/*
  gcode.c - rs274/ngc parser.
  Part of Grbl

  Copyright (c) 2009 Simen Svale Skogsrud

  Grbl 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.

  Grbl 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 Grbl.  If not, see <http://www.gnu.org/licenses/>.
*/

/* This code is inspired by the Arduino GCode Interpreter by Mike Ellery and the NIST RS274/NGC Interpreter
   by Kramer, Proctor and Messina. */

/* Intentionally not supported:
  - Canned cycles
  - Tool radius compensatino
  - A,B,C-axes
  - Multiple coordinate systems
  - Evaluation of expressions
  - Variables
  - Multiple home locations
  - Probing
  - Spindle direction  
  - Override control
*/

/* 
   Omitted for the time being:
   
   group 0 = {G10, G28, G30, G53, G92, G92.1, G92.2, G92.3} (Non modal G-codes)
   group 5 = {G93, G94} feed rate mode
   group 12 = {G54, G55, G56, G57, G58, G59, G59.1, G59.2, G59.3} coordinate system selection
   group 13 = {G61, G61.1, G64} path control mode
   group 4 = {M0, M1, M2, M30, M60} stopping
   group 8 = {M7, M8, M9} coolant (special case: M7 and M8 may be active at the same time)
   group 9 = {M48, M49} enable/disable feed and speed override switches
*/

#include "gcode.h"
#include <stdlib.h>
#include <string.h>
#include "nuts_bolts.h"
#include <math.h>
#include "config.h"
#include "motion_control.h"
#include "spindle_control.h"

#define NEXT_ACTION_DEFAULT 0
#define NEXT_ACTION_DWELL 1
#define NEXT_ACTION_GO_HOME 2

#define MOTION_MODE_RAPID_LINEAR 0 // G0 
#define MOTION_MODE_LINEAR 1 // G1
#define MOTION_MODE_CW_ARC 2  // G2
#define MOTION_MODE_CCW_ARC 3  // G3
#define MOTION_MODE_CANCEL 4 // G80

#define PLANE_XY 0; // G17
#define PLANE_XZ 1; // G18
#define PLANE_YZ 2; // G19

#define PATH_CONTROL_MODE_EXACT_PATH 0
#define PATH_CONTROL_MODE_EXACT_STOP 1
#define PATH_CONTROL_MODE_CONTINOUS  2

#define PROGRAM_FLOW_RUNNING 0
#define PROGRAM_FLOW_PAUSED 1
#define PROGRAM_FLOW_COMPLETED 2

#define SPINDLE_DIRECTION_CW 0
#define SPINDLE_DIRECTION_CCW 1

// Using packed bit fields saves a "lot" of invaluable SRAM, but bumps the compiled size of this unit
// by 100 bytes. If we get tight on code space, consider using byte aligned values again.
struct ParserState {
  uint32_t line_number;
  uint8_t status_code:5;

  uint8_t motion_mode:3;         /* {G0, G1, G2, G3, G38.2, G80, G81, G82, G83, G84, G85, G86, G87, G88, G89} */
  uint8_t inverse_feed_rate_mode:1; /* G93, G94 */
  uint8_t plane:2;               /* {G17, G18, G19} */
  uint8_t inches_mode:1;         /* 0 = millimeter mode, 1 = inches mode {G20, G21} */
  uint8_t program_flow:2;
  int spindle_direction:2;
  double feed_rate;              /* Millimeters/second */
  double logical_position[3];    /* Where the interpreter considers the tool to be at this point in the code */
  uint8_t tool;
  int16_t spindle_speed;         /* RPM/100 */
};
struct ParserState state;

#define FAIL(status) state.status_code = status;

int read_double(char *line, //!< string: line of RS274/NGC code being processed
                     int *counter,       //!< pointer to a counter for logical_position on the line 
                     double *double_ptr); //!< pointer to double to be read                  

int next_statement(char *letter, double *double_ptr, char *line, int *counter);


void gc_init() {
  memset(&state, 0, sizeof(state));
  state.feed_rate = DEFAULT_FEEDRATE;
}

inline float to_millimeters(double value) {
  return(state.inches_mode ? value * INCHES_PER_MM : value);
}

// Executes one line of 0-terminated G-Code. The line is assumed to contain only uppercase
// characters and signed floats (no whitespace).
uint8_t gc_execute_line(char *line) {
  int counter;  
  char letter;
  double value;
  double unit_converted_value;
  double inverse_feed_rate;
  
  uint8_t absolute_mode = 0;       /* 0 = relative motion, 1 = absolute motion {G90, G91} */
  uint8_t next_action = NEXT_ACTION_DEFAULT;         /* One of the NEXT_ACTION_-constants */
  
  double target[3], offset[3];
  
  double p, r;
  int int_value, axis;

  state.line_number++;
  state.status_code = GCSTATUS_OK;
  
  /* First: parse all statements */
  
  if (line[0] == '(') { return(state.status_code); }
  if (line[0] == '/') { counter++; } // ignore block delete
  
