/**
 * 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/>.
 *
 */
#include "MarlinConfig.h"

#if ENABLED(AUTO_BED_LEVELING_UBL)

  #include "Marlin.h"
  #include "ubl.h"
  #include "planner.h"
  #include <avr/io.h>
  #include <math.h>

  extern float destination[XYZE];
  extern void set_current_to_destination();

  static void debug_echo_axis(const AxisEnum axis) {
    if (current_position[axis] == destination[axis])
      SERIAL_ECHOPGM("-------------");
    else
      SERIAL_ECHO_F(destination[X_AXIS], 6);
  }

  void debug_current_and_destination(const char *title) {

    // if the title message starts with a '!' it is so important, we are going to
    // ignore the status of the g26_debug_flag
    if (*title != '!' && !ubl.g26_debug_flag) return;

    const float de = destination[E_AXIS] - current_position[E_AXIS];

    if (de == 0.0) return;

    const float dx = current_position[X_AXIS] - destination[X_AXIS],
                dy = current_position[Y_AXIS] - destination[Y_AXIS],
                xy_dist = HYPOT(dx, dy);

    if (xy_dist == 0.0) {
      return;
      //SERIAL_ECHOPGM("   FPMM=");
      //const float fpmm = de / xy_dist;
      //SERIAL_PROTOCOL_F(fpmm, 6);
    }
    else {
      SERIAL_ECHOPGM("   fpmm=");
      const float fpmm = de / xy_dist;
      SERIAL_ECHO_F(fpmm, 6);
    }

    SERIAL_ECHOPGM("    current=( ");
    SERIAL_ECHO_F(current_position[X_AXIS], 6);
    SERIAL_ECHOPGM(", ");
    SERIAL_ECHO_F(current_position[Y_AXIS], 6);
    SERIAL_ECHOPGM(", ");
    SERIAL_ECHO_F(current_position[Z_AXIS], 6);
    SERIAL_ECHOPGM(", ");
    SERIAL_ECHO_F(current_position[E_AXIS], 6);
    SERIAL_ECHOPGM(" )   destination=( ");
    debug_echo_axis(X_AXIS);
    SERIAL_ECHOPGM(", ");
    debug_echo_axis(Y_AXIS);
    SERIAL_ECHOPGM(", ");
    debug_echo_axis(Z_AXIS);
    SERIAL_ECHOPGM(", ");
    debug_echo_axis(E_AXIS);
    SERIAL_ECHOPGM(" )   ");
    SERIAL_ECHO(title);
    SERIAL_EOL;

  }

  void ubl_line_to_destination(const float &feed_rate, uint8_t extruder) {
    /**
     * Much of the nozzle movement will be within the same cell. So we will do as little computation
     * as possible to determine if this is the case. If this move is within the same cell, we will
     * just do the required Z-Height correction, call the Planner's buffer_line() routine, and leave
     */
    const float start[XYZE] = {
                  current_position[X_AXIS],
                  current_position[Y_AXIS],
                  current_position[Z_AXIS],
                  current_position[E_AXIS]
                },
                end[XYZE] = {
                  destination[X_AXIS],
                  destination[Y_AXIS],
                  destination[Z_AXIS],
                  destination[E_AXIS]
                };

    const int cell_start_xi = ubl.get_cell_index_x(RAW_X_POSITION(start[X_AXIS])),
              cell_start_yi = ubl.get_cell_index_y(RAW_Y_POSITION(start[Y_AXIS])),
              cell_dest_xi  = ubl.get_cell_index_x(RAW_X_POSITION(end[X_AXIS])),
              cell_dest_yi  = ubl.get_cell_index_y(RAW_Y_POSITION(end[Y_AXIS]));

