#include "formats.h"

#include "ra_gl.h"

static struct ra_fns ra_fns_gl;

int ra_init_gl(struct ra *ra, GL *gl)
{
    if (gl->version < 210 && gl->es < 200) {
        MP_ERR(ra, "At least OpenGL 2.1 or OpenGL ES 2.0 required.\n");
        return -1;
    }

    struct ra_gl *p = ra->priv = talloc_zero(NULL, struct ra_gl);
    p->gl = gl;

    ra->fns = &ra_fns_gl;
    ra->caps = 0;
    if (gl->mpgl_caps & MPGL_CAP_1D_TEX)
        ra->caps |= RA_CAP_TEX_1D;
    if (gl->mpgl_caps & MPGL_CAP_3D_TEX)
        ra->caps |= RA_CAP_TEX_3D;
    if (gl->BlitFramebuffer)
        ra->caps |= RA_CAP_BLIT;

    int gl_fmt_features = gl_format_feature_flags(gl);

    // Test whether we can use 10 bit.
    int depth16 = gl_determine_16bit_tex_depth(gl);
    MP_VERBOSE(ra, "16 bit texture depth: %d.\n", depth16);

    for (int n = 0; gl_formats[n].internal_format; n++) {
        const struct gl_format *gl_fmt = &gl_formats[n];

        if (!(gl_fmt->flags & gl_fmt_features))
            continue;

        struct ra_format *fmt = talloc_zero(ra, struct ra_format);
        *fmt = (struct ra_format){
            .name           = gl_fmt->name,
            .priv           = (void *)gl_fmt,
            .ctype          = gl_format_type(gl_fmt),
            .num_components = gl_format_components(gl_fmt->format),
            .pixel_size     = gl_bytes_per_pixel(gl_fmt->format, gl_fmt->type),
            .luminance_alpha = gl_fmt->format == GL_LUMINANCE_ALPHA,
            .linear_filter  = gl_fmt->flags & F_TF,
            .renderable     = (gl_fmt->flags & F_CR) &&
                              (gl->mpgl_caps & MPGL_CAP_FB),
        };

        int csize = gl_component_size(gl_fmt->type) * 8;
        int depth = csize;
        if (fmt->ctype == RA_CTYPE_UNORM)
            depth = MPMIN(csize, depth16); // naive/approximate
        if (gl_fmt->flags & F_F16) {
            depth = 16;
            csize = 32; // always upload as GL_FLOAT (simpler for us)
        }

        for (int i = 0; i < fmt->num_components; i++) {
            fmt->component_size[i] = csize;
            fmt->component_depth[i] = depth;
        }

        // Special formats for which OpenGL happens to have direct support.
        if (strcmp(fmt->name, "rgb565") == 0) {
            fmt->special_imgfmt = IMGFMT_RGB565;
            struct ra_imgfmt_desc *desc = talloc_zero(fmt, struct ra_imgfmt_desc);
            fmt->special_imgfmt_desc = desc;
            desc->num_planes = 1;
            desc->planes[0] = fmt;
            for (int i = 0; i < 3; i++)
                desc->components[0][i] = i + 1;
            desc->chroma_w = desc->chroma_h = 1;
        }
        if (strcmp(fmt->name, "appleyp") == 0) {
            fmt->special_imgfmt = IMGFMT_UYVY;
            struct ra_imgfmt_desc *desc = talloc_zero(fmt, struct ra_imgfmt_desc);
            fmt->special_imgfmt_desc = desc;
            desc->num_planes = 1;
            desc->planes[0] = fmt;
            desc->components[0][0] = 3;
            desc->components[0][1] = 1;
            desc->components[0][2] = 2;
            desc->chroma_w = desc->chroma_h = 1;
        }

        MP_TARRAY_APPEND(ra, ra->formats, ra->num_formats, fmt);
    }

    gl->Disable(GL_DITHER);

    return 0;
}

static void gl_destroy(struct ra *ra)
{
    talloc_free(ra->priv);
}

static void gl_tex_destroy(struct ra *ra, struct ra_tex *tex)
{
    struct ra_gl *p = ra->priv;
    struct ra_tex_gl *tex_gl = tex->priv;

    if (tex_gl->own_objects) {
        if (tex_gl->fbo)
            p->gl->DeleteFramