/*
 * Copyright (c) 2002-2020 Michael Ruff (mruff at chiaro.com)
 *                         Michael Runyan (mrunyan at chiaro.com)
 *
 *    This source code is free software; you can redistribute it
 *    and/or modify it in source code form under the terms of the GNU
 *    General Public License as published by the Free Software
 *    Foundation; either version 2 of the License, or (at your option)
 *    any later version.
 *
 *    This program 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 this program; if not, write to the Free Software
 *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

/*
 * Contains the routines required to implement veriusertfs routines
 * via VPI. This is extremely ugly, so don't look after eating dinner.
 */

# include <string.h>
# include <stdlib.h>
# include <assert.h>
# include <math.h>
# include "config.h"
# include "priv.h"
# include "vpi_user.h"
# include "veriuser.h"
# include "ivl_alloc.h"

/*
 * Data to be passed to the callback function via the VPI callback
 * user data pointer.
 */
typedef struct t_pli_data {
      p_tfcell	tf;		/* pointer to veriusertfs cell */
      vpiHandle call_handle;	/* handle returned by vpiSysTfCall */
      int	paramvc;	/* parameter number for misctf */
} s_pli_data, *p_pli_data;

static PLI_INT32 compiletf(ICARUS_VPI_CONST PLI_BYTE8 *);
static PLI_INT32 calltf(ICARUS_VPI_CONST PLI_BYTE8 *);
static PLI_INT32 sizetf(ICARUS_VPI_CONST PLI_BYTE8 *);
static PLI_INT32 callback(p_cb_data);

/*
 * Keep a pointer to the user data so that it can be freed when the
 * simulation is finished.
 */
static p_pli_data* udata_store = 0;
static unsigned udata_count = 0;

static p_pli_data new_pli_data(p_tfcell tf, vpiHandle call_handle, int paramvc)
{
      p_pli_data data = calloc(1, sizeof(s_pli_data));
      data->tf = tf;
      data->call_handle = call_handle;
      data->paramvc = paramvc;

      udata_count += 1;
      udata_store = (p_pli_data*)realloc(udata_store,
                    udata_count*sizeof(p_pli_data*));
      udata_store[udata_count-1] = data;

      return data;
}

static PLI_INT32 sys_end_of_simulation(p_cb_data cb_data)
{
      unsigned idx;

      (void)cb_data; /* Parameter is not used. */

      for (idx = 0; idx < udata_count; idx += 1) {
        free(udata_store[idx]);
      }
      free(udata_store);
      udata_store = 0;
      udata_count = 0;

      return 0;
}

/*
 * Register veriusertfs routines/wrappers. Iterate over the tfcell
 * array, registering each function.
 */
void veriusertfs_register_table(p_tfcell vtable)
{
      static int need_EOS_cb = 1;
      const char*path;
      p_tfcell tf;
      s_vpi_systf_data tf_data;

      if (!pli_trace && (path = getenv("PLI_TRACE"))) {
	    static char trace_buf[1024];
	    if (strcmp(path,"-") == 0)
		  pli_trace = stdout;
	    else {
		  pli_trace = fopen(path, "w");
		  if (!pli_trace) {
			perror(path);
			exit(1);
		  }
	    }
	    setvbuf(pli_trace, trace_buf, _IOLBF, sizeof(trace_buf));
      }

      for (tf = vtable; tf; tf++) {
	    /* last element */
	    if (tf->type == 0) break;

	    /* force forwref true */
	    if (!tf->forwref) {
		  vpi_printf("veriusertfs: %s, forcing forwref = true\n",
			tf->tfname);
	    }

	    if (need_EOS_cb) {
		  s_cb_data cb_data;

		  cb_data.reason = cbEndOfSimulation;
		  cb_data.time = 0;
		  cb_data.cb_rtn = sys_end_of_simulation;
		  cb_data.user_data = "system";
		  vpi_register_cb(&cb_data);

		  need_EOS_cb = 0;
	    }

	      /* Build a VPI system task/function structure, and point
		 it to the pli_data that represents this
		 function. Supply wrapper functions for the system
		 task actions. */
	    memset(&tf_data, 0, sizeof(s_vpi_systf_data));
	    switch (tf->type) {
		case usertask:
		  tf_data.type = vpiSysTask;
		  break;
		case userfunction:
		  tf_data.sysfunctype = vpiIntFunc;
		  tf_data.type = vpiSysFunc;
		  break;
		case userrealfunction:
		  tf_data.sysfunctype = vpiRealFunc;
		  tf_data.type = vpiSysFunc;
		  break;
		default:
		  vpi_printf("veriusertfs: %s, unsupported type %d\n",
			     tf->tfname, tf->type);
		  continue;
	    }

