/*
 * This file is part of mpv.
 *
 * mpv 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.
 *
 * 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <assert.h>

#include "config.h"

#include "vaapi.h"
#include "common/common.h"
#include "common/msg.h"
#include "osdep/threads.h"
#include "mp_image.h"
#include "img_format.h"
#include "mp_image_pool.h"

#include <libavutil/hwcontext.h>
#include <libavutil/hwcontext_vaapi.h>

int va_get_colorspace_flag(enum mp_csp csp)
{
    switch (csp) {
    case MP_CSP_BT_601:         return VA_SRC_BT601;
    case MP_CSP_BT_709:         return VA_SRC_BT709;
    case MP_CSP_SMPTE_240M:     return VA_SRC_SMPTE_240;
    }
    return 0;
}

// VA message callbacks are global and do not have a context parameter, so it's
// impossible to know from which VADisplay they originate. Try to route them
// to existing mpv/libmpv instances within this process.
static pthread_mutex_t va_log_mutex = PTHREAD_MUTEX_INITIALIZER;
static struct mp_vaapi_ctx **va_mpv_clients;
static int num_va_mpv_clients;

static void va_message_callback(const char *msg, int mp_level)
{
    pthread_mutex_lock(&va_log_mutex);

    if (num_va_mpv_clients) {
        struct mp_log *dst = va_mpv_clients[num_va_mpv_clients - 1]->log;
        mp_msg(dst, mp_level, "libva: %s", msg);
    } else {
        // We can't get or call the original libva handler (vaSet... return
        // them, but it might be from some other lib etc.). So just do what
        // libva happened to do at the time of this writing.
        if (mp_level <= MSGL_ERR) {
            fprintf(stderr, "libva error: %s", msg);
        } else {
            fprintf(stderr, "libva info: %s", msg);
        }
    }

    pthread_mutex_unlock(&va_log_mutex);
}

static void va_error_callback(const char *msg)
{
    va_message_callback(msg, MSGL_ERR);
}

static void va_info_callback(const char *msg)
{
    va_message_callback(msg, MSGL_V);
}

static void open_lavu_vaapi_device(struct mp_vaapi_ctx *ctx)
{
    ctx->av_device_ref = av_hwdevice_ctx_alloc(AV_HWDEVICE_TYPE_VAAPI);
    if (!ctx->av_device_ref)
        return;

    AVHWDeviceContext *hwctx = (void *)ctx->av_device_ref->data;
    AVVAAPIDeviceContext *vactx = hwctx->hwctx;

    vactx->display = ctx->display;

    if (av_hwdevice_ctx_init(ctx->av_device_ref) < 0)
        av_buffer_unref(&ctx->av_device_ref);

    ctx->hwctx.av_device_ref = ctx->av_device_ref;
}

struct mp_vaapi_ctx *va_initialize(VADisplay *display, struct mp_log *plog,
                                   bool probing)
{
    struct mp_vaapi_ctx *res = talloc_ptrtype(NULL, res);
    *res = (struct mp_vaapi_ctx) {
        .log = mp_log_new(res, plog, "/vaapi"),
        .display = display,
        .hwctx = {
            .type = HWDEC_VAAPI,
            .ctx = res,
        },
    };

    pthread_mutex_lock(&va_log_mutex);
    MP_TARRAY_APPEND(NULL, va_mpv_clients, num_va_mpv_clients, res);
    pthread_mutex_unlock(&va_log_mutex);

    // Check some random symbol added after message callbacks.
    // VA_MICRO_VERSION wasn't bumped at the time.
#ifdef VA_FOURCC_I010
    vaSetErrorCallback(va_error_callback);
    vaSetInfoCallback(va_info_callback);
#endif

    int major, minor;
    int status = vaInitialize(display, &major, &minor);
    if (status != VA_STATUS_SUCCESS) {
        if (!probing)
            MP_ERR(res, "Failed to initialize VAAPI: %s\n", vaErrorStr(status));
        goto error;
    }
    MP_VERBOSE(res, "Initialized VAAPI: version %d.%d\n", major, minor);

    // For now, some code will still work even if libavutil fails on old crap
    // libva drivers (such as the vdpau wraper). So don't error out on failure.
    open_lavu_vaapi_device(res);

    res->hwctx.emulated = va_guess_if_emulated(res);

    return res;

error:
    res->display = NULL; // do not vaTerminate this
    va_destroy(res);
    return NULL;
}

