/*
  protocol.c - the serial protocol master control unit
  Part of Grbl

  The MIT License (MIT)

  GRBL(tm) - Embedded CNC g-code interpreter and motion-controller
  Copyright (c) 2009-2011 Simen Svale Skogsrud
  Copyright (c) 2011-2012 Sungeun K. Jeon

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
*/

#include <avr/io.h>
#include <avr/interrupt.h>
#include "protocol.h"
#include "gcode.h"
#include "serial.h"
#include "print.h"
#include "settings.h"
#include "config.h"
#include "nuts_bolts.h"
#include "stepper.h"
#include "report.h"
#include "motion_control.h"

static char line[LINE_BUFFER_SIZE]; // Line to be executed. Zero-terminated.
static uint8_t char_counter; // Last character counter in line variable.
static uint8_t iscomment; // Comment/block delete flag for processor to ignore comment characters.


static void protocol_reset_line_buffer()
{
  char_counter = 0; // Reset line input
  iscomment = false;
}


void protocol_init() 
{
  protocol_reset_line_buffer();
  report_init_message(); // Welcome message   
  
  PINOUT_DDR &= ~(PINOUT_MASK); // Set as input pins
  PINOUT_PORT |= PINOUT_MASK; // Enable internal pull-up resistors. Normal high operation.
  PINOUT_PCMSK |= PINOUT_MASK;   // Enable specific pins of the Pin Change Interrupt
  PCICR |= (1 << PINOUT_INT);   // Enable Pin Change Interrupt
}

// Executes user startup script, if stored.
void protocol_execute_startup() 
{
  uint8_t n;
  for (n=0; n < N_STARTUP_LINE; n++) {
    if (!(settings_read_startup_line(n, line))) {
      report_status_message(STATUS_SETTING_READ_FAIL);
    } else {
      if (line[0] != 0) {
        printString(line); // Echo startup line to indicate execution.
        report_status_message(gc_execute_line(line));
      }
    } 
  }  
}

// Pin change interrupt for pin-out commands, i.e. cycle start, feed hold, and reset. Sets
// only the runtime command execute variable to have the main program execute these when 
// its ready. This works exactly like the character-based runtime commands when picked off
// directly from the incoming serial data stream.
ISR(PINOUT_INT_vect) 
{
  // Enter only if any pinout pin is actively low.
  if ((PINOUT_PIN & PINOUT_MASK) ^ PINOUT_MASK) { 
    if (bit_isfalse(PINOUT_PIN,bit(PIN_RESET))) {
      mc_reset();
    } else if (bit_isfalse(PINOUT_PIN,bit(PIN_FEED_HOLD))) {
      sys.execute |= EXEC_FEED_HOLD; 
    } else if (bit_isfalse(PINOUT_PIN,bit(PIN_CYCLE_START))) {
      sys.execute |= EXEC_CYCLE_START;
    }
  }
}

// Executes run-time commands, when required. This is called from various check points in the main
// program, primarily where there may be a while loop waiting for a buffer to clear space or any
// point where the execution time from the last check point may be more than a fraction of a second.
// This is a way to execute runtime commands asynchronously (aka multitasking) with grbl's g-code
// parsing and planning functions. This function also serves as an interface for the interrupts to 
// set the system runtime flags, where only the main program handles them, removing the need to
// define more computationally-expensive volatile variables. This also provides a controlled way to 
// execute certain tasks without having two or more instances of the same task, such as the planner
// recalculating the buffer upon a feedhold or override.
// NOTE: The sys.execute variable flags are set by any process, step or serial interrupts, pinouts,
// limit switches, or the main program.
void protocol_execute_runtime()
{
  if (sys.execute) { // Enter only if any bit flag is true
    uint8_t rt_exec = sys.execute; // Avoid calling volatile multiple times
    
    // System alarm. Everything has shutdown by something that has gone severely wrong. Report
    // the source of the error to the user. If critical, Grbl disables by entering an infinite
    // loop until system reset/abort.
    if (rt_exec & (EXEC_ALARM | EXEC_CRIT_EVENT)) {      
      sys.state = STATE_ALARM; // Set system alarm state

      // Critical event. Only hard limit qualifies. Update this as new critical events surface.
      if (rt_exec & EXEC_CRIT_EVENT) {
        report_alarm_message(ALARM_HARD_LIMIT); 
        report_feedback_message(MESSAGE_CRITICAL_EVENT);
        bit_false(sys.execute,EXEC_RESET); // Disable any existing reset
        do { 
          // Nothing. Block EVERYTHING until user issues reset or power cycles. Hard limits
          // typically occur while unattended or not paying attention. Gives the user time
          // to do what is needed before resetting, like killing the incoming stream.
        } while (bit_isfalse(sys.execute,EXEC_RESET));