    if (ubl.g26_debug_flag) {
      SERIAL_ECHOPAIR(" ubl_line_to_destination(xe=", end[X_AXIS]);
      SERIAL_ECHOPAIR(", ye=", end[Y_AXIS]);
      SERIAL_ECHOPAIR(", ze=", end[Z_AXIS]);
      SERIAL_ECHOPAIR(", ee=", end[E_AXIS]);
      SERIAL_CHAR(')');
      SERIAL_EOL;
      debug_current_and_destination(PSTR("Start of ubl_line_to_destination()"));
    }

    if (cell_start_xi == cell_dest_xi && cell_start_yi == cell_dest_yi) { // if the whole move is within the same cell,
      /**
       * we don't need to break up the move
       *
       * If we are moving off the print bed, we are going to allow the move at this level.
       * But we detect it and isolate it. For now, we just pass along the request.
       */

      if (!WITHIN(cell_dest_xi, 0, GRID_MAX_POINTS_X - 1) || !WITHIN(cell_dest_yi, 0, GRID_MAX_POINTS_Y - 1)) {

        // Note: There is no Z Correction in this case. We are off the grid and don't know what
        // a reasonable correction would be.

        planner.buffer_line(end[X_AXIS], end[Y_AXIS], end[Z_AXIS] + ubl.state.z_offset, end[E_AXIS], feed_rate, extruder);
        set_current_to_destination();

        if (ubl.g26_debug_flag)
          debug_current_and_destination(PSTR("out of bounds in ubl_line_to_destination()"));

        return;
      }

      FINAL_MOVE:

      /**
       * Optimize some floating point operations here. We could call float get_z_correction(float x0, float y0) to
       * generate the correction for us. But we can lighten the load on the CPU by doing a modified version of the function.
       * We are going to only calculate the amount we are from the first mesh line towards the second mesh line once.
       * We will use this fraction in both of the original two Z Height calculations for the bi-linear interpolation. And,
       * instead of doing a generic divide of the distance, we know the distance is MESH_X_DIST so we can use the preprocessor
       * to create a 1-over number for us. That will allow us to do a floating point multiply instead of a floating point divide.
       */

      const float xratio = (RAW_X_POSITION(end[X_AXIS]) - pgm_read_float(&ubl.mesh_index_to_xpos[cell_dest_xi])) * (1.0 / (MESH_X_DIST)),
                  z1 = ubl.z_values[cell_dest_xi    ][cell_dest_yi    ] + xratio *
                      (ubl.z_values[cell_dest_xi + 1][cell_dest_yi    ] - ubl.z_values[cell_dest_xi][cell_dest_yi    ]),
                  z2 = ubl.z_values[cell_dest_xi    ][cell_dest_yi + 1] + xratio *
                      (ubl.z_values[cell_dest_xi + 1][cell_dest_yi + 1] - ubl.z_values[cell_dest_xi][cell_dest_yi + 1]);

      // we are done with the fractional X distance into the cell. Now with the two Z-Heights we have calculated, we
      // are going to apply the Y-Distance into the cell to interpolate the final Z correction.

      const float yratio = (RAW_Y_POSITION(end[Y_AXIS]) - pgm_read_float(&ubl.mesh_index_to_ypos[cell_dest_yi])) * (1.0 / (MESH_Y_DIST));

      float z0 = z1 + (z2 - z1) * yratio;

      z0 *= ubl.fade_scaling_factor_for_z(end[Z_AXIS]);

      /**
       * If part of the Mesh is undefined, it will show up as NAN
       * in z_values[][] and propagate through the
       * calculations. If our correction is NAN, we throw it out
       * because part of the Mesh is undefined and we don't have the
       * information we need to complete the height correction.
       */
      if (isnan(z0)) z0 = 0.0;

      planner.buffer_line(end[X_AXIS], end[Y_AXIS], end[Z_AXIS] + z0 + ubl.state.z_offset, end[E_AXIS], feed_rate, extruder);

      if (ubl.g26_debug_flag)
        debug_current_and_destination(PSTR("FINAL_MOVE in ubl_line_to_destination()"));

