#include <stdio.h>
#include <stdint.h>

const uint8_t fsqvbl_CommandHandlerESR_context = 1;
const uint8_t fsqvbl_CommandHandlerSTB_context = 2;

#define SCPI_ARGS_N 0
#include "app/scpi/scpi_handler.h"

#include "app/scpi/commandHandlers/esr.h"
#include "app/nfm/nfm_base.h"

// Refer to:
// [1] SCPI Specification, revision 1999.0
//     "Standard Commands for Programmable Instruments (SCPI), VERSION 1999.0, May 1999"
// [2] Gpib Programming Tutorial, (http://g2pc1.bu.edu/~qzpeng/gpib/manual/GpibProgTut.pdf)
//     Electronics Group (http://www.few.vu.nl/~elec), 11 January 2000 Electronics Group

// =================================================================================
// @fsqvbl_CommandHandlerESRSTB
// State's virtual table

static void fsqe_CommandHandlerESRSTB( const struct fFSeqEntry_t * this, tFSeqCtx_t ctx );
static void fsql_CommandHandlerESRSTB( const struct fFSeqEntry_t * this, tFSeqCtx_t ctx );
static const struct fFSeqEntry_t * fsqf_CommandHandlerESRSTB( const struct fFSeqEntry_t * this, tFSeqCtx_t ctx, const struct fFSeqEntry_t * * pDeferredNext );

const fFSeqVTable_t fsqvbl_CommandHandlerESRSTB = 
{
     .f = fsqf_CommandHandlerESRSTB,
     .enter = fsqe_CommandHandlerESRSTB,  
     .leave = fsql_CommandHandlerESRSTB
};

static void fsqe_CommandHandlerESRSTB( const struct fFSeqEntry_t * this, tFSeqCtx_t ctx )
{
    sProcessProgramDataCommonContext_t * common_ctx = ctx;

    common_ctx->ESRSTB.idx = 0; // reset position
    
    SCPI_PARSE_ARGUMENTS( common_ctx ); (void)common_ctx->argsParserStatus; // status is modified
}

static void fsql_CommandHandlerESRSTB( const struct fFSeqEntry_t * this, tFSeqCtx_t ctx )
{
}

static const struct fFSeqEntry_t * fsqf_CommandHandlerESRSTB( const struct fFSeqEntry_t * this, 
                                                            tFSeqCtx_t ctx, 
                                                             const struct fFSeqEntry_t * * pDeferredNext )
{
    const fFSeqEntry_t * nextstate = NULL;
    
    sProcessProgramDataCommonContext_t * common_ctx = ctx;
    sScpiParserContext_t * global_ctx = common_ctx->global_ctx;

    switch( common_ctx->event )
    {
        case eProgramData_Event_Write:
        {
            if( ! common_ctx->isQuery )
            {
               common_ctx->status = eProgramDataSyntaxError; // invalid command header type: COMMAND not supported (only query)
            }
            else if( eScpiStatus_success != common_ctx->argsParserStatus ) // check argument parser status
            {
               common_ctx->status = eProgramDataArgumentSyntax;  // parameter syntax error, caller should generate error message
            }
            else
            {
               common_ctx->status = eProgramDataNeedRead;  // request processed, wait for reading...
               (void)nextstate; // stay in this state
            }
        }
        break;
        
        case eProgramData_Event_Read:
        {
             // @idx - current position of the source data to be outputed
             if( 0 == common_ctx->ESRSTB.idx )
             {
                 memset( common_ctx->tempBuffer, 0, sizeof(common_ctx->tempBuffer) );

                 uint8_t esrstb = 0;
                 
                 if( common_ctx->handler_ctx == &fsqvbl_CommandHandlerESR_context )                 
                 {
                 // Read ESB:
                 // "11.5.1.2 Standard Event Status Register Operation", [3]
                 // "<...> The Standard Event Status Register is destructively read (that is, read and cleared) <...>", [3]
                 // retrieve ESB and clear it
                 GPIBMachine.fGPIB_get_event_status_register(  &global_ctx->sGPIB.registers, &esrstb );
                 }

                 if( common_ctx->handler_ctx == &fsqvbl_CommandHandlerSTB_context )                 
                 {
                 // It is required to call 'scpi_UpdateMessageAvailable' here due to the following reason:
                 // The MAV bit is set automatically by SCPI core after this handler returns 'eProgramDataNeedRead'
                 // above on 'Write' event in advance even there no data in the output buffer. So after the handler is
                 // called the SCPI core updates this bit again, and if the EOM is set, the MAV bit will be reset.
                 // But here, during the handler call, this bit is set ever for this command handler, so, it is required
                 // to update the MAV bit value: only set if any data is already pushed into the output buffer by the
                 // previous handler, and reset otherwise. If it is not done, the *STB? command will return this 
                 // bit as 1 each call whenever is there data in the buffer or not.
                 scpi_UpdateMessageAvailable();
                 // Read STB
                 // "11.2.2.1 Reading with a Serial Poll", [3]
                 // "11.2.2.2 Reading With the *STB? Query", [3]
                 GPIBMachine.fGPIB_get_status_byte_normal_poll(  &global_ctx->sGPIB.registers, &esrstb );
                 }

                 int iesrstb = (int)esrstb;

                 // first call: prepare buffer
                 _snprintf( common_ctx->tempBuffer, sizeof(common_ctx->tempBuffer), "%d", iesrstb );
             }

             // Since @done flag is set, this dispatcher shall not be called anymore.
             // Since this handler is implemented as a single-state automat, there no
             // ... other states to go to:
             (void)nextstate;

             // modify current postion index:
             SCPI_RESPONSE_HELPER( common_ctx, common_ctx->ESRSTB.idx );
        }
        break;
    }

    return nextstate;
}