/**
 * \file mlt_multitrack.c
 * \brief multitrack service class
 * \see mlt_multitrack_s
 *
 * Copyright (C) 2003-2025 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 "mlt_multitrack.h"
#include "mlt_cache.h"
#include "mlt_factory.h"
#include "mlt_frame.h"
#include "mlt_playlist.h"

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

/* Forward reference. */

static int producer_get_frame(mlt_producer producer, mlt_frame_ptr frame, int index);

/** Construct and initialize a new multitrack.
 *
 * Sets the resource property to "<multitrack>".
 *
 * \public \memberof mlt_multitrack_s
 * \return a new multitrack
 */

mlt_multitrack mlt_multitrack_init()
{
    // Allocate the multitrack object
    mlt_multitrack self = calloc(1, sizeof(struct mlt_multitrack_s));

    if (self != NULL) {
        mlt_producer producer = &self->parent;
        if (mlt_producer_init(producer, self) == 0) {
            mlt_properties properties = MLT_MULTITRACK_PROPERTIES(self);
            producer->get_frame = producer_get_frame;
            mlt_properties_set_data(properties, "multitrack", self, 0, NULL, NULL);
            mlt_properties_set(properties, "log_id", "multitrack");
            mlt_properties_set(properties, "resource", "<multitrack>");
            mlt_properties_set_int(properties, "in", 0);
            mlt_properties_set_int(properties, "out", -1);
            mlt_properties_set_int(properties, "length", 0);
            producer->close = (mlt_destructor) mlt_multitrack_close;
        } else {
            free(self);
            self = NULL;
        }
    }

    return self;
}

/** Get the producer associated to this multitrack.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \return the producer object
 * \see MLT_MULTITRACK_PRODUCER
 */

mlt_producer mlt_multitrack_producer(mlt_multitrack self)
{
    return self != NULL ? &self->parent : NULL;
}

/** Get the service associated this multitrack.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \return the service object
 * \see MLT_MULTITRACK_SERVICE
 */

mlt_service mlt_multitrack_service(mlt_multitrack self)
{
    return MLT_MULTITRACK_SERVICE(self);
}

/** Get the properties associated this multitrack.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \return the multitrack's property list
 * \see MLT_MULTITRACK_PROPERTIES
 */

mlt_properties mlt_multitrack_properties(mlt_multitrack self)
{
    return MLT_MULTITRACK_PROPERTIES(self);
}

/** Initialize position related information.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 */

void mlt_multitrack_refresh(mlt_multitrack self)
{
    int i = 0;

    // Obtain the properties of this multitrack
    mlt_properties properties = MLT_MULTITRACK_PROPERTIES(self);

    // We need to ensure that the multitrack reports the longest track as its length
    mlt_position length = 0;

    // Obtain stats on all connected services
    for (i = 0; i < self->count; i++) {
        // Get the producer from this index
        mlt_track track = self->list[i];
        mlt_producer producer = track->producer;

        // If it's allocated then, update our stats
        if (producer != NULL) {
            // If we have more than 1 track, we must be in continue mode
            if (self->count > 1)
                mlt_properties_set(MLT_PRODUCER_PROPERTIES(producer), "eof", "continue");

            // Determine the longest length
            //if ( !mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( producer ), "hide" ) )
            length = mlt_producer_get_playtime(producer) > length
                         ? mlt_producer_get_playtime(producer)
                         : length;
        }
    }

    // Update multitrack properties now - we'll not destroy the in point here
    mlt_events_block(properties, properties);
    mlt_properties_set_position(properties, "length", length);
    mlt_events_unblock(properties, properties);
    mlt_properties_set_position(properties, "out", length - 1);
}

/** Listener for producers on the playlist.
 *
 * \private \memberof mlt_multitrack_s
 * \param producer a producer
 * \param self a multitrack
 */

static void mlt_multitrack_listener(mlt_producer producer, mlt_multitrack self)
{
    mlt_multitrack_refresh(self);
}

static void resize_service_caches(mlt_multitrack self)
{
    mlt_properties caches = mlt_properties_get_data(mlt_global_properties(), "caches", NULL);
    if (caches) {
        int i;
        for (i = 0; i < mlt_properties_count(caches); ++i) {
            mlt_cache cache = mlt_properties_get_data_at(caches, i, NULL);
            if (self->count * 2 > mlt_cache_get_size(cache))
                mlt_cache_set_size(cache, self->count * 2);
        }
    }
}