      set_current_to_destination();
      return;
    }

    /**
     * If we get here, we are processing a move that crosses at least one Mesh Line. We will check
     * for the simple case of just crossing X or just crossing Y Mesh Lines after we get all the details
     * of the move figured out. We can process the easy case of just crossing an X or Y Mesh Line with less
     * computation and in fact most lines are of this nature. We will check for that in the following
     * blocks of code:
     */

    const float dx = end[X_AXIS] - start[X_AXIS],
                dy = end[Y_AXIS] - start[Y_AXIS];

    const int left_flag = dx < 0.0 ? 1 : 0,
              down_flag = dy < 0.0 ? 1 : 0;

    const float adx = left_flag ? -dx : dx,
                ady = down_flag ? -dy : dy;

    const int dxi = cell_start_xi == cell_dest_xi ? 0 : left_flag ? -1 : 1,
              dyi = cell_start_yi == cell_dest_yi ? 0 : down_flag ? -1 : 1;

    /**
     * Compute the scaling factor for the extruder for each partial move.
     * We need to watch out for zero length moves because it will cause us to
     * have an infinate scaling factor. We are stuck doing a floating point
     * divide to get our scaling factor, but after that, we just multiply by this
     * number. We also pick our scaling factor based on whether the X or Y
     * component is larger. We use the biggest of the two to preserve precision.
     */

    const bool use_x_dist = adx > ady;

    float on_axis_distance = use_x_dist ? dx : dy,
          e_position = end[E_AXIS] - start[E_AXIS],
          z_position = end[Z_AXIS] - start[Z_AXIS];

    const float e_normalized_dist = e_position / on_axis_distance,
                z_normalized_dist = z_position / on_axis_distance;

    int current_xi = cell_start_xi,
        current_yi = cell_start_yi;

    const float m = dy / dx,
                c = start[Y_AXIS] - m * start[X_AXIS];

    const bool inf_normalized_flag = isinf(e_normalized_dist),
               inf_m_flag = isinf(m);
    /**
     * This block handles vertical lines. These are lines that stay within the same
     * X Cell column. They do not need to be perfectly vertical. They just can
     * not cross into another X Cell column.
     */
    if (dxi == 0) {       // Check for a vertical line
      current_yi += down_flag;  // Line is heading down, we just want to go to the bottom
      while (current_yi != cell_dest_yi + down_flag) {
        current_yi += dyi;
        const float next_mesh_line_y = LOGICAL_Y_POSITION(pgm_read_float(&ubl.mesh_index_to_ypos[current_yi]));

        /**
         * if the slope of the line is infinite, we won't do the calculations
         * else, we know the next X is the same so we can recover and continue!
         * Calculate X at the next Y mesh line
         */
        const float x = inf_m_flag ? start[X_AXIS] : (next_mesh_line_y - c) / m;

        float z0 = ubl.z_correction_for_x_on_horizontal_mesh_line(x, current_xi, current_yi);

        z0 *= ubl.fade_scaling_factor_for_z(end[Z_AXIS]);

        /**
         * If part of the Mesh is undefined, it will show up as NAN
         * in z_values[][] and propagate through the
         * calculations. If our correction is NAN, we throw it out
         * because part of the Mesh is undefined and we don't have the
         * information we need to complete the height correction.
         */
        if (isnan(z0)) z0 = 0.0;

        const float y = LOGICAL_Y_POSITION(pgm_read_float(&ubl.mesh_index_to_ypos[current_yi]));

        /**
         * Without this check, it is possible for the algorithm to generate a zero length move in the case
         * where the line is heading down and it is starting right on a Mesh Line boundary. For how often that
         * happens, it might be best to remove the check and always 'schedule' the move because
         * the planner.buffer_line() routine will filter it if that happens.
         */
        if (y != start[Y_AXIS]) {
          if (!inf_normalized_flag) {

            //on_axis_distance = y - start[Y_AXIS];
            on_axis_distance = use_x_dist ? x - start[X_AXIS] : y - start[Y_AXIS];

