// Copyright (C) 2015 Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

#ifndef EVAL_CONTEXT_H
#define EVAL_CONTEXT_H
#include <string>
#include <map>
#include <eval/parser.h>
#include <eval/eval_context_decl.h>
#include <exceptions/exceptions.h>

// Tell Flex the lexer's prototype ...
#define YY_DECL isc::eval::EvalParser::symbol_type yylex (EvalContext& driver)

// ... and declare it for the parser's sake.
YY_DECL;

namespace isc {
namespace eval {

/// @brief Evaluation error exception raised when trying to parse an axceptions.
class EvalParseError : public isc::Exception {
public:
    EvalParseError(const char* file, size_t line, const char* what) :
        isc::Exception(file, line, what) { };
};


/// @brief Evaluation context, an interface to the expression evaluation.
class EvalContext
{
public:
    /// @brief Default constructor.
    ///
    /// @param option_universe Option universe: DHCPv4 or DHCPv6. This is used
    /// by the parser to determine which option definitions set should be used
    /// to map option names to option codes.
    EvalContext(const Option::Universe& option_universe);

    /// @brief destructor
    virtual ~EvalContext();

    /// @brief Parsed expression (output tokens are stored here)
    isc::dhcp::Expression expression;

    /// @brief Method called before scanning starts on a string.
    void scanStringBegin();

    /// @brief Method called after the last tokens are scanned from a string.
    void scanStringEnd();

    /// @brief Run the parser on the string specified.
    ///
    /// @param str string to be written
    /// @return true on success.
    bool parseString(const std::string& str);

    /// @brief The name of the file being parsed.
    /// Used later to pass the file name to the location tracker.
    std::string file_;

    /// @brief The string being parsed.
    std::string string_;

    /// @brief Error handler
    ///
    /// @param loc location within the parsed file when experienced a problem.
    /// @param what string explaining the nature of the error.
    void error(const isc::eval::location& loc, const std::string& what);

    /// @brief Error handler
    ///
    /// This is a simplified error reporting tool for possible future
    /// cases when the EvalParser is not able to handle the packet.
    void error(const std::string& what);

    /// @brief Fatal error handler
    ///
    /// This is for should not happen but fatal errors
    static void fatal(const std::string& what);

    /// @brief Option code convertion
    ///
    /// @param option_code a string representing the integer code
    /// @param loc the location of the token
    /// @result the option code
    /// @throw calls the syntax error function if the value is no in
    ///        the range 0..255 or 0..65535
    uint16_t convertOptionCode(const std::string& option_code,
                               const isc::eval::location& loc);

    /// @brief Option name convertion
    ///
    /// @param option_name the option name
    /// @param loc the location of the token
    /// @result the option code
    /// @throw calls the syntax error function if the name cannot be resolved
    uint16_t convertOptionName(const std::string& option_name,
                               const isc::eval::location& loc);

 private:
    /// @brief Flag determining scanner debugging.
    bool trace_scanning_;

    /// @brief Flag determing parser debugging.
    bool trace_parsing_;

    /// @brief Option universe: DHCPv4 or DHCPv6.
    ///
    /// This is used by the parser to determine which option definitions
    /// set should be used to map option name to option code.
    Option::Universe option_universe_;

};

}; // end of isc::eval namespace
}; // end of isc namespace

#endif