/*
 * Copyright (C) 2015-2016 Gerd Hoffmann <kraxel@redhat.com>
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */
#include "qemu/osdep.h"
#include <glob.h>
#include <dirent.h>

#include "qemu/error-report.h"
#include "ui/egl-helpers.h"

EGLDisplay *qemu_egl_display;
EGLConfig qemu_egl_config;

/* ------------------------------------------------------------------ */

static void egl_fb_delete_texture(egl_fb *fb)
{
    if (!fb->delete_texture) {
        return;
    }

    glDeleteTextures(1, &fb->texture);
    fb->delete_texture = false;
}

void egl_fb_destroy(egl_fb *fb)
{
    if (!fb->framebuffer) {
        return;
    }

    egl_fb_delete_texture(fb);
    glDeleteFramebuffers(1, &fb->framebuffer);

    fb->width = 0;
    fb->height = 0;
    fb->texture = 0;
    fb->framebuffer = 0;
}

void egl_fb_setup_default(egl_fb *fb, int width, int height)
{
    fb->width = width;
    fb->height = height;
    fb->framebuffer = 0; /* default framebuffer */
}

void egl_fb_setup_for_tex(egl_fb *fb, int width, int height,
                          GLuint texture, bool delete)
{
    egl_fb_delete_texture(fb);

    fb->width = width;
    fb->height = height;
    fb->texture = texture;
    fb->delete_texture = delete;
    if (!fb->framebuffer) {
        glGenFramebuffers(1, &fb->framebuffer);
    }

    glBindFramebuffer(GL_FRAMEBUFFER_EXT, fb->framebuffer);
    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                              GL_TEXTURE_2D, fb->texture, 0);
}

void egl_fb_setup_new_tex(egl_fb *fb, int width, int height)
{
    GLuint texture;

    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height,
                 0, GL_BGRA, GL_UNSIGNED_BYTE, 0);

    egl_fb_setup_for_tex(fb, width, height, texture, true);
}

void egl_fb_blit(egl_fb *dst, egl_fb *src, bool flip)
{
    GLuint y1, y2;

    glBindFramebuffer(GL_READ_FRAMEBUFFER, src->framebuffer);
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, dst->framebuffer);
    glViewport(0, 0, dst->width, dst->height);
    y1 = flip ? src->height : 0;
    y2 = flip ? 0 : src->height;
    glBlitFramebuffer(0, y1, src->width, y2,
                      0, 0, dst->width, dst->height,
                      GL_COLOR_BUFFER_BIT, GL_LINEAR);
}

void egl_fb_read(void *dst, egl_fb *src)
{
    glBindFramebuffer(GL_READ_FRAMEBUFFER, src->framebuffer);
    glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
    glReadPixels(0, 0, src->width, src->height,
                 GL_BGRA, GL_UNSIGNED_BYTE, dst);
}

/* ---------------------------------------------------------------------- */

#ifdef CONFIG_OPENGL_DMABUF

int qemu_egl_rn_fd;
struct gbm_device *qemu_egl_rn_gbm_dev;
EGLContext qemu_egl_rn_ctx;

static int qemu_egl_rendernode_open(const char *rendernode)
{
    DIR *dir;
    struct dirent *e;
    int r, fd;
    char *p;

    if (rendernode) {
        return open(rendernode, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
    }

    dir = opendir("/dev/dri");
    if (!dir) {
        return -1;
    }

    fd = -1;
    while ((e = readdir(dir))) {
        if (e->d_type != DT_CHR) {
            continue;
        }

        if (strncmp(e->d_name, "renderD", 7)) {
            continue;
        }

        p = g_strdup_printf("/dev/dri/%s", e->d_name);

        r = open(p, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
        if (r < 0) {
            g_free(p);
            continue;
        }
        fd = r;
        g_free(p);
        break;
    }

    closedir(dir);
    if (fd < 0) {
        return -1;
    }
    return fd;
}

int egl_rendernode_init(const char *rendernode)
{
    qemu_egl_rn_fd = -1;
    int rc;

