#include <string.h>
#include "pci.h"
#include "pcilib.h"
#include <Python.h>
#include "views.h"
#include "error.h"
#include <strings.h>
#include <stdlib.h>
#include "unit.h" 

/**
 *
 * replace a substring within a string by another
 * @param[in] txt - the string to be modified
 *@param[in] before - the substring in the string that will be replaced
 *@param[in] after - the new value of before substring
 *@return the modified txt string
 */
static char*
pcilib_view_formula_replace (const char *txt, const char *before, const char *after)
{
	const char *pos; 
	char *return_txt; 
	size_t pos_return_txt; 
	size_t len; 
	size_t allocated_size; 
	
	/*get the first occurence of before. then we need one time to be out of the loop to correctly set the diverses varaibles (malloc instead of realloc notably)*/
	pos = strstr (txt, before);
	 
	if (pos == NULL)
	{
		pcilib_warning("problem with a formula");
	}
 
	/* get the position of this occurence*/
	len = (size_t)pos - (size_t)txt;
	allocated_size = len + strlen (after) + 1;
	return_txt = malloc (allocated_size);
	pos_return_txt = 0;
	
	/* we copy there the in a newly allocated string the start of txt before the "before" occurence, and then we copy after instead*/
	strncpy (return_txt + pos_return_txt, txt, len);
	pos_return_txt += len;
	txt = pos + strlen (before);
	 
	len = strlen (after);
	strncpy (return_txt + pos_return_txt, after, len);
	pos_return_txt += len;
	
	/* we then iterate with the same principle to all occurences of before*/
	pos = strstr (txt, before);
	while (pos != NULL)
	{
		len = (size_t)pos - (size_t)txt;
		allocated_size += len + strlen (after);
		return_txt = (char *)realloc (return_txt, allocated_size);
		 
		strncpy (return_txt + pos_return_txt, txt, len);
		pos_return_txt += len;
		 
		txt = pos + strlen (before);
		 
		len = strlen (after);
		strncpy (return_txt + pos_return_txt, after, len);
		pos_return_txt += len;
		pos = strstr (txt, before);
	}
	/* put the rest of txt string at the end*/
	len = strlen (txt) + 1;
	allocated_size += len;
	return_txt = realloc (return_txt, allocated_size);
	strncpy (return_txt + pos_return_txt, txt, len);
	
	return return_txt;
}

/**
 * function used to get the substring of a string s, from the starting and ending indexes
  * @param[in] s string containing the substring we want to extract.
 * @param[in] start the start index of the substring.
 * @param[in] end the ending index of the substring.
 * @return the extracted substring.
 */
char*
pcilib_view_str_sub (const char *s, unsigned int start, unsigned int end)
{
   char *new_s = NULL;

   if (s != NULL && start < end)
   {
      new_s = malloc (sizeof (*new_s) * (end - start + 2));
      if (new_s != NULL)
      {
         int i;

         for (i = start; i <= end; i++)
         {
            new_s[i-start] = s[i];
         }
         new_s[i-start] = '\0';
      }
      else
      {
         pcilib_error("insufficient memory for string manipulation\n");
         return NULL;
      }
   }
   return new_s;
}


/**
 * get the bank name associated with a register name
 */
static const char*
pcilib_view_get_bank_from_reg_name(pcilib_t* ctx,char* reg_name){
  int k;
  for(k=0;ctx->registers[k].bits;k++){
    if(!(strcasecmp(reg_name,ctx->registers[k].name))){
	return ctx->banks[pcilib_find_register_bank_by_addr(ctx,ctx->registers[k].bank)].name;
      }
  }
  return NULL;
}

/**
 * replace plain registers name in a formula by their value
 */
static char*
pcilib_view_compute_plain_registers(pcilib_t* ctx, char* formula, int direction){
  int j,k;
  char *substr, *substr2;
  char temp[66];
  pcilib_register_value_t value;
  
