//  Windows.m  Copyright (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2013-07-16  Objective-C version of this program was created.
//  2013-07-17  Last modification.

//  This program displays simple character-based 'windows' to
//  the Terminal screen.

//  The classes of this program provide an example of
//  a class hierarchy.

//  NOTE: As this is an educational program, the classes defined
//  here are not safe for all kinds of uses. If you try to define
//  very large or very small windows, or put long texts inside
//  the windows, the classes may not work properly.

#include  <stdio.h>
#import <Foundation/Foundation.h>
#include  <string.h>

#define  MAXIMUM_WINDOW_WIDTH        78
#define  MAXIMUM_WINDOW_HEIGHT       22


/* Class Window is the topmost class in the class hierarchy.
   A Window could look like

////////////
////////////
////////////
////////////

In this window the width is 12, the height is 4, and the 
background character is '/'
*/

@interface Window : NSObject
{
   char  window_contents [ MAXIMUM_WINDOW_WIDTH ]
                         [ MAXIMUM_WINDOW_HEIGHT ] ;
   int   window_width ;
   int   window_height ;
   char  background_character ;
}

- (id) init ;
- (id) init_width: (int) desired_window_width 
       and_height: (int) desired_window_height
       and_background: (char) given_background_character ;
       
- (int) window_width ;
- (int) window_height ;
- (char) window_contents_at_x: (int) character_index_x
                         at_y: (int) character_index_y ;

- (void) fill_with_character: (char) filling_character ;
- (void) print ;
- (void) move_window: (Window*) another_window
         to_x: (int) destination_x_index
         to_y: (int) destination_y_index ;
@end

@implementation Window

- (id) init_width: (int) desired_window_width 
       and_height: (int) desired_window_height
       and_background: (char) given_background_character
{
   self = [ super init ] ;
   
   if ( self )
   {
      window_width          =  desired_window_width ;
      window_height         =  desired_window_height ;
      background_character  =  given_background_character ;

      [ self fill_with_character: background_character ] ;
   }
   
   return self ;
}

- (id) init
{
   self = [ super init ] ;
   
   if ( self )
   {
      [ self init_width: MAXIMUM_WINDOW_WIDTH
             and_height: MAXIMUM_WINDOW_HEIGHT
             and_background: ' ' ] ;
   }
   
   return self ;
}


- (int) window_width
{
   return window_width ;
}

- (int) window_height
{
   return window_height ;
}

- (char) window_contents_at_x: (int) character_index_x
                         at_y: (int) character_index_y
{
   return window_contents [ character_index_x ]
                          [ character_index_y ] ;
}


- (void) fill_with_character: (char) filling_character
{
   int row_index  =  0  ;
   
   while ( row_index  <  window_height )
   {
      int column_index  =  0 ;
      
      while ( column_index  <  window_width )
      {
         window_contents[ column_index ] [ row_index ]  = filling_character ;
         column_index ++ ;
      }
      
      row_index ++ ;
   }
}

- (void) print
{
   printf( "\n" ) ;

   int row_index  =  0  ;
   
   while ( row_index  <  window_height )
   {
      int column_index  =  0 ;
      
      while ( column_index  <  window_width )
      {
         printf( "%c", window_contents[ column_index ] [ row_index ] ) ;
         column_index ++ ;
      }
      
      row_index ++ ;
      
      printf( "\n" ) ;
   }
}

//  The following method moves another window over 'this' window.

- (void) move_window: (Window*) another_window
         to_x: (int) destination_x_index
         to_y: (int) destination_y_index
{
   int  source_y_index  =  0 ;

   while ( source_y_index  <  [ another_window window_height ] )
   {
      if ( destination_y_index  >=  0   &&
           destination_y_index  <   window_height )
      {
         int  source_x_index  =  0 ;
         int  saved_destination_x_index  =  destination_x_index ;

         while ( source_x_index < [ another_window window_width ] )
         {
            if ( destination_x_index  >=  0  &&
                 destination_x_index  <   window_width )
            {
               window_contents [ destination_x_index ]
                               [ destination_y_index ]  =

                  [ another_window window_contents_at_x: source_x_index
                                                   at_y: source_y_index ] ;
            }
            source_x_index        ++ ;
            destination_x_index   ++ ;
         }
         destination_x_index  =  saved_destination_x_index ;
      }
      source_y_index        ++ ;
      destination_y_index   ++ ;
   }
}

@end

/* Class FrameWindow represents a window  that looks like

|----------------------|
|                      |
|                      |
|                      |
|                      |
|                      |
|----------------------|

The window has frames that are made by using characters '|' and '-'.
The inner area of the window contains space characters.
*/

@interface FrameWindow : Window

- (id) init_width: (int) desired_window_width
       and_height: (int) desired_window_height ;
@end

@implementation FrameWindow

- (id) init_width: (int) desired_window_width
       and_height: (int) desired_window_height
{
   [ super init_width: desired_window_width
           and_height: desired_window_height
           and_background: '|' ] ;

