/*
 * This file is part of mpv.
 *
 * With some chunks from original MPlayer VAAPI patch:
 * Copyright (C) 2008-2009 Splitted-Desktop Systems
 *
 * mpv 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 2 of the License, or
 * (at your option) any later version.
 *
 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stddef.h>
#include <assert.h>

#include <libavcodec/avcodec.h>
#include <libavcodec/vaapi.h>
#include <libavutil/common.h>

#include <X11/Xlib.h>

#include "lavc.h"
#include "common/common.h"
#include "common/av_common.h"
#include "video/fmt-conversion.h"
#include "video/vaapi.h"
#include "video/mp_image_pool.h"
#include "video/hwdec.h"
#include "video/filter/vf.h"

/*
 * The VAAPI decoder can work only with surfaces passed to the decoder at
 * creation time. This means all surfaces have to be created in advance.
 * So, additionally to the maximum number of reference frames, we need
 * surfaces for all kinds of buffering between decoder and VO.
 * Note that redundant additional surfaces also might allow for some
 * buffering (i.e. not trying to reuse a surface while it's busy).
 */
#define ADDTIONAL_SURFACES 6

// Some upper bound.
#define MAX_SURFACES 25

struct priv {
    struct mp_log *log;
    struct mp_vaapi_ctx *ctx;
    VADisplay display;
    Display *x11_display;

    // libavcodec shared struct
    struct vaapi_context *va_context;
    struct vaapi_context va_context_storage;

    struct mp_image_pool *pool;
    int rt_format;

    struct mp_image_pool *sw_pool;
};

#define PE(av_codec_id, ff_profile, vdp_profile)                \
    {AV_CODEC_ID_ ## av_codec_id, FF_PROFILE_ ## ff_profile,    \
     VAProfile ## vdp_profile}

static const struct hwdec_profile_entry profiles[] = {
    PE(MPEG2VIDEO,  MPEG2_MAIN,         MPEG2Main),
    PE(MPEG2VIDEO,  MPEG2_SIMPLE,       MPEG2Simple),
    PE(MPEG4,       MPEG4_ADVANCED_SIMPLE, MPEG4AdvancedSimple),
    PE(MPEG4,       MPEG4_MAIN,         MPEG4Main),
    PE(MPEG4,       MPEG4_SIMPLE,       MPEG4Simple),
    PE(H264,        H264_HIGH,          H264High),
    PE(H264,        H264_MAIN,          H264Main),
    PE(H264,        H264_BASELINE,      H264Baseline),
    PE(VC1,         VC1_ADVANCED,       VC1Advanced),
    PE(VC1,         VC1_MAIN,           VC1Main),
    PE(VC1,         VC1_SIMPLE,         VC1Simple),
    PE(WMV3,        VC1_ADVANCED,       VC1Advanced),
    PE(WMV3,        VC1_MAIN,           VC1Main),
    PE(WMV3,        VC1_SIMPLE,         VC1Simple),
    {0}
};

static const char *str_va_profile(VAProfile profile)
{
    switch (profile) {
#define PROFILE(profile) \
        case VAProfile##profile: return "VAProfile" #profile
        PROFILE(MPEG2Simple);
        PROFILE(MPEG2Main);
        PROFILE(MPEG4Simple);
        PROFILE(MPEG4AdvancedSimple);
        PROFILE(MPEG4Main);
        PROFILE(H264Baseline);
        PROFILE(H264Main);
        PROFILE(H264High);
        PROFILE(VC1Simple);
        PROFILE(VC1Main);
        PROFILE(VC1Advanced);
#undef PROFILE
    }
    return "<unknown>";
}

static int find_entrypoint(int format, VAEntrypoint *ep, int num_ep)
{
    int entrypoint = -1;
    switch (format) {
    case IMGFMT_VAAPI:              entrypoint = VAEntrypointVLD;    break;
    }
    for (int n = 0; n < num_ep; n++) {
        if (ep[n] == entrypoint)
            return entrypoint;
    }
    return -1;
}

// We must allocate only surfaces that were passed to the decoder on creation.
// We achieve this by reserving surfaces in the pool as needed.
// Releasing surfaces is necessary after filling the surface id list so
// that reserved surfaces can be reused for decoding.
static bool preallocate_surfaces(struct lavc_ctx *ctx, int num, int w, int h,
                                 VASurfaceID out_surfaces[MAX_SURFACES])
{
    struct priv *p = ctx->hwdec_priv;
    struct mp_image *reserve[MAX_SURFACES] = {0};
    bool res = true;

    if (num > MAX_SURFACES)
        return false;

    for (int n = 0; n < num; n++) {
        reserve[n] = mp_image_pool_get(p->pool, IMGFMT_VAAPI, w, h);
        out_surfaces[n] = va_surface_id(reserve[n]);
        if (out_surfaces[n] == VA_INVALID_ID) {
            MP_ERR(p, "Could not allocate surfaces.\n");
            res = false;
            break;
        }
    }
    for (int i = 0; i < num; i++)
        talloc_free(reserve[i]);
    return res;
}

