/**
 * Jexer - Java Text User Interface
 *
 * License: LGPLv3 or later
 *
 * This module is licensed under the GNU Lesser General Public License
 * Version 3.  Please see the file "COPYING" in this directory for more
 * information about the GNU Lesser General Public License Version 3.
 *
 *     Copyright (C) 2015  Kevin Lamonte
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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 Lesser General Public
 * License along with this program; if not, see
 * http://www.gnu.org/licenses/, or write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 * @author Kevin Lamonte [kevin.lamonte@gmail.com]
 * @version 1
 */
package jexer.io;

import jexer.bits.Cell;
import jexer.bits.CellAttributes;
import jexer.bits.GraphicsChars;

/**
 * This class represents a text-based screen.  Drawing operations write to a
 * logical screen.
 */
public abstract class Screen {

    /**
     * Width of the visible window.
     */
    protected int width;

    /**
     * Height of the visible window.
     */
    protected int height;

    /**
     * Drawing offset for x.
     */
    protected int offsetX;

    /**
     * Set drawing offset for x.
     *
     * @param offsetX new drawing offset
     */
    public final void setOffsetX(final int offsetX) {
        this.offsetX = offsetX;
    }

    /**
     * Drawing offset for y.
     */
    protected int offsetY;

    /**
     * Set drawing offset for y.
     *
     * @param offsetY new drawing offset
     */
    public final void setOffsetY(final int offsetY) {
        this.offsetY = offsetY;
    }
    
    /**
     * Ignore anything drawn right of clipRight.
     */
    protected int clipRight;

    /**
     * Get right drawing clipping boundary.
     *
     * @return drawing boundary
     */
    public final int getClipRight() {
        return clipRight;
    }

    /**
     * Set right drawing clipping boundary.
     *
     * @param clipRight new boundary
     */
    public final void setClipRight(final int clipRight) {
        this.clipRight = clipRight;
    }

    /**
     * Ignore anything drawn below clipBottom.
     */
    protected int clipBottom;

    /**
     * Get bottom drawing clipping boundary.
     *
     * @return drawing boundary
     */
    public final int getClipBottom() {
        return clipBottom;
    }

    /**
     * Set bottom drawing clipping boundary.
     *
     * @param clipBottom new boundary
     */
    public final void setClipBottom(final int clipBottom) {
        this.clipBottom = clipBottom;
    }

    /**
     * Ignore anything drawn left of clipLeft.
     */
    protected int clipLeft;

    /**
     * Get left drawing clipping boundary.
     *
     * @return drawing boundary
     */
    public final int getClipLeft() {
        return clipLeft;
    }

    /**
     * Set left drawing clipping boundary.
     *
     * @param clipLeft new boundary
     */
    public final void setClipLeft(final int clipLeft) {
        this.clipLeft = clipLeft;
    }

    /**
     * Ignore anything drawn above clipTop.
     */
    protected int clipTop;

    /**
     * Get top drawing clipping boundary.
     *
     * @return drawing boundary
     */
    public final int getClipTop() {
        return clipTop;
    }

    /**
     * Set top drawing clipping boundary.
     *
     * @param clipTop new boundary
     */
    public final void setClipTop(final int clipTop) {
        this.clipTop = clipTop;
    }

    /**
     * The physical screen last sent out on flush().
     */
    protected Cell [][] physical;

    /**
     * The logical screen being rendered to.
     */
    protected Cell [][] logical;

    /**
     * When true, logical != physical.
     */
    protected boolean dirty;

    /**
     * Set if the user explicitly wants to redraw everything starting with a
     * ECMATerminal.clearAll().
     */
    protected boolean reallyCleared;

    /**
     * If true, the cursor is visible and should be placed onscreen at
     * (cursorX, cursorY) during a call to flushPhysical().
     */
    protected boolean cursorVisible;

    /**
     * Cursor X position if visible.
     */
    protected int cursorX;

    /**
     * Cursor Y position if visible.
     */
    protected int cursorY;

    /**
     * Get the attributes at one location.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @return attributes at (x, y)
     */
    public CellAttributes getAttrXY(final int x, final int y) {
        CellAttributes attr = new CellAttributes();
        attr.setTo(logical[x][y]);
        return attr;
    }

    /**
     * Set the attributes at one location.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param attr attributes to use (bold, foreColor, backColor)
     */
    public void putAttrXY(final int x, final int y, final CellAttributes attr) {
        putAttrXY(x, y, attr, true);
    }