   Window*  horizontal_frames =
               [ [ Window alloc ] init_width: desired_window_width - 2
                                  and_height: desired_window_height
                                  and_background:  '-' ] ;

   Window*  spaces_inside_window =
               [ [ Window alloc ] init_width: desired_window_width - 2
                                  and_height: desired_window_height - 2
                                  and_background:  ' ' ] ;
   
   [ self move_window: horizontal_frames to_x: 1 to_y: 0 ] ;
   [ self move_window: spaces_inside_window to_x: 1 to_y: 1 ] ;
   
   return self ;
}

@end

/* A TextWindow can look like the following

|----------------------------|
|                            |
|                            |
|                            |
|       Hello, world.        |
|                            |
|                            |
|----------------------------|

The text is stored as a C-style string.
*/

@interface TextWindow : FrameWindow
{
   char  text_inside_window[ MAXIMUM_WINDOW_WIDTH ] ;
}

- (id) init_width: (int) desired_window_width
       and_height: (int) desired_window_height
       and_text:   (char*) given_line_of_text ;

- (void) change_text: (char*) new_line_of_text ;

@end

@implementation TextWindow

//  embed_text_in_window is a private method that is not
//  mentioned in the interface of the class

- (void) embed_text_in_window
{
   int  text_length  =  strlen( text_inside_window ) ;
   int  text_row     =  window_height / 2 ;

   int  text_start_column = (window_width - text_length) / 2 ;

   int  character_index ;
   
   for ( character_index  =  0 ;
         character_index  <  text_length ;
         character_index  ++ )
   {
      window_contents [ text_start_column + character_index ]
                      [ text_row ]  =  

              text_inside_window[ character_index ] ;
   }
}

- (id) init_width: (int) desired_window_width
       and_height: (int) desired_window_height
       and_text:   (char*) given_line_of_text
{
   [ super init_width: desired_window_width
           and_height: desired_window_height ] ;

   // String function strcpy() copies the given string to
   // the data field (attribute) in this class.
   strcpy( text_inside_window, given_line_of_text  ) ;
   
   [ self embed_text_in_window ] ;
   
   return self ;
}

- (void) change_text: (char*) new_line_of_text
{
   strcpy( text_inside_window, new_line_of_text ) ;
   
   [ self embed_text_in_window ] ;
}

@end

/*  The lowest class in the hierarchy is DecoratedTextWindow.
Such a window has a decoration frame that is made with characters '*':

****************************
*|------------------------|*
*|                        |*
*|                        |*
*|                        |*
*|         Smile!         |*
*|                        |*
*|                        |*
*|                        |*
*|------------------------|*
****************************

*/


@interface DecoratedTextWindow : TextWindow

- (id) init_width: (int) desired_window_width
       and_height: (int) desired_window_height
       and_text:   (char*) given_line_of_text ;
@end

@implementation DecoratedTextWindow

- (id) init_width: (int) desired_window_width
       and_height: (int) desired_window_height
       and_text:   (char*) given_line_of_text
{
   [ super init_width: desired_window_width
           and_height: desired_window_height
           and_text: given_line_of_text ] ;

   Window*  decoration_frame =
               [ [ Window alloc ] init_width: desired_window_width
                                  and_height: desired_window_height
                                  and_background:  '*' ] ;
                                  
   TextWindow* window_inside_window =
               [ [ TextWindow alloc ] init_width: desired_window_width - 2
                                      and_height: desired_window_height - 2
                                      and_text: given_line_of_text ] ;

   [ decoration_frame move_window: window_inside_window to_x: 1 to_y: 1 ] ;
   
   [ self move_window: decoration_frame to_x: 0 to_y: 0 ] ;
   
   return self ;
}

@end



int main( void )
{
   NSAutoreleasePool* autorelease_pool = [ [ NSAutoreleasePool alloc ] init ] ;

   Window* background_window =
   
         [ [ Window alloc ] init_width: 76
                            and_height: 22 and_background: '/' ] ;
                            
   FrameWindow* empty_window =
   
         [ [ FrameWindow alloc ] init_width: 24 and_height:  7 ] ;
                            
   TextWindow* greeting_window =
   
         [ [ TextWindow alloc ] init_width: 30 and_height:  8
                                and_text: "Hello, world." ] ;
                            
   DecoratedTextWindow* smiling_window =
   
         [ [ DecoratedTextWindow alloc ] init_width: 28 and_height:  11
                                         and_text: "Smile!" ] ;
                            
   [ background_window move_window: empty_window to_x: 6 to_y: 2 ] ;
   [ background_window move_window: greeting_window to_x: 4 to_y: 12 ] ;
   
   [ greeting_window change_text: "HELLO, UNIVERSE!" ] ;
   [ background_window move_window: greeting_window to_x: 43 to_y: 11 ] ;
   
   [ background_window move_window: smiling_window to_x: 40 to_y: 3 ] ;

   //  When we print the background_window, it will contain all the
   //  other windows that were moved onto it.

   [ background_window print ] ;

   [ autorelease_pool drain ] ;
}