  /*we get recursively all registers of string , and if they are not equel to '@reg', then we get their value and put it in formula*/
  for(j=0;j<strlen((char*)formula);j++){
    if(formula[j]=='@'){
      k=j+1;
      while((formula[k]!=' ' && formula[k]!=')' && formula[k]!='/' && formula[k]!='+' && formula[k]!='-' && formula[k]!='*' && formula[k]!='=') && (k<strlen((char*)formula))){
	k++;
      }
      substr2=pcilib_view_str_sub((char*)formula,j,k-1); /**< we get the name of the register+@*/
      substr=pcilib_view_str_sub(substr2,1,k-j/*length of substr2*/); /**< we get the name of the register*/
      if(direction==0){
	if((strcasecmp(substr,"reg"))){
	  /* we get the bank name associated to the register, and read its value*/
	  pcilib_read_register(ctx, pcilib_view_get_bank_from_reg_name(ctx, substr),substr,&value);
	  /* we put the value in formula*/
	  sprintf(temp,"%i",value);
	  formula = pcilib_view_formula_replace(formula,substr2,temp);
	}
      }
      else if(direction==1){
	if((strcasecmp(substr,"value"))){
	  /* we get the bank name associated to the register, and read its value*/
	  pcilib_read_register(ctx, pcilib_view_get_bank_from_reg_name(ctx, substr),substr,&value);
	  /* we put the value in formula*/
	  sprintf(temp,"%i",value);
	  formula = pcilib_view_formula_replace(formula,substr2,temp);
	}
      }	
    }
  }
  return formula;
}

/**
 * this function calls the python script and the function "evaluate" in it to evaluate the given formula
 *@param[in] the formula to be evaluated
 *@return the integer value of the evaluated formula (maybe go to float instead)
 */
static pcilib_register_value_t
pcilib_view_eval_formula(char* formula){
  
   /* initialization of python interpreter*/
   Py_Initialize();
   
   /*compilation of the formula as python string*/
   PyCodeObject* code=(PyCodeObject*)Py_CompileString(formula,"test",Py_eval_input);
   PyObject* main_module = PyImport_AddModule("__parser__");
   PyObject* global_dict = PyModule_GetDict(main_module);
   PyObject* local_dict = PyDict_New();
   /*evaluation of formula*/
   PyObject* obj = PyEval_EvalCode(code, global_dict, local_dict);
   double c=PyFloat_AsDouble(obj);

   /* close interpreter*/
   Py_Finalize();
   pcilib_register_value_t value=(pcilib_register_value_t)c;
   return value;
}

/**
 * function to apply a unit for the views of type formula
 *@param[in] view - the view we want to get the units supported
  *@param[in] unit - the requested unit in which we want to get the value
 *@param[in,out] value - the number that needs to get transformed
 */
static void
pcilib_view_apply_unit(pcilib_transform_unit_t unit_desc, const char* unit,pcilib_register_value_t* value){
  char* formula;
  char temp[66];
  
	    formula=malloc(strlen(unit_desc.transform_formula)*sizeof(char));
	    strcpy(formula,unit_desc.transform_formula);
	    sprintf(temp,"%i",*value);
	    formula=pcilib_view_formula_replace(formula,"@self",temp); 
	    *value=(int)pcilib_view_eval_formula(formula);
}


static void
pcilib_view_apply_formula(pcilib_t* ctx, char* formula, pcilib_register_value_t reg_value, pcilib_register_value_t* out_value, int direction)
{
  /* when applying a formula, we need to:
     1) compute the values of all registers present in plain name in the formulas and replace their name with their value : for example, if we have the formula" ((1./4)*(@reg - 1200)) if @freq==0 else ((3./10)*(@reg - 1000)) " we need to get the value of the register "freq"
     2) compute the "@reg" component, corresponding to the raw value of the register
     3) pass the formula to python interpreter for evaluation
     4) return the final evaluation
     
     remark: it might be worth to use python regular expression interpreter (the following return all words following @ in formula : 
         >>> import re
	 >>> m = re.search('(?<=@)\w+', formula)
	 >>> m.group(0)
  */
  
  char reg_value_string[66]; /* to register reg_value as a string, need to check the length*/
  sprintf(reg_value_string,"%u",reg_value);
  