            //on_axis_distance = use_x_dist ? next_mesh_line_x - start[X_AXIS] : y - start[Y_AXIS];
            //on_axis_distance = use_x_dist ? x - start[X_AXIS] : next_mesh_line_y - start[Y_AXIS];

            //on_axis_distance = use_x_dist ? next_mesh_line_x - start[X_AXIS] : y - start[Y_AXIS];
            //on_axis_distance = use_x_dist ? x - start[X_AXIS] : next_mesh_line_y - start[Y_AXIS];

            e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist;
            z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist;
          }
          else {
            e_position = end[E_AXIS];
            z_position = end[Z_AXIS];
          }

          planner.buffer_line(x, y, z_position + z0 + ubl.state.z_offset, e_position, feed_rate, extruder);
        } //else printf("FIRST MOVE PRUNED  ");
      }

      if (ubl.g26_debug_flag)
        debug_current_and_destination(PSTR("vertical move done in ubl_line_to_destination()"));

      //
      // Check if we are at the final destination. Usually, we won't be, but if it is on a Y Mesh Line, we are done.
      //
      if (current_position[X_AXIS] != end[X_AXIS] || current_position[Y_AXIS] != end[Y_AXIS])
        goto FINAL_MOVE;

      set_current_to_destination();
      return;
    }

    /**
     *
     * This block handles horizontal lines. These are lines that stay within the same
     * Y Cell row. They do not need to be perfectly horizontal. They just can
     * not cross into another Y Cell row.
     *
     */

    if (dyi == 0) {             // Check for a horizontal line
      current_xi += left_flag;  // Line is heading left, we just want to go to the left
                                // edge of this cell for the first move.
      while (current_xi != cell_dest_xi + left_flag) {
        current_xi += dxi;
        const float next_mesh_line_x = LOGICAL_X_POSITION(pgm_read_float(&ubl.mesh_index_to_xpos[current_xi])),
                    y = m * next_mesh_line_x + c;   // Calculate Y at the next X mesh line

        float z0 = ubl.z_correction_for_y_on_vertical_mesh_line(y, current_xi, current_yi);

        z0 *= ubl.fade_scaling_factor_for_z(end[Z_AXIS]);

        /**
         * If part of the Mesh is undefined, it will show up as NAN
         * in z_values[][] and propagate through the
         * calculations. If our correction is NAN, we throw it out
         * because part of the Mesh is undefined and we don't have the
         * information we need to complete the height correction.
         */
        if (isnan(z0)) z0 = 0.0;

        const float x = LOGICAL_X_POSITION(pgm_read_float(&ubl.mesh_index_to_xpos[current_xi]));

        /**
         * Without this check, it is possible for the algorithm to generate a zero length move in the case
         * where the line is heading left and it is starting right on a Mesh Line boundary. For how often
         * that happens, it might be best to remove the check and always 'schedule' the move because
         * the planner.buffer_line() routine will filter it if that happens.
         */
        if (x != start[X_AXIS]) {
          if (!inf_normalized_flag) {

            //on_axis_distance = x - start[X_AXIS];
            on_axis_distance = use_x_dist ? x - start[X_AXIS] : y - start[Y_AXIS];

            //on_axis_distance = use_x_dist ? next_mesh_line_x - start[X_AXIS] : y - start[Y_AXIS];
            //on_axis_distance = use_x_dist ? x - start[X_AXIS] : next_mesh_line_y - start[Y_AXIS];

            e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist;  // is based on X or Y because this is a horizontal move
            z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist;
          }
          else {
            e_position = end[E_AXIS];
            z_position = end[Z_AXIS];
          }

          planner.buffer_line(x, y, z_position + z0 + ubl.state.z_offset, e_position, feed_rate, extruder);
        } //else printf("FIRST MOVE PRUNED  ");
      }

      if (ubl.g26_debug_flag)
        debug_current_and_destination(PSTR("horizontal move done in ubl_line_to_destination()"));