	    tf_data.tfname = tf->tfname;
	    tf_data.compiletf = compiletf;
	    tf_data.calltf = calltf;
	    tf_data.sizetf = sizetf;
	    tf_data.user_data = (PLI_BYTE8*)tf;

	    if (pli_trace) {
		  fprintf(pli_trace, "Registering system %s:\n",
			tf->type == usertask ? "task" : "function");
		  fprintf(pli_trace, "  tfname : %s\n", tf->tfname);
		  if (tf->data)
			fprintf(pli_trace, "  data   : %d\n", tf->data);
		  if (tf->checktf)
			fprintf(pli_trace, "  checktf: %p\n", tf->checktf);
		  if (tf->sizetf)
			fprintf(pli_trace, "  sizetf : %p\n", tf->sizetf);
		  if (tf->calltf)
			fprintf(pli_trace, "  calltf : %p\n", tf->calltf);
		  if (tf->misctf)
			fprintf(pli_trace, "  misctf : %p\n", tf->misctf);
	    }

	    /* register */
	    vpi_register_systf(&tf_data);
      }

      return;
}

/*
 * This function calls the veriusertfs checktf and sets up all the
 * callbacks misctf requires.
 */
static PLI_INT32 compiletf(ICARUS_VPI_CONST PLI_BYTE8*data)
{
      p_tfcell tf;
      p_pli_data pli;
      s_cb_data cb_data;
      vpiHandle arg_i, arg_h;
      int rtn = 0;

      /* cast back from opaque */
      tf = (p_tfcell)data;

      /* get call handle */
      cur_instance = vpi_handle(vpiSysTfCall, NULL);

      /* build callback user data for this instance */
      pli = new_pli_data(tf, cur_instance, 0);

	/* Attach the pli_data structure to the VPI handle of the
	   system task. This is how I manage the map from vpiHandle to
	   PLI1 user data. We do it here (instead of during register)
	   because this is the first that I have both the vpiHandle
	   and the user data. */
      vpi_put_userdata(cur_instance, pli);

      /* default cb_data */
      memset(&cb_data, 0, sizeof(s_cb_data));
      cb_data.cb_rtn = callback;
      cb_data.user_data = (PLI_BYTE8*)pli;

      /* register EOS misctf callback */
      cb_data.reason = cbEndOfSimulation;
      vpi_register_cb(&cb_data);

	/* If there is a misctf function, then create a value change
	   callback for all the arguments. In the tf_* API, misctf
	   functions get value change callbacks, controlled by the
	   tf_asyncon and tf_asyncoff functions. */
      if (tf->misctf && ((arg_i = vpi_iterate(vpiArgument, cur_instance)) != NULL)) {
	    int paramvc = 1;

	    cb_data.reason = cbValueChange;
	    while ((arg_h = vpi_scan(arg_i)) != NULL) {
		  /* replicate user_data for each instance */
		  p_pli_data dp = new_pli_data(tf, cur_instance, paramvc++);
		  cb_data.user_data = (PLI_BYTE8*)dp;
		  cb_data.obj = arg_h;
		  vpi_register_cb(&cb_data);
	    }
      }

      /*
       * Since we are in compiletf, checktf and misctf need to
       * be executed. Check runs first to match other simulators.
       */
      if (tf->checktf) {
	    if (pli_trace) {
		  fprintf(pli_trace, "Call %s->checktf(reason_checktf)\n",
			  tf->tfname);
	    }

	    rtn = tf->checktf(tf->data, reason_checktf);
      }

      if (tf->misctf) {
	    if (pli_trace) {
		  fprintf(pli_trace, "Call %s->misctf"
			  "(user_data=%d, reason=%d, paramvc=%d)\n",
			  tf->tfname, tf->data, reason_endofcompile, 0);
	    }

	    tf->misctf(tf->data, reason_endofcompile, 0);
      }

      cur_instance = 0;
      return rtn;
}

/*
 * This function is the wrapper for the veriusertfs calltf routine.
 */
static PLI_INT32 calltf(ICARUS_VPI_CONST PLI_BYTE8*data)
{
      int rc = 0;
      p_tfcell tf;

      /* cast back from opaque */
      tf = (p_tfcell)data;

      /* get call handle */
      cur_instance = vpi_handle(vpiSysTfCall, NULL);

      /* execute calltf */
      if (tf->calltf) {
	    if (pli_trace) {
		  fprintf(pli_trace, "Call %s->calltf(%d, %d)\n",
			  tf->tfname, tf->data, reason_calltf);
	    }

	    rc = tf->calltf(tf->data, reason_calltf);
      }

      cur_instance = 0;
      return rc;
}

/*
 * This function is the wrapper for the veriusertfs sizetf routine.
 */
static PLI_INT32 sizetf(ICARUS_VPI_CONST PLI_BYTE8*data)
{
      int rc = 32;
      p_tfcell tf;

