/*
  system.h - Header for system level commands and real-time processes
  Part of Grbl

  Copyright (c) 2014-2015 Sungeun K. Jeon  

  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/>.
*/

#ifndef system_h
#define system_h

#include "grbl.h"

// Define system executor bit map. Used internally by realtime protocol as realtime command flags, 
// which notifies the main program to execute the specified realtime command asynchronously.
// NOTE: The system executor uses an unsigned 8-bit volatile variable (8 flag limit.) The default
// flags are always false, so the realtime protocol only needs to check for a non-zero value to 
// know when there is a realtime command to execute.
#define EXEC_STATUS_REPORT  bit(0) // bitmask 00000001
#define EXEC_CYCLE_START    bit(1) // bitmask 00000010
#define EXEC_CYCLE_STOP     bit(2) // bitmask 00000100
#define EXEC_FEED_HOLD      bit(3) // bitmask 00001000
#define EXEC_RESET          bit(4) // bitmask 00010000
#define EXEC_SAFETY_DOOR    bit(5) // bitmask 00100000
#define EXEC_MOTION_CANCEL  bit(6) // bitmask 01000000

// Alarm executor bit map.
// NOTE: EXEC_CRITICAL_EVENT is an optional flag that must be set with an alarm flag. When enabled,
// this halts Grbl into an infinite loop until the user aknowledges the problem and issues a soft-
// reset command. For example, a hard limit event needs this type of halt and aknowledgement.
#define EXEC_CRITICAL_EVENT     bit(0) // bitmask 00000001 (SPECIAL FLAG. See NOTE:)
#define EXEC_ALARM_HARD_LIMIT   bit(1) // bitmask 00000010
#define EXEC_ALARM_SOFT_LIMIT   bit(2) // bitmask 00000100
#define EXEC_ALARM_ABORT_CYCLE  bit(3) // bitmask 00001000
#define EXEC_ALARM_PROBE_FAIL   bit(4) // bitmask 00010000
#define EXEC_ALARM_HOMING_FAIL  bit(5) // bitmask 00100000

// Define system state bit map. The state variable primarily tracks the individual functions
// of Grbl to manage each without overlapping. It is also used as a messaging flag for
// critical events.
#define STATE_IDLE          0      // Must be zero. No flags.
#define STATE_ALARM         bit(0) // In alarm state. Locks out all g-code processes. Allows settings access.
#define STATE_CHECK_MODE    bit(1) // G-code check mode. Locks out planner and motion only.
#define STATE_HOMING        bit(2) // Performing homing cycle
#define STATE_CYCLE         bit(3) // Cycle is running or motions are being executed.
#define STATE_HOLD          bit(4) // Active feed hold
#define STATE_SAFETY_DOOR   bit(5) // Safety door is ajar. Feed holds and de-energizes system.
#define STATE_MOTION_CANCEL bit(6) // Motion cancel by feed hold and return to idle. 

// Define system suspend states.
#define SUSPEND_DISABLE       0      // Must be zero.
#define SUSPEND_ENABLE_HOLD   bit(0) // Enabled. Indicates the cycle is active and currently undergoing a hold.
#define SUSPEND_ENABLE_READY  bit(1) // Ready to resume with a cycle start command.
#define SUSPEND_ENERGIZE      bit(2) // Re-energizes output before resume.
#define SUSPEND_MOTION_CANCEL bit(3) // Cancels resume motion. Used by probing routine.


// Define global system variables
typedef struct {
  uint8_t abort;                 // System abort flag. Forces exit back to main loop for reset.
  uint8_t state;                 // Tracks the current state of Grbl.
  uint8_t suspend;               // System suspend bitflag variable that manages holds, cancels, and safety door.
  uint8_t soft_limit;            // Tracks soft limit errors for the state machine. (boolean)
  
  int32_t position[N_AXIS];      // Real-time machine (aka home) position vector in steps. 
                                 // NOTE: This may need to be a volatile variable, if problems arise.                             

  int32_t probe_position[N_AXIS]; // Last probe position in machine coordinates and steps.
  uint8_t probe_succeeded;        // Tracks if last probing cycle was successful.
  uint8_t homing_axis_lock;       // Locks axes when limits engage. Used as an axis motion mask in the stepper ISR.
} system_t;
extern system_t sys;

volatile uint8_t sys_probe_state;   // Probing state value.  Used to coordinate the probing cycle with stepper ISR.
volatile uint8_t sys_rt_exec_state;  // Global realtime executor bitflag variable for state management. See EXEC bitmasks.
volatile uint8_t sys_rt_exec_alarm;  // Global realtime executor bitflag variable for setting various alarms.


// Initialize the serial protocol
void system_init();

// Returns if safety door is open or closed, based on pin state.
uint8_t system_check_safety_door_ajar();

// Executes an internal system command, defined as a string starting with a '$'
uint8_t system_execute_line(char *line);

// Execute the startup script lines stored in EEPROM upon initialization
void system_execute_startup(char *line);

// Returns machine position of axis 'idx'. Must be sent a 'step' array.
float system_convert_axis_steps_to_mpos(int32_t *steps, uint8_t idx);

// Updates a machine 'position' array based on the 'step' array sent.
void system_convert_array_steps_to_mpos(float *position, int32_t *steps);

#endif