/***************************************************************************
 *                   ctlike - CTA maximum likelihood tool                  *
 * ----------------------------------------------------------------------- *
 *  copyright (C) 2010-2011 by Jurgen Knodlseder                           *
 * ----------------------------------------------------------------------- *
 *                                                                         *
 *  This program is free software: you can redistribute it and/or modify   *
 *  it under the terms of the GNU General Public License as published by   *
 *  the Free Software Foundation, either version 3 of the License, or      *
 *  (at your option) any later version.                                    *
 *                                                                         *
 *  This program 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 General Public License for more details.                           *
 *                                                                         *
 *  You should have received a copy of the GNU General Public License      *
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.  *
 *                                                                         *
 ***************************************************************************/
/**
 * @file ctlike.cpp
 * @brief CTA maximum likelihood tool implementation
 * @author J. Knodlseder
 */

/* __ Includes ___________________________________________________________ */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <cstdio>
#include "ctlike.hpp"
#include "GTools.hpp"

/* __ Method name definitions ____________________________________________ */
#define G_GET_PARAMETERS                           "ctlike::get_parameters()"

/* __ Debug definitions __________________________________________________ */

/* __ Coding definitions _________________________________________________ */


/*==========================================================================
 =                                                                         =
 =                        Constructors/destructors                         =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Void constructor
 ***************************************************************************/
ctlike::ctlike(void) : GApplication(CTLIKE_NAME, CTLIKE_VERSION)
{
    // Initialise members
    init_members();

    // Write header into logger
    log_header();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Observations constructor
 *
 * This method creates an instance of the class by copying an existing
 * observations container.
 ***************************************************************************/
ctlike::ctlike(GObservations obs) : GApplication(CTLIKE_NAME, CTLIKE_VERSION)
{
    // Initialise members
    init_members();

    // Set observations
    m_obs = obs;

    // Write header into logger
    log_header();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Command line constructor
 *
 * @param[in] argc Number of arguments in command line.
 * @param[in] argv Array of command line arguments.
 ***************************************************************************/
ctlike::ctlike(int argc, char *argv[]) : 
                        GApplication(CTLIKE_NAME, CTLIKE_VERSION, argc, argv)
{
    // Initialise members
    init_members();

    // Write header into logger
    log_header();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Copy constructor
 *
 * @param[in] app Application.
 ***************************************************************************/
ctlike::ctlike(const ctlike& app) : GApplication(app)
{
    // Initialise members
    init_members();

    // Copy members
    copy_members(app);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Destructor
 ***************************************************************************/
ctlike::~ctlike(void)
{
    // Free members
    free_members();

    // Return
    return;
}


/*==========================================================================
 =                                                                         =
 =                               Operators                                 =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Assignment operator
 *
 * @param[in] app Application.
 ***************************************************************************/
ctlike& ctlike::operator= (const ctlike& app)
{
    // Execute only if object is not identical
    if (this != &app) {

        // Copy base class members
        this->GApplication::operator=(app);

        // Free members
        free_members();

        // Initialise members
        init_members();

        // Copy members
        copy_members(app);

    } // endif: object was not identical

    // Return this object
    return *this;
}


/*==========================================================================
 =                                                                         =
 =                            Public methods                               =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Clear instance
 ***************************************************************************/
void ctlike::clear(void)
{
    // Free members
    free_members();
    this->GApplication::free_members();

    // Initialise members
    this->GApplication::init_members();
    init_members();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Execute application
 *
 * This method performs a maximum likelihood analysis of a observation given
 * in an observation container and saves the results in an XML file.
 ***************************************************************************/
void ctlike::execute(void)
{
    // Read ahead output filename so that it gets dumped correctly in the
    // parameters log
    m_outmdl = (*this)["outmdl"].filename();

    // Bin the event data
    run();

    // Save the results into XML file
    save();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Run maximum likelihood analysis
 *
 * The following analysis steps are performed:
 * 1. Read the parameters (and write them into logger)
 * 2. Load observation
 * 3. Setup models for optimizing
 * 4. Optimize model (and write result into logger)
 ***************************************************************************/
void ctlike::run(void)
{
    // Switch screen logging on in debug mode
    if (logDebug())
        log.cout(true);

    // Get parameters
    get_parameters();

    // Write parameters into logger
    if (logTerse()) {
        log_parameters();
        log << std::endl;
    }

    // Write observation(s) into logger
    if (logTerse()) {
        log << std::endl;
        if (m_obs.size() > 1)
            log.header1("Observations");
        else
            log.header1("Observation");
        log << m_obs << std::endl;
    }

    // Optimize model parameters using LM optimizer
    optimize_lm();

    // Write results into logger
    if (logTerse()) {
        log << " Maximum log likelihood ....: " << m_logL << std::endl;
        log << " Npred .....................: " << m_obs.npred() << std::endl;
        log << m_obs.models() << std::endl;
    }

    // Return
    return;
}


/***********************************************************************//**
 * @brief Save results
 *
 * This method saves the fit results in a XML file.
 ***************************************************************************/
void ctlike::save(void)
{
    // Write header
    if (logTerse()) {
        log << std::endl;
        log.header1("Save results");
    }

    // Get output filename
    m_outmdl = (*this)["outmdl"].value();

    // Write results out as XML model
    if (toupper(m_outmdl) != "NONE")
        m_obs.models().save(m_outmdl);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Get application parameters
 *
 * GException::par_error
 *             Invalid analysis method specified (neither BINNED nor UNBINNED).
 *
 * Get all required task parameters from the parameter file or (if specified)
 * by querying the user. Observation dependent parameters will only be read
 * if the observation container is actually empty. Observation dependent
 * parameters are:
 * "method" (analysis method),
 * "stat" (statistics to be used for observation),
 * "caldb" (calibration database),
 * "irf" (instrument response function),
 * "evfile" (event file name), and
 * "cntmap" (counts map file name).
 * The model will only be loaded if no model components exist in the
 * observation container.
 ***************************************************************************/
void ctlike::get_parameters(void)
{
    // If there is are no models associated with the observations then
    // load now the model definition
    if (m_obs.models().size() == 0) {

