#include <RcppArmadillo.h>

#include <rgen.h>

#include <simcdm.h>

//' Update attributes and latent class probabilities

//'

//' Update attributes and latent class probabilities by sampling from full

//' conditional distribution.

//'

//' @param Amat   A \eqn{C \times K}{C x K} `matrix` of latent classes.

//' @param Q      A \eqn{N \times K}{N x K} `matrix` indicating which

//'               skills are required for which items.

//' @param ss     A \eqn{J} `vector` of item slipping parameters.

//' @param gs     A \eqn{J} `vector` of item guessing parameters.

//' @param Y      A \eqn{N \times J}{N x J} `matrix` of observed responses.

//' @param PIs    A \eqn{C} `vector` of latent class probabilities.

//' @param ALPHAS A \eqn{N \times K}{N x K} `matrix` of latent attributes.

//' @param delta0 A \eqn{J} `vector` of Dirichlet prior parameters.

//'

//' @return

//' A \eqn{N \times K}{N x K} `matrix` of attributes and a C `vector` of

//' class probabilities.

//'

//' @author

//' Steven Andrew Culpepper

//'

//' @noRd

// [[Rcpp::export]]

                        const arma::vec &ss, const arma::vec &gs,

                        const arma::mat &Y, const arma::vec &PIs,

                        arma::mat &ALPHAS, const arma::vec &delta0)

{

    double ci;

    double etaij;

                }

                }

                }

                } else {

                }

            }

        }

    }

    return Rcpp::List::create(

}

//' Update item parameters

//'

//' Update guessing and slipping parameters from full conditional distribution.

//'

//' @param Y      A N by J `matrix` of observed responses.

//' @param Q      A N by K `matrix` indicating which skills are required 

//'               for which items. 

//' @param ALPHAS A N by K `matrix` of latent attributes. 

//' @param ss_old A J `vector` of item slipping parameters from prior iteration.

//' @param as0    Slipping prior alpha parameter for Beta distribution.

//' @param bs0    Slipping prior beta parameter for Beta distribution. 

//' @param ag0    Guessing prior alpha parameter for Beta distribution. 

//' @param bg0    Guessing prior beta parameter for Beta distribution.

//'

//' @return

//' A `list` with two J `vectors` of guessing and slipping parameters.

//'

//' @author Steven Andrew Culpepper

//' @noRd

// [[Rcpp::export]]

                     const arma::mat &ALPHAS, const arma::vec &ss_old,

                     double as0, double bs0, double ag0, double bg0)

{

    double T, S, G, y_dot_eta, qq, ps, pg;

    double ug, us;

        // sample s and g as linearly truncated bivariate beta

        // draw g conditoned upon s_t-1

        // draw s conditoned upon g

    }

}

//' Generate Posterior Distribution with Gibbs sampler

//'

//' Function for sampling parameters from full conditional distributions.

//' The function returns a list of arrays or matrices with parameter posterior

//' samples. Note that the output includes the posterior samples in objects.

//'

//' @param Y            A \eqn{N \times J}{N x J} `matrix` of observed

//'                     responses. 

//' @param Amat         A \eqn{C \times K}{C x K} `matrix` of latent

//'                     classes. 

//' @param Q            A \eqn{N \times K}{N x K} `matrix` indicating

//'                     which skills are required for which items. 

//' @param chain_length Number of MCMC iterations.

//'

//' @return

//' A `list` with samples from the posterior distribution with each

//' entry named:

//'

//' - `CLASSES` = individual attribute profiles,

//' - `PIs` = latent class proportions,

//' - `SigS` = item slipping parameters, and

//' - `GamS` = item guessing parameters.

//'

//' @author

//' Steven Andrew Culpepper

//'

//' @seealso

//' [simcdm::sim_dina_items()] and [simcdm::attribute_classes()]

//'

//' @noRd

// [[Rcpp::export]]

                          unsigned int chain_length = 10000)

{

    // Number of Observations

    // Number of Items

    // Number of Attributes

    // Number of Latent Classes (2^k)

    // Generate the latent class alpha matrix

    // Prior values for betas and Dirichlet distribution

    // Saving output

    // Need to initialize, alphas, ss, gs, and pis

    //  arma::mat alphas = arma::zeros<arma::mat>(N,K); //K>1 is assumed

    // Start Markov chain

        // updata alpha and pi

        Rcpp::List step1a =

        // update value for pis. alphas are updated via pointer. save classes

        // and PIs

        // update s and g

        // update value for ss and gs.

    }

    return Rcpp::List::create(

}