      /* cast back from opaque */
      tf = (p_tfcell)data;

      /* get call handle */
      cur_instance = vpi_handle(vpiSysTfCall, NULL);

      /* execute sizetf */
      if (tf->sizetf) {
	    if (pli_trace) {
		  fprintf(pli_trace, "Call %s->sizetf(%d, %d)\n",
			  tf->tfname, tf->data, reason_sizetf);
	    }

	    rc = tf->sizetf(tf->data, reason_sizetf);
      }

      cur_instance = 0;
      return rc;
}

/*
 * This function is the wrapper for all the misctf callbacks
 */
extern int async_misctf_enable;

static PLI_INT32 callback(p_cb_data data)
{
      p_pli_data pli;
      p_tfcell tf;
      int reason;
      int paramvc = 0;
      PLI_INT32 rc;

	/* not enabled */
      if (data->reason == cbValueChange && !async_misctf_enable)
	    return 0;

	/* cast back from opaque */
      pli = (p_pli_data)data->user_data;

      tf = pli->tf;
      cur_instance = pli->call_handle;

      switch (data->reason) {
	  case cbValueChange:
	    reason = reason_paramvc;
	    paramvc = pli->paramvc;
	    break;
	  case cbEndOfSimulation:
	    reason = reason_finish;
	    break;
	  case cbReadWriteSynch:
	    reason = reason_synch;
	    break;
	  case cbReadOnlySynch:
	    reason = reason_rosynch;
	    break;
	  case cbAfterDelay:
	    reason = reason_reactivate;
	    break;
	  default:
	    reason = -1;
	    assert(0);
      }

      if (pli_trace) {
	    fprintf(pli_trace, "Call %s->misctf"
		    "(user_data=%d, reason=%d, paramvc=%d)\n",
		    tf->tfname, tf->data, reason, paramvc);
      }

      /* execute misctf */
      rc = (tf->misctf) ? tf->misctf(tf->data, reason, paramvc) : 0;

      cur_instance = 0;
      return rc;
}

PLI_INT32 tf_isynchronize(void*obj)
{
      vpiHandle sys = (vpiHandle)obj;
      p_pli_data pli = vpi_get_userdata(sys);
      s_cb_data cb;
      s_vpi_time ti;

      ti.type = vpiSuppressTime;

      cb.reason = cbReadWriteSynch;
      cb.cb_rtn = callback;
      cb.obj = sys;
      cb.time = &ti;
      cb.user_data = (PLI_BYTE8*)pli;

      vpi_register_cb(&cb);

      if (pli_trace)
	    fprintf(pli_trace, "tf_isynchronize(%p) --> %d\n", obj, 0);

      return 0;
}

PLI_INT32 tf_synchronize(void)
{
      return tf_isynchronize(tf_getinstance());
}


PLI_INT32 tf_irosynchronize(void*obj)
{
      vpiHandle sys = (vpiHandle)obj;
      p_pli_data pli = vpi_get_userdata(sys);
      s_cb_data cb;
      s_vpi_time ti = {vpiSuppressTime, 0, 0, 0.0};

      cb.reason = cbReadOnlySynch;
      cb.cb_rtn = callback;
      cb.obj = sys;
      cb.time = &ti;
      cb.user_data = (PLI_BYTE8*)pli;

      vpi_register_cb(&cb);

      if (pli_trace)
	    fprintf(pli_trace, "tf_irosynchronize(%p) --> %d\n", obj, 0);

      return 0;
}

PLI_INT32 tf_rosynchronize(void)
{
      return tf_irosynchronize(tf_getinstance());
}


PLI_INT32 tf_isetrealdelay(double dly, void*obj)
{
      vpiHandle sys = (vpiHandle)obj;
      p_pli_data pli = vpi_get_userdata(sys);
      s_cb_data cb;
      s_vpi_time ti = {vpiSimTime, 0, 0, 0.0};

      /* Scale delay to SimTime */
      ivl_u64_t delay = ((dly
			 / pow(10, tf_gettimeunit() - tf_gettimeprecision()))
			 + 0.5);
      ti.high = delay >> 32 & 0xffffffff;
      ti.low = delay & 0xffffffff;

      cb.reason = cbAfterDelay;
      cb.cb_rtn = callback;
      cb.obj = sys;
      cb.time = &ti;
      cb.user_data = (PLI_BYTE8*)pli;

      vpi_register_cb(&cb);

      if (pli_trace)
	    fprintf(pli_trace, "tf_isetrealdelay(%f, %p) --> %d\n",
		  dly, obj, 0);

      return 0;
}

PLI_INT32 tf_setrealdelay(double dly)
{
      return tf_isetrealdelay(dly, tf_getinstance());
}