/*
 * producer_noise.c -- noise generating producer
 * Copyright (C) 2003-2014 Meltytech, LLC
 *
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <framework/mlt_frame.h>
#include <framework/mlt_pool.h>
#include <framework/mlt_producer.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/** Random number generator
*/

typedef struct
{
    unsigned int x;
    unsigned int y;
} rand_seed;

static void init_seed(rand_seed *seed, int init)
{
    // Use the initial value to initialize the seed to arbitrary values.
    // This causes the algorithm to produce consistent results each time for the same frame number.
    seed->x = 521288629 + init - (init << 16);
    seed->y = 362436069 - init + (init << 16);
}

static inline unsigned int fast_rand(rand_seed *seed)
{
    static unsigned int a = 18000, b = 30903;
    seed->x = a * (seed->x & 65535) + (seed->x >> 16);
    seed->y = b * (seed->y & 65535) + (seed->y >> 16);
    return ((seed->x << 16) + (seed->y & 65535));
}

// Forward declarations
static int producer_get_frame(mlt_producer producer, mlt_frame_ptr frame, int index);
static void producer_close(mlt_producer producer);

/** Initialise.
*/

mlt_producer producer_noise_init(mlt_profile profile,
                                 mlt_service_type type,
                                 const char *id,
                                 char *arg)
{
    // Create a new producer object
    mlt_producer producer = mlt_producer_new(profile);

    // Initialise the producer
    if (producer != NULL) {
        // Callback registration
        producer->get_frame = producer_get_frame;
        producer->close = (mlt_destructor) producer_close;
    }

    return producer;
}

static int producer_get_image(mlt_frame frame,
                              uint8_t **buffer,
                              mlt_image_format *format,
                              int *width,
                              int *height,
                              int writable)
{
    // Choose suitable out values if nothing specific requested
    if (*width <= 0)
        *width = mlt_service_profile(MLT_PRODUCER_SERVICE(mlt_frame_get_original_producer(frame)))
                     ->width;
    if (*height <= 0)
        *height = mlt_service_profile(MLT_PRODUCER_SERVICE(mlt_frame_get_original_producer(frame)))
                      ->height;

    // Calculate the size of the image
    int size = *width * *height * 2;

    // Set the format being returned
    *format = mlt_image_yuv422;

    // Allocate the image
    *buffer = mlt_pool_alloc(size);

    // Update the frame
    mlt_frame_set_image(frame, *buffer, size, mlt_pool_release);

    // Before we write to the image, make sure we have one
    if (*buffer != NULL) {
        // Calculate the end of the buffer
        uint8_t *p = *buffer + *width * *height * 2;

        // Value to hold a random number
        uint32_t value;

        // Initialize seed from the frame number.
        rand_seed seed;
        init_seed(&seed, mlt_frame_get_position(frame));

        // Generate random noise
        while (p != *buffer) {
            value = fast_rand(&seed) & 0xff;
            *(--p) = 128;
            *(--p) = value < 16 ? 16 : value > 240 ? 240 : value;
        }
    }

    return 0;
}

static int producer_get_audio(mlt_frame frame,
                              int16_t **buffer,
                              mlt_audio_format *format,
                              int *frequency,
                              int *channels,
                              int *samples)
{
    int size = 0;

    // Correct the returns if necessary
    *samples = *samples <= 0 ? 1920 : *samples;
    *channels = *channels <= 0 ? 2 : *channels;
    *frequency = *frequency <= 0 ? 48000 : *frequency;
    *format = mlt_audio_s16;

    // Calculate the size of the buffer
    size = *samples * *channels * sizeof(int16_t);

    // Allocate the buffer
    *buffer = mlt_pool_alloc(size);

    // Make sure we got one and fill it
    if (*buffer != NULL) {
        int16_t *p = *buffer + size / 2;
        rand_seed seed;
        init_seed(&seed, mlt_frame_get_position(frame));
        while (p != *buffer) {
            int16_t val = (int16_t) fast_rand(&seed);
            *(--p) = val;
        }
    }

    // Set the buffer for destruction
    mlt_frame_set_audio(frame, *buffer, *format, size, mlt_pool_release);

    return 0;
}

static int producer_get_frame(mlt_producer producer, mlt_frame_ptr frame, int index)
{
    // Generate a frame
    *frame = mlt_frame_init(MLT_PRODUCER_SERVICE(producer));

    // Check that we created a frame and initialise it
    if (*frame != NULL) {
        // Obtain properties of frame
        mlt_properties properties = MLT_FRAME_PROPERTIES(*frame);

        // Aspect ratio is whatever it needs to be
        mlt_profile profile = mlt_service_profile(MLT_PRODUCER_SERVICE(producer));
        mlt_properties_set_double(properties, "aspect_ratio", mlt_profile_sar(profile));

        // Set producer-specific frame properties
        mlt_properties_set_int(properties, "progressive", 1);

        // Inform framework that this producer creates yuv frames by default
        mlt_properties_set_int(properties, "format", mlt_image_yuv422);

        // Update timecode on the frame we're creating
        mlt_frame_set_position(*frame, mlt_producer_position(producer));

        // Push the get_image method
        mlt_frame_push_get_image(*frame, producer_get_image);

        // Specify the audio
        mlt_frame_push_audio(*frame, producer_get_audio);
    }

    // Calculate the next timecode
    mlt_producer_prepare_next(producer);

    return 0;
}

static void producer_close(mlt_producer producer)
{
    producer->close = NULL;
    mlt_producer_close(producer);
    free(producer);
}
