/********************************************************************
 KWin - the KDE window manager
 This file is part of the KDE project.

Copyright (C) 2015 Martin Gräßlin <mgraesslin@kde.org>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU 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 General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#include "egl_hwcomposer_backend.h"
#include "hwcomposer_backend.h"
#include "logging.h"
#include "screens_hwcomposer.h"
#include <hardware/hardware.h>
#include <hardware/hwcomposer.h>

// based on test_hwcomposer.c from libhybris project (Apache 2 licensed)

namespace KWin
{

HwcomposerBackend::HwcomposerBackend(QObject *parent)
    : AbstractBackend(parent)
{
}

HwcomposerBackend::~HwcomposerBackend()
{
    if (m_device) {
        hwc_close_1(m_device);
    }
}

static QSize getDisplaySize(hwc_composer_device_1_t *device)
{
    uint32_t configs[5];
    size_t numConfigs = 5;
    if (device->getDisplayConfigs(device, 0, configs, &numConfigs) != 0) {
        qCWarning(KWIN_HWCOMPOSER) << "Failed to get hwcomposer display configurations";
        return QSize();
    }

    int32_t attr_values[2];
    uint32_t attributes[] = {
        HWC_DISPLAY_WIDTH,
        HWC_DISPLAY_HEIGHT,
        HWC_DISPLAY_NO_ATTRIBUTE
    };
    device->getDisplayAttributes(device, 0, configs[0], attributes, attr_values);
    return QSize(attr_values[0], attr_values[1]);
}

void HwcomposerBackend::init()
{
    hw_module_t *hwcModule = nullptr;
    if (hw_get_module(HWC_HARDWARE_MODULE_ID, (const hw_module_t **)&hwcModule) != 0) {
        qCWarning(KWIN_HWCOMPOSER) << "Failed to get hwcomposer module";
        emit initFailed();
        return;
    }

    hwc_composer_device_1_t *hwcDevice = nullptr;
    if (hwc_open_1(hwcModule, &hwcDevice) != 0) {
        qCWarning(KWIN_HWCOMPOSER) << "Failed to open hwcomposer device";
        emit initFailed();
        return;
    }

    // unblank, setPowerMode?
    hwcDevice->blank(hwcDevice, 0, 0);

    // get display configuration
    m_displaySize = getDisplaySize(hwcDevice);
    if (!m_displaySize.isValid()) {
        emit initFailed();
        return;
    }
    qCDebug(KWIN_HWCOMPOSER) << "Display size:" << m_displaySize;
    m_device = hwcDevice;

    emit screensQueried();
    setReady(true);
}

HwcomposerWindow *HwcomposerBackend::createSurface()
{
    return new HwcomposerWindow(this);
}

Screens *HwcomposerBackend::createScreens(QObject *parent)
{
    return new HwcomposerScreens(this, parent);
}

OpenGLBackend *HwcomposerBackend::createOpenGLBackend()
{
    return new EglHwcomposerBackend(this);
}

static void initLayer(hwc_layer_1_t *layer, const hwc_rect_t &rect)
{
    memset(layer, 0, sizeof(hwc_layer_1_t));
    layer->compositionType = HWC_FRAMEBUFFER;
    layer->hints = 0;
    layer->flags = 0;
    layer->handle = 0;
    layer->transform = 0;
    layer->blending = HWC_BLENDING_NONE;
    layer->sourceCrop = rect;
    layer->displayFrame = rect;
    layer->visibleRegionScreen.numRects = 1;
    layer->visibleRegionScreen.rects = &layer->displayFrame;
    layer->acquireFenceFd = -1;
    layer->releaseFenceFd = -1;
}

HwcomposerWindow::HwcomposerWindow(HwcomposerBackend *backend)
    : HWComposerNativeWindow(backend->size().width(), backend->size().height(), HAL_PIXEL_FORMAT_RGBA_8888)
    , m_backend(backend)
{
    size_t size = sizeof(hwc_display_contents_1_t) + 2 * sizeof(hwc_layer_1_t);
    hwc_display_contents_1_t *list = (hwc_display_contents_1_t*)malloc(size);
    m_list = (hwc_display_contents_1_t**)malloc(HWC_NUM_DISPLAY_TYPES * sizeof(hwc_display_contents_1_t *));
    for (int i = 0; i < HWC_NUM_DISPLAY_TYPES; ++i) {
        m_list[i] = list;
    }
    const hwc_rect_t rect = {
        0,
        0,
        m_backend->size().width(),
        m_backend->size().height()
    };
    initLayer(&list->hwLayers[0], rect);
    initLayer(&list->hwLayers[1], rect);

    list->retireFenceFd = -1;
    list->flags = HWC_GEOMETRY_CHANGED;
    list->numHwLayers = 2;
}

HwcomposerWindow::~HwcomposerWindow()
{
    // TODO: cleanup
}

static void syncWait(int fd)
{
    if (fd == -1) {
        return;
    }
    sync_wait(fd, -1);
    close(fd);
}

void HwcomposerWindow::present()
{
    HWComposerNativeWindowBuffer *front;
    lockFrontBuffer(&front);

    m_list[0]->hwLayers[1].handle = front->handle;
    m_list[0]->hwLayers[0].handle = NULL;
    m_list[0]->hwLayers[0].flags = HWC_SKIP_LAYER;

    int oldretire = m_list[0]->retireFenceFd;
    int oldrelease = m_list[0]->hwLayers[1].releaseFenceFd;
    int oldrelease2 = m_list[0]->hwLayers[0].releaseFenceFd;

    hwc_composer_device_1_t *device = m_backend->device();
    if (device->prepare(device, HWC_NUM_DISPLAY_TYPES, m_list) != 0) {
        qCWarning(KWIN_HWCOMPOSER) << "Error preparing hwcomposer for frame";
    }
    if (device->set(device, HWC_NUM_DISPLAY_TYPES, m_list) != 0) {
        qCWarning(KWIN_HWCOMPOSER) << "Error setting device for frame";
    }

    unlockFrontBuffer(front);

    syncWait(oldrelease);
    syncWait(oldrelease2);
    syncWait(oldretire);
}

}