#include "tintin.h"
#include <ctype.h>
int stacks[100][3];
extern struct listnode *common_myvars;

#if IRIX
  #include <stdlib.h>
  #include <unistd.h>
#endif

extern char *get_arg_in_braces();
extern struct listnode *searchnode_list();

void math_command(line, ses)
     char *line;
     struct session *ses;
{
  /* char left[BUFFER_SIZE], right[BUFFER_SIZE], arg2[BUFFER_SIZE], */ 
  char left[BUFFER_SIZE], right[BUFFER_SIZE], 
       temp[BUFFER_SIZE], result[BUFFER_SIZE];
  struct listnode *my_vars, *ln;
  int i; 
  my_vars=(ses) ? ses->myvars : common_myvars;
  line=get_arg_in_braces(line, left, 0);
  line=get_arg_in_braces(line, right, 1);
  substitute_vars(right, result);
  substitute_myvars(result, right,ses);
  i=eval_expression(right);
  sprintf(temp,"%d",i);
  if ((ln=searchnode_list(my_vars,left))!=NULL) 
    deletenode_list(my_vars, ln);
  insertnode_list(my_vars, left, temp, "0", ALPHA); 
}

void if_command(line, ses)
     char *line;
     struct session *ses;
{
  /* char left[BUFFER_SIZE], right[BUFFER_SIZE], arg2[BUFFER_SIZE],  */
  char left[BUFFER_SIZE], right[BUFFER_SIZE], 
       temp[BUFFER_SIZE];
  /* int i; */
  line=get_arg_in_braces(line, left, 0);
  line=get_arg_in_braces(line, right, 1);
  substitute_vars(right,temp);
  substitute_myvars(temp,right,ses);
  substitute_vars(left,temp);
  substitute_myvars(temp,left,ses);  
  if (eval_expression(left)) {
    parse_input(right, ses); 
  }
}


int eval_expression(arg)
     char *arg;
{
  /* int i, begin, end, flag, prev, ptr; */
  int i, begin, end, flag, prev;
  char temp[BUFFER_SIZE];
  i=conv_to_ints(arg);
  if (i) {
    while(1) {
      i=0;
      flag=1;
      begin= -1;
      end= -1;
      prev= -1;
      while(stacks[i][0] && flag) {
        if (stacks[i][1]==0) {
          begin=i;
        }
        else if(stacks[i][1]==1) {
          end=i;
          flag=0;
        }
        prev=i;
        i=stacks[i][0];
      }
      if ((flag && (begin!= -1)) || (!flag && (begin== -1))) {
        tintin_puts2("#Unmatched parentheses error.", (struct session *)NULL);
        return 0;
      }
      if (flag) {
        if (prev== -1)
          return(stacks[0][2]);
        begin= -1;
        end=i;
      }
      i=do_one_inside(begin,end);
      if (!i) {
        sprintf(temp, "#Invalid expression to evaluate in {%s}", arg);
        tintin_puts2(temp, (struct session *)NULL);
        return 0;
      }
    }   
  }
  else return 0;  
}
int conv_to_ints(arg)
     char *arg;
{
  int i, flag;
  char *ptr, *tptr;
  i=0;
  ptr=arg;
  while (*ptr) {
    if (*ptr==' ') ;
    else if (*ptr=='(') {
      stacks[i][1]=0;
    }
    else if(*ptr==')') {
      stacks[i][1]=1;
    }
    else if(*ptr=='!') {
      if (*(ptr+1)=='=') { 
        stacks[i][1]=12;
        ptr++;
      }
      else
        stacks[i][1]=2;
    }
    else if(*ptr=='*') {
      stacks[i][1]=3;
    }
    else if(*ptr=='/') {
      stacks[i][1]=4;
    }
    else if(*ptr=='+') {
      stacks[i][1]=5;
    }
    else if(*ptr=='-') {
      flag= -1;
      if (i>0)
        flag=stacks[i-1][1];
      if (flag==15)
        stacks[i][1]=6;
      else {
        tptr=ptr;
        ptr++;
        while(isdigit(*ptr))
          ptr++;
        sscanf(tptr,"%d",&stacks[i][2]);
        stacks[i][1]=15;
        ptr--;
      }
    }
    else if(*ptr=='>') {
      if (*(ptr+1)=='=') {
        stacks[i][1]=8;
        ptr++;
      }
      else
        stacks[i][1]=7;
    }
    else if(*ptr=='<') {
      if (*(ptr+1)=='=') {
        ptr++;
        stacks[i][1]=10;
      }
      else
        stacks[i][1]=9;
    }
    else if(*ptr=='=') {
      stacks[i][1]=11;
      if (*(ptr+1)=='=')
        ptr++;
    }
    else if(*ptr=='&') {
      stacks[i][1]=13;
      if (*(ptr+1)=='&')
        ptr++;
    }
    else if(*ptr=='|') {
      stacks[i][1]=14;
      if (*(ptr+1)=='|')
        ptr++;
    }
    else if (isdigit(*ptr)) {
      stacks[i][1]=15;
      tptr=ptr;
      while (isdigit(*ptr))
        ptr++;
      sscanf(tptr,"%d",&stacks[i][2]);
      ptr--;
    }
    else if (*ptr=='T') {
      stacks[i][1]=15;
      stacks[i][2]=1;
    }
    else if(*ptr=='F') {
      stacks[i][1]=15;
      stacks[i][2]=0;
    }
    else {
      tintin_puts2("#Error. Invalid expression in #if or #math", (struct session *)NULL);
      return 0;
    }
    if (*ptr!=' ') {
      stacks[i][0]=i+1;
      i++;
    }
    ptr++;
  }
  if (i>0)
    stacks[i][0]=0;
  return 1;
}