      if (current_position[X_AXIS] != end[X_AXIS] || current_position[Y_AXIS] != end[Y_AXIS])
        goto FINAL_MOVE;

      set_current_to_destination();
      return;
    }

    /**
     *
     * This block handles the generic case of a line crossing both X and Y Mesh lines.
     *
     */

    int xi_cnt = cell_start_xi - cell_dest_xi,
        yi_cnt = cell_start_yi - cell_dest_yi;

    if (xi_cnt < 0) xi_cnt = -xi_cnt;
    if (yi_cnt < 0) yi_cnt = -yi_cnt;

    current_xi += left_flag;
    current_yi += down_flag;

    while (xi_cnt > 0 || yi_cnt > 0) {

      const float next_mesh_line_x = LOGICAL_X_POSITION(pgm_read_float(&ubl.mesh_index_to_xpos[current_xi + dxi])),
                  next_mesh_line_y = LOGICAL_Y_POSITION(pgm_read_float(&ubl.mesh_index_to_ypos[current_yi + dyi])),
                  y = m * next_mesh_line_x + c,   // Calculate Y at the next X mesh line
                  x = (next_mesh_line_y - c) / m; // Calculate X at the next Y mesh line
                                                  // (No need to worry about m being zero.
                                                  //  If that was the case, it was already detected
                                                  //  as a vertical line move above.)

      if (left_flag == (x > next_mesh_line_x)) { // Check if we hit the Y line first
        //
        // Yes!  Crossing a Y Mesh Line next
        //
        float z0 = ubl.z_correction_for_x_on_horizontal_mesh_line(x, current_xi - left_flag, current_yi + dyi);

        z0 *= ubl.fade_scaling_factor_for_z(end[Z_AXIS]);

        /**
         * If part of the Mesh is undefined, it will show up as NAN
         * in z_values[][] and propagate through the
         * calculations. If our correction is NAN, we throw it out
         * because part of the Mesh is undefined and we don't have the
         * information we need to complete the height correction.
         */
        if (isnan(z0)) z0 = 0.0;

        if (!inf_normalized_flag) {
          on_axis_distance = use_x_dist ? x - start[X_AXIS] : next_mesh_line_y - start[Y_AXIS];
          e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist;
          z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist;
        }
        else {
          e_position = end[E_AXIS];
          z_position = end[Z_AXIS];
        }
        planner.buffer_line(x, next_mesh_line_y, z_position + z0 + ubl.state.z_offset, e_position, feed_rate, extruder);
        current_yi += dyi;
        yi_cnt--;
      }
      else {
        //
        // Yes!  Crossing a X Mesh Line next
        //
        float z0 = ubl.z_correction_for_y_on_vertical_mesh_line(y, current_xi + dxi, current_yi - down_flag);

        z0 *= ubl.fade_scaling_factor_for_z(end[Z_AXIS]);

        /**
         * If part of the Mesh is undefined, it will show up as NAN
         * in z_values[][] and propagate through the
         * calculations. If our correction is NAN, we throw it out
         * because part of the Mesh is undefined and we don't have the
         * information we need to complete the height correction.
         */
        if (isnan(z0)) z0 = 0.0;

        if (!inf_normalized_flag) {
          on_axis_distance = use_x_dist ? next_mesh_line_x - start[X_AXIS] : y - start[Y_AXIS];
          e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist;
          z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist;
        }
        else {
          e_position = end[E_AXIS];
          z_position = end[Z_AXIS];
        }

        planner.buffer_line(next_mesh_line_x, y, z_position + z0 + ubl.state.z_offset, e_position, feed_rate, extruder);
        current_xi += dxi;
        xi_cnt--;
      }
    }

    if (ubl.g26_debug_flag)
      debug_current_and_destination(PSTR("generic move done in ubl_line_to_destination()"));

    if (current_position[X_AXIS] != end[X_AXIS] || current_position[Y_AXIS] != end[Y_AXIS])
      goto FINAL_MOVE;

    set_current_to_destination();
  }

#endif