/** Connect a producer to a given track.
 *
 * Note that any producer can be connected here, but see special case treatment
 * of playlist in clip point determination below.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \param producer the producer to connect to the multitrack producer
 * \param track the 0-based index of the track on which to connect the multitrack
 * \return true on error
 */

int mlt_multitrack_connect(mlt_multitrack self, mlt_producer producer, int track)
{
    // Connect to the producer to ourselves at the specified track
    int result = mlt_service_connect_producer(MLT_MULTITRACK_SERVICE(self),
                                              MLT_PRODUCER_SERVICE(producer),
                                              track);

    if (result == 0) {
        mlt_track current_track = (track < self->count) ? self->list[track] : NULL;
        // Resize the producer list if need be
        if (track >= self->size) {
            int i;
            self->list = realloc(self->list, (track + 10) * sizeof(mlt_track));
            for (i = self->size; i < track + 10; i++)
                self->list[i] = NULL;
            self->size = track + 10;
        }

        if (current_track) {
            mlt_event_close(current_track->event);
            mlt_producer_close(current_track->producer);
        } else {
            self->list[track] = malloc(sizeof(struct mlt_track_s));
        }

        // Assign the track in our list here
        self->list[track]->producer = producer;
        self->list[track]->event = mlt_events_listen(MLT_PRODUCER_PROPERTIES(producer),
                                                     self,
                                                     "producer-changed",
                                                     (mlt_listener) mlt_multitrack_listener);
        mlt_properties_inc_ref(MLT_PRODUCER_PROPERTIES(producer));
        mlt_event_inc_ref(self->list[track]->event);

        // Increment the track count if need be
        if (track >= self->count) {
            self->count = track + 1;
            resize_service_caches(self);
        }

        // Refresh our stats
        mlt_multitrack_refresh(self);
    }

    return result;
}

/** Insert a producer to a given track.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \param producer the producer to connect to the multitrack producer
 * \param track the 0-based index of the track on which to connect the multitrack
 * \return true on error
 */

int mlt_multitrack_insert(mlt_multitrack self, mlt_producer producer, int track)
{
    if (track >= self->count)
        return mlt_multitrack_connect(self, producer, track);

    // Connect to the producer to ourselves at the specified track
    int result = mlt_service_insert_producer(MLT_MULTITRACK_SERVICE(self),
                                             MLT_PRODUCER_SERVICE(producer),
                                             track);

    if (result == 0) {
        // Resize the producer list if needed.
        if (self->count + 1 > self->size) {
            int new_size = self->size + 10;
            self->list = realloc(self->list, new_size * sizeof(mlt_track));
            if (self->list) {
                memset(&self->list[self->size], 0, new_size - self->size);
                self->size = new_size;
            }
        }

        if (self->list) {
            // Move all of the list elements following track N down by 1.
            memmove(&self->list[track + 1],
                    &self->list[track],
                    (self->count - track) * sizeof(mlt_track));
            self->count++;
            resize_service_caches(self);

            // Assign the track in our list.
            self->list[track] = malloc(sizeof(struct mlt_track_s));
            self->list[track]->producer = producer;
            self->list[track]->event = mlt_events_listen(MLT_PRODUCER_PROPERTIES(producer),
                                                         self,
                                                         "producer-changed",
                                                         (mlt_listener) mlt_multitrack_listener);
            mlt_properties_inc_ref(MLT_PRODUCER_PROPERTIES(producer));
            mlt_event_inc_ref(self->list[track]->event);

            // Refresh our stats
            mlt_multitrack_refresh(self);
        } else {
            result = -1;
        }
    }

    return result;
}

/** Remove the N-th track.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \param track the index of the track to remove
 * \return true if there was an error
 */

int mlt_multitrack_disconnect(mlt_multitrack self, int track)
{
    int error = -1;

    if (self && self->list && track >= 0 && track < self->count) {
        // Disconnect the track producer.
        error = mlt_service_disconnect_producer(MLT_MULTITRACK_SERVICE(self), track);
        if (!error) {
            // Release references on track.
            if (self->list[track]) {
                mlt_producer_close(self->list[track]->producer);
                mlt_event_close(self->list[track]->event);
            }

            // Contract the list of tracks.
            for (; track + 1 < self->count; track++) {
                if (self->list[track] && self->list[track + 1]) {
                    self->list[track]->producer = self->list[track + 1]->producer;
                    self->list[track]->event = self->list[track + 1]->event;
                }
            }
            if (self->list[self->count - 1]) {
                free(self->list[self->count - 1]);
                self->list[self->count - 1] = NULL;
            }
            self->count--;