  /*computation of plain registers in the formula*/
  formula=pcilib_view_compute_plain_registers(ctx,formula,direction);
  /* computation of @reg with register value*/
  if(direction==0) formula=pcilib_view_formula_replace(formula,"@reg",reg_value_string);
  else if (direction==1) formula=pcilib_view_formula_replace(formula,"@value",reg_value_string);
  /* evaluation of the formula*/
  *out_value= pcilib_view_eval_formula(formula);
}

int pcilib_read_view(pcilib_t *ctx, const char *bank, const char *regname, const char *unit, size_t value_size, void *value)
{
  int i,j,err=0;
  pcilib_register_value_t temp_value;
  
  /* we get the index of the register to find the corresponding register context*/
  if((i=pcilib_find_register(ctx,bank,regname))==PCILIB_REGISTER_INVALID){
    pcilib_error("can't get the index of the register %s", regname);
    return PCILIB_ERROR_INVALID_REQUEST;
  }
  
  /* we get the value of the register, as we will apply the view on it*/
  err=pcilib_read_register_by_id(ctx,i,&temp_value);
  if(err){
    pcilib_error("can't read the register %s value before applying views : error %i",regname);
    return PCILIB_ERROR_INVALID_REQUEST;
  }

    for(j=0;ctx->register_ctx[i].views[j].name;j++){
      if(!(strcasecmp(ctx->register_ctx[i].views[j].base_unit.name,unit))){/*if we asked for the unit "name"*/
	err=ctx->register_ctx[i].views[j].op(ctx,ctx->register_ctx[i].views[j].parameters,value/*the command name*/,0,&temp_value,0,&(ctx->register_ctx[i].views[j]));
	if(err){
	  pcilib_error("can't write to the register with the enum view");
	  return PCILIB_ERROR_FAILED;
	}
	break;
      }else if(!(strcasecmp(ctx->register_ctx[i].views[j].name,(char*)unit))){/*in this case we asked for the name of the view in unit*/
	err=ctx->register_ctx[i].views[j].op(ctx,ctx->register_ctx[i].views[j].parameters,(char*)unit, 0, &temp_value,0,&(ctx->register_ctx[i].views[j]));
      if(err){
	pcilib_error("can't write to the register with the formula view %s", unit);
	return PCILIB_ERROR_FAILED;
      }
      *(pcilib_register_value_t*)value=temp_value;
      break;
      }
    return 0;
    }
     pcilib_error("the view asked and the register do not correspond");
  return PCILIB_ERROR_NOTAVAILABLE;
}


/**
 * function to write to a register using a view
 */ 
int pcilib_write_view(pcilib_t *ctx, const char *bank, const char *regname, const char *unit, size_t value_size,void* value){
   int i,j;
   pcilib_register_value_t temp_value;
   int err;
   
  /* we get the index of the register to find the corresponding register context*/
  if((i=pcilib_find_register(ctx,bank,regname))==PCILIB_REGISTER_INVALID){
    pcilib_error("can't get the index of the register %s", regname);
    return PCILIB_ERROR_INVALID_REQUEST;
  }
 
  for(j=0;ctx->register_ctx[i].views[j].name;j++){
    if(!(strcasecmp(ctx->register_ctx[i].views[j].base_unit.name,unit))){/*if we asked for the unit "name"*/
      err=ctx->register_ctx[i].views[j].op(ctx,ctx->register_ctx[i].views[j].parameters,value/*the command name*/,1,&temp_value,0,&(ctx->register_ctx[i].views[j]));
      if(err){
	pcilib_error("can't write to the register with the enum view");
	return PCILIB_ERROR_FAILED;
      }
      break;
    }else if(!(strcasecmp(ctx->register_ctx[i].views[j].name,(char*)unit))){/*in this case we asked for then name of the view in unit*/
      temp_value=*(pcilib_register_value_t*)value /*the value to put in the register*/;
      err=ctx->register_ctx[i].views[j].op(ctx,ctx->register_ctx[i].views[j].parameters, (char*)unit, 1, &temp_value,0,&(ctx->register_ctx[i].views[j]));
      if(err){
	pcilib_error("can't write to the register with the formula view %s", unit);
	return PCILIB_ERROR_FAILED;
      }
      break;
    }
    pcilib_write_register(ctx,bank,regname,temp_value);
    return 0;
  }

  pcilib_error("the view asked and the register do not correspond");
  return PCILIB_ERROR_NOTAVAILABLE;
}