  // Pass 1: Commands
  while(next_statement(&letter, &value, line, &counter)) {
    int_value = trunc(value);
    switch(letter) {
      case 'G':
      switch(int_value) {
        case 0: state.motion_mode = MOTION_MODE_RAPID_LINEAR; break;
        case 1: state.motion_mode = MOTION_MODE_LINEAR; break;
        case 2: state.motion_mode = MOTION_MODE_CW_ARC; break;
        case 3: state.motion_mode = MOTION_MODE_CCW_ARC; break;
        case 4: next_action = NEXT_ACTION_DWELL; break;
        case 17: state.plane = PLANE_XY; break;
        case 18: state.plane = PLANE_XZ; break;
        case 19: state.plane = PLANE_YZ; break;
        case 20: state.inches_mode = true; break;
        case 21: state.inches_mode = false; break;
        case 28: case 30: next_action = NEXT_ACTION_GO_HOME; break;
        case 53: absolute_mode = 1; break;
        case 80: state.motion_mode = MOTION_MODE_CANCEL; break;
        case 93: state.inverse_feed_rate_mode = true; break;
        case 94: state.inverse_feed_rate_mode = false; break;
        default: FAIL(GCSTATUS_UNSUPPORTED_STATEMENT);
      }
      break;
      
      case 'M':
      switch(int_value) {
        case 0: case 1: state.program_flow = PROGRAM_FLOW_PAUSED; break;
        case 2: state.program_flow = PROGRAM_FLOW_COMPLETED; break;
        case 3: state.spindle_direction = 1; break;
        case 4: state.spindle_direction = -1; break;
        case 5: state.spindle_direction = 0; break;
        default: FAIL(GCSTATUS_UNSUPPORTED_STATEMENT);
      }            
      break;
      case 'T': state.tool = trunc(value); break;
    }
    if(state.status_code) { break; }
  }
  
  // If there were any errors parsing this line, we will return right away with the bad news
  if (state.status_code) { return(state.status_code); }

  // Pass 2: Parameters
  counter = 0;
  clear_vector(offset);
  while(next_statement(&letter, &value, line, &counter)) {
    int_value = trunc(value);
    unit_converted_value = to_millimeters(value);
    switch(letter) {
      case 'F': 
      if (state.inverse_feed_rate_mode) {
        inverse_feed_rate = unit_converted_value; // seconds per motion for this motion only
      } else {
        state.feed_rate = unit_converted_value; // millimeters pr second
      }
      break;
      case 'I': case 'J': case 'K': offset[letter-'I'] = unit_converted_value; break;
      case 'P': p = value; break;
      case 'R': r = unit_converted_value; break;
      case 'S': state.spindle_speed = value; break;
      case 'X': case 'Y': case 'Z':
      axis = letter - 'X';
      if (absolute_mode) {
        target[axis] = unit_converted_value;
      } else {
        target[axis] = state.logical_position[axis]+unit_converted_value;
      };
      break;
    }
  }
  
  // Update spindle state
  if (state.spindle_direction) {
    spindle_run(state.spindle_direction, state.spindle_speed);
  } else {
    spindle_stop();
  }
  
  // Perform any physical actions
  switch (next_action) {
    case NEXT_ACTION_GO_HOME: mc_go_home(); break;
    case NEXT_ACTION_DWELL: mc_dwell(trunc(p*1000)); break;
    case NEXT_ACTION_DEFAULT: 
    switch (state.motion_mode) {
      case MOTION_MODE_CANCEL: break;
      case MOTION_MODE_RAPID_LINEAR: case MOTION_MODE_LINEAR:
      if (inverse_feed_rate) {
        mc_linear_motion(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], 
          inverse_feed_rate, true);
      } else {
        mc_linear_motion(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], 
          (state.motion_mode == MOTION_MODE_LINEAR) ? state.feed_rate : RAPID_FEEDRATE,
          false);
      }
      break;
      case MOTION_MODE_CW_ARC: case MOTION_MODE_CCW_ARC:
      // to be implemented
      break;      
    }    
  }
  
  mc_execute();
  
  // As far as the parser is concerned, the logical_position is now == target. In reality the
  // motion control system might still be processing the action and the real tool position
  // in any intermediate location.
  memcpy(state.logical_position, target, sizeof(state.logical_position));
  
  return(state.status_code);
}

void gc_get_status(double *position, uint8_t *status_code, int *inches_mode, uint32_t *line_number) 
{
  int axis;
  if (state.inches_mode) {
    for(axis = X_AXIS; axis <= Z_AXIS; axis++) {
      position[axis] = state.logical_position[axis]*INCHES_PER_MM;
    }
  } else {
    memcpy(position, state.logical_position, sizeof(position));    
  }
  *status_code = state.status_code;
  *inches_mode = state.inches_mode;
  *line_number = state.line_number;
}

// Parses the next statement and leaves the counter on the first character following
// the statement. Returns 1 if there was a statements, 0 if end of string was reached
// or there was an error (check state.status_code).
int next_statement(char *letter, double *double_ptr, char *line, int *counter) {
  if (*line == 0) {
    return(0); // No more statements
  }
  
  *letter = *line;
  if((*letter < 'A') || (*letter > 'Z')) {
    FAIL(GCSTATUS_EXPECTED_COMMAND_LETTER);
    return(0);
  }
  *counter++;
  if (!read_double(line, counter, double_ptr)) {
    return(0);
  };
  return(1);
}

int read_double(char *line, //!< string: line of RS274/NGC code being processed
                     int *counter,       //!< pointer to a counter for position on the line 
                     double *double_ptr) //!< pointer to double to be read                  
{
  char *start = line + *counter;
  char *end;
  
  *double_ptr = strtod(start, &end);
  if(end == start) { 
    FAIL(GCSTATUS_BAD_NUMBER_FORMAT); 
    return(0); 
  };

  *counter = end - line;
  return(1);
}