/*
 *  LLCalcParser.h
 *  Copyright 2008 Aimee Walton.
 * $LicenseInfo:firstyear=2008&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2008, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 *
 */

#ifndef LL_CALCPARSER_H
#define LL_CALCPARSER_H

#include <boost/spirit/include/classic_attribute.hpp>
#include <boost/spirit/include/classic_core.hpp>
#include <boost/spirit/include/classic_error_handling.hpp>
#include <boost/spirit/include/classic_position_iterator.hpp>
#include <boost/spirit/include/phoenix1_binders.hpp>
#include <boost/spirit/include/classic_symbols.hpp>
using namespace boost::spirit::classic;

#include "llcalc.h"
#include "llmath.h"

struct LLCalcParser : grammar<LLCalcParser>
{
    LLCalcParser(F32& result, LLCalc::calc_map_t* constants, LLCalc::calc_map_t* vars) :
        mResult(result), mConstants(constants), mVariables(vars) {};

    struct value_closure : closure<value_closure, F32>
    {
        member1 value;
    };

    template <typename ScannerT>
    struct definition
    {
        // Rule declarations
        rule<ScannerT> statement, identifier;
        rule<ScannerT, value_closure::context_t> expression, term,
            power,
            unary_expr,
            factor,
            unary_func,
            binary_func,
            group;

        // start() should return the starting symbol
        rule<ScannerT> const& start() const { return statement; }

        definition(LLCalcParser const& self)
        {
            using namespace phoenix;

            assertion<std::string> assert_domain("Domain error");
//          assertion<std::string> assert_symbol("Unknown symbol");
            assertion<std::string> assert_syntax("Syntax error");

            identifier =
                lexeme_d[(alpha_p | '_') >> *(alnum_p | '_')]
            ;

            group =
                '(' >> expression[group.value = arg1] >> assert_syntax(ch_p(')'))
            ;

            unary_func =
                ((str_p("SIN") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_sin)(self,arg1)]) |
                 (str_p("COS") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_cos)(self,arg1)]) |
                 (str_p("TAN") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_tan)(self,arg1)]) |
                 (str_p("ASIN") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_asin)(self,arg1)]) |
                 (str_p("ACOS") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_acos)(self,arg1)]) |
                 (str_p("ATAN") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_atan)(self,arg1)]) |
                 (str_p("SQRT") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_sqrt)(self,arg1)]) |
                 (str_p("LOG") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_log)(self,arg1)]) |
                 (str_p("EXP") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_exp)(self,arg1)]) |
                 (str_p("ABS") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_fabs)(self,arg1)]) |
                 (str_p("FLR") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_floor)(self,arg1)]) |
                 (str_p("CEIL") >> '(' >> expression[unary_func.value = phoenix::bind(&LLCalcParser::_ceil)(self,arg1)])
                ) >> assert_syntax(ch_p(')'))
            ;

            binary_func =
                ((str_p("ATAN2") >> '(' >> expression[binary_func.value = arg1] >> ',' >>
                  expression[binary_func.value = phoenix::bind(&LLCalcParser::_atan2)(self, binary_func.value, arg1)]) |
                 (str_p("MIN") >> '(' >> expression[binary_func.value = arg1] >> ',' >>
                  expression[binary_func.value = phoenix::bind(&LLCalcParser::_min)(self, binary_func.value, arg1)]) |
                 (str_p("MAX") >> '(' >> expression[binary_func.value = arg1] >> ',' >>
                  expression[binary_func.value = phoenix::bind(&LLCalcParser::_max)(self, binary_func.value, arg1)])
                ) >> assert_syntax(ch_p(')'))
            ;

            // *TODO: Localisation of the decimal point?
            // Problem, LLLineEditor::postvalidateFloat accepts a comma when appropriate
            // for the current locale. However to do that here could clash with using
            // the comma as a separator when passing arguments to functions.
            factor =
                (ureal_p[factor.value = arg1] |
                 group[factor.value = arg1] |
                 unary_func[factor.value = arg1] |
                 binary_func[factor.value = arg1] |
                 // Lookup throws an Unknown Symbol error if it is unknown, while this works fine,
                 // would be "neater" to handle symbol lookup from here with an assertive parser.
//               constants_p[factor.value = arg1]|
                 identifier[factor.value = phoenix::bind(&LLCalcParser::lookup)(self, arg1, arg2)]
                ) >>
                // Detect and throw math errors.
                assert_domain(eps_p(phoenix::bind(&LLCalcParser::checkNaN)(self, factor.value)))
            ;

            unary_expr =
                !ch_p('+') >> factor[unary_expr.value = arg1] |
                '-' >> factor[unary_expr.value = -arg1]
            ;

            power =
                unary_expr[power.value = arg1] >>
                *('^' >> assert_syntax(unary_expr[power.value = phoenix::bind(&LLCalcParser::_pow)(self, power.value, arg1)]))
            ;

            term =
                power[term.value = arg1] >>
                *(('*' >> assert_syntax(power[term.value *= arg1])) |
                  ('/' >> assert_syntax(power[term.value /= arg1])) |
                  ('%' >> assert_syntax(power[term.value = phoenix::bind(&LLCalcParser::_fmod)(self, term.value, arg1)]))
                )
            ;

            expression =
                assert_syntax(term[expression.value = arg1]) >>
                *(('+' >> assert_syntax(term[expression.value += arg1])) |
                  ('-' >> assert_syntax(term[expression.value -= arg1]))
                )
            ;

            statement =
                !ch_p('=') >> ( expression )[var(self.mResult) = arg1] >> (end_p)
            ;
        }
    };

private:
    // Member functions for semantic actions
    F32 lookup(const std::string::iterator&, const std::string::iterator&) const;
    F32 _min(const F32& a, const F32& b) const { return llmin(a, b); }
    F32 _max(const F32& a, const F32& b) const { return llmax(a, b); }

    bool checkNaN(const F32& a) const { return !llisnan(a); }

    //FIX* non ambiguous function fix making SIN() work for calc -Cryogenic Blitz
    F32 _sin(const F32& a) const { return sin(DEG_TO_RAD * a); }
    F32 _cos(const F32& a) const { return cos(DEG_TO_RAD * a); }
    F32 _tan(const F32& a) const { return tan(DEG_TO_RAD * a); }
    F32 _asin(const F32& a) const { return asin(a) * RAD_TO_DEG; }
    F32 _acos(const F32& a) const { return acos(a) * RAD_TO_DEG; }
    F32 _atan(const F32& a) const { return atan(a) * RAD_TO_DEG; }
    F32 _sqrt(const F32& a) const { return sqrt(a); }
    F32 _log(const F32& a) const { return log(a); }
    F32 _exp(const F32& a) const { return exp(a); }
    F32 _fabs(const F32& a) const { return fabs(a); }
    F32 _floor(const F32& a) const { return (F32)llfloor(a); }
    F32 _ceil(const F32& a) const { return (F32)llceil(a); }
    F32 _atan2(const F32& a,const F32& b) const { return atan2(a,b); }
    F32 _pow(const F32& a, const F32& b) const { return powf(a, b); }
    F32 _fmod(const F32&a, const F32& b) const { return fmodf(a, b); }

    LLCalc::calc_map_t* mConstants;
    LLCalc::calc_map_t* mVariables;

    F32&        mResult;
};

#endif // LL_CALCPARSER_H