      // Standard alarm event. Only abort during motion qualifies.
      } else {
        // Runtime abort command issued during a cycle, feed hold, or homing cycle. Message the
        // user that position may have been lost and set alarm state to enable the alarm lockout
        // to indicate the possible severity of the problem.
        report_alarm_message(ALARM_ABORT_CYCLE);
      }
      bit_false(sys.execute,(EXEC_ALARM | EXEC_CRIT_EVENT));
    } 
  
    // Execute system abort. 
    if (rt_exec & EXEC_RESET) {
      sys.abort = true;  // Only place this is set true.
      return; // Nothing else to do but exit.
    }
    
    // Execute and serial print status
    if (rt_exec & EXEC_STATUS_REPORT) { 
      report_realtime_status();
      bit_false(sys.execute,EXEC_STATUS_REPORT);
    }
    
    // Initiate stepper feed hold
    if (rt_exec & EXEC_FEED_HOLD) {
      st_feed_hold(); // Initiate feed hold.
      bit_false(sys.execute,EXEC_FEED_HOLD);
    }
    
    // Reinitializes the stepper module running state and, if a feed hold, re-plans the buffer.
    // NOTE: EXEC_CYCLE_STOP is set by the stepper subsystem when a cycle or feed hold completes.
    if (rt_exec & EXEC_CYCLE_STOP) {
      st_cycle_reinitialize();
      bit_false(sys.execute,EXEC_CYCLE_STOP);
    }
    
    if (rt_exec & EXEC_CYCLE_START) { 
      st_cycle_start(); // Issue cycle start command to stepper subsystem
      if (bit_istrue(settings.flags,BITFLAG_AUTO_START)) {
        sys.auto_start = true; // Re-enable auto start after feed hold.
      }
      bit_false(sys.execute,EXEC_CYCLE_START);
    }
  }
  
  // Overrides flag byte (sys.override) and execution should be installed here, since they 
  // are runtime and require a direct and controlled interface to the main stepper program.
}  


// Directs and executes one line of formatted input from protocol_process. While mostly
// incoming streaming g-code blocks, this also executes Grbl internal commands, such as 
// settings, initiating the homing cycle, and toggling switch states. This differs from
// the runtime command module by being susceptible to when Grbl is ready to execute the 
// next line during a cycle, so for switches like block delete, the switch only effects
// the lines that are processed afterward, not necessarily real-time during a cycle, 
// since there are motions already stored in the buffer. However, this 'lag' should not
// be an issue, since these commands are not typically used during a cycle.
uint8_t protocol_execute_line(char *line) 
{   
  // Grbl internal command and parameter lines are of the form '$4=374.3' or '$' for help  
  if(line[0] == '$') {
    
