// ServerFunctionsList.cc

// This file is part of bes, A C++ back-end server implementation framework
// for the OPeNDAP Data Access Protocol.

// Copyright (c) 2013 OPeNDAP, Inc.
// Author: James Gallagher <jgallagher@opendap.org>
//
// 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; either
// version 2.1 of the License, or (at your option) any later version.
//
// 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
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.

#include "config.h"

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#include <pthread.h>

#include <iostream>
#include <algorithm>

//#define DODS_DEBUG

#include <expr.h>
#include "debug.h"

#include "ServerFunctionsList.h"

using namespace std;
using namespace libdap;

namespace libdap {

static pthread_once_t ServerFunctionsList_instance_control = PTHREAD_ONCE_INIT;

ServerFunctionsList *ServerFunctionsList::d_instance = 0 ;

/**
 * private static that only gets called once in the life cycle of the process.
 */
void ServerFunctionsList::initialize_instance() {
    if (d_instance == 0) {
        DBG(cerr << "ServerFunctionsList::initialize_instance() - Creating singleton ServerFunctionList instance." << endl);
        d_instance = new ServerFunctionsList;
        #if HAVE_ATEXIT
            atexit(delete_instance);
        #endif
    }
}

/**
 * Private static function can only be called by friends andf pThreads code.
 */
void ServerFunctionsList::delete_instance() {
    DBG(cerr << "ServerFunctionsList::delete_instance() - Deleting singleton ServerFunctionList instance." << endl);
    delete d_instance;
    d_instance = 0;
}

/**
 * Private method insures that nobody can try to delete the singleton class.
 */

ServerFunctionsList::~ServerFunctionsList() {
    SFLIter fit;
    for(fit=d_func_list.begin(); fit!=d_func_list.end() ; fit++){
        ServerFunction *func = fit->second;
        DBG(cerr << "ServerFunctionsList::~ServerFunctionsList() - Deleting ServerFunction " << func->getName() << " from ServerFunctionsList." << endl);
        delete func;
    }
    d_func_list.clear();
}

ServerFunctionsList * ServerFunctionsList::TheList() {
    pthread_once(&ServerFunctionsList_instance_control, initialize_instance);
    DBG(cerr << "ServerFunctionsList::TheList() - Returning singleton ServerFunctionList instance." << endl);
    return d_instance;
}

/**
 * Adds the passed ServerFunction pointer to the list of ServerFunctions using
 * the value of ServerFunction.getName() as the key in the list.
 *
 * @brief Adds the passed ServerFunction pointer to the list of ServerFunctions.
 * @param *func A pointer to the ServerFunction object to add to the ServerFunctionList.
 * The pointer is copied, not the object referenced; this class does not
 * delete the pointer.
 */
void ServerFunctionsList::add_function(ServerFunction *func )
{
    DBG(cerr << "ServerFunctionsList::add_function() - Adding ServerFunction " << func->getName() << endl);
    d_func_list.insert(std::make_pair(func->getName(),func));
}

/**
 * Returns the first boolean function in the list whose key value matches the passed string name.
 * When a match is found the function returns true and sets returned value parameter *f to
 * the boolean function held by the ServerFunction object extracted from the list.
 *
 * Method:
 * Looks through the list of ServerFunctions and compares each function's key value (which
 * would be the value of SurverFunction.getName()) with the value of the string parameter
 * 'name'. When they match then the returned value parameter is set to the value returned
 * by ServerFunction.get_btp_func(). If the ServerFunction _is not_  a instance of a boolean
 * function then the return value will be 0 (null) and the search for matching function will continue.
 * If the ServerFunction _is_ a boolean function then the returned value will be non-zero and
 * the search will return true (it found the thing) and the returned value parameter *f will have
 * it's value set to the boolean function.
 *
 *  @brief Find a boolean function with a given name in the function list.
 *  @param name A string containing the name of the function to find.
 *  @param *f   A returned value parameter through which a point to the desired function is returned.
 *
 */
bool ServerFunctionsList::find_function(const std::string &name, bool_func *f) const
{
    if (d_func_list.empty())
        return false;

    std::pair <SFLCIter, SFLCIter> ret;
    ret = d_func_list.equal_range(name);
    for (SFLCIter it = ret.first; it != ret.second; ++it) {
        if (name == it->first && it->second->get_bool_func()) {
            *f = it->second->get_bool_func();
            return true;
        }
    }

