/*
 *
 * Copyright (c) 2006 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include "Options.h"
#include "qpid/Exception.h"

#include <boost/bind.hpp>

#include <fstream>
#include <algorithm>
#include <iostream>

namespace qpid {

using namespace std;

namespace {

struct EnvOptMapper {
    static bool matchChar(char env, char opt) {
        return (env==toupper(opt)) || (strchr("-.", opt) && env=='_');
    }

    static bool matchStr(const string& env, boost::shared_ptr<po::option_description> desc) {
        return std::equal(env.begin(), env.end(), desc->long_name().begin(), &matchChar);
    }
            
    static bool matchCase(const string& env, boost::shared_ptr<po::option_description> desc) {
        return env == desc->long_name();
    }
            
    EnvOptMapper(const Options& o) : opts(o) {}
    
    string operator()(const string& envVar) {
        static const std::string prefix("QPID_");
        if (envVar.substr(0, prefix.size()) == prefix) {
            string env = envVar.substr(prefix.size());
#if (BOOST_VERSION >= 103300)
            typedef const std::vector< boost::shared_ptr<po::option_description> > OptDescs;
            OptDescs::const_iterator i =
                find_if(opts.options().begin(), opts.options().end(), boost::bind(matchStr, env, _1));
            if (i != opts.options().end())
                return (*i)->long_name();
#else
            /*===================================================================
              For Boost version 103200 and below.

              In Boost version 103200, the options_description::options member,
              used above, is private.  So what I will do here is use the 
              count() funtion, which returns a 1 or 0 indicating presence or
              absence of the environment variable.  
              
              If it is present, I will return its name.  Env vars do not have
              short and long forms, so the name is synonymous with the long 
              name.  (This would not work for command line args.)
              And if it's absent -- an empty string.
            =====================================================================*/


            /*------------------------------------------------------------
              The env vars come in unaltered, i.e. QPID_FOO, but the 
              options are stored normalized as "qpid-foo".  Change the
              local variable "env" so it can be found by "opts".
            ------------------------------------------------------------*/
            for (std::string::iterator i = env.begin(); i != env.end(); ++i) 
            {
                *i = (*i == '_') 
                     ? '-' 
                     : ::tolower(*i);
            }

            if ( opts.count(env.c_str()) > 0 )
            {
              return env.c_str();
            }
            else
            {
              return string();
            }
#endif
        }
        return string();
    }

    string configFileLine (string& line) {
        size_t pos = line.find ('=');
        if (pos == string::npos)
            return string();
        string key = line.substr (0, pos);
#if (BOOST_VERSION >= 103300)
        typedef const std::vector< boost::shared_ptr<po::option_description> > OptDescs;
        OptDescs::const_iterator i = 
            find_if(opts.options().begin(), opts.options().end(), boost::bind(matchCase, key, _1));
        if (i != opts.options().end())
            return string (line) + "\n";
#else
        try {
            po::option_description desc = opts.find(key.c_str());
            return string (line) + "\n";
        }
        catch (const std::exception& e) {}
#endif
        return string ();
    }

    const Options& opts;
};

}
std::string prettyArg(const std::string& name, const std::string& value) {
    return value.empty() ? name+" " : name+" ("+value+") ";
}

Options::Options(const string& name) : po::options_description(name) {}

void Options::parse(int argc, char** argv, const std::string& configFile, bool allowUnknown)
{
    string defaultConfigFile = configFile; // May be changed by env/cmdline
    string parsing;
    try {
        po::variables_map vm;
        parsing="command line options";
        if (argc > 0 && argv != 0) {
            if (allowUnknown) {
#if (BOOST_VERSION >= 103300)
                // This hideous workaround is required because boost 1.33 has a bug
                // that causes 'allow_unregistered' to not work.
                po::command_line_parser clp = po::command_line_parser(argc, const_cast<char**>(argv)).
                    options(*this).allow_unregistered();
                po::parsed_options opts     = clp.run();
                po::parsed_options filtopts = clp.run();
                filtopts.options.clear ();
                for (std::vector< po::basic_option<char> >::iterator i = opts.options.begin();
                     i != opts.options.end(); i++)
                    if (!i->unregistered)
                        filtopts.options.push_back (*i);
                po::store(filtopts, vm);
#endif
            }
            else
                po::store(po::parse_command_line(argc, const_cast<char**>(argv), *this), vm);
        }
        parsing="environment variables";
        po::store(po::parse_environment(*this, EnvOptMapper(*this)), vm);
        po::notify(vm); // configFile may be updated from arg/env options.
        if (!configFile.empty()) {
            parsing="configuration file "+configFile;
            ifstream conf(configFile.c_str());
            if (conf.good()) {
                // Remove this hack when we get a stable version of boost that
                // can allow unregistered options in config files.
                EnvOptMapper mapper(*this);
                stringstream filtered;

                while (!conf.eof()) {
                    string line;
                    getline (conf, line);
                    filtered << mapper.configFileLine (line);
                }

                po::store(po::parse_config_file(filtered, *this), vm);
                // End of hack
            }
            else {
                // No error if default configfile is missing/unreadable
                // but complain for non-default config file.
                if (configFile != defaultConfigFile)
                    throw Exception("cannot read configuration file "
                                    +configFile);
            }
        }
        po::notify(vm);
    }
    catch (const std::exception& e) {
        ostringstream msg;
        msg << "Error in " << parsing << ": " << e.what() << endl;
#if (BOOST_VERSION >= 103300)
        if (find_nothrow("help", false))
            msg << "Use --help to see valid options" << endl;
#endif
        throw Exception(msg.str());
    }
}

CommonOptions::CommonOptions(const string& name, const string& configfile)
    : Options(name), config(configfile)
{
    addOptions()
        ("help,h", optValue(help), "Displays the help message")
        ("version,v", optValue(version), "Displays version information")
        ("config", optValue(config, "FILE"), "Reads configuration from FILE");
}

} // namespace qpid