int do_one_inside(begin, end)
     int begin;
     int end;
{
  /* int prev, ptr, highest, loc, ploc, next, nval, flag; */
  int prev, ptr, highest, loc, ploc, next;
  while(1) {
    ptr=0;
    if (begin>-1)
      ptr=stacks[begin][0];
    highest=16;
    loc= -1;
    ploc= -1;
    prev= -1;
    while (ptr<end) {
      if (stacks[ptr][1]<highest) {
        highest=stacks[ptr][1];
        loc=ptr;
        ploc=prev;
      }
      prev=ptr;
      ptr=stacks[ptr][0];
    }
    if (highest==15) {
      if (begin>-1) {
        stacks[begin][1]=15;
        stacks[begin][2]=stacks[loc][2];
        stacks[begin][0]=stacks[end][0];
        return 1;
      }
      else {
        stacks[0][0]=stacks[end][0];
        stacks[0][1]=15;
        stacks[0][2]=stacks[loc][2];
        return 1;
      }
    }
    else if (highest==2) {
      next=stacks[loc][0];
      if (stacks[next][1]!=15 || stacks[next][0]==0) {
        return 0;
      }  
      stacks[loc][0]=stacks[next][0];
      stacks[loc][1]=15;
      stacks[loc][2]=!stacks[next][2];
    }  
    else {
      next=stacks[loc][0];
      if (ploc== -1 || stacks[next][0]==0 || stacks[next][1]!=15) 
        return 0;
      if (stacks[ploc][1]!=15)
        return 0;    
      switch (highest) {
        case 3: /* highest priority is * */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]*=stacks[next][2];
          break;
        case 4: /* highest priority is / */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]/=stacks[next][2];
          break;
        case 5: /* highest priority is + */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]+=stacks[next][2];
          break;
        case 6: /* highest priority is - */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]-=stacks[next][2];
          break;
        case 7: /* highest priority is > */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]>stacks[next][2]);
          break;
        case 8: /* highest priority is >= */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]>=stacks[next][2]);
          break;
        case 9: /* highest priority is < */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]<stacks[next][2]);
          break;
        case 10: /* highest priority is <= */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]<=stacks[next][2]);
          break;
        case 11: /* highest priority is == */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]==stacks[next][2]);
          break;
        case 12: /* highest priority is != */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]!=stacks[next][2]);
          break;
        case 13: /* highest priority is && */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]&&stacks[next][2]);
          break;
        case 14: /* highest priority is || */
          stacks[ploc][0]=stacks[next][0];
          stacks[ploc][2]=(stacks[ploc][2]||stacks[next][2]);
          break;
        default:
          tintin_puts2("#Programming error *slap Bill*", (struct session *)NULL);
          return 0;     
      }
    }
  }
}