            // Recalculate the duration.
            mlt_multitrack_refresh(self);
        }
    }
    return error;
}

/** Get the number of tracks.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \return the number of tracks
 */

int mlt_multitrack_count(mlt_multitrack self)
{
    if (self == NULL)
        return 0;
    else
        return self->count;
}

/** Get an individual track as a producer.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \param track the 0-based index of the producer to get
 * \return the producer or NULL if not valid
 */

mlt_producer mlt_multitrack_track(mlt_multitrack self, int track)
{
    mlt_producer producer = NULL;

    if (self->list != NULL && track >= 0 && track < self->count)
        producer = self->list[track]->producer;

    return producer;
}

/** Position comparison function for sorting.
 *
 * \private \memberof mlt_multitrack_s
 * \param p1 a position
 * \param p2 another position
 * \return <0 if \p p1 is less than \p p2, 0 if equal, >0 if greater
 */

static int position_compare(const void *p1, const void *p2)
{
    return *(const mlt_position *) p1 - *(const mlt_position *) p2;
}

/** Add a position to a set.
 *
 * \private \memberof mlt_multitrack_s
 * \param array an array of positions (the set)
 * \param size the current number of positions in the array (not the capacity of the array)
 * \param position the position to add
 * \return the new size of the array
 */

static int add_unique(mlt_position *array, int size, mlt_position position)
{
    int i = 0;
    for (i = 0; i < size; i++)
        if (array[i] == position)
            break;
    if (i == size)
        array[size++] = position;
    return size;
}

/** Increase the capacity of a set of mlt_position.
 *
 * \private \memberof mlt_multitrack_s
 * \param array an array of positions (the set)
 * \param count the current number of elements in the array (not the capacity)
 * \param[out] size the current capacity of the array
 * \return the new address of the array
 */

static mlt_position *resize_set(mlt_position *map, int count, int *size)
{
    // Resize only if needed.
    if (count + 1 >= *size) {
        map = realloc(map, (*size + 1000) * sizeof(*map));
        memset(map + *size, 0, 1000 * sizeof(*map));
        *size += 1000;
    }
    return map;
}

/** Determine the clip point.
 *
 * <pre>
 * Special case here: a 'producer' has no concept of multiple clips - only the
 * playlist and multitrack producers have clip functionality. Further to that a
 * multitrack determines clip information from any connected tracks that happen
 * to be playlists.
 *
 * Additionally, it must locate clips in the correct order, for example, consider
 * the following track arrangement:
 *
 * playlist1 |0.0     |b0.0      |0.1          |0.1         |0.2           |
 * playlist2 |b1.0  |1.0           |b1.1     |1.1             |
 *
 * Note - b clips represent blanks. They are also reported as clip positions.
 *
 * When extracting clip positions from these playlists, we should get a sequence of:
 *
 * 0.0, 1.0, b0.0, 0.1, b1.1, 1.1, 0.1, 0.2, [out of playlist2], [out of playlist1]
 * </pre>
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 * \param whence from where to extract
 * \param index the 0-based index of which clip to extract
 * \return the position of clip \p index relative to \p whence
 */

mlt_position mlt_multitrack_clip(mlt_multitrack self, mlt_whence whence, int index)
{
    mlt_position position = 0;
    int i = 0;
    int j = 0;
    int size = 1000;
    mlt_position *map = calloc(size, sizeof(*map));
    int count = 0;

    for (i = 0; i < self->count; i++) {
        // Get the producer for this track
        mlt_producer producer = self->list[i]->producer;

        // If it's assigned and not a hidden track
        if (producer != NULL) {
            // Get the properties of this producer
            mlt_properties properties = MLT_PRODUCER_PROPERTIES(producer);

            // Determine if it's a playlist
            mlt_playlist playlist = mlt_properties_get_data(properties, "playlist", NULL);

            map = resize_set(map, count, &size);

            // Special case consideration of playlists
            if (playlist != NULL) {
                for (j = 0; j < mlt_playlist_count(playlist); j++) {
                    count = add_unique(map,
                                       count,
                                       mlt_playlist_clip(playlist, mlt_whence_relative_start, j));
                    map = resize_set(map, count, &size);
                }
                count = add_unique(map, count, mlt_producer_get_out(producer) + 1);
            } else {
                count = add_unique(map, count, 0);
                count = add_unique(map, count, mlt_producer_get_out(producer) + 1);
            }
        }
    }

    // Now sort the map
    qsort(map, count, sizeof(mlt_position), position_compare);

