() * cur_scale/ZM_SCALE_BASE,
        disp_image_height = image->Height() * cur_scale / ZM_SCALE_BASE;
    /* x and y are scaled by web UI to base dimensions units.
     * When zooming, we blow up the image by the amount 150 for first zoom, right? 150%, then cut out a base sized chunk
     * However if we have zoomed before, then we are zooming into the previous cutout
     * The box stored in last_crop should be in base_image units, So we need to turn x,y into percentages, then apply to last_crop
     */
    if (!last_crop.Hi().x_ && !last_crop.Hi().y_) last_crop = Box({0, 0}, {base_image_width, base_image_height});

    double x_percent = static_cast<double>(cur_x * ZM_SCALE_BASE) / base_image_width;
    double y_percent = static_cast<double>(cur_y * ZM_SCALE_BASE) / base_image_height;
    Debug(2, "click percent %dx%d => %.2fx%.2f", cur_x, cur_y, x_percent, y_percent);

    // If we were previously zoomed in, then the coordinate percentages are into the crop, so calculate the click coordinates in base image
    int crop_x = last_crop.Lo().x_ + (x_percent * last_crop.Width() / ZM_SCALE_BASE);
    int crop_y = last_crop.Lo().y_ + (y_percent * last_crop.Height() / ZM_SCALE_BASE);
    Debug(2, "crop click %dx%d => %dx%d out of %dx%d", cur_x, cur_y, crop_x, crop_y, last_crop.Width(), last_crop.Height());

    int zoom_image_width = base_image_width * cur_zoom / ZM_SCALE_BASE,
        zoom_image_height = base_image_height * cur_zoom / ZM_SCALE_BASE,
        click_x = crop_x * cur_zoom / ZM_SCALE_BASE,
        click_y = crop_y * cur_zoom / ZM_SCALE_BASE;
    Debug(2, "adjusted click %dx%d * %d zoom => %dx%d out of %dx%d", cur_x, cur_y, cur_zoom, click_x, click_y, zoom_image_width, zoom_image_height);

    // These can go out of image. Resulting size will be less than base image. That's ok.
    // We don't want to center it, we want to keep the relative offset from center where the click is.
    int left_dist = base_image_width * x_percent/ZM_SCALE_BASE;
    int top_dist = base_image_height * y_percent/ZM_SCALE_BASE;
    Debug(2, "Dest at %d,%d", left_dist, top_dist);

    int lo_x = click_x - left_dist;
    int hi_x = lo_x + base_image_width;
    Debug(2, "hi_x = lo_x %d + base_image_width %d - left_dist %d = %d", lo_x, base_image_width, left_dist, hi_x);
    int lo_y = click_y - top_dist;
    int hi_y = lo_y + base_image_height;
    Debug(2, "hi_y = lo_y %d + base_image_h %d - top_dist %d = %d", lo_y, base_image_height, top_dist, hi_y);

    int amount_to_shrink_y = 0;
    if (lo_x < 0) {
      amount_to_shrink_y = (-1 * lo_x) * base_image_height / base_image_width;
      lo_x = 0;
    } else if (hi_x >= zoom_image_width) {
      amount_to_shrink_y = (hi_x - zoom_image_width) * base_image_height / base_image_width;
      hi_x = zoom_image_width - 1;
    }
    Debug(1, "Shrinking y by %d from %d,%d to %d,%d", amount_to_shrink_y, lo_y, hi_y, lo_y+(amount_to_shrink_y/2), hi_y-(amount_to_shrink_y/2));
    if (amount_to_shrink_y) {
      lo_y += amount_to_shrink_y/2;
      hi_y -= amount_to_shrink_y/2;
    }

    int amount_to_shrink_x = 0;
    if (lo_y < 0) {
      amount_to_shrink_x = (-1 * lo_y) * base_image_width / base_image_height;
      Debug(1, "%d to %d = %d", lo_y, -1*lo_y, amount_to_shrink_x);
      lo_y = 0;
    } else if (hi_y >= zoom_image_height) {
      amount_to_shrink_x = (hi_y - zoom_image_height) * base_image_width / base_image_height;
      hi_y = zoom_image_height - 1;
    }
    Debug(1, "Shrinking x by %d from %d,%d to %d,%d", amount_to_shrink_x, lo_x, hi_x, lo_x+(amount_to_shrink_x/2), hi_x-(amount_to_shrink_x/2));
    if (amount_to_shrink_x) {
      lo_x += amount_to_shrink_x/2;
      hi_x -= amount_to_shrink_x/2;
    }

    Debug(3, "Cropping to %d,%d -> %d,%d %dx%din blown up image", lo_x, lo_y, hi_x, hi_y, hi_x-lo_x, hi_y-lo_y);
    // Scaled back to base_image dimensions
    last_crop = Box({lo_x*ZM_SCALE_BASE/zoom, lo_y*ZM_SCALE_BASE/zoom}, {hi_x*ZM_SCALE_BASE/zoom, hi_y*ZM_SCALE_BASE/zoom});

