// Copyright (c) 2013 The Chromium Embedded Framework Authors. All rights
// reserved. Use of this source code is governed by a BSD-style license that
// can be found in the LICENSE file.

package org.cef.browser;

import org.cef.CefApp;

import javax.media.opengl.GL2;
import java.awt.*;
import java.nio.ByteBuffer;
import java.nio.FloatBuffer;

class CefRenderer {
    private boolean transparent_;
    private GL2 initialized_context_ = null;
    private int[] texture_id_ = new int[1];
    private int view_width_ = 0;
    private int view_height_ = 0;
    private float spin_x_ = 0f;
    private float spin_y_ = 0f;
    private Rectangle popup_rect_ = new Rectangle(0, 0, 0, 0);
    private Rectangle original_popup_rect_ = new Rectangle(0, 0, 0, 0);
    private boolean use_draw_pixels_ = false;

    protected CefRenderer(boolean transparent) {
        transparent_ = transparent;
    }

    protected boolean isTransparent() {
        return transparent_;
    }

    @SuppressWarnings("static-access")
    protected void initialize(GL2 gl2) {
        if (initialized_context_ == gl2) {
            return;
        }

        initialized_context_ = gl2;

        if (!gl2.getContext().isHardwareRasterizer()) {
            // Workaround for Windows Remote Desktop which requires pot textures.
            CefApp.getLogger().info("opengl rendering may be slow as hardware rendering isn't available");
            use_draw_pixels_ = true;
            return;
        }

        gl2.glHint(gl2.GL_POLYGON_SMOOTH_HINT, gl2.GL_NICEST);

        gl2.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

        // Necessary for non-power-of-2 textures to render correctly.
        gl2.glPixelStorei(gl2.GL_UNPACK_ALIGNMENT, 1);

        // Create the texture.
        gl2.glGenTextures(1, texture_id_, 0);
        assert (texture_id_[0] != 0);

        gl2.glBindTexture(gl2.GL_TEXTURE_2D, texture_id_[0]);
        gl2.glTexParameteri(gl2.GL_TEXTURE_2D, gl2.GL_TEXTURE_MIN_FILTER, gl2.GL_NEAREST);
        gl2.glTexParameteri(gl2.GL_TEXTURE_2D, gl2.GL_TEXTURE_MAG_FILTER, gl2.GL_NEAREST);
        gl2.glTexEnvf(gl2.GL_TEXTURE_ENV, gl2.GL_TEXTURE_ENV_MODE, gl2.GL_MODULATE);
    }

    protected void cleanup(GL2 gl2) {
        if (texture_id_[0] != 0) {
            gl2.glDeleteTextures(1, texture_id_, 0);
        }
    }

    @SuppressWarnings("static-access")
    protected void render(GL2 gl2) {
        if (use_draw_pixels_ || view_width_ == 0 || view_height_ == 0) {
            return;
        }

        assert (initialized_context_ != null);

        final float[] vertex_data = {
                //tu,   tv,     x,     y,    z
                0.0f, 1.0f, -1.0f, -1.0f, 0.0f, 1.0f, 1.0f, 1.0f, -1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f };
        FloatBuffer vertices = FloatBuffer.wrap(vertex_data);

        gl2.glClear(gl2.GL_COLOR_BUFFER_BIT | gl2.GL_DEPTH_BUFFER_BIT);

        gl2.glMatrixMode(gl2.GL_MODELVIEW);
        gl2.glLoadIdentity();

        // Match GL units to screen coordinates.
        gl2.glViewport(0, 0, view_width_, view_height_);
        gl2.glMatrixMode(gl2.GL_PROJECTION);
        gl2.glLoadIdentity();

        // Draw the background gradient.
        gl2.glPushAttrib(gl2.GL_ALL_ATTRIB_BITS);
        gl2.glBegin(gl2.GL_QUADS);
        gl2.glColor4f(1.0f, 0.0f, 0.0f, 1.0f);  // red
        gl2.glVertex2f(-1.0f, -1.0f);
        gl2.glVertex2f(1.0f, -1.0f);
        gl2.glColor4f(0.0f, 0.0f, 1.0f, 1.0f);  // blue
        gl2.glVertex2f(1.0f, 1.0f);
        gl2.glVertex2f(-1.0f, 1.0f);
        gl2.glEnd();
        gl2.glPopAttrib();

        // Rotate the view based on the mouse spin.
        if (spin_x_ != 0) {
            gl2.glRotatef(-spin_x_, 1.0f, 0.0f, 0.0f);
        }
        if (spin_y_ != 0) {
            gl2.glRotatef(-spin_y_, 0.0f, 1.0f, 0.0f);
        }

        if (transparent_) {
            // Alpha blending style. Texture values have premultiplied alpha.
            gl2.glBlendFunc(gl2.GL_ONE, gl2.GL_ONE_MINUS_SRC_ALPHA);

            // Enable alpha blending.
            gl2.glEnable(gl2.GL_BLEND);
        }

        // Enable 2D textures.
        gl2.glEnable(gl2.GL_TEXTURE_2D);

        // Draw the facets with the texture.
        assert (texture_id_[0] != 0);
        gl2.glBindTexture(gl2.GL_TEXTURE_2D, texture_id_[0]);
        gl2.glInterleavedArrays(gl2.GL_T2F_V3F, 0, vertices);
        gl2.glDrawArrays(gl2.GL_QUADS, 0, 4);