    // Now locate the requested index
    switch (whence) {
    case mlt_whence_relative_start:
        if (index < count)
            position = map[index];
        else
            position = map[count - 1];
        break;

    case mlt_whence_relative_current:
        position = mlt_producer_position(MLT_MULTITRACK_PRODUCER(self));
        for (i = 0; i < count - 2; i++)
            if (position >= map[i] && position < map[i + 1])
                break;
        index += i;
        if (index >= 0 && index < count)
            position = map[index];
        else if (index < 0)
            position = map[0];
        else
            position = map[count - 1];
        break;

    case mlt_whence_relative_end:
        if (index < count)
            position = map[count - index - 1];
        else
            position = map[0];
        break;
    }

    // Free the map
    free(map);

    return position;
}

/** Get frame method.
 *
 * <pre>
 * Special case here: The multitrack must be used in a conjunction with a downstream
 * tractor-type service, ie:
 *
 * Producer1 \
 * Producer2 - multitrack - { filters/transitions } - tractor - consumer
 * Producer3 /
 *
 * The get_frame of a tractor pulls frames from it's connected service on all tracks and
 * will terminate as soon as it receives a test card with a last_track property. The
 * important case here is that the mulitrack does not move to the next frame until all
 * tracks have been pulled.
 *
 * Reasoning: In order to seek on a network such as above, the multitrack needs to ensure
 * that all producers are positioned on the same frame. It uses the 'last track' logic
 * to determine when to move to the next frame.
 *
 * Flaw: if a transition is configured to read from a b-track which happens to trigger
 * the last frame logic (ie: it's configured incorrectly), then things are going to go
 * out of sync.
 *
 * See playlist logic too.
 * </pre>
 *
 * \private \memberof mlt_multitrack_s
 * \param parent the producer interface to a mulitrack
 * \param[out] frame a frame by reference
 * \param index the 0-based track index
 * \return true if there was an error
 */

static int producer_get_frame(mlt_producer parent, mlt_frame_ptr frame, int index)
{
    // Get the mutiltrack object
    mlt_multitrack self = parent->child;

    // Check if we have a track for this index
    if (index >= 0 && index < self->count && self->list[index] != NULL) {
        // Get the producer for this track
        mlt_producer producer = self->list[index]->producer;

        // Get the track hide property
        int hide = mlt_properties_get_int(MLT_PRODUCER_PROPERTIES(mlt_producer_cut_parent(producer)),
                                          "hide");

        // Obtain the current position
        mlt_position position = mlt_producer_frame(parent);

        // Get the parent properties
        mlt_properties producer_properties = MLT_PRODUCER_PROPERTIES(parent);

        // Get the speed
        double speed = mlt_properties_get_double(producer_properties, "_speed");

        if (hide == 3) {
            *frame = mlt_frame_init(MLT_PRODUCER_SERVICE(producer));
        } else {
            // Make sure we're at the same point
            mlt_producer_seek(producer, position);

            // Get the frame from the producer
            mlt_service_get_frame(MLT_PRODUCER_SERVICE(producer), frame, 0);
        }

        // Indicate speed of this producer
        mlt_properties properties = MLT_FRAME_PROPERTIES(*frame);
        mlt_properties_set_double(properties, "_speed", speed);
        mlt_frame_set_position(*frame, position);
        mlt_properties_set_int(properties, "hide", hide);
    } else {
        // Generate a test frame
        *frame = mlt_frame_init(MLT_PRODUCER_SERVICE(parent));

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

        // Move on to the next frame
        if (index >= self->count) {
            // Let tractor know if we've reached the end
            mlt_properties_set_int(MLT_FRAME_PROPERTIES(*frame), "last_track", 1);

            // Move to the next frame
            mlt_producer_prepare_next(parent);
        }
    }

    return 0;
}

/** Close this instance and free its resources.
 *
 * \public \memberof mlt_multitrack_s
 * \param self a multitrack
 */

void mlt_multitrack_close(mlt_multitrack self)
{
    if (self != NULL && mlt_properties_dec_ref(MLT_MULTITRACK_PROPERTIES(self)) <= 0) {
        int i = 0;
        for (i = 0; i < self->count; i++) {
            if (self->list[i] != NULL) {
                mlt_event_close(self->list[i]->event);
                mlt_producer_close(self->list[i]->producer);
                free(self->list[i]);
            }
        }

        // Close the producer
        self->parent.close = NULL;
        mlt_producer_close(&self->parent);

        // Free the list
        free(self->list);

        // Free the object
        free(self);
    }
}