    Debug(3, "Cropping to %d,%d -> %d,%d", last_crop.Lo().x_, last_crop.Lo().y_, last_crop.Hi().x_, last_crop.Hi().y_);
    if ( !image_copied ) {
      static Image copy_image;
      copy_image.Assign(*image);
      image = &copy_image;
      image_copied = true;
    }
    image->Crop(last_crop);
    image->Scale(disp_image_width, disp_image_height);
  } else if (cur_scale != ZM_SCALE_BASE) {
    Debug(3, "scaling by %d from %dx%d", cur_scale, image->Width(), image->Height());
    static Image copy_image;
    copy_image.Assign(*image);
    image = &copy_image;
    image_copied = true;
    image->Scale(cur_scale);
  }
  Debug(3, "Sending %dx%d", image->Width(), image->Height());

  // Record what was actually rendered, not whatever the command thread may
  // have set since.
  last_scale = cur_scale;
  last_zoom = cur_zoom;
  last_x = cur_x;
  last_y = cur_y;

  return image;
}  // end Image *StreamBase::prepareImage(Image *image, int pre_scaled_by)

bool StreamBase::sendTextFrame(const char *frame_text) {
  int width = 640;
  int height = 480;
  int colours = ZM_COLOUR_RGB32;
  int subpixelorder = ZM_SUBPIX_ORDER_RGBA;
  int labelsize = 2;

  if (monitor) {
    width = monitor->Width();
    height = monitor->Height();
    colours = monitor->Colours();
    subpixelorder = monitor->SubpixelOrder();
    labelsize = monitor->LabelSize();
  }
  Debug(2, "Sending %dx%dx%dx%d * %d scale text frame '%s'",
        width, height, colours, subpixelorder, scale.load(), frame_text);

  Image image(width, height, colours, subpixelorder);
  image.Clear();
  image.Annotate(frame_text, image.centreCoord(frame_text, labelsize), labelsize);

  if (scale != 100) {
    image.Scale(scale);
    Debug(2, "Scaled to %dx%d", image.Width(), image.Height());
  }
  if (type == STREAM_MPEG) {
    if (!vid_stream) {
      vid_stream = new VideoStream("pipe:", format, bitrate, effective_fps, image.Colours(), image.SubpixelOrder(), image.Width(), image.Height());
      fprintf(stdout, "Content-Type: %s\r\n\r\n", vid_stream->MimeType());
      if (!vid_stream->OpenStream()) {
        Error("Failed to open video stream");
        delete vid_stream;
        vid_stream = nullptr;
        return false;
      }
    }
    /* double pts = */ vid_stream->EncodeFrame(image.Buffer(), image.Size());
  } else {
    static unsigned char buffer[ZM_MAX_IMAGE_SIZE];
    size_t n_bytes = 0;

    image.EncodeJpeg(buffer, &n_bytes);

    if (type == STREAM_JPEG) {
      if (0 > fputs("--" BOUNDARY "\r\n", stdout)) {
        Debug(1, "Error sending  --" BOUNDARY "\r\n");
        return false;
      }
    }
    if (0 > fprintf(stdout, "Content-Type: image/jpeg\r\nContent-Length: %zu\r\n\r\n", n_bytes)) {
      Debug(1, "Error sending Content-Type: image/jpeg\r\nContent-Length: %zu\r\n\r\n", n_bytes);
      return false;
    }
    int rc = fwrite(buffer, n_bytes, 1, stdout);
    if (rc != 1) {
      if (!zm_terminate)
        Error("Unable to send stream text frame: %d %s", rc, strerror(errno));
      return false;
    }
    fputs("\r\n\r\n", stdout);
    fflush(stdout);
  }
  last_frame_sent = now;
  return true;
}

void StreamBase::openComms() {
  if ( connkey > 0 ) {

    // Have to mkdir because systemd is now chrooting and the dir may not exist
    if ( mkdir(staticConfig.PATH_SOCKS.c_str(), 0755) ) {
      if ( errno != EEXIST ) {
        Error("Can't mkdir ZM_PATH_SOCKS %s: %s.", staticConfig.PATH_SOCKS.c_str(), strerror(errno));
      }
    }

    unsigned int length = snprintf(
                            sock_path_lock,
                            sizeof(sock_path_lock),
                            "%s/zms-%06d.lock",
                            staticConfig.PATH_SOCKS.c_str(),
                            connkey
                          );
    if ( length >= sizeof(sock_path_lock) ) {
      Warning("Socket lock path was truncated.");
    }
    Debug(1, "Trying to open the lock on %s", sock_path_lock);