/**
 * always: viewval=view params=view params
 * write: name=enum command regval:the value corresponding to the command
 */
int operation_enum(pcilib_t *ctx, void *params, char* name, int view2reg, pcilib_register_value_t *regval, size_t viewval_size, void* viewval){
  int j,k;
  if(view2reg==1){
    for(j=0; ((pcilib_view_enum_t*)(params))[j].name;j++){
      if(!(strcasecmp(((pcilib_view_enum_t*)(params))[j].name,name))){
	*regval=((pcilib_view_enum_t*)(params))[j].value;
	return 0;
      }
    }
  }else if (view2reg==0){
    for(j=0; ((pcilib_view_enum_t*)(params))[j].name;j++){
      if (*regval<((pcilib_view_enum_t*)(params))[j].max && *regval>((pcilib_view_enum_t*)(params))[j].min){
	name=(char*)realloc(name,strlen(((pcilib_view_enum_t*)(params))[j].name)*sizeof(char));
	strncpy(name,((pcilib_view_enum_t*)(params))[j].name, strlen(((pcilib_view_enum_t*)(params))[j].name));
	k=strlen(((pcilib_view_enum_t*)(params))[j].name);
	name[k]='\0';
	return 0;
      }
    }
  } 
  return PCILIB_ERROR_INVALID_REQUEST;
}

/**
 * pârams: view params unit=unit wanted regval:value before formula/after formula viewval=view
 */
int operation_formula(pcilib_t *ctx, void *params, char* unit, int view2reg, pcilib_register_value_t *regval, size_t viewval_size, void* viewval){
    int j=0;
    pcilib_register_value_t value=0;
    char* formula;

    if(view2reg==0){
      if(!(strcasecmp(unit, ((pcilib_view_t*)viewval)->base_unit.name))){
	formula=malloc(sizeof(char)*strlen(((pcilib_formula_t*)params)->read_formula));
	if(!(formula)){
	  pcilib_error("can't allocate memory for the formula");
	  return PCILIB_ERROR_MEMORY;
	}
	strncpy(formula,((pcilib_formula_t*)params)->read_formula,strlen(((pcilib_formula_t*)params)->read_formula));
	pcilib_view_apply_formula(ctx,formula,*regval,&value,0);
	return value;
      }
      
      for(j=0; ((pcilib_view_t*)viewval)->base_unit.other_units[j].name;j++){
	if(!(strcasecmp(((pcilib_view_t*)viewval)->base_unit.other_units[j].name,unit))){
	  /* when we have found the correct view of type formula, we apply the formula, that get the good value for return*/
	  formula=malloc(sizeof(char)*strlen(((pcilib_formula_t*)params)->read_formula));
	  if(!(formula)){
	    pcilib_error("can't allocate memory for the formula");
	    return PCILIB_ERROR_MEMORY;
	  }
	  strncpy(formula,((pcilib_formula_t*)params)->read_formula,strlen(((pcilib_formula_t*)params)->read_formula));
	  pcilib_view_apply_formula(ctx,formula, *regval,&value,0);
	  pcilib_view_apply_unit(((pcilib_view_t*)viewval)->base_unit.other_units[j],unit,&value);
	  return value;
	}
      }
    }else if(view2reg==1){
      if(!(strcasecmp(unit, ((pcilib_view_t*)viewval)->base_unit.name))){
	formula=malloc(sizeof(char)*strlen(((pcilib_formula_t*)params)->write_formula));
	strncpy(formula,((pcilib_formula_t*)params)->write_formula,strlen(((pcilib_formula_t*)params)->write_formula));
	pcilib_view_apply_formula(ctx,formula,*regval,&value,1);
	return 0;
    }
      
