/*
 * Copyright (C) 2008 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.
 */

#include <sys/mman.h>

#include <dlfcn.h>

#include <cutils/ashmem.h>
#include <cutils/log.h>

#include <hardware/hardware.h>
#include <hardware/gralloc.h>

#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <string.h>
#include <stdlib.h>

#include <utils/Vector.h>

#include <cutils/log.h>
#include <cutils/atomic.h>

#if HAVE_ANDROID_OS
#include <linux/fb.h>
#endif

#include "gralloc_priv.h"

/*****************************************************************************/

// numbers of buffers for page flipping
#define NUM_BUFFERS 2

struct hwc_callback_entry 
{
    void (*callback)(void *, private_handle_t *);
    void *data;
};

typedef android::Vector<struct hwc_callback_entry> hwc_callback_queue_t;

struct fb_context_t {
    framebuffer_device_t  device;
};

/*****************************************************************************/

static int fb_setSwapInterval(struct framebuffer_device_t* dev,
                              int interval)
{
    fb_context_t* ctx = (fb_context_t*)dev;
    if (interval < dev->minSwapInterval || interval > dev->maxSwapInterval)
        return -EINVAL;
    // FIXME: implement fb_setSwapInterval
    return 0;
}

static int fb_post(struct framebuffer_device_t* dev, buffer_handle_t buffer)
{
    if (private_handle_t::validate(buffer) < 0)
        return -EINVAL;

    private_handle_t const* hnd = reinterpret_cast<private_handle_t const*>(buffer);
    private_module_t* m = reinterpret_cast<private_module_t*>(dev->common.module);

    hwc_callback_queue_t *queue = reinterpret_cast<hwc_callback_queue_t *>(m->queue);
    pthread_mutex_lock(&m->queue_lock);
    if(queue->isEmpty())
        pthread_mutex_unlock(&m->queue_lock);
    else {
        private_handle_t *hnd = private_handle_t::dynamicCast(buffer);
        struct hwc_callback_entry entry = queue->top();
        queue->pop();
        pthread_mutex_unlock(&m->queue_lock);
        entry.callback(entry.data, hnd);
    }

    return 0;
}

/*****************************************************************************/

static int fb_close(struct hw_device_t *dev)
{
    fb_context_t* ctx = (fb_context_t*)dev;
    if (ctx) {
        free(ctx);
    }
    return 0;
}

static void get_screen_res(const char *fbname, int32_t *xres, int32_t *yres,
                           int32_t *refresh)
{
    char *path;
    int fd;
    char buf[128];
    int ret;
    unsigned int _x, _y, _r;

    asprintf(&path, "/sys/class/graphics/%s/modes", fbname);
    if (!path)
        goto err_asprintf;
    fd = open(path, O_RDONLY);
    if (fd < 0)
        goto err_open;
    ret = read(fd, buf, sizeof(buf));
    if (ret <= 0)
        goto err_read;
    buf[sizeof(buf)-1] = '\0';

    ret = sscanf(buf, "U:%ux%up-%u", &_x, &_y, &_r);
    if (ret != 3)
        goto err_sscanf;

    ALOGI("Using %ux%u %uHz resolution for '%s' from modes list\n",
          _x, _y, _r, fbname);

    *xres = (int32_t)_x;
    *yres = (int32_t)_y;
    *refresh = (int32_t)_r;

    close(fd);
    free(path);
    return;

err_sscanf:
err_read:
    close(fd);
err_open:
    free(path);
err_asprintf:
    *xres = 2560;
    *yres = 1600;
    *refresh = 60;
}

int init_fb(struct private_module_t* module)
{
    char const * const device_template[] = {
        "/dev/graphics/fb%u",
        "/dev/fb%u",
        NULL
    };

    int fd = -1;
    int i = 0;
    char name[64];

    fd = open("/dev/graphics/fb0", O_RDWR);
    if (fd < 0) {
        ALOGE("/dev/graphics/fb0 Open fail");
        return -errno;
    }

    struct fb_fix_screeninfo finfo;
    if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1) {
        ALOGE("Fail to get FB Screen Info");
        return -errno;
    }

    struct fb_var_screeninfo info;
    if (ioctl(fd, FBIOGET_VSCREENINFO, &info) == -1) {
        ALOGE("First, Fail to get FB VScreen Info");
        return -errno;
    }

    int32_t refreshRate;
    get_screen_res("fb0", &module->xres, &module->yres, &refreshRate);
    if (refreshRate == 0)
        refreshRate = 60;  /* 60 Hz */

    float xdpi = (module->xres * 25.4f) / info.width;
    float ydpi = (module->yres * 25.4f) / info.height;

    ALOGI("using (id=%s)\n"
          "xres         = %d px\n"
          "yres         = %d px\n"
          "width        = %d mm (%f dpi)\n"
          "height       = %d mm (%f dpi)\n"
          "refresh rate = %.2f Hz\n",
          finfo.id, module->xres, module->yres, info.width,  xdpi, info.height,
          ydpi, (float)refreshRate);

    module->line_length = module->xres * 4;
    module->xdpi = xdpi;
    module->ydpi = ydpi;
    module->fps = (float)refreshRate;

    return 0;
}

int fb_device_open(hw_module_t const* module, const char* name,
                   hw_device_t** device)
{
    int status = -EINVAL;
#ifdef GRALLOC_16_BITS
    int bits_per_pixel = 16;
    int format = HAL_PIXEL_FORMAT_RGB_565;
#else
    int bits_per_pixel = 32;
    int format = HAL_PIXEL_FORMAT_RGBA_8888;
#endif

    alloc_device_t* gralloc_device;
    status = gralloc_open(module, &gralloc_device);
    if (status < 0) {
        ALOGE("Fail to Open gralloc device");
        return status;
    }

    framebuffer_device_t *dev = (framebuffer_device_t *)malloc(sizeof(framebuffer_device_t));
    if (dev == NULL) {
        ALOGE("Failed to allocate memory for dev");
        gralloc_close(gralloc_device);
        return status;
    }

    private_module_t* m = (private_module_t*)module;
    status = init_fb(m);
    if (status < 0) {
        ALOGE("Fail to init framebuffer");
        free(dev);
        gralloc_close(gralloc_device);
        return status;
    }

    /* initialize our state here */
    memset(dev, 0, sizeof(*dev));

    /* initialize the procs */
    dev->common.tag = HARDWARE_DEVICE_TAG;
    dev->common.version = 0;
    dev->common.module = const_cast<hw_module_t*>(module);
    dev->common.close = fb_close;
    dev->setSwapInterval = 0;
    dev->post = fb_post;
    dev->setUpdateRect = 0;
    dev->compositionComplete = 0;
    m->queue = new hwc_callback_queue_t;
    pthread_mutex_init(&m->queue_lock, NULL);

    int stride = m->line_length / (bits_per_pixel >> 3);
    const_cast<uint32_t&>(dev->flags) = 0;
    const_cast<uint32_t&>(dev->width) = m->xres;
    const_cast<uint32_t&>(dev->height) = m->yres;
    const_cast<int&>(dev->stride) = stride;
    const_cast<int&>(dev->format) = format;
    const_cast<float&>(dev->xdpi) = m->xdpi;
    const_cast<float&>(dev->ydpi) = m->ydpi;
    const_cast<float&>(dev->fps) = m->fps;
    const_cast<int&>(dev->minSwapInterval) = 1;
    const_cast<int&>(dev->maxSwapInterval) = 1;
    *device = &dev->common;
    status = 0;

    return status;
}