/*
 * 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 <windows.h>
#include <EGL/egl.h>
#include <EGL/eglext.h>

#include "common/common.h"
#include "osdep/timer.h"
#include "osdep/windows_utils.h"
#include "hwdec.h"
#include "video/dxva2.h"
#include "video/d3d.h"
#include "video/hwdec.h"

struct priv {
    struct mp_d3d_ctx ctx;

    HMODULE             d3d9_dll;
    IDirect3D9Ex       *d3d9ex;
    IDirect3DDevice9Ex *device9ex;
    IDirect3DQuery9    *query9;
    IDirect3DTexture9  *texture9;
    IDirect3DSurface9  *surface9;

    EGLDisplay egl_display;
    EGLConfig  egl_config;
    EGLint     alpha;
    EGLSurface egl_surface;

    GLuint gl_texture;
};

static void destroy_textures(struct gl_hwdec *hw)
{
    struct priv *p = hw->priv;
    GL *gl = hw->gl;

    gl->DeleteTextures(1, &p->gl_texture);
    p->gl_texture = 0;

    if (p->egl_display && p->egl_surface) {
        eglReleaseTexImage(p->egl_display, p->egl_surface, EGL_BACK_BUFFER);
        eglDestroySurface(p->egl_display, p->egl_surface);
        p->egl_surface = NULL;
    }

    if (p->surface9) {
        IDirect3DSurface9_Release(p->surface9);
        p->surface9 = NULL;
    }

    if (p->texture9) {
        IDirect3DTexture9_Release(p->texture9);
        p->texture9 = NULL;
    }
}

static void destroy(struct gl_hwdec *hw)
{
    struct priv *p = hw->priv;

    destroy_textures(hw);

    if (p->query9)
        IDirect3DQuery9_Release(p->query9);

    if (p->device9ex)
        IDirect3DDevice9Ex_Release(p->device9ex);

    if (p->d3d9ex)
        IDirect3D9Ex_Release(p->d3d9ex);

    if (p->d3d9_dll)
        FreeLibrary(p->d3d9_dll);
}

static int create(struct gl_hwdec *hw)
{
    if (hw->hwctx)
        return -1;

    EGLDisplay egl_display = eglGetCurrentDisplay();
    if (!egl_display)
        return -1;

    const char *exts = eglQueryString(egl_display, EGL_EXTENSIONS);
    if (!exts ||
        !strstr(exts, "EGL_ANGLE_d3d_share_handle_client_buffer")) {
        return -1;
    }

    HRESULT hr;
    struct priv *p = talloc_zero(hw, struct priv);
    hw->priv = p;

    p->egl_display = egl_display;

    p->d3d9_dll = LoadLibraryW(L"d3d9.dll");
    if (!p->d3d9_dll) {
        MP_FATAL(hw, "Failed to load \"d3d9.dll\": %s\n",
                 mp_LastError_to_str());
        goto fail;
    }

    HRESULT (WINAPI *Direct3DCreate9Ex)(UINT SDKVersion, IDirect3D9Ex **ppD3D);
    Direct3DCreate9Ex = (void *)GetProcAddress(p->d3d9_dll, "Direct3DCreate9Ex");
    if (!Direct3DCreate9Ex) {
        MP_FATAL(hw, "Direct3D 9Ex not supported\n");
        goto fail;
    }

    hr = Direct3DCreate9Ex(D3D_SDK_VERSION, &p->d3d9ex);
    if (FAILED(hr)) {
        MP_FATAL(hw, "Couldn't create Direct3D9Ex: %s\n",
                 mp_HRESULT_to_str(hr));
        goto fail;
    }

