import java.awt.*;
import objectdraw.*;

/**
 * Program will manage a collection of digital photographs for the user. At
 * start up, photos will be displayed as thumbnails. User may select the desired
 * thumbnail to view the full-size photo within the same display window. The
 * PhotoViewer class creates the initial display and processes mouse/event
 * handling methods.
 */
public class PhotoViewer extends FrameWindowController {
	/**
	 * Where the top of the bottom row should be
	 */
	private static final int THUMBNAIL_BOTTOM_ROW_TOP = 600;
	
	/**
	 * Where the left edge of the first thumbnail goes.
	 */
	private static final int THUMBNAIL_FIRST_COL_LEFT = 10;
	
	/**
	 * The size of the font in the title bar 
	 */
	private static final int TEXT_FONT_SIZE = 20;
	
	/**
	 * The height of the title bar 
	 */
	private static final int BAR_HEIGHT = 30;
	
	/**
	 * How far the title bar should be from the right edge of the window 
	 */
	private static final int BAR_RIGHT_MARGIN = 40;
	
	/**
	 * How far the title bar should be from the top edge of the window  
	 */
	private static final int BAR_TOP_MARGIN = 48;
	
	/**
	 * How far the title bar should be from the left edge of the window  
	 */
	private static final int BAR_LEFT_MARGIN = 5;
	
	/**
	 * How far the title text should be from the top edge of the title bar 
	 */
	private static final int TEXT_TOP_MARGIN = 2;
	
	/**
	 * How far the title text should be from the top edge of the window
	 */
	private static final int TEXT_TOP = BAR_TOP_MARGIN + TEXT_TOP_MARGIN;
	
	/**
	 *  How far the title text should be from the left edge of the title bar
	 */
	private static final int TEXT_LEFT_MARGIN = 5;
	
	/**
	 * How far the title text should be from the left edge of the window
	 */
	private static final int TEXT_LEFT = BAR_LEFT_MARGIN + TEXT_LEFT_MARGIN;
	
	/**
	 * The amount of space from the left edge of one thumbnail to the left edge
	 * of the next thumbnail. 
	 */
	private static final int HORIZONTAL_SPACING = 100;
	
	/**
	 * The amount of space from the top edge of one thumbnail to the top edge
	 * of the next thumbnail. 
	 */
	private static final int VERTICAL_SPACING = 100;
	
	/**
	 * background color of display window.
	 */
	private static final Color BACKGROUND_COLOR = Color.BLUE;
	
	/**
	 * Background color when the mouse is not in the window.
	 */
	private static final Color DARK_BACKGROUND = BACKGROUND_COLOR.darker();
	
	/**
	 * Color of the title bar.
	 */
	private static final Color BACKBAR_COLOR = Color.WHITE;
	
	/**
	 * Color of the title bar when the mouse is not in the window.
	 */
	private static final Color DARK_BACKBAR = BACKBAR_COLOR.darker();
	
	/**
	 * Size of the window.
	 */
	private static final int GRID_SIZE = 800;
	
	/**
	 * Number of columns of thumbnails
	 */
	private static final int NUM_COLS = 4;
	
	/**
	 * Number of thumbnails
	 */
	private static final int NUM_PICS = 25;
	
	/**
	 * Number of rows of thumbnails
	 */
	private static final int NUM_ROWS = NUM_PICS / NUM_COLS;

	/**
	 * The background rectangle
	 */
	private FilledRect background;

	/**
	 * The title bar
	 */
	private FilledRect backgroundBar;

	/**
	 * The picture being displayed at full size
	 */
	private Thumbnail bigPic;

	/**
	 * All the thumbnails.
	 */
	private ThumbnailCollection allThumbnails = new ThumbnailCollection();

	/**
	 * When the program starts, draw the background and title bar.  Display the
	 * thumbnails in a grid.
	 * 
	 * @see objectdraw.WindowController#begin()
	 */
	public void begin() {
		// Resizing window to fit thumbnails.
		resize(GRID_SIZE, GRID_SIZE);
		
		// Draw the background and title bar
		background = new FilledRect(0, 0, GRID_SIZE, GRID_SIZE, canvas);
		background.setColor(BACKGROUND_COLOR);
		backgroundBar = new FilledRect(BAR_LEFT_MARGIN, BAR_TOP_MARGIN, GRID_SIZE - BAR_RIGHT_MARGIN, BAR_HEIGHT, canvas);
		backgroundBar.setColor(BACKBAR_COLOR);
		Text text = new Text("PHOTO VIEWER", TEXT_LEFT, TEXT_TOP, canvas);
		text.setFontSize(TEXT_FONT_SIZE);
		text.setBold();
		
		// Draw the grid of thumbnails
		drawThumbnailGrid();
	}

	/**
	 * Draws the thumbnails in a grid
	 */
	private void drawThumbnailGrid() {
		Thumbnail picture;
		double start_X = THUMBNAIL_FIRST_COL_LEFT;
		double start_Y = THUMBNAIL_BOTTOM_ROW_TOP;
		int whichPic = 0;
		
		// Draw all but the last row.
		for (int row = 0; row < NUM_ROWS - 1; row++) {
			for (int col = 0; col < NUM_COLS; col++) {
				addThumbnail(start_X, start_Y, whichPic);
				start_X = start_X + HORIZONTAL_SPACING;
				whichPic++;
			}
			start_X = 0;
			start_Y = start_Y - VERTICAL_SPACING;
		}

		// The last row has more thumbnails.
		while (whichPic < NUM_PICS) {
			addThumbnail(start_X, start_Y, whichPic);
			start_X = start_X + HORIZONTAL_SPACING;
			whichPic++;
		}
	}

	/**
	 * Add a thumbnail to the grid
	 * @param start_X the left edge of the thumbnail
	 * @param start_Y the top edge of the thumbnail
	 * @param whichPic the thumbnail index
	 */
	private void addThumbnail(double start_X, double start_Y, int whichPic) {
		Thumbnail picture;
		String p = "pic" + whichPic + ".jpg";
		picture = new Thumbnail(p, start_X, start_Y, canvas);
		allThumbnails.addPic(picture);
	}

	/**
	 * Restore the original colors when the mouse enters the window
	 * @param point where the mouse is
	 * @see objectdraw.WindowController#onMouseEnter(objectdraw.Location)
	 */
	public void onMouseEnter(Location point) {
		background.setColor(BACKGROUND_COLOR);
		backgroundBar.setColor(BACKBAR_COLOR);
	}

	/**
	 * Make the window darker when the mouse leaves the window
	 * @param point where the mouse is
	 * @see objectdraw.WindowController#onMouseExit(objectdraw.Location)
	 */
	public void onMouseExit(Location point) {
		background.setColor(DARK_BACKGROUND);
		backgroundBar.setColor(DARK_BACKBAR);
	}

	/**
	 * Display a fullsize version of the thumbnail the user depresses the mouse button on.  
	 * If the user presses on the background.  Do nothing.
	 * @param point where the user depressed the mouse button.
	 * @see objectdraw.WindowController#onMousePress(objectdraw.Location)
	 */
	public void onMousePress(Location point) {
		Thumbnail selectedPic = allThumbnails.getPicAt(point);
		if (selectedPic != null) {
			if (bigPic != null) {
				bigPic.hidePic();
			}
			bigPic = selectedPic;
			bigPic.showPic();
		}
	}
}