    /**
     * Set the attributes at one location.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param attr attributes to use (bold, foreColor, backColor)
     * @param clip if true, honor clipping/offset
     */
    public void putAttrXY(final int x, final int y, final CellAttributes attr,
        final boolean clip) {

        int X = x;
        int Y = y;

        if (clip) {
            if ((x < clipLeft)
                || (x >= clipRight)
                || (y < clipTop)
                || (y >= clipBottom)
            ) {
                return;
            }
            X += offsetX;
            Y += offsetY;
        }

        if ((X >= 0) && (X < width) && (Y >= 0) && (Y < height)) {
            dirty = true;
            logical[X][Y].setForeColor(attr.getForeColor());
            logical[X][Y].setBackColor(attr.getBackColor());
            logical[X][Y].setBold(attr.getBold());
            logical[X][Y].setBlink(attr.getBlink());
            logical[X][Y].setReverse(attr.getReverse());
            logical[X][Y].setUnderline(attr.getUnderline());
            logical[X][Y].setProtect(attr.getProtect());
        }
    }

    /**
     * Fill the entire screen with one character with attributes.
     *
     * @param ch character to draw
     * @param attr attributes to use (bold, foreColor, backColor)
     */
    public void putAll(final char ch, final CellAttributes attr) {
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                putCharXY(x, y, ch, attr);
            }
        }
    }

    /**
     * Render one character with attributes.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param ch character + attributes to draw
     */
    public void putCharXY(final int x, final int y, final Cell ch) {
        putCharXY(x, y, ch.getChar(), ch);
    }

    /**
     * Render one character with attributes.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param ch character to draw
     * @param attr attributes to use (bold, foreColor, backColor)
     */
    public void putCharXY(final int x, final int y, final char ch,
        final CellAttributes attr) {

        if ((x < clipLeft)
            || (x >= clipRight)
            || (y < clipTop)
            || (y >= clipBottom)
        ) {
            return;
        }

        int X = x + offsetX;
        int Y = y + offsetY;

        // System.err.printf("putCharXY: %d, %d, %c\n", X, Y, ch);

        if ((X >= 0) && (X < width) && (Y >= 0) && (Y < height)) {
            dirty = true;

            // Do not put control characters on the display
            assert (ch >= 0x20);
            assert (ch != 0x7F);

            logical[X][Y].setChar(ch);
            logical[X][Y].setForeColor(attr.getForeColor());
            logical[X][Y].setBackColor(attr.getBackColor());
            logical[X][Y].setBold(attr.getBold());
            logical[X][Y].setBlink(attr.getBlink());
            logical[X][Y].setReverse(attr.getReverse());
            logical[X][Y].setUnderline(attr.getUnderline());
            logical[X][Y].setProtect(attr.getProtect());
        }
    }

    /**
     * Render one character without changing the underlying attributes.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param ch character to draw
     */
    public void putCharXY(final int x, final int y, final char ch) {
        if ((x < clipLeft)
            || (x >= clipRight)
            || (y < clipTop)
            || (y >= clipBottom)
        ) {
            return;
        }

        int X = x + offsetX;
        int Y = y + offsetY;

        // System.err.printf("putCharXY: %d, %d, %c\n", X, Y, ch);

        if ((X >= 0) && (X < width) && (Y >= 0) && (Y < height)) {
            dirty = true;
            logical[X][Y].setChar(ch);
        }
    }

    /**
     * Render a string.  Does not wrap if the string exceeds the line.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param str string to draw
     * @param attr attributes to use (bold, foreColor, backColor)
     */
    public void putStrXY(final int x, final int y, final String str,
        final CellAttributes attr) {

        int i = x;
        for (int j = 0; j < str.length(); j++) {
            char ch = str.charAt(j);
            putCharXY(i, y, ch, attr);
            i++;
            if (i == width) {
                break;
            }
        }
    }

    /**
     * Render a string without changing the underlying attribute.  Does not
     * wrap if the string exceeds the line.
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param str string to draw
     */
    public void putStrXY(final int x, final int y, final String str) {
        int i = x;
        for (int j = 0; j < str.length(); j++) {
            char ch = str.charAt(j);
            putCharXY(i, y, ch);
            i++;
            if (i == width) {
                break;
            }
        }
    }

    /**
     * Draw a vertical line from (x, y) to (x, y + n).
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param n number of characters to draw
     * @param ch character to draw
     * @param attr attributes to use (bold, foreColor, backColor)
     */
    public void vLineXY(final int x, final int y, final int n, final char ch,
        final CellAttributes attr) {

        for (int i = y; i < y + n; i++) {
            putCharXY(x, i, ch, attr);
        }
    }