    // We must create our own Direct3D9Ex device. ANGLE can give us the device
    // it's using, but that's probably a ID3D11Device.
    // (copied from chromium dxva_video_decode_accelerator_win.cc)
    D3DPRESENT_PARAMETERS present_params = {
        .BackBufferWidth = 1,
        .BackBufferHeight = 1,
        .BackBufferFormat = D3DFMT_UNKNOWN,
        .BackBufferCount = 1,
        .SwapEffect = D3DSWAPEFFECT_DISCARD,
        .hDeviceWindow = NULL,
        .Windowed = TRUE,
        .Flags = D3DPRESENTFLAG_VIDEO,
        .FullScreen_RefreshRateInHz = 0,
        .PresentationInterval = 0,
    };
    hr = IDirect3D9Ex_CreateDeviceEx(p->d3d9ex,
                                     D3DADAPTER_DEFAULT,
                                     D3DDEVTYPE_HAL,
                                     NULL,
                                     D3DCREATE_FPU_PRESERVE |
                                     D3DCREATE_HARDWARE_VERTEXPROCESSING |
                                     D3DCREATE_DISABLE_PSGP_THREADING |
                                     D3DCREATE_MULTITHREADED,
                                     &present_params,
                                     NULL,
                                     &p->device9ex);
    if (FAILED(hr)) {
        MP_FATAL(hw, "Failed to create Direct3D9Ex device: %s\n",
                 mp_HRESULT_to_str(hr));
        goto fail;
    }

    hr = IDirect3DDevice9_CreateQuery(p->device9ex, D3DQUERYTYPE_EVENT,
                                      &p->query9);
    if (FAILED(hr)) {
        MP_FATAL(hw, "Failed to create Direct3D query interface: %s\n",
                 mp_HRESULT_to_str(hr));
        goto fail;
    }

    // Test the query API
    hr = IDirect3DQuery9_Issue(p->query9, D3DISSUE_END);
    if (FAILED(hr)) {
        MP_FATAL(hw, "Failed to issue Direct3D END test query: %s\n",
                 mp_HRESULT_to_str(hr));
        goto fail;
    }

    EGLint attrs[] = {
        EGL_BUFFER_SIZE, 32,
        EGL_RED_SIZE, 8,
        EGL_GREEN_SIZE, 8,
        EGL_BLUE_SIZE, 8,
        EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
        EGL_ALPHA_SIZE, 0,
        EGL_NONE
    };
    EGLint count;
    if (!eglChooseConfig(p->egl_display, attrs, &p->egl_config, 1, &count) ||
        !count) {
        MP_ERR(hw, "Failed to get EGL surface configuration\n");
        goto fail;
    }

    if (!eglGetConfigAttrib(p->egl_display, p->egl_config,
                            EGL_BIND_TO_TEXTURE_RGBA, &p->alpha)) {
        MP_FATAL(hw, "Failed to query EGL surface alpha\n");
        goto fail;
    }

    hw->converted_imgfmt = IMGFMT_RGB0;

    p->ctx.d3d9_device = (IDirect3DDevice9 *)p->device9ex;
    p->ctx.hwctx.type = HWDEC_DXVA2;
    p->ctx.hwctx.d3d_ctx = &p->ctx;

    hw->hwctx = &p->ctx.hwctx;
    return 0;
fail:
    destroy(hw);
    return -1;
}

static int reinit(struct gl_hwdec *hw, struct mp_image_params *params)
{
    struct priv *p = hw->priv;
    GL *gl = hw->gl;
    HRESULT hr;

    destroy_textures(hw);

    assert(params->imgfmt == hw->driver->imgfmt);

    HANDLE share_handle = NULL;
    hr = IDirect3DDevice9Ex_CreateTexture(p->device9ex,
                                          params->w, params->h,
                                          1, D3DUSAGE_RENDERTARGET,
                                          p->alpha ?  D3DFMT_A8R8G8B8 : D3DFMT_X8R8G8B8,
                                          D3DPOOL_DEFAULT,
                                          &p->texture9,
                                          &share_handle);
    if (FAILED(hr)) {
        MP_ERR(hw, "Failed to create Direct3D9 texture: %s\n",
               mp_HRESULT_to_str(hr));
        goto fail;
    }

    hr = IDirect3DTexture9_GetSurfaceLevel(p->texture9, 0, &p->surface9);
    if (FAILED(hr)) {
        MP_ERR(hw, "Failed to get Direct3D9 surface from texture: %s\n",
               mp_HRESULT_to_str(hr));
        goto fail;
    }