        // Get models XML filename
        std::string filename = (*this)["srcmdl"].filename();

        // Setup models for optimizing.
        m_obs.models(GModels(filename));

    } // endif: no models were associated with observations

    // If there are no observations in container then add a single CTA
    // observation using the parameters from the parameter file
    if (m_obs.size() == 0) {

        // Get observation parameters
        m_method = toupper((*this)["method"].string());
        m_stat   = toupper((*this)["stat"].string());
        m_caldb  = (*this)["caldb"].string();
        m_irf    = (*this)["irf"].string();

        // Case A: set-up unbinned CTA observation
        if (m_method == "UNBINNED") {

            // Get event file name
            std::string filename = (*this)["evfile"].filename();

            // Load and append unbinned CTA observation
            load_unbinned(filename);

        } // endif: unbinned analysis mode

        // Case B: set-up binned CTA observation
        else if (m_method == "BINNED") {

            // Get counts map file name
            std::string filename = (*this)["cntmap"].filename();

            // Load and append binned CTA observation
            load_binned(filename);

        } // endif: binned analysis mode

        // ... otherwise signal an invalid analysis method
        else {
            throw GException::par_error(G_GET_PARAMETERS, "method", 
                  "only \"BINNED\" or \"UNBINNED\" supported.");
        }

    } // endif: there was no observation in the container

    // Get standard parameters
    m_refit  = (*this)["refit"].boolean();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Optimize model parameters using Levenberg-Marquardt method
 ***************************************************************************/
void ctlike::optimize_lm(void)
{
    // Free any existing optimizer
    if (m_opt != NULL) delete m_opt;
    m_opt = NULL;

    // Allocate optimizer. The logger is only passed to the optimizer
    // constructor if optimizer logging is requested.
    GOptimizerLM* opt = (logTerse()) ? new GOptimizerLM(log)
                                     : new GOptimizerLM();

    // Assign optimizer
    m_opt = opt;

    // Set optimizer parameters
    opt->max_iter(m_max_iter);
    opt->max_stalls(m_max_stall);

    // Write Header for optimization and indent for optimizer logging
    if (logTerse()) {
        log << std::endl;
        log.header1("Maximum likelihood optimisation");
        log.indent(1);
    }

    // Perform LM optimization
    m_obs.optimize(*opt);

    // Optionally refit
    if (m_refit)
        m_obs.optimize(*opt);

    // Store maximum log likelihood value
    m_logL = -(opt->value());

    // Write optimization results
    log.indent(0);
    if (logTerse()) {
        log << std::endl;
        log.header1("Maximum likelihood optimization results");
        log << *opt << std::endl;
    }

    // Return
    return;
}


/***********************************************************************//**
 * @brief Load unbinned observation and append it to observations container
 *
 * @param[in] evfile Events file name.
 ***************************************************************************/
void ctlike::load_unbinned(const std::string& evfile)
{
    // Declare CTA observation
    GCTAObservation obs;

    // Set statistics
    obs.statistics(m_stat);

    // Load data
    obs.load_unbinned(evfile);

    // Set reponse
    obs.response(m_irf, m_caldb);

    // Append observation to contained
    m_obs.append(obs);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Load binned observation and append it to observations container
 *
 * @param[in] cntmap Counts map file name.
 ***************************************************************************/
void ctlike::load_binned(const std::string& cntmap)
{
    // Declare CTA observation
    GCTAObservation obs;

    // Set statistics
    obs.statistics(m_stat);

    // Load data
    obs.load_binned(cntmap);

    // Set reponse
    obs.response(m_irf, m_caldb);

    // Append observation to contained
    m_obs.append(obs);

    // Return
    return;
}


/*==========================================================================
 =                                                                         =
 =                             Private methods                             =
 =                                                                         =
 ==========================================================================*/

/***********************************************************************//**
 * @brief Initialise class members
 ***************************************************************************/
void ctlike::init_members(void)
{
    // Initialise members
    m_method.clear();
    m_stat.clear();
    m_caldb.clear();
    m_irf.clear();
    m_outmdl.clear();
    m_obs.clear();
    m_refit     = false;
    m_max_iter  = 100;   // Set maximum number of iterations
    m_max_stall = 10;    // Set maximum number of stalls
    m_logL      = 0.0;
    m_opt       = NULL;

    // Set logger properties
    log.date(true);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Copy class members
 *
 * @param[in] app Application.
 ***************************************************************************/
void ctlike::copy_members(const ctlike& app)
{
    // Copy attributes
    m_method    = app.m_method;
    m_stat      = app.m_stat;
    m_refit     = app.m_refit;
    m_caldb     = app.m_caldb;
    m_irf       = app.m_irf;
    m_outmdl    = app.m_outmdl;
    m_obs       = app.m_obs;
    m_max_iter  = app.m_max_iter;
    m_max_stall = app.m_max_stall;
    m_logL      = app.m_logL;
    m_opt       = app.m_opt->clone();

    // Return
    return;
}


/***********************************************************************//**
 * @brief Delete class members
 ***************************************************************************/
void ctlike::free_members(void)
{
    // Free members
    if (m_opt != NULL) delete m_opt;

    // Mark pointers as free
    m_opt = NULL;

    // Write separator into logger
    if (logTerse())
        log << std::endl;

    // Return
    return;
}