    uint8_t char_counter = 1; 
    uint8_t helper_var = 0; // Helper variable
    float parameter, value;
    switch( line[char_counter] ) {
      case 0 : report_grbl_help(); break;
      case '$' : // Prints Grbl settings
        if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
        else { report_grbl_settings(); }
        break;
      case '#' : // Print gcode parameters
        if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
        else { report_gcode_parameters(); }
        break;
      case 'G' : // Prints gcode parser state
        if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
        else { report_gcode_modes(); }
        break;
      case 'C' : // Set check g-code mode
        if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
        // Perform reset when toggling off. Check g-code mode should only work if Grbl
        // is idle and ready, regardless of alarm locks. This is mainly to keep things
        // simple and consistent.
        if ( sys.state == STATE_CHECK_MODE ) { 
          mc_reset(); 
          report_feedback_message(MESSAGE_DISABLED);
        } else {
          if (sys.state) { return(STATUS_IDLE_ERROR); }
          sys.state = STATE_CHECK_MODE;
          report_feedback_message(MESSAGE_ENABLED);
        }
        break; 
      case 'X' : // Disable alarm lock
        if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
        if (sys.state == STATE_ALARM) { 
          report_feedback_message(MESSAGE_ALARM_UNLOCK);
          sys.state = STATE_IDLE;
          // Don't run startup script. Prevents stored moves in startup from causing accidents.
        }
        break;               
      case 'H' : // Perform homing cycle
        if (bit_istrue(settings.flags,BITFLAG_HOMING_ENABLE)) { 
          // Only perform homing if Grbl is idle or lost.
          if ( sys.state==STATE_IDLE || sys.state==STATE_ALARM ) { 
            mc_go_home(); 
            if (!sys.abort) { protocol_execute_startup(); } // Execute startup scripts after successful homing.
          } else { return(STATUS_IDLE_ERROR); }
        } else { return(STATUS_SETTING_DISABLED); }
        break;
//    case 'J' : break;  // Jogging methods
      // TODO: Here jogging can be placed for execution as a seperate subprogram. It does not need to be 
      // susceptible to other runtime commands except for e-stop. The jogging function is intended to
      // be a basic toggle on/off with controlled acceleration and deceleration to prevent skipped 
      // steps. The user would supply the desired feedrate, axis to move, and direction. Toggle on would
      // start motion and toggle off would initiate a deceleration to stop. One could 'feather' the
      // motion by repeatedly toggling to slow the motion to the desired location. Location data would 
      // need to be updated real-time and supplied to the user through status queries.
      //   More controlled exact motions can be taken care of by inputting G0 or G1 commands, which are 
      // handled by the planner. It would be possible for the jog subprogram to insert blocks into the
      // block buffer without having the planner plan them. It would need to manage de/ac-celerations 
      // on its own carefully. This approach could be effective and possibly size/memory efficient.
      case 'N' : // Startup lines. 
        if ( line[++char_counter] == 0 ) { // Print startup lines
          for (helper_var=0; helper_var < N_STARTUP_LINE; helper_var++) {
            if (!(settings_read_startup_line(helper_var, line))) {
              report_status_message(STATUS_SETTING_READ_FAIL);
            } else {
              report_startup_line(helper_var,line);
            }
          }
          break;
        } else { // Store startup line
          helper_var = true;  // Set helper_var to flag storing method. 
          // No break. Continues into default: to read remaining command characters.
        }
      default :  // Storing setting methods
        if(!read_float(line, &char_counter, &parameter)) { return(STATUS_BAD_NUMBER_FORMAT); }
        if(line[char_counter++] != '=') { return(STATUS_UNSUPPORTED_STATEMENT); }
        if (helper_var) { // Store startup line
          // Prepare sending gcode block to gcode parser by shifting all characters
          helper_var = char_counter; // Set helper variable as counter to start of gcode block
          do {
            line[char_counter-helper_var] = line[char_counter];
          } while (line[char_counter++] != 0);
          // Execute gcode block to ensure block is valid.
          helper_var = gc_execute_line(line); // Set helper_var to returned status code.
          if (helper_var) { return(helper_var); }
          else { 
            helper_var = trunc(parameter); // Set helper_var to int value of parameter
            settings_store_startup_line(helper_var,line);
          }
        } else { // Store global setting.
          if(!read_float(line, &char_counter, &value)) { return(STATUS_BAD_NUMBER_FORMAT); }
          if(line[char_counter] != 0) { return(STATUS_UNSUPPORTED_STATEMENT); }
          return(settings_store_global_setting(parameter, value));
        }
    }
    return(STATUS_OK); // If '$' command makes it to here, then everything's ok.

  } else {
    return(gc_execute_line(line));    // Everything else is gcode
  }
}


// Process and report status one line of incoming serial data. Performs an initial filtering
// by removing spaces and comments and capitalizing all letters.
void protocol_process()
{
  uint8_t c;
  while((c = serial_read()) != SERIAL_NO_DATA) {
    if ((c == '\n') || (c == '\r')) { // End of line reached

      // Runtime command check point before executing line. Prevent any furthur line executions.
      // NOTE: If there is no line, this function should quickly return to the main program when
      // the buffer empties of non-executable data.
      protocol_execute_runtime();
      if (sys.abort) { return; } // Bail to main program upon system abort    

      if (char_counter > 0) {// Line is complete. Then execute!
        line[char_counter] = 0; // Terminate string
        report_status_message(protocol_execute_line(line));
      } else { 
        // Empty or comment line. Skip block.
        report_status_message(STATUS_OK); // Send status message for syncing purposes.
      }
      protocol_reset_line_buffer();      
    
    } else {
      if (iscomment) {
        // Throw away all comment characters
        if (c == ')') {
          // End of comment. Resume line.
          iscomment = false;
        }
      } else {
        if (c <= ' ') { 
          // Throw away whitepace and control characters
        } else if (c == '/') { 
          // Block delete not supported. Ignore character.
        } else if (c == '(') {
          // Enable comments flag and ignore all characters until ')' or EOL.
          iscomment = true;
        } else if (char_counter >= LINE_BUFFER_SIZE-1) {
          // Report line buffer overflow and reset
          report_status_message(STATUS_OVERFLOW);
          protocol_reset_line_buffer();
        } else if (c >= 'a' && c <= 'z') { // Upcase lowercase
          line[char_counter++] = c-'a'+'A';
        } else {
          line[char_counter++] = c;
        }
      }
    }
  }
}