/**********************************************************************//**
 *
 *  Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
 *
 *  THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 *  WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 *  @file ModeStandby.c
 *
 *  @date 11-Dec-2019
 *  @author L. Baloa
 *
 *  @brief Top-level state machine for the standby mode.
 *
 **************************************************************************/

#include "CPLD.h"
#include "OperationModes.h"
#include "SystemComm.h"
#include "Timers.h"
#include "ModeStandby.h"

/**
 *  @addtogroup StandbyMode
 *  @{
 */

// ********** private definitions **********

#define WATER_SAMPLE_TIME_MS              ( 10 * MS_PER_SECOND )        ///< Duration of water sample state (in ms).

/// Enumeration of standby mode states.
typedef enum Standby_Mode_States
{
    STANDBY_MODE_STATE_START = 0,                                       ///< Start standby mode state.
    STANDBY_MODE_STATE_IDLE,                                            ///< Idle standby mode state.
    STANDBY_MODE_STATE_SAMPLE_WATER,                                    ///< Sample water standby mode state.
    NUM_OF_STANDBY_MODE_STATES                                          ///< Number of standby mode states.
} STANDBY_MODE_STATE_T;

// ********** private data **********

static STANDBY_MODE_STATE_T standbyState = STANDBY_MODE_STATE_START;    ///< Currently active standby state.
static BOOL pendingSampleWaterRequest = FALSE;                          ///< Flag indicating HD has requested a water sample.
static BOOL pendingStartDGRequest = FALSE;                              ///< Flag indicating HD has requested DG start (go to re-circulate mode).
static U32 waterSampleStartTime = 0;                                    ///< Time stamp for start of water sample state.

// ********** private function prototypes **********

static STANDBY_MODE_STATE_T handleStandbyIdleState( void );
static STANDBY_MODE_STATE_T handleStandbySampleWaterState( void );

/*********************************************************************//**
 * @brief
 * The initStandbyMode function initializes the Standby Mode module.
 * @details
 * Inputs : none
 * Outputs : Standby Mode module initialized.
 * @return none
 *************************************************************************/
void initStandbyMode( void )
{
    standbyState = STANDBY_MODE_STATE_START;
    pendingSampleWaterRequest = FALSE;
    pendingStartDGRequest = FALSE;
    waterSampleStartTime = 0;
}

/*********************************************************************//**
 * @brief
 * The transitionToStandbyMode function prepares for transition to standby mode.
 * @details
 * Inputs : none
 * Outputs :
 * @return none
 *************************************************************************/
void transitionToStandbyMode( void )
{
    // re-initialize standby mode each time we transition to standby mode
    initStandbyMode();

    // TODO - set initial actuator states
}

/*********************************************************************//**
 * @brief
 * The execStandbyMode function executes the Standby Mode state machine.
 * @details
 * Inputs : none
 * Outputs :
 * @return none
 *************************************************************************/
void execStandbyMode( void )
{
    // execute current Standby state
    switch ( standbyState )
    {
        case STANDBY_MODE_STATE_START:
            standbyState = STANDBY_MODE_STATE_IDLE;
            break;

        case STANDBY_MODE_STATE_IDLE:
            standbyState = handleStandbyIdleState();
            break;

        case STANDBY_MODE_STATE_SAMPLE_WATER:
            standbyState = handleStandbySampleWaterState();
            break;

        default:
            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_SOFTWARE_FAULT, 0, standbyState )     // TODO - add s/w fault enum to 1st data param
            standbyState = STANDBY_MODE_STATE_START;
            break;
    }
}

/*********************************************************************//**
 * @brief
 * The handleStandbyIdleState function executes the Idle state of the \n
 * Standby Mode state machine.
 * @details
 * Inputs : pendingSampleWaterRequest, pendingStartDGRequest
 * Outputs : possibly op mode
 * @return the next state
 *************************************************************************/
static STANDBY_MODE_STATE_T handleStandbyIdleState( void )
{
    STANDBY_MODE_STATE_T result = STANDBY_MODE_STATE_IDLE;

    // go to standby solo mode if HD is turned off or stops communicating.
    if ( FALSE == isHDCommunicating() )
    {   // TODO if HD comm loss, should we wait an hour or so before going to solo standby?
        requestNewOperationMode( MODE_SOLO );
    }
    // if HD requests water sample, go to water sample state
    else if ( TRUE == pendingSampleWaterRequest )
    {
        pendingSampleWaterRequest = FALSE;
        waterSampleStartTime = getMSTimerCount();
        // TODO - open VPi and VSP valves
        result = STANDBY_MODE_STATE_SAMPLE_WATER;
    }
    else if ( TRUE == pendingStartDGRequest )
    {
        pendingStartDGRequest = FALSE;
        requestNewOperationMode( MODE_CIRC );
    }

    return result;
}

/*********************************************************************//**
 * @brief
 * The handleStandbySampleWaterState function executes the sample water state \n
 * of the Standby Mode state machine.
 * @details
 * Inputs : none
 * Outputs :
 * @return the next state
 *************************************************************************/
static STANDBY_MODE_STATE_T handleStandbySampleWaterState( void )
{
    STANDBY_MODE_STATE_T result = STANDBY_MODE_STATE_SAMPLE_WATER;

    // VPi and VSP valves open for 10 seconds, then close and return to idle state
    if ( TRUE == didTimeout( waterSampleStartTime, WATER_SAMPLE_TIME_MS ) )
    {
        // TODO - close VPi and VSP valves.
        result = STANDBY_MODE_STATE_IDLE;
    }

    return result;
}

/*********************************************************************//**
 * @brief
 * The requestWaterSample function handles an HD request to sample water.
 * @details
 * Inputs : standbyState
 * Outputs : pendingSampleWaterRequest
 * @return TRUE if request accepted, FALSE if not.
 *************************************************************************/
BOOL requestWaterSample( void )
{
    BOOL result = FALSE;

    if ( STANDBY_MODE_STATE_IDLE == standbyState )
    {
        result = TRUE;
        pendingSampleWaterRequest = TRUE;
    }

    return result;
}

/*********************************************************************//**
 * @brief
 * The requestDGStart function handles an HD request to start (go to re-circulate mode).
 * @details
 * Inputs : standbyState
 * Outputs : pendingSampleWaterRequest
 * @return TRUE if request accepted, FALSE if not.
 *************************************************************************/
BOOL requestDGStart( void )
{
    BOOL result = FALSE;

    if ( STANDBY_MODE_STATE_IDLE == standbyState )
    {
        result = TRUE;
        pendingStartDGRequest = TRUE;
    }

    return result;
}

/**@}*/