/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "OpenGLRenderer"

#include <stdlib.h>
#include <stdint.h>
#include <sys/types.h>

#include <utils/Errors.h>
#include <utils/Log.h>

#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>

#include <SkXfermode.h>

#include "OpenGLRenderer.h"
#include "Matrix.h"

namespace android {

///////////////////////////////////////////////////////////////////////////////
// Constructors/destructor
///////////////////////////////////////////////////////////////////////////////

OpenGLRenderer::OpenGLRenderer() {
    LOGD("Create OpenGLRenderer");
}

OpenGLRenderer::~OpenGLRenderer() {
    LOGD("Destroy OpenGLRenderer");
}

///////////////////////////////////////////////////////////////////////////////
// Setup
///////////////////////////////////////////////////////////////////////////////

void OpenGLRenderer::setViewport(int width, int height) {
    glViewport(0, 0, width, height);

    mat4 ortho;
    ortho.loadOrtho(0, width, height, 0, 0, 1);
    ortho.copyTo(mOrthoMatrix);

    mWidth = width;
    mHeight = height;
}

void OpenGLRenderer::prepare() {
	mSnapshot = &mFirstSnapshot;
	mSaveCount = 0;

    glDisable(GL_SCISSOR_TEST);

    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    glEnable(GL_SCISSOR_TEST);

    mSnapshot->clipRect.set(0.0f, 0.0f, mWidth, mHeight);
}

///////////////////////////////////////////////////////////////////////////////
// State management
///////////////////////////////////////////////////////////////////////////////

int OpenGLRenderer::getSaveCount() const {
	return mSaveCount;
}

int OpenGLRenderer::save(int flags) {
	return saveSnapshot();
}

void OpenGLRenderer::restore() {
	if (mSaveCount == 0) return;

	if (restoreSnapshot()) {
		setScissorFromClip();
	}
}

void OpenGLRenderer::restoreToCount(int saveCount) {
	if (saveCount <= 0 || saveCount > mSaveCount) return;

	bool restoreClip = false;

	while (mSaveCount != saveCount - 1) {
		restoreClip |= restoreSnapshot();
	}

	if (restoreClip) {
		setScissorFromClip();
	}
}

int OpenGLRenderer::saveSnapshot() {
	mSnapshot = new Snapshot(mSnapshot);
	return ++mSaveCount;
}

bool OpenGLRenderer::restoreSnapshot() {
	// TODO: handle local transformations
	bool restoreClip = mSnapshot->flags & Snapshot::kFlagClipSet;

	mSaveCount--;

	// Do not merge these two lines!
	sp<Snapshot> previous = mSnapshot->previous;
	mSnapshot = previous;

	return restoreClip;
}

///////////////////////////////////////////////////////////////////////////////
// Transforms
///////////////////////////////////////////////////////////////////////////////

void OpenGLRenderer::translate(float dx, float dy) {
	mSnapshot->transform.translate(dx, dy, 0.0f);
}

void OpenGLRenderer::rotate(float degrees) {
	mSnapshot->transform.rotate(degrees, 0.0f, 0.0f, 1.0f);
}

void OpenGLRenderer::scale(float sx, float sy) {
	mSnapshot->transform.scale(sx, sy, 1.0f);
}

void OpenGLRenderer::setMatrix(SkMatrix* matrix) {
	mSnapshot->transform.load(*matrix);
}

void OpenGLRenderer::getMatrix(SkMatrix* matrix) {
	mSnapshot->transform.copyTo(*matrix);
}

void OpenGLRenderer::concatMatrix(SkMatrix* matrix) {
	mat4 m(*matrix);
	mSnapshot->transform.multiply(m);
}

///////////////////////////////////////////////////////////////////////////////
// Clipping
///////////////////////////////////////////////////////////////////////////////

void OpenGLRenderer::setScissorFromClip() {
	Rect* clip = &(mSnapshot->clipRect);
	glScissor(clip->left, clip->top, clip->getWidth(), clip->getHeight());
}

bool OpenGLRenderer::clipRect(float left, float top, float right, float bottom) {
	// TODO: take local translate transform into account
	bool clipped = mSnapshot->clipRect.intersect(left, top, right, bottom);
	if (clipped) {
		mSnapshot->flags |= Snapshot::kFlagClipSet;
		setScissorFromClip();
	}
	return clipped;
}

///////////////////////////////////////////////////////////////////////////////
// Drawing
///////////////////////////////////////////////////////////////////////////////

void OpenGLRenderer::drawColor(int color, SkXfermode::Mode mode) {
	LOGD("Drawing color");
}

}; // namespace android