/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008-2009 Ariff Abdullah <ariff@FreeBSD.org>
 * All rights reserved.
 * Copyright (c) 2024-2025 The FreeBSD Foundation
 *
 * Portions of this software were developed by Christos Margiolis
 * <christos@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifdef _KERNEL
#ifdef HAVE_KERNEL_OPTION_HEADERS
#include "opt_snd.h"
#endif
#include <dev/sound/pcm/sound.h>
#include <dev/sound/pcm/pcm.h>
#include <dev/sound/pcm/vchan.h>
#include "feeder_if.h"

#define SND_USE_FXDIV
#include "snd_fxdiv_gen.h"
#endif

struct feed_mixer_info {
        uint32_t format;
        uint32_t channels;
        int bps;
};

__always_inline static void
feed_mixer_apply(uint8_t *src, uint8_t *dst, uint32_t count, const uint32_t fmt)
{
        intpcm32_t z;
        intpcm_t x, y;

        src += count;
        dst += count;

        do {
                src -= AFMT_BPS(fmt);
                dst -= AFMT_BPS(fmt);
                count -= AFMT_BPS(fmt);
                x = pcm_sample_read_calc(src, fmt);
                y = pcm_sample_read_calc(dst, fmt);
                z = INTPCM_T(x) + y;
                x = pcm_clamp_calc(z, fmt);
                pcm_sample_write(dst, x, fmt);
        } while (count != 0);
}

static int
feed_mixer_init(struct pcm_feeder *f)
{
        struct feed_mixer_info *info;

        if (f->desc.in != f->desc.out)
                return (EINVAL);

        info = malloc(sizeof(*info), M_DEVBUF, M_NOWAIT | M_ZERO);
        if (info == NULL)
                return (ENOMEM);

        info->format = AFMT_ENCODING(f->desc.in);
        info->channels = AFMT_CHANNEL(f->desc.in);
        info->bps = AFMT_BPS(f->desc.in);

        f->data = info;

        return (0);
}

static int
feed_mixer_free(struct pcm_feeder *f)
{
        struct feed_mixer_info *info;

        info = f->data;
        free(info, M_DEVBUF);

        f->data = NULL;

        return (0);
}

static int
feed_mixer_set(struct pcm_feeder *f, int what, int value)
{
        struct feed_mixer_info *info;

        info = f->data;

        switch (what) {
        case FEEDMIXER_CHANNELS:
                if (value < SND_CHN_MIN || value > SND_CHN_MAX)
                        return (EINVAL);
                info->channels = (uint32_t)value;
                break;
        default:
                return (EINVAL);
        }

        return (0);
}

static __inline int
feed_mixer_rec(struct pcm_channel *c)
{
        struct pcm_channel *ch;
        struct snd_dbuf *b, *bs;
        uint32_t cnt, maxfeed;
        int rdy;

        /*
         * Reset ready and moving pointer. We're not using bufsoft
         * anywhere since its sole purpose is to become the primary
         * distributor for the recorded buffer and also as an interrupt
         * threshold progress indicator.
         */
        b = c->bufsoft;
        b->rp = 0;
        b->rl = 0;
        cnt = b->bufsize;
        maxfeed = SND_FXROUND(SND_FXDIV_MAX, b->align);

        do {
                cnt = FEEDER_FEED(c->feeder->source, c, b->tmpbuf,
                    min(cnt, maxfeed), c->bufhard);
                if (cnt != 0) {
                        sndbuf_acquire(b, b->tmpbuf, cnt);
                        cnt = sndbuf_getfree(b);
                }
        } while (cnt != 0);

        /* Not enough data */
        if (b->rl < b->align) {
                b->rl = 0;
                return (0);
        }

        /*
         * Keep track of ready and moving pointer since we will use
         * bufsoft over and over again, pretending nothing has happened.
         */
        rdy = b->rl;

        CHN_FOREACH(ch, c, children.busy) {
                CHN_LOCK(ch);
                if (CHN_STOPPED(ch) || (ch->flags & CHN_F_DIRTY)) {
                        CHN_UNLOCK(ch);
                        continue;
                }
                bs = ch->bufsoft;
                if (ch->flags & CHN_F_MMAP)
                        sndbuf_dispose(bs, NULL, sndbuf_getready(bs));
                cnt = sndbuf_getfree(bs);
                if (cnt < bs->align) {
                        CHN_UNLOCK(ch);
                        continue;
                }
                maxfeed = SND_FXROUND(SND_FXDIV_MAX, bs->align);
                do {
                        cnt = FEEDER_FEED(ch->feeder, ch, bs->tmpbuf,
                            min(cnt, maxfeed), b);
                        if (cnt != 0) {
                                sndbuf_acquire(bs, bs->tmpbuf, cnt);
                                cnt = sndbuf_getfree(bs);
                        }
                } while (cnt != 0);
                /*
                 * Not entirely flushed out...
                 */
                if (b->rl != 0)
                        ch->xruns++;
                CHN_UNLOCK(ch);
                /*
                 * Rewind buffer position for next virtual channel.
                 */
                b->rp = 0;
                b->rl = rdy;
        }