    // Under systemd, we get chrooted to something like /tmp/systemd-apache-blh/ so the dir may not exist.
    if ( mkdir(staticConfig.PATH_SOCKS.c_str(), 0755) ) {
      if ( errno != EEXIST ) {
        Error("Can't mkdir %s: %s", staticConfig.PATH_SOCKS.c_str(), strerror(errno));
        return;
      } else {
        Debug(3, "SOCKS dir %s already exists", staticConfig.PATH_SOCKS.c_str() );
      }
    } else {
      Debug(3, "Success making SOCKS dir %s", staticConfig.PATH_SOCKS.c_str() );
    }

    lock_fd = open(sock_path_lock, O_CREAT|O_WRONLY, S_IRUSR | S_IWUSR);
    if ( lock_fd < 0 ) {
      Error("Unable to open sock lock file %s: %s", sock_path_lock, strerror(errno));
      lock_fd = -1;
    } else if ( flock(lock_fd, LOCK_EX) != 0 ) {
      Error("Unable to lock sock lock file %s: %s", sock_path_lock, strerror(errno));
      close(lock_fd);
      lock_fd = -1;
    } else {
      Debug(1, "We have obtained a lock on %s fd: %d", sock_path_lock, lock_fd);
    }

    sd = socket(AF_UNIX, SOCK_DGRAM, 0);
    if ( sd < 0 ) {
      Fatal("Can't create socket: %s", strerror(errno));
    } else {
      Debug(3, "Have socket %d", sd);
    }

    length = snprintf(
               loc_sock_path,
               sizeof(loc_sock_path),
               "%s/zms-%06ds.sock",
               staticConfig.PATH_SOCKS.c_str(),
               connkey
             );
    if ( length >= sizeof(loc_sock_path) ) {
      Warning("Socket path was truncated.");
      length = sizeof(loc_sock_path)-1;
    }
    // Unlink before bind, in case it already exists
    unlink(loc_sock_path);
    if ( sizeof(loc_addr.sun_path) < length ) {
      Error("Not enough space %zu in loc_addr.sun_path for socket file %s", sizeof(loc_addr.sun_path), loc_sock_path);
    }

    strncpy(loc_addr.sun_path, loc_sock_path, sizeof(loc_addr.sun_path));
    loc_addr.sun_family = AF_UNIX;
    Debug(3, "Binding to %s", loc_sock_path);
    if ( ::bind(sd, (struct sockaddr *)&loc_addr, strlen(loc_addr.sun_path)+sizeof(loc_addr.sun_family)+1) < 0 ) {
      Fatal("Can't bind: %s", strerror(errno));
    }

    snprintf(rem_sock_path, sizeof(rem_sock_path), "%s/zms-%06dw.sock", staticConfig.PATH_SOCKS.c_str(), connkey);
    strncpy(rem_addr.sun_path, rem_sock_path, sizeof(rem_addr.sun_path));
    rem_addr.sun_family = AF_UNIX;

    struct timeval tv {1,0}; /* 1 Secs Timeout */
    setsockopt(sd, SOL_SOCKET, SO_RCVTIMEO,(struct timeval *)&tv, sizeof(struct timeval));

    last_comm_update = std::chrono::steady_clock::now();
    Debug(3, "comms open at %s", loc_sock_path);
  } // end if connKey > 0
} // end void StreamBase::openComms()

void StreamBase::closeComms() {
  if ( connkey > 0 ) {
    if ( sd >= 0 ) {
      close(sd);
      sd = -1;
    }
    // Remove our command socket, but only while we still hold the lock, and only
    // if we actually got the lock.
    //
    // Note this is zms-<connkey>s.sock, not the .lock file. A second zms sharing
    // this connkey is blocked in flock(LOCK_EX) on the .lock file, and the first
    // thing it does after winning that lock is unlink this very path itself
    // ("Unlink before bind" in openComms()). It never reads our socket file, so
    // removing it here only does early what our successor would do anyway.
    //
    // Ordering matters: if we unlinked after releasing the lock we could delete
    // a socket the successor had already bound, leaving it unreachable.
    //
    // The lock_fd guard matters because openComms() carries on and binds even
    // when it fails to take the lock, so without it a lockless zms could delete
    // a socket belonging to the zms that does hold the lock. Leaking the file in
    // that case is no worse than the behaviour before this check existed.
    //
    // This is worth doing because web/ajax/stream.php uses file_exists() on this
    // path to decide whether zms is listening. A socket left behind by an exited
    // zms makes that check succeed, so the sendto() fails with ECONNREFUSED
    // instead of waiting for the new process to bind, and the command is lost.
    if ( (lock_fd >= 0) && loc_sock_path[0]
         && (unlink(loc_sock_path) < 0) && (errno != ENOENT) ) {
      Warning("Failed to unlink '%s': %s", loc_sock_path, strerror(errno));
    }
    // Don't unlink sock_path_lock: another zms may already be waiting on it.
    if ( lock_fd >= 0 ) {
      close(lock_fd); //close it rather than unlock it in case it got deleted.
      lock_fd = -1;
    }
  }
} // end void StreamBase::closeComms

void StreamBase::reserveTempImgBuffer(size_t size) {
  if (temp_img_buffer_size < size) {
    Debug(1, "Resizing image buffer from %zu to %zu", temp_img_buffer_size, size);
    delete[] temp_img_buffer;
    temp_img_buffer = new uint8_t[size];
    temp_img_buffer_size = size;
  }
}