    qemu_egl_rn_fd = qemu_egl_rendernode_open(rendernode);
    if (qemu_egl_rn_fd == -1) {
        error_report("egl: no drm render node available");
        goto err;
    }

    qemu_egl_rn_gbm_dev = gbm_create_device(qemu_egl_rn_fd);
    if (!qemu_egl_rn_gbm_dev) {
        error_report("egl: gbm_create_device failed");
        goto err;
    }

    rc = qemu_egl_init_dpy_mesa((EGLNativeDisplayType)qemu_egl_rn_gbm_dev);
    if (rc != 0) {
        /* qemu_egl_init_dpy_mesa reports error */
        goto err;
    }

    if (!epoxy_has_egl_extension(qemu_egl_display,
                                 "EGL_KHR_surfaceless_context")) {
        error_report("egl: EGL_KHR_surfaceless_context not supported");
        goto err;
    }
    if (!epoxy_has_egl_extension(qemu_egl_display,
                                 "EGL_MESA_image_dma_buf_export")) {
        error_report("egl: EGL_MESA_image_dma_buf_export not supported");
        goto err;
    }

    qemu_egl_rn_ctx = qemu_egl_init_ctx();
    if (!qemu_egl_rn_ctx) {
        error_report("egl: egl_init_ctx failed");
        goto err;
    }

    return 0;

err:
    if (qemu_egl_rn_gbm_dev) {
        gbm_device_destroy(qemu_egl_rn_gbm_dev);
    }
    if (qemu_egl_rn_fd != -1) {
        close(qemu_egl_rn_fd);
    }

    return -1;
}

int egl_get_fd_for_texture(uint32_t tex_id, EGLint *stride, EGLint *fourcc)
{
    EGLImageKHR image;
    EGLint num_planes, fd;

    image = eglCreateImageKHR(qemu_egl_display, eglGetCurrentContext(),
                              EGL_GL_TEXTURE_2D_KHR,
                              (EGLClientBuffer)(unsigned long)tex_id,
                              NULL);
    if (!image) {
        return -1;
    }

    eglExportDMABUFImageQueryMESA(qemu_egl_display, image, fourcc,
                                  &num_planes, NULL);
    if (num_planes != 1) {
        eglDestroyImageKHR(qemu_egl_display, image);
        return -1;
    }
    eglExportDMABUFImageMESA(qemu_egl_display, image, &fd, stride, NULL);
    eglDestroyImageKHR(qemu_egl_display, image);

    return fd;
}

#endif /* CONFIG_OPENGL_DMABUF */

/* ---------------------------------------------------------------------- */

EGLSurface qemu_egl_init_surface_x11(EGLContext ectx, Window win)
{
    EGLSurface esurface;
    EGLBoolean b;

    esurface = eglCreateWindowSurface(qemu_egl_display,
                                      qemu_egl_config,
                                      (EGLNativeWindowType)win, NULL);
    if (esurface == EGL_NO_SURFACE) {
        error_report("egl: eglCreateWindowSurface failed");
        return NULL;
    }

    b = eglMakeCurrent(qemu_egl_display, esurface, esurface, ectx);
    if (b == EGL_FALSE) {
        error_report("egl: eglMakeCurrent failed");
        return NULL;
    }

    return esurface;
}

/* ---------------------------------------------------------------------- */

/*
 * Taken from glamor_egl.h from the Xorg xserver, which is MIT licensed
 *
 * Create an EGLDisplay from a native display type. This is a little quirky
 * for a few reasons.
 *
 * 1: GetPlatformDisplayEXT and GetPlatformDisplay are the API you want to
 * use, but have different function signatures in the third argument; this
 * happens not to matter for us, at the moment, but it means epoxy won't alias
 * them together.
 *
 * 2: epoxy 1.3 and earlier don't understand EGL client extensions, which
 * means you can't call "eglGetPlatformDisplayEXT" directly, as the resolver
 * will crash.
 *
 * 3: You can't tell whether you have EGL 1.5 at this point, because
 * eglQueryString(EGL_VERSION) is a property of the display, which we don't
 * have yet. So you have to query for extensions no matter what. Fortunately
 * epoxy_has_egl_extension _does_ let you query for client extensions, so
 * we don't have to write our own extension string parsing.
 *
 * 4. There is no EGL_KHR_platform_base to complement the EXT one, thus one
 * needs to know EGL 1.5 is supported in order to use the eglGetPlatformDisplay
 * function pointer.
 * We can workaround this (circular dependency) by probing for the EGL 1.5
 * platform extensions (EGL_KHR_platform_gbm and friends) yet it doesn't seem
 * like mesa will be able to advertise these (even though it can do EGL 1.5).
 */
static EGLDisplay qemu_egl_get_display(EGLNativeDisplayType native,
                                       EGLenum platform)
{
    EGLDisplay dpy = EGL_NO_DISPLAY;