    EGLint attrib_list[] = {
        EGL_WIDTH, params->w,
        EGL_HEIGHT, params->h,
        EGL_TEXTURE_FORMAT, p->alpha ? EGL_TEXTURE_RGBA : EGL_TEXTURE_RGB,
        EGL_TEXTURE_TARGET, EGL_TEXTURE_2D,
        EGL_NONE
    };
    p->egl_surface = eglCreatePbufferFromClientBuffer(
        p->egl_display, EGL_D3D_TEXTURE_2D_SHARE_HANDLE_ANGLE,
        share_handle, p->egl_config, attrib_list);
    if (p->egl_surface == EGL_NO_SURFACE) {
        MP_ERR(hw, "Failed to create EGL surface\n");
        goto fail;
    }

    gl->GenTextures(1, &p->gl_texture);
    gl->BindTexture(GL_TEXTURE_2D, p->gl_texture);
    gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    gl->BindTexture(GL_TEXTURE_2D, 0);

    return 0;
fail:
    destroy_textures(hw);
    return -1;
}

static int map_image(struct gl_hwdec *hw, struct mp_image *hw_image,
                     GLuint *out_textures)
{
    struct priv *p = hw->priv;
    GL *gl = hw->gl;
    if (!p->surface9 || !p->egl_surface || !p->gl_texture)
        return -1;

    HRESULT hr;
    RECT rc = {0, 0, hw_image->w, hw_image->h};
    IDirect3DSurface9* hw_surface = d3d9_surface_in_mp_image(hw_image);
    hr = IDirect3DDevice9Ex_StretchRect(p->device9ex,
                                        hw_surface, &rc,
                                        p->surface9, &rc,
                                        D3DTEXF_NONE);
    if (FAILED(hr)) {
        MP_ERR(hw, "Direct3D RGB conversion failed: %s\n",
               mp_HRESULT_to_str(hr));
        return -1;
    }

    hr = IDirect3DQuery9_Issue(p->query9, D3DISSUE_END);
    if (FAILED(hr)) {
        MP_ERR(hw, "Failed to issue Direct3D END query\n");
        return -1;
    }

    // There doesn't appear to be an efficient way to do a blocking flush
    // of the above StretchRect. Timeout of 8ms is required to reliably
    // render 4k on Intel Haswell, Ivybridge and Cherry Trail Atom.
    const int max_retries = 8;
    const int64_t wait_us = 1000;
    int retries = 0;
    while (true) {
        hr = IDirect3DQuery9_GetData(p->query9, NULL, 0, D3DGETDATA_FLUSH);
        if (FAILED(hr)) {
            MP_ERR(hw, "Failed to query Direct3D flush state\n");
            return -1;
        } else if (hr == S_FALSE) {
            if (++retries > max_retries) {
                MP_VERBOSE(hw, "Failed to flush frame after %lld ms\n",
                           (long long)(wait_us * max_retries) / 1000);
                break;
            }
            mp_sleep_us(wait_us);
        } else {
            break;
        }
    }

    gl->BindTexture(GL_TEXTURE_2D, p->gl_texture);
    eglBindTexImage(p->egl_display, p->egl_surface, EGL_BACK_BUFFER);
    gl->BindTexture(GL_TEXTURE_2D, 0);

    out_textures[0] = p->gl_texture;
    return 0;
}

const struct gl_hwdec_driver gl_hwdec_dxva2egl = {
    .name = "dxva2-egl",
    .api = HWDEC_DXVA2,
    .imgfmt = IMGFMT_DXVA2,
    .create = create,
    .reinit = reinit,
    .map_image = map_image,
    .destroy = destroy,
};