## knnGtk.R -- an example of using GtkNotebook, GtkEntry, GtkCheckButton, GtkCombo, and GtkButton
##
## by Artem Sokolov

library( RGtk )

##############################################
## Callbacks
##############################################

nClasses.callback <- function( widget )
{
  nClasses <- as.integer( entry.nClasses$GetText() )
  if( is.na( nClasses ) || nClasses < 1 || nClasses > 8 )
    {
      cat( "Number of classes must be a positive integer between 1 and 8\n" )
      return(0)
    }

  nBoxes <- length(class.coords)
  if( nBoxes < nClasses )
    {
      ## Append more boxes
      for( i in (nBoxes+1):nClasses )
        {
          entry.x <- gtkEntry(3); entry.x$SetUsize( 30, 20 ); entry.x$SetText( paste(i) )
          entry.y <- gtkEntry(3); entry.y$SetUsize( 30, 20 ); entry.y$SetText( paste(round( 5*sin(i/2) )) )

          class.coords[[i]] <<- gtkHBox( FALSE, 5 )
          class.coords[[i]]$PackStart( gtkLabel( paste("X",i,sep="") ), FALSE ); class.coords[[i]]$PackStart( entry.x, FALSE )
          class.coords[[i]]$PackStart( gtkLabel( paste("Y",i,sep="") ), FALSE ); class.coords[[i]]$PackStart( entry.y, FALSE )
          first.page$PackStart( class.coords[[i]], FALSE )
        }
    }
  if( nBoxes > nClasses )
    {
      ## Remove extra boxes
      for( i in (nClasses+1):nBoxes )
        first.page$Remove( class.coords[[i]] )
      class.coords <<- class.coords[1:nClasses]
    }
}

train.callback <- function( widget )
  {
    ## Retrieve class coordinates
    x.coords <- lapply( lapply( lapply( class.coords, gtkContainerGetChildren ), "[[", 2 ), gtkEntryGetText )
    y.coords <- lapply( lapply( lapply( class.coords, gtkContainerGetChildren ), "[[", 4 ), gtkEntryGetText )

    x.coords <- as.integer( unlist(x.coords) )
    y.coords <- as.integer( unlist(y.coords) )

    if( any( is.na(x.coords) ) || any( is.na(y.coords) ) )
      {
        cat( "Coordinates must be integer values\n" )
        return(0)
      }

    ## Generate data
    X <- cbind( rep( x.coords, each=10 ) + rnorm( length(x.coords)*10 ),
               rep( y.coords, each=10 ) + rnorm( length(y.coords)*10 ) )

    Y <- rep( 1:length(x.coords), each=10 )

    ## Generate grid
    bounds <- round( apply( X, 2, range ) )
    bounds[1,] <- bounds[1,] - 1
    bounds[2,] <- bounds[2,] + 1
    myseq1 <- seq( bounds[1,1], bounds[2,1], length=20 )
    myseq2 <- seq( bounds[1,2], bounds[2,2], length=20 )
    my.grid.X <- expand.grid( myseq1, myseq2 )
    my.grid.X <- as.matrix( my.grid.X )

    ## Retrieve parameters
    dist.metr <- pmatch( dist.choice$GetEntry()$GetText(), c("Manhattan", "Euclidean" ) )
    if( is.na(dist.metr) )
      {
        cat( "Failed to resolve distance metric choice\n" )
        return(0)
      }
    
    k <- as.integer( entry.nNeighbors$GetText() )
    if( is.na(k) || k < 1 )
      {
        cat( "The number of neighbors must be a positive integer\n" )
        return(0)
      }

    ## Compute k nearest neighbors for each grid point
    my.grid.Y <- NULL
    for( i in 1:nrow(my.grid.X) )
      {
        ## Replicate the current grid point
        mypoint <- matrix( my.grid.X[i,], nrow(X), 2, byrow=TRUE )

        ## Compute distance
        mydist <- mypoint - X
        if( dist.metr == 1 ) mydist <- abs(mydist)
        else mydist <- mydist^2
        mydist <- apply( mydist, 1, sum )

        ## Find the closest neighbors
        myindex <- order( mydist )[1:k]

        ## Retrieve the corresponding labels and find the one that occurs most frequently
        mylabels <- Y[myindex]
        my.grid.Y <- c( my.grid.Y, which.max(hist(mylabels, breaks=1:9, right=FALSE,plot=FALSE)$counts) )
      }

    plot( my.grid.X, col=my.grid.Y )
    if( chk.contour$GetActive() == TRUE )
      contour( x=myseq1, y=myseq2, z=matrix(my.grid.Y, 20, 20), levels=1:8+0.5, drawlabels=FALSE, add=TRUE )
    points( X, col=Y, pch=19 )
  }

##############################################
## GUI
##############################################

## Create main window
main.window <- gtkWindow( show=FALSE )
main.window$SetTitle( "k nearest neighbors" )

## Create the notebook
the.notebook <- gtkNotebook()
main.window$Add( the.notebook )

## Create the first page
first.page <- gtkVBox()
the.notebook$AppendPage( first.page, gtkLabel("Data") )

## Add content to the first page
hbox.nClasses <- gtkHBox(FALSE, 5)
hbox.nClasses$PackStart( gtkLabel("Number of classes:"), FALSE )
entry.nClasses <- gtkEntry(1)
entry.nClasses$SetText( "3" )
entry.nClasses$SetUsize( 30, 20 )
entry.nClasses$AddCallback( "activate", nClasses.callback )
hbox.nClasses$PackStart( entry.nClasses, FALSE )
but.nClasses <- gtkButton( "Update" )
but.nClasses$AddCallback( "clicked", nClasses.callback )
hbox.nClasses$PackStart( but.nClasses, FALSE )
first.page$PackStart(hbox.nClasses, FALSE)

class.coords <- list()		# holds coordinates for each class
nClasses.callback( entry.nClasses )

## Create the second page
second.page <- gtkVBox()
the.notebook$AppendPage( second.page, gtkLabel("Parameters") )

## Add content to the second page
hbox.dist <- gtkHBox(FALSE, 10)
hbox.dist$PackStart( gtkLabel( "Distance:" ), FALSE )
dist.choice <- gtkCombo()
dist.choice$SetPopdownStrings( c("Euclidean", "Manhattan") )
dist.choice$DisableActivate()
hbox.dist$PackStart( dist.choice, FALSE )
second.page$PackStart( hbox.dist, FALSE )

hbox.nNeighbors <- gtkHBox(FALSE, 50)
hbox.nNeighbors$PackStart( gtkLabel( "Number of Neighbors:" ), FALSE )
entry.nNeighbors <- gtkEntry(1)
entry.nNeighbors$SetText( "1" )
entry.nNeighbors$SetUsize( 30, 20 )
hbox.nNeighbors$PackStart( entry.nNeighbors, FALSE )
second.page$Add( hbox.nNeighbors )

chk.contour <- gtkCheckButton( "Draw Contour?" )
chk.contour$SetActive( TRUE )
second.page$Add( chk.contour )

but.train <- gtkButton( "Train" )
but.train$AddCallback( "clicked", train.callback )
second.page$Add( but.train )

## Show the GUI
main.window$Show()