      for(j=0;((pcilib_view_t*)viewval)->base_unit.other_units[j].name;j++){
	if(!(strcasecmp(((pcilib_view_t*)viewval)->base_unit.other_units[j].name,unit))){
	  /* when we have found the correct view of type formula, we apply the formula, that get the good value for return*/
	  formula=malloc(sizeof(char)*strlen(((pcilib_formula_t*)params)->write_formula));
	  strncpy(formula,((pcilib_formula_t*)params)->write_formula,strlen((( pcilib_formula_t*)params)->write_formula));
	  pcilib_view_apply_unit(((pcilib_view_t*)viewval)->base_unit.other_units[j],unit,&value);
	  pcilib_view_apply_formula(ctx,formula,*regval,&value,1);
	  *regval=value;
	  /* we maybe need some error checking there , like temp_value >min and <max*/
	  return 0;
	}
      }
    }
      return PCILIB_ERROR_INVALID_REQUEST;
}


/**
 * function to populate ctx enum views, as we could do for registers or banks
 */
int pcilib_add_views_enum(pcilib_t *ctx, size_t n, const pcilib_view_enum2_t* views) {
	
    pcilib_view_enum2_t *views_enum;
    size_t size;

    if (!n) {
	for (n = 0; views[n].enums_list[0].value; n++);
    }

    if ((ctx->num_enum_views + n + 1) > ctx->alloc_enum_views) {
	for (size = ctx->alloc_enum_views; size < 2 * (n + ctx->num_enum_views + 1); size<<=1);

	views_enum = (pcilib_view_enum2_t*)realloc(ctx->enum_views, size * sizeof(pcilib_view_enum2_t));
	if (!views_enum) return PCILIB_ERROR_MEMORY;

	ctx->enum_views = views_enum;
	ctx->alloc_enum_views = size;
    }

    memcpy(ctx->enum_views + ctx->num_enum_views, views, n * sizeof(pcilib_view_enum2_t));
    memset(ctx->enum_views + ctx->num_enum_views + n, 0, sizeof(pcilib_view_enum2_t));

    ctx->num_enum_views += n;
    

    return 0;
}


/**
 * function to populate ctx formula views, as we could do for registers or banks
 */
int pcilib_add_views_formula(pcilib_t *ctx, size_t n, const pcilib_view_formula_t* views) {
	
    pcilib_view_formula_t *views_formula;
    size_t size;

    if (!n) {
	for (n = 0; views[n].name; n++);
    }

    if ((ctx->num_formula_views + n + 1) > ctx->alloc_formula_views) {
      for (size = ctx->alloc_formula_views; size < 2 * (n + ctx->num_formula_views + 1); size<<=1);

	views_formula = (pcilib_view_formula_t*)realloc(ctx->formula_views, size * sizeof(pcilib_view_formula_t));
	if (!views_formula) return PCILIB_ERROR_MEMORY;

	ctx->formula_views = views_formula;
	ctx->alloc_formula_views = size;
    }

    memcpy(ctx->formula_views + ctx->num_formula_views, views, n * sizeof(pcilib_view_formula_t));
    memset(ctx->formula_views + ctx->num_formula_views + n, 0, sizeof(pcilib_view_formula_t));

    ctx->num_formula_views += n;
    return 0;
}

/**
 * function to populate ctx views, as we could do for registers or banks
 */
int pcilib_add_views(pcilib_t *ctx, size_t n, const pcilib_view_t* views) {
	
    pcilib_view_t *views2;
    size_t size;

    if (!n) {
	for (n = 0; views[n].name; n++);
    }

    if ((ctx->num_views + n + 1) > ctx->alloc_views) {
      for (size = ctx->alloc_views; size < 2 * (n + ctx->num_views + 1); size<<=1);

	views2 = (pcilib_view_t*)realloc(ctx->views, size * sizeof(pcilib_view_t));
	if (!views2) return PCILIB_ERROR_MEMORY;

	ctx->views = views2;
	ctx->alloc_views = size;
    }

    memcpy(ctx->views + ctx->num_views, views, n * sizeof(pcilib_view_t));
    memset(ctx->views + ctx->num_views + n, 0, sizeof(pcilib_view_t));

    ctx->num_views += n;
    return 0;
}