static void destroy_decoder(struct lavc_ctx *ctx)
{
    struct priv *p = ctx->hwdec_priv;

    va_lock(p->ctx);

    if (p->va_context->context_id != VA_INVALID_ID) {
        vaDestroyContext(p->display, p->va_context->context_id);
        p->va_context->context_id = VA_INVALID_ID;
    }

    if (p->va_context->config_id != VA_INVALID_ID) {
        vaDestroyConfig(p->display, p->va_context->config_id);
        p->va_context->config_id = VA_INVALID_ID;
    }

    va_unlock(p->ctx);

    mp_image_pool_clear(p->pool);
}

static bool has_profile(VAProfile *va_profiles, int num_profiles, VAProfile p)
{
    for (int i = 0; i < num_profiles; i++) {
        if (va_profiles[i] == p)
            return true;
    }
    return false;
}

static int init_decoder(struct lavc_ctx *ctx, int fmt, int w, int h)
{
    void *tmp = talloc_new(NULL);

    struct priv *p = ctx->hwdec_priv;
    VAStatus status;
    int res = -1;

    destroy_decoder(ctx);

    va_lock(p->ctx);

    const struct hwdec_profile_entry *pe = hwdec_find_profile(ctx, profiles);
    if (!pe) {
        MP_ERR(p, "Unsupported codec or profile.\n");
        goto error;
    }

    int num_profiles = vaMaxNumProfiles(p->display);
    VAProfile *va_profiles = talloc_zero_array(tmp, VAProfile, num_profiles);
    status = vaQueryConfigProfiles(p->display, va_profiles, &num_profiles);
    if (!CHECK_VA_STATUS(p, "vaQueryConfigProfiles()"))
        goto error;
    MP_DBG(p, "%d profiles available:\n", num_profiles);
    for (int i = 0; i < num_profiles; i++)
        MP_DBG(p, "  %s\n", str_va_profile(va_profiles[i]));

    VAProfile va_profile = pe->hw_profile;
    if (!has_profile(va_profiles, num_profiles, va_profile)) {
        MP_ERR(p, "Decoder profile '%s' not available.\n",
               str_va_profile(va_profile));
        goto error;
    }

    MP_VERBOSE(p, "Using profile '%s'.\n", str_va_profile(va_profile));

    int num_surfaces = hwdec_get_max_refs(ctx) + ADDTIONAL_SURFACES;
    if (num_surfaces > MAX_SURFACES) {
        MP_ERR(p, "Internal error: too many surfaces.\n");
        goto error;
    }

    VASurfaceID surfaces[MAX_SURFACES];
    if (!preallocate_surfaces(ctx, num_surfaces, w, h, surfaces)) {
        MP_ERR(p, "Could not allocate surfaces.\n");
        goto error;
    }

    int num_ep = vaMaxNumEntrypoints(p->display);
    VAEntrypoint *ep = talloc_zero_array(tmp, VAEntrypoint, num_ep);
    status = vaQueryConfigEntrypoints(p->display, va_profile, ep, &num_ep);
    if (!CHECK_VA_STATUS(p, "vaQueryConfigEntrypoints()"))
        goto error;

    int entrypoint = find_entrypoint(IMGFMT_VAAPI, ep, num_ep);
    if (entrypoint < 0) {
        MP_ERR(p, "Could not find VA entrypoint.\n");
        goto error;
    }

    VAConfigAttrib attrib = {
        .type = VAConfigAttribRTFormat,
    };
    status = vaGetConfigAttributes(p->display, va_profile, entrypoint,
                                   &attrib, 1);
    if (!CHECK_VA_STATUS(p, "vaGetConfigAttributes()"))
        goto error;
    if ((attrib.value & p->rt_format) == 0) {
        MP_ERR(p, "Chroma format not supported.\n");
        goto error;
    }

    status = vaCreateConfig(p->display, va_profile, entrypoint, &attrib, 1,
                            &p->va_context->config_id);
    if (!CHECK_VA_STATUS(p, "vaCreateConfig()"))
        goto error;

    status = vaCreateContext(p->display, p->va_context->config_id,
                             w, h, VA_PROGRESSIVE,
                             surfaces, num_surfaces,
                             &p->va_context->context_id);
    if (!CHECK_VA_STATUS(p, "vaCreateContext()"))
        goto error;

    res = 0;
error:
    va_unlock(p->ctx);
    talloc_free(tmp);
    return res;
}

static struct mp_image *allocate_image(struct lavc_ctx *ctx, int format,
                                       int w, int h)
{
    struct priv *p = ctx->hwdec_priv;

    struct mp_image *img =
        mp_image_pool_get_no_alloc(p->pool, IMGFMT_VAAPI, w, h);
    if (!img)
        MP_ERR(p, "Insufficient number of surfaces.\n");
    return img;
}

static void destroy_va_dummy_ctx(struct priv *p)
{
    va_destroy(p->ctx);
    p->ctx = NULL;
    p->display = NULL;
    if (p->x11_display)
        XCloseDisplay(p->x11_display);
    p->x11_display = NULL;
}