    return false;
}

/**
 * Returns the first BaseType function in the list whose key value matches the passed string name.
 * When a match is found the function returns true and sets returned value parameter *f to
 * the BaseType function held by the ServerFunction object extracted from the list.
 *
 * Method:
 * Looks through the list of ServerFunctions and compares each function's key value (which
 * would be the value of SurverFunction.getName()) with the value of the string parameter
 * 'name'. When they match then the returned value parameter is set to the value returned
 * by ServerFunction.get_btp_func(). If the ServerFunction _is not_  a instance of a BaseType
 * function then the return value will be 0 (null) and the search for matching function will continue.
 * If the ServerFunction _is_ a BaseType function then the returned value will be non-zero and
 * the search will return true (it found the thing) and the returned value parameter *f will have
 * it's value set to the BaseType function.
 *
 *  @brief Find a BaseType function with a given name in the function list.
 *  @param name A string containing the name of the function to find.
 *  @param *f   A returned value parameter through which a point to the desired function is returned.
 *
 */
bool ServerFunctionsList::find_function(const string &name, btp_func *f) const
{
    if (d_func_list.empty())
        return false;
    DBG(cerr << "ServerFunctionsList::find_function() - Looking for ServerFunction '" << name << "'" << endl);

    std::pair <SFLCIter, SFLCIter> ret;
    ret = d_func_list.equal_range(name);
    for (SFLCIter it = ret.first; it != ret.second; ++it) {
        if (name == it->first && it->second->get_btp_func()) {
            *f = it->second->get_btp_func();
            return true;
        }
    }

    return false;
}

/**
 * Returns the first projection function in the list whose key value matches the passed string name.
 * When a match is found the function returns true and sets returned value parameter *f to
 * the projection function held by the ServerFunction object extracted from the list.
 *
 * Method:
 * Looks through the list of ServerFunctions and looks at each function's key value (which
 * would be the value of SurverFunction.getName() for each function). When a function has the same
 * key name as the value of the string parameter 'name', then the returned value parameter is set
 * the value returned by ServerFunction.get_proj_func(). If the ServerFunction _is not_  a projection
 * function then the return value will be 0 (null) and the search for matching function will continue.
 * If the ServerFunction _is_ a projection then the returned value will be non-zero and the search will
 * return true (it found the thing) and the returned value parameter *f will have it's value set
 * to the projection function.
 *
 *  @brief Find a projection function with a given name in the function list.
 *  @param name A string containing the name of the function to find.
 *  @param *f   A returned value parameter through which a point to the desired function is returned.
 *
 */
bool ServerFunctionsList::find_function(const string &name, proj_func *f) const
{
    if (d_func_list.empty())
        return false;

    std::pair <SFLCIter, SFLCIter> ret;
    ret = d_func_list.equal_range(name);
    for (SFLCIter it = ret.first; it != ret.second; ++it) {
        if (name == it->first && it->second->get_proj_func()) {
            *f = it->second->get_proj_func();
            return true;
        }
    }

    return false;
}

/**
 * Find a DAP4 function in the Server Functions List.
 *
 * @param name Look for this function name
 * @param f Value-result parameter. NULL if the function is not found
 * @return True if the function was found, otherwise false.
 */
bool ServerFunctionsList::find_function(const string &name, D4Function *f) const
{
    if (d_func_list.empty())
        return false;

    std::pair <SFLCIter, SFLCIter> ret;
    ret = d_func_list.equal_range(name);
    for (SFLCIter it = ret.first; it != ret.second; ++it) {
        if (name == it->first && it->second->get_d4_function()) {
            *f = it->second->get_d4_function();
            return true;
        }
    }

    return false;
}

/** @brief Returns an iterator pointing to the first key pair in the ServerFunctionList. */
ServerFunctionsList::SFLIter ServerFunctionsList::begin()
{
    return d_func_list.begin();
}

/** @brief Returns an iterator pointing to the last key pair in the ServerFunctionList. */
ServerFunctionsList::SFLIter ServerFunctionsList::end()
{
    return d_func_list.end();
}

/**
 *
 *
 * @brief Returns the ServerFunction pointed to by the passed iterator.
 *
 */
ServerFunction *ServerFunctionsList::getFunction(SFLIter it)
{
    return (*it).second;
}

void ServerFunctionsList::getFunctionNames(vector<string> *names){
	SFLIter fit;
    for(fit = d_func_list.begin(); fit != d_func_list.end(); fit++) {
        ServerFunction *func = fit->second;
        names->push_back(func->getName());
    }
}

} // namespace libdap