    /**
     * Draw a horizontal line from (x, y) to (x + n, y).
     *
     * @param x column coordinate.  0 is the left-most column.
     * @param y row coordinate.  0 is the top-most row.
     * @param n number of characters to draw
     * @param ch character to draw
     * @param attr attributes to use (bold, foreColor, backColor)
     */
    public void hLineXY(final int x, final int y, final int n, final char ch,
        final CellAttributes attr) {

        for (int i = x; i < x + n; i++) {
            putCharXY(i, y, ch, attr);
        }
    }

    /**
     * Reallocate screen buffers.
     *
     * @param width new width
     * @param height new height
     */
    private void reallocate(final int width, final int height) {
        if (logical != null) {
            for (int row = 0; row < this.height; row++) {
                for (int col = 0; col < this.width; col++) {
                    logical[col][row] = null;
                }
            }
            logical = null;
        }
        logical = new Cell[width][height];
        if (physical != null) {
            for (int row = 0; row < this.height; row++) {
                for (int col = 0; col < this.width; col++) {
                    physical[col][row] = null;
                }
            }
            physical = null;
        }
        physical = new Cell[width][height];

        for (int row = 0; row < height; row++) {
            for (int col = 0; col < width; col++) {
                physical[col][row] = new Cell();
                logical[col][row] = new Cell();
            }
        }

        this.width = width;
        this.height = height;

        clipLeft = 0;
        clipTop = 0;
        clipRight = width;
        clipBottom = height;

        reallyCleared = true;
        dirty = true;
    }

    /**
     * Change the width.  Everything on-screen will be destroyed and must be
     * redrawn.
     *
     * @param width new screen width
     */
    public void setWidth(final int width) {
        reallocate(width, this.height);
    }

    /**
     * Change the height.  Everything on-screen will be destroyed and must be
     * redrawn.
     *
     * @param height new screen height
     */
    public void setHeight(final int height) {
        reallocate(this.width, height);
    }

    /**
     * Change the width and height.  Everything on-screen will be destroyed
     * and must be redrawn.
     *
     * @param width new screen width
     * @param height new screen height
     */
    public void setDimensions(final int width, final int height) {
        reallocate(width, height);
    }

    /**
     * Get the height.
     *
     * @return current screen height
     */
    public int getHeight() {
        return this.height;
    }

    /**
     * Get the width.
     *
     * @return current screen width
     */
    public int getWidth() {
        return this.width;
    }

    /**
     * Public constructor.  Sets everything to not-bold, white-on-black.
     */
    public Screen() {
        offsetX  = 0;
        offsetY  = 0;
        width    = 80;
        height   = 24;
        logical  = null;
        physical = null;
        reallocate(width, height);
    }

    /**
     * Reset screen to not-bold, white-on-black.  Also flushes the offset and
     * clip variables.
     */
    public void reset() {
        dirty = true;
        for (int row = 0; row < height; row++) {
            for (int col = 0; col < width; col++) {
                logical[col][row].reset();
            }
        }
        resetClipping();
    }

    /**
     * Flush the offset and clip variables.
     */
    public void resetClipping() {
        offsetX    = 0;
        offsetY    = 0;
        clipLeft   = 0;
        clipTop    = 0;
        clipRight  = width;
        clipBottom = height;
    }

    /**
     * Force the screen to be fully cleared and redrawn on the next flush().
     */
    public void clear() {
        reset();
    }

    /**
     * Draw a box with a border and empty background.
     *
     * @param left left column of box.  0 is the left-most row.
     * @param top top row of the box.  0 is the top-most row.
     * @param right right column of box
     * @param bottom bottom row of the box
     * @param border attributes to use for the border
     * @param background attributes to use for the background
     */
    public void drawBox(final int left, final int top,
        final int right, final int bottom,
        final CellAttributes border, final CellAttributes background) {

        drawBox(left, top, right, bottom, border, background, 1, false);
    }

    /**
     * Draw a box with a border and empty background.
     *
     * @param left left column of box.  0 is the left-most row.
     * @param top top row of the box.  0 is the top-most row.
     * @param right right column of box
     * @param bottom bottom row of the box
     * @param border attributes to use for the border
     * @param background attributes to use for the background
     * @param borderType if 1, draw a single-line border; if 2, draw a
     * double-line border; if 3, draw double-line top/bottom edges and
     * single-line left/right edges (like Qmodem)
     * @param shadow if true, draw a "shadow" on the box
     */
    public void drawBox(final int left, final int top,
        final int right, final int bottom,
        final CellAttributes border, final CellAttributes background,
        final int borderType, final boolean shadow) {

        int boxTop = top;
        int boxLeft = left;
        int boxWidth = right - left;
        int boxHeight = bottom - top;

