/**
 * Marlin 3D Printer Firmware
 * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
 *
 * 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/>.
 *
 */

/**
 * M421: Set a single Mesh Bed Leveling Z coordinate
 *
 * Usage:
 *   M421 I<xindex> J<yindex> Z<linear>
 *   M421 I<xindex> J<yindex> Q<offset>
 *   M421 C Z<linear>
 *   M421 C Q<offset>
 */
void gcode_M421() {
  int8_t ix = parser.intval('I', -1), iy = parser.intval('J', -1);
  const bool hasI = ix >= 0,
             hasJ = iy >= 0,
             hasC = parser.seen('C'),
             hasZ = parser.seen('Z'),
             hasQ = !hasZ && parser.seen('Q');

  if (hasC) {
    const mesh_index_pair location = ubl.find_closest_mesh_point_of_type(REAL, current_position[X_AXIS], current_position[Y_AXIS], USE_NOZZLE_AS_REFERENCE, NULL, false);
    ix = location.x_index;
    iy = location.y_index;
  }

  if (int(hasC) + int(hasI && hasJ) != 1 || !(hasZ || hasQ)) {
    SERIAL_ERROR_START();
    SERIAL_ERRORLNPGM(MSG_ERR_M421_PARAMETERS);
  }
  else if (!WITHIN(ix, 0, GRID_MAX_POINTS_X - 1) || !WITHIN(iy, 0, GRID_MAX_POINTS_Y - 1)) {
    SERIAL_ERROR_START();
    SERIAL_ERRORLNPGM(MSG_ERR_MESH_XY);
  }
  else
    ubl.z_values[ix][iy] = parser.value_linear_units() + (hasQ ? ubl.z_values[ix][iy] : 0);
}