        /*
         * Set ready pointer to indicate that our children are ready
         * to be woken up, also as an interrupt threshold progress
         * indicator.
         */
        b->rl = 1;

        c->flags &= ~CHN_F_DIRTY;

        /*
         * Return 0 to bail out early from sndbuf_feed() loop.
         * No need to increase feedcount counter since part of this
         * feeder chains already include feed_root().
         */
        return (0);
}

static int
feed_mixer_feed(struct pcm_feeder *f, struct pcm_channel *c, uint8_t *b,
    uint32_t count, void *source)
{
        struct feed_mixer_info *info;
        struct snd_dbuf *src = source;
        struct pcm_channel *ch;
        uint32_t cnt, mcnt, rcnt, sz;
        int passthrough;
        uint8_t *tmp;

        if (c->direction == PCMDIR_REC)
                return (feed_mixer_rec(c));

        sz = src->bufsize;
        if (sz < count)
                count = sz;

        info = f->data;
        sz = info->bps * info->channels;
        count = SND_FXROUND(count, sz);
        if (count < sz)
                return (0);

        /*
         * We are going to use our source as a temporary buffer since it's
         * got no other purpose.  We obtain our data by traversing the channel
         * list of children and calling mixer function to mix count bytes from
         * each into our destination buffer, b.
         */
        tmp = src->buf;
        rcnt = 0;
        mcnt = 0;
        passthrough = 0;        /* 'passthrough' / 'exclusive' marker */

        CHN_FOREACH(ch, c, children.busy) {
                CHN_LOCK(ch);
                if (CHN_STOPPED(ch) || (ch->flags & CHN_F_DIRTY)) {
                        CHN_UNLOCK(ch);
                        continue;
                }
                if ((ch->flags & CHN_F_MMAP) && !(ch->flags & CHN_F_CLOSING))
                        sndbuf_acquire(ch->bufsoft, NULL,
                            sndbuf_getfree(ch->bufsoft));
                if (c->flags & CHN_F_PASSTHROUGH) {
                        /*
                         * Passthrough. Dump the first digital/passthrough
                         * channel into destination buffer, and the rest into
                         * nothingness (mute effect).
                         */
                        if (passthrough == 0 &&
                            (ch->format & AFMT_PASSTHROUGH)) {
                                rcnt = SND_FXROUND(FEEDER_FEED(ch->feeder, ch,
                                    b, count, ch->bufsoft), sz);
                                passthrough = 1;
                        } else
                                FEEDER_FEED(ch->feeder, ch, tmp, count,
                                    ch->bufsoft);
                } else if (c->flags & CHN_F_EXCLUSIVE) {
                        /*
                         * Exclusive. Dump the first 'exclusive' channel into
                         * destination buffer, and the rest into nothingness
                         * (mute effect).
                         */
                        if (passthrough == 0 && (ch->flags & CHN_F_EXCLUSIVE)) {
                                rcnt = SND_FXROUND(FEEDER_FEED(ch->feeder, ch,
                                    b, count, ch->bufsoft), sz);
                                passthrough = 1;
                        } else
                                FEEDER_FEED(ch->feeder, ch, tmp, count,
                                    ch->bufsoft);
                } else {
                        if (rcnt == 0) {
                                rcnt = SND_FXROUND(FEEDER_FEED(ch->feeder, ch,
                                    b, count, ch->bufsoft), sz);
                                mcnt = count - rcnt;
                        } else {
                                cnt = SND_FXROUND(FEEDER_FEED(ch->feeder, ch,
                                    tmp, count, ch->bufsoft), sz);
                                if (cnt != 0) {
                                        if (mcnt != 0) {
                                                memset(b + rcnt,
                                                    sndbuf_zerodata(
                                                    f->desc.out), mcnt);
                                                mcnt = 0;
                                        }
                                        switch (info->format) {
                                        case AFMT_S16_NE:
                                                feed_mixer_apply(tmp, b, cnt,
                                                    AFMT_S16_NE);
                                                break;
                                        case AFMT_S24_NE:
                                                feed_mixer_apply(tmp, b, cnt,
                                                    AFMT_S24_NE);
                                                break;
                                        case AFMT_S32_NE:
                                                feed_mixer_apply(tmp, b, cnt,
                                                    AFMT_S32_NE);
                                                break;
                                        default:
                                                feed_mixer_apply(tmp, b, cnt,
                                                    info->format);
                                                break;
                                        }
                                        if (cnt > rcnt)
                                                rcnt = cnt;
                                }
                        }
                }
                CHN_UNLOCK(ch);
        }

        if (++c->feedcount == 0)
                c->feedcount = 2;

        c->flags &= ~CHN_F_DIRTY;

        return (rcnt);
}

static kobj_method_t feeder_mixer_methods[] = {
        KOBJMETHOD(feeder_init,         feed_mixer_init),
        KOBJMETHOD(feeder_free,         feed_mixer_free),
        KOBJMETHOD(feeder_set,          feed_mixer_set),
        KOBJMETHOD(feeder_feed,         feed_mixer_feed),
        KOBJMETHOD_END
};

FEEDER_DECLARE(feeder_mixer, FEEDER_MIXER);