        char cTopLeft;
        char cTopRight;
        char cBottomLeft;
        char cBottomRight;
        char cHSide;
        char cVSide;

        switch (borderType) {
        case 1:
            cTopLeft = GraphicsChars.ULCORNER;
            cTopRight = GraphicsChars.URCORNER;
            cBottomLeft = GraphicsChars.LLCORNER;
            cBottomRight = GraphicsChars.LRCORNER;
            cHSide = GraphicsChars.SINGLE_BAR;
            cVSide = GraphicsChars.WINDOW_SIDE;
            break;

        case 2:
            cTopLeft = GraphicsChars.WINDOW_LEFT_TOP_DOUBLE;
            cTopRight = GraphicsChars.WINDOW_RIGHT_TOP_DOUBLE;
            cBottomLeft = GraphicsChars.WINDOW_LEFT_BOTTOM_DOUBLE;
            cBottomRight = GraphicsChars.WINDOW_RIGHT_BOTTOM_DOUBLE;
            cHSide = GraphicsChars.DOUBLE_BAR;
            cVSide = GraphicsChars.WINDOW_SIDE_DOUBLE;
            break;

        case 3:
            cTopLeft = GraphicsChars.WINDOW_LEFT_TOP;
            cTopRight = GraphicsChars.WINDOW_RIGHT_TOP;
            cBottomLeft = GraphicsChars.WINDOW_LEFT_BOTTOM;
            cBottomRight = GraphicsChars.WINDOW_RIGHT_BOTTOM;
            cHSide = GraphicsChars.WINDOW_TOP;
            cVSide = GraphicsChars.WINDOW_SIDE;
            break;
        default:
            throw new IllegalArgumentException("Invalid border type: "
                + borderType);
        }

        // Place the corner characters
        putCharXY(left, top, cTopLeft, border);
        putCharXY(left + boxWidth - 1, top, cTopRight, border);
        putCharXY(left, top + boxHeight - 1, cBottomLeft, border);
        putCharXY(left + boxWidth - 1, top + boxHeight - 1, cBottomRight,
            border);

        // Draw the box lines
        hLineXY(left + 1, top, boxWidth - 2, cHSide, border);
        vLineXY(left, top + 1, boxHeight - 2, cVSide, border);
        hLineXY(left + 1, top + boxHeight - 1, boxWidth - 2, cHSide, border);
        vLineXY(left + boxWidth - 1, top + 1, boxHeight - 2, cVSide, border);

        // Fill in the interior background
        for (int i = 1; i < boxHeight - 1; i++) {
            hLineXY(1 + left, i + top, boxWidth - 2, ' ', background);
        }

        if (shadow) {
            // Draw a shadow
            drawBoxShadow(left, top, right, bottom);
        }
    }

    /**
     * Draw a box shadow
     *
     * @param left left column of box.  0 is the left-most row.
     * @param top top row of the box.  0 is the top-most row.
     * @param right right column of box
     * @param bottom bottom row of the box
     */
    public void drawBoxShadow(final int left, final int top,
        final int right, final int bottom) {

        int boxTop = top;
        int boxLeft = left;
        int boxWidth = right - left;
        int boxHeight = bottom - top;
        CellAttributes shadowAttr = new CellAttributes();

        // Shadows do not honor clipping but they DO honor offset.
        int oldClipRight = clipRight;
        int oldClipBottom = clipBottom;
        /*
        clipRight = boxWidth + 2;
        clipBottom = boxHeight + 1;
        */
        clipRight = width;
        clipBottom = height;

        for (int i = 0; i < boxHeight; i++) {
            putAttrXY(boxLeft + boxWidth, boxTop + 1 + i, shadowAttr);
            putAttrXY(boxLeft + boxWidth + 1, boxTop + 1 + i, shadowAttr);
        }
        for (int i = 0; i < boxWidth; i++) {
            putAttrXY(boxLeft + 2 + i, boxTop + boxHeight, shadowAttr);
        }
        clipRight = oldClipRight;
        clipBottom = oldClipBottom;
    }

    /**
     * Subclasses must provide an implementation to push the logical screen
     * to the physical device.
     */
    abstract public void flushPhysical();

    /**
     * Put the cursor at (x,y).
     *
     * @param visible if true, the cursor should be visible
     * @param x column coordinate to put the cursor on
     * @param y row coordinate to put the cursor on
     */
    public void putCursor(final boolean visible, final int x, final int y) {
        cursorVisible = visible;
        cursorX = x;
        cursorY = y;
    }

    /**
     * Hide the cursor
     */
    public void hideCursor() {
        cursorVisible = false;
    }
}