        // Disable 2D textures.
        gl2.glDisable(gl2.GL_TEXTURE_2D);

        if (transparent_) {
            // Disable alpha blending.
            gl2.glDisable(gl2.GL_BLEND);
        }
    }

    protected void onPopupSize(Rectangle rect) {
        if (rect.width <= 0 || rect.height <= 0) {
            return;
        }
        original_popup_rect_ = rect;
        popup_rect_ = getPopupRectInWebView(original_popup_rect_);
    }

    protected Rectangle getPopupRect() {
        return (Rectangle) popup_rect_.clone();
    }

    protected Rectangle getPopupRectInWebView(Rectangle original_rect) {
        Rectangle rc = original_rect;
        // if x or y are negative, move them to 0.
        if (rc.x < 0) {
            rc.x = 0;
        }
        if (rc.y < 0) {
            rc.y = 0;
        }
        // if popup goes outside the view, try to reposition origin
        if (rc.x + rc.width > view_width_) {
            rc.x = view_width_ - rc.width;
        }
        if (rc.y + rc.height > view_height_) {
            rc.y = view_height_ - rc.height;
        }
        // if x or y became negative, move them to 0 again.
        if (rc.x < 0) {
            rc.x = 0;
        }
        if (rc.y < 0) {
            rc.y = 0;
        }
        return rc;
    }

    protected void clearPopupRects() {
        popup_rect_.setBounds(0, 0, 0, 0);
        original_popup_rect_.setBounds(0, 0, 0, 0);
    }

    @SuppressWarnings("static-access")
    protected void onPaint(GL2 gl2, boolean popup, Rectangle[] dirtyRects, ByteBuffer buffer, int width, int height) {
        initialize(gl2);

        if (use_draw_pixels_) {
            gl2.glRasterPos2f(-1, 1);
            gl2.glPixelZoom(1, -1);
            gl2.glDrawPixels(width, height, GL2.GL_BGRA, GL2.GL_UNSIGNED_BYTE, buffer);
            return;
        }

        if (transparent_) {
            // Enable alpha blending.
            gl2.glEnable(gl2.GL_BLEND);
        }

        // Enable 2D textures.
        gl2.glEnable(gl2.GL_TEXTURE_2D);

        assert (texture_id_[0] != 0);
        gl2.glBindTexture(gl2.GL_TEXTURE_2D, texture_id_[0]);

        if (!popup) {
            int old_width = view_width_;
            int old_height = view_height_;

            view_width_ = width;
            view_height_ = height;

            gl2.glPixelStorei(gl2.GL_UNPACK_ROW_LENGTH, view_width_);

            if (old_width != view_width_ || old_height != view_height_) {
                // Update/resize the whole texture.
                gl2.glPixelStorei(gl2.GL_UNPACK_SKIP_PIXELS, 0);
                gl2.glPixelStorei(gl2.GL_UNPACK_SKIP_ROWS, 0);
                gl2.glTexImage2D(gl2.GL_TEXTURE_2D, 0, gl2.GL_RGBA, view_width_, view_height_, 0, gl2.GL_BGRA, gl2.GL_UNSIGNED_INT_8_8_8_8_REV, buffer);
            }
            else {
                // Update just the dirty rectangles.
                for (int i = 0; i < dirtyRects.length; ++i) {
                    Rectangle rect = dirtyRects[i];
                    gl2.glPixelStorei(gl2.GL_UNPACK_SKIP_PIXELS, rect.x);
                    gl2.glPixelStorei(gl2.GL_UNPACK_SKIP_ROWS, rect.y);
                    gl2.glTexSubImage2D(gl2.GL_TEXTURE_2D, 0, rect.x, rect.y, rect.width, rect.height, gl2.GL_BGRA, gl2.GL_UNSIGNED_INT_8_8_8_8_REV, buffer);
                }
            }
        }
        else if (popup && popup_rect_.width > 0 && popup_rect_.height > 0) {
            int skip_pixels = 0, x = popup_rect_.x;
            int skip_rows = 0, y = popup_rect_.y;
            int w = width;
            int h = height;

            // Adjust the popup to fit inside the view.
            if (x < 0) {
                skip_pixels = -x;
                x = 0;
            }
            if (y < 0) {
                skip_rows = -y;
                y = 0;
            }
            if (x + w > view_width_) {
                w -= x + w - view_width_;
            }
            if (y + h > view_height_) {
                h -= y + h - view_height_;
            }

            // Update the popup rectangle.
            gl2.glPixelStorei(gl2.GL_UNPACK_ROW_LENGTH, width);
            gl2.glPixelStorei(gl2.GL_UNPACK_SKIP_PIXELS, skip_pixels);
            gl2.glPixelStorei(gl2.GL_UNPACK_SKIP_ROWS, skip_rows);
            gl2.glTexSubImage2D(gl2.GL_TEXTURE_2D, 0, x, y, w, h, gl2.GL_BGRA, gl2.GL_UNSIGNED_INT_8_8_8_8_REV, buffer);
        }

        // Disable 2D textures.
        gl2.glDisable(gl2.GL_TEXTURE_2D);

        if (transparent_) {
            // Disable alpha blending.
            gl2.glDisable(gl2.GL_BLEND);
        }
    }

    protected void setSpin(float spinX, float spinY) {
        spin_x_ = spinX;
        spin_y_ = spinY;
    }

    protected void incrementSpin(float spinDX, float spinDY) {
        spin_x_ -= spinDX;
        spin_y_ -= spinDY;
    }
}