// Creates a "private" VADisplay, disconnected from the VO. We just create a
// new X connection, because that's simpler. (We could also pass the X
// connection along with struct mp_hwdec_info, if we wanted.)
static bool create_va_dummy_ctx(struct priv *p)
{
    p->x11_display = XOpenDisplay(NULL);
    if (!p->x11_display)
        goto destroy_ctx;
    VADisplay *display = vaGetDisplay(p->x11_display);
    if (!display)
        goto destroy_ctx;
    p->ctx = va_initialize(display, p->log, true);
    if (!p->ctx) {
        vaTerminate(display);
        goto destroy_ctx;
    }
    return true;
destroy_ctx:
    destroy_va_dummy_ctx(p);
    return false;
}

static void uninit(struct lavc_ctx *ctx)
{
    struct priv *p = ctx->hwdec_priv;

    if (!p)
        return;

    destroy_decoder(ctx);

    talloc_free(p->pool);
    p->pool = NULL;

    if (p->x11_display)
        destroy_va_dummy_ctx(p);

    talloc_free(p);
    ctx->hwdec_priv = NULL;
}

static int init_with_vactx(struct lavc_ctx *ctx, struct mp_vaapi_ctx *vactx)
{
    struct priv *p = talloc_ptrtype(NULL, p);
    *p = (struct priv) {
        .log = mp_log_new(p, ctx->log, "vaapi"),
        .ctx = vactx,
        .va_context = &p->va_context_storage,
        .rt_format = VA_RT_FORMAT_YUV420
    };

    if (!p->ctx)
        create_va_dummy_ctx(p);
    if (!p->ctx) {
        talloc_free(p);
        return -1;
    }

    p->display = p->ctx->display;
    p->pool = talloc_steal(p, mp_image_pool_new(MAX_SURFACES));
    va_pool_set_allocator(p->pool, p->ctx, p->rt_format);
    p->sw_pool = talloc_steal(p, mp_image_pool_new(17));

    p->va_context->display = p->display;
    p->va_context->config_id = VA_INVALID_ID;
    p->va_context->context_id = VA_INVALID_ID;

    ctx->avctx->hwaccel_context = p->va_context;
    ctx->hwdec_priv = p;

    return 0;
}

static int init(struct lavc_ctx *ctx)
{
    return init_with_vactx(ctx, ctx->hwdec_info->hwctx->vaapi_ctx);
}

static int probe(struct vd_lavc_hwdec *hwdec, struct mp_hwdec_info *info,
                 const char *decoder)
{
    hwdec_request_api(info, "vaapi");
    if (!info || !info->hwctx || !info->hwctx->vaapi_ctx)
        return HWDEC_ERR_NO_CTX;
    if (!hwdec_check_codec_support(decoder, profiles))
        return HWDEC_ERR_NO_CODEC;
    if (va_guess_if_emulated(info->hwctx->vaapi_ctx))
        return HWDEC_ERR_EMULATED;
    return 0;
}

static int probe_copy(struct vd_lavc_hwdec *hwdec, struct mp_hwdec_info *info,
                      const char *decoder)
{
    struct priv dummy = {mp_null_log};
    if (!create_va_dummy_ctx(&dummy))
        return HWDEC_ERR_NO_CTX;
    bool emulated = va_guess_if_emulated(dummy.ctx);
    destroy_va_dummy_ctx(&dummy);
    if (!hwdec_check_codec_support(decoder, profiles))
        return HWDEC_ERR_NO_CODEC;
    if (emulated)
        return HWDEC_ERR_EMULATED;
    return 0;
}

static int init_copy(struct lavc_ctx *ctx)
{
    return init_with_vactx(ctx, NULL);
}

static struct mp_image *copy_image(struct lavc_ctx *ctx, struct mp_image *img)
{
    struct priv *p = ctx->hwdec_priv;

    struct mp_image *simg = va_surface_download(img, p->sw_pool);
    if (simg) {
        talloc_free(img);
        return simg;
    }
    return img;
}

static void intel_shit_lock(struct lavc_ctx *ctx)
{
    struct priv *p = ctx->hwdec_priv;
    va_lock(p->ctx);
}

static void intel_crap_unlock(struct lavc_ctx *ctx)
{
    struct priv *p = ctx->hwdec_priv;
    va_unlock(p->ctx);
}

const struct vd_lavc_hwdec mp_vd_lavc_vaapi = {
    .type = HWDEC_VAAPI,
    .image_format = IMGFMT_VAAPI,
    .probe = probe,
    .init = init,
    .uninit = uninit,
    .init_decoder = init_decoder,
    .allocate_image = allocate_image,
    .lock = intel_shit_lock,
    .unlock = intel_crap_unlock,
};

const struct vd_lavc_hwdec mp_vd_lavc_vaapi_copy = {
    .type = HWDEC_VAAPI_COPY,
    .image_format = IMGFMT_VAAPI,
    .probe = probe_copy,
    .init = init_copy,
    .uninit = uninit,
    .init_decoder = init_decoder,
    .allocate_image = allocate_image,
    .process_image = copy_image,
};