    /* In practise any EGL 1.5 implementation would support the EXT extension */
    if (epoxy_has_egl_extension(NULL, "EGL_EXT_platform_base")) {
        PFNEGLGETPLATFORMDISPLAYEXTPROC getPlatformDisplayEXT =
            (void *) eglGetProcAddress("eglGetPlatformDisplayEXT");
        if (getPlatformDisplayEXT && platform != 0) {
            dpy = getPlatformDisplayEXT(platform, native, NULL);
        }
    }

    if (dpy == EGL_NO_DISPLAY) {
        /* fallback */
        dpy = eglGetDisplay(native);
    }
    return dpy;
}

static int qemu_egl_init_dpy(EGLNativeDisplayType dpy,
                             EGLenum platform)
{
    static const EGLint conf_att_gl[] = {
        EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
        EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,
        EGL_RED_SIZE,   5,
        EGL_GREEN_SIZE, 5,
        EGL_BLUE_SIZE,  5,
        EGL_ALPHA_SIZE, 0,
        EGL_NONE,
    };
    EGLint major, minor;
    EGLBoolean b;
    EGLint n;

    qemu_egl_display = qemu_egl_get_display(dpy, platform);
    if (qemu_egl_display == EGL_NO_DISPLAY) {
        error_report("egl: eglGetDisplay failed");
        return -1;
    }

    b = eglInitialize(qemu_egl_display, &major, &minor);
    if (b == EGL_FALSE) {
        error_report("egl: eglInitialize failed");
        return -1;
    }

    b = eglBindAPI(EGL_OPENGL_API);
    if (b == EGL_FALSE) {
        error_report("egl: eglBindAPI failed");
        return -1;
    }

    b = eglChooseConfig(qemu_egl_display, conf_att_gl,
                        &qemu_egl_config, 1, &n);
    if (b == EGL_FALSE || n != 1) {
        error_report("egl: eglChooseConfig failed");
        return -1;
    }
    return 0;
}

int qemu_egl_init_dpy_x11(EGLNativeDisplayType dpy)
{
#ifdef EGL_KHR_platform_x11
    return qemu_egl_init_dpy(dpy, EGL_PLATFORM_X11_KHR);
#else
    return qemu_egl_init_dpy(dpy, 0);
#endif
}

int qemu_egl_init_dpy_mesa(EGLNativeDisplayType dpy)
{
#ifdef EGL_MESA_platform_gbm
    return qemu_egl_init_dpy(dpy, EGL_PLATFORM_GBM_MESA);
#else
    return qemu_egl_init_dpy(dpy, 0);
#endif
}

EGLContext qemu_egl_init_ctx(void)
{
    static const EGLint ctx_att_gl[] = {
        EGL_CONTEXT_OPENGL_PROFILE_MASK, EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT,
        EGL_NONE
    };
    EGLContext ectx;
    EGLBoolean b;

    ectx = eglCreateContext(qemu_egl_display, qemu_egl_config, EGL_NO_CONTEXT,
                            ctx_att_gl);
    if (ectx == EGL_NO_CONTEXT) {
        error_report("egl: eglCreateContext failed");
        return NULL;
    }

    b = eglMakeCurrent(qemu_egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE, ectx);
    if (b == EGL_FALSE) {
        error_report("egl: eglMakeCurrent failed");
        return NULL;
    }

    return ectx;
}