// Undo va_initialize, and close the VADisplay.
void va_destroy(struct mp_vaapi_ctx *ctx)
{
    if (ctx) {
        av_buffer_unref(&ctx->av_device_ref);

        if (ctx->display)
            vaTerminate(ctx->display);

        if (ctx->destroy_native_ctx)
            ctx->destroy_native_ctx(ctx->native_ctx);

        pthread_mutex_lock(&va_log_mutex);
        for (int n = 0; n < num_va_mpv_clients; n++) {
            if (va_mpv_clients[n] == ctx) {
                MP_TARRAY_REMOVE_AT(va_mpv_clients, num_va_mpv_clients, n);
                break;
            }
        }
        if (num_va_mpv_clients == 0)
            TA_FREEP(&va_mpv_clients); // avoid triggering leak detectors
        pthread_mutex_unlock(&va_log_mutex);

        talloc_free(ctx);
    }
}

VASurfaceID va_surface_id(struct mp_image *mpi)
{
    return mpi && mpi->imgfmt == IMGFMT_VAAPI ?
        (VASurfaceID)(uintptr_t)mpi->planes[3] : VA_INVALID_ID;
}

bool va_guess_if_emulated(struct mp_vaapi_ctx *ctx)
{
    const char *s = vaQueryVendorString(ctx->display);
    return s && strstr(s, "VDPAU backend");
}

struct va_native_display {
    void (*create)(VADisplay **out_display, void **out_native_ctx);
    void (*destroy)(void *native_ctx);
};

#if HAVE_VAAPI_X11
#include <X11/Xlib.h>
#include <va/va_x11.h>

static void x11_destroy(void *native_ctx)
{
    XCloseDisplay(native_ctx);
}

static void x11_create(VADisplay **out_display, void **out_native_ctx)
{
    void *native_display = XOpenDisplay(NULL);
    if (!native_display)
        return;
    *out_display = vaGetDisplay(native_display);
    if (*out_display) {
        *out_native_ctx = native_display;
    } else {
        XCloseDisplay(native_display);
    }
}

static const struct va_native_display disp_x11 = {
    .create = x11_create,
    .destroy = x11_destroy,
};
#endif

#if HAVE_VAAPI_DRM
#include <unistd.h>
#include <fcntl.h>
#include <va/va_drm.h>

struct va_native_display_drm {
    int drm_fd;
};

static void drm_destroy(void *native_ctx)
{
    struct va_native_display_drm *ctx = native_ctx;
    close(ctx->drm_fd);
    talloc_free(ctx);
}

static void drm_create(VADisplay **out_display, void **out_native_ctx)
{
    static const char *drm_device_paths[] = {
        "/dev/dri/renderD128",
        "/dev/dri/card0",
        NULL
    };

    for (int i = 0; drm_device_paths[i]; i++) {
        int drm_fd = open(drm_device_paths[i], O_RDWR);
        if (drm_fd < 0)
            continue;

        struct va_native_display_drm *ctx = talloc_ptrtype(NULL, ctx);
        ctx->drm_fd = drm_fd;
        *out_display = vaGetDisplayDRM(drm_fd);
        if (out_display) {
            *out_native_ctx = ctx;
            return;
        }

        close(drm_fd);
        talloc_free(ctx);
    }
}

static const struct va_native_display disp_drm = {
    .create = drm_create,
    .destroy = drm_destroy,
};
#endif

static const struct va_native_display *const native_displays[] = {
#if HAVE_VAAPI_DRM
    &disp_drm,
#endif
#if HAVE_VAAPI_X11
    &disp_x11,
#endif
    NULL
};

static void va_destroy_ctx(struct mp_hwdec_ctx *ctx)
{
    va_destroy(ctx->ctx);
}

struct mp_hwdec_ctx *va_create_standalone(struct mpv_global *global,
                                          struct mp_log *plog, bool probing)
{
    for (int n = 0; native_displays[n]; n++) {
        VADisplay *display = NULL;
        void *native_ctx = NULL;
        native_displays[n]->create(&display, &native_ctx);
        if (display) {
            struct mp_vaapi_ctx *ctx = va_initialize(display, plog, probing);
            if (!ctx) {
                vaTerminate(display);
                native_displays[n]->destroy(native_ctx);
                return NULL;
            }
            ctx->native_ctx = native_ctx;
            ctx->destroy_native_ctx = native_displays[n]->destroy;
            ctx->hwctx.destroy = va_destroy_ctx;
            return &ctx->hwctx;
        }
    }
    return NULL;
}