#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <misc.h>
#include "util.h"
#include <string>
#include <map>

using namespace std;

enum TOKEN {
	TOK_END,
	TOK_INVAL,
	TOK_PLUS,
	TOK_MINUS,
	TOK_MULT,
	TOK_DIV,
	TOK_MODULO,
	TOK_OPNPAR,
	TOK_CLSPAR,
	TOK_VAR,
	TOK_NUM,
	TOK_FUNC,
};

struct ELM{
	TOKEN tok;
	string val;
	double res;
	ELM(TOKEN _tok, const string &_val, double _res){
		tok = _tok;
		val = _val;
		res = _res;
	}
	ELM(TOKEN _tok, const char *_val){
		tok = _tok;
		val = _val;
		res = 0;
	}
	ELM(TOKEN _tok, const char _val){
		tok = _tok;
		val = _val;
		res = 0;
	}
	void inval(){
		tok = TOK_INVAL;
		val = "";
		res = 0;
	}
};

struct PARSER{
	string expr;
	const char *pt;
	map<string,double> vars;
	PARSER (const string &_expr){
		expr = _expr;
		pt = expr.c_str();
	}
	void setvar(const char *name, double val){
		vars[name] = val;
	}
	ELM get(){
		pt = str_skip(pt);
		if (*pt == '$' || *pt == '\0'){
			return ELM(TOK_END,'\0');
		}else if (*pt == '('){
			pt++;
			return ELM(TOK_OPNPAR,'(');
		}else if (*pt == ')'){
			pt++;
			return ELM(TOK_CLSPAR,')');
		}else if (*pt == '+'){
			pt++;
			return ELM(TOK_PLUS,'+');
		}else if (*pt == '-'){
			pt++;
			return ELM(TOK_MINUS,'-');
		}else if (*pt == '/'){
			pt++;
			return ELM(TOK_DIV,'/');
		}else if (*pt == '*'){
			pt++;
			return ELM(TOK_MULT,'*');
		}else if (*pt == '%'){
			pt++;
			return ELM(TOK_MODULO,'%');
		}else if (isalpha(*pt)){
			const char *start = pt;
			while (isalpha(*pt) || isdigit(*pt)) pt++;
			string tmp(start,pt-start);
			if (tmp == "sin"){
				return ELM(TOK_FUNC,"sin");
			}else if (tmp == "cos"){
				return ELM(TOK_FUNC,"cos");
			}else if (tmp == "tan"){
				return ELM(TOK_FUNC,"tan");
			}
			return ELM(TOK_VAR,tmp,vars[tmp]);
		}else if (isdigit(*pt) || *pt == '-'){
			const char *start = pt;
			pt++;
			while (isdigit(*pt) || *pt == '.') pt++;
			string tmp(start,pt-start);
			return ELM(TOK_NUM,tmp,atof(tmp.c_str()));
		}
		return ELM(TOK_INVAL,*pt);
	}
};

static ELM math_expr (PARSER &p, double &res);

static ELM math_item (PARSER &p, double &res)
{
	ELM e = p.get();
	res = 0;
	if (e.tok == TOK_OPNPAR){
		e = math_expr(p,res);
		if (e.tok == TOK_CLSPAR){
			e = p.get();
		}else{
			e.inval();
		}
	}else if (e.tok == TOK_NUM || e.tok == TOK_VAR){
		res = e.res;
		e = p.get();
	}else if (e.tok == TOK_FUNC){
		string func = e.val;
		e = p.get();
		if (e.tok == TOK_OPNPAR){
			e = math_expr(p,res);
			if (e.tok == TOK_CLSPAR){
				e = p.get();
				if (func == "sin"){
					res = sin(res);
				}else if (func == "cos"){
					res = cos(res);
				}else if (func == "tan"){
					res = tan(res);
				}
			}else{
				e.inval();
			}
		}else{
			e.inval();
		}
	}else{
		e.inval();
	}
	return e;
}

static ELM math_mult (PARSER &p, double &res)
{
	ELM e = math_item(p,res);
	while (1){
		if (e.tok == TOK_MULT || e.tok == TOK_DIV || e.tok == TOK_MODULO){
			TOKEN tok = e.tok;
			double res2;
			e = math_item(p,res2);
			if (tok == TOK_MULT){
				res *= res2;
			}else if (tok == TOK_DIV){
				res /= res2;
			}else if (tok == TOK_MODULO){
				res = ((int)res % (int)res2);
			}
		}else{
			break;
		}
	}
	return e;
}
static ELM math_plus (PARSER &p, double &res)
{
	ELM e = math_mult(p,res);
	while (1){
		if (e.tok == TOK_PLUS || e.tok == TOK_MINUS){
			TOKEN tok = e.tok;
			double res2;
			e = math_mult(p,res2);
			if (tok == TOK_PLUS){
				res += res2;
			}else if (tok == TOK_MINUS){
				res -= res2;
			}
		}else{
			break;
		}
	}
	return e;
}

static ELM math_expr (PARSER &p, double &res)
{
	return math_plus (p,res);
}
		

static double math_expr (
	const string &line,
	int x,
	int y,
	int w,
	int h)
{
	PARSER p (line);
	p.setvar ("x",x);
	p.setvar ("y",y);
	p.setvar ("w",w);
	p.setvar ("h",h);
	double res = 0;
	ELM e = math_expr(p,res);
	if (e.tok != TOK_END){
		const char *start = p.expr.c_str();
		fprintf (stderr,"Invalid expression %s\n"
				"                   %*s\n"
			,start,(int)(p.pt-start),"^");
	}
	return res;
}
	

string math_patch (const string &line, double x, double y, double w, double h)
{
	string ret;
	size_t pos = 0;
	while (1){
		size_t newpos = line.find("$",pos);
		if (newpos == string::npos){
			ret += line.substr(pos);
			break;
		}else{
			ret += line.substr(pos,newpos-pos);
			newpos++;
			size_t endpos = line.find("$",newpos);
			if (endpos == string::npos){
				// No end $
				break;
			}
			double res = math_expr (line.substr(newpos,endpos-newpos),x,y,w,h);
			char tmp[100];
			snprintf (tmp,sizeof(tmp),"%lf",res);
			ret += tmp;
			
			pos = endpos + 1;
		}
		
	}
	return ret;
}

#ifdef TEST

int main (int argc, char *argv[])
{
	for (int i=1; i<argc; i++){
		string tmp = argv[i];
		if (strchr(tmp.c_str(),'$') != NULL){
			string res = math_patch (tmp,10,11,12,13);
			printf ("res=%s\n",res.c_str());
		}else{
			double res = math_expr (tmp,10,11,12,13);
			printf ("res=%lf\n",res);
		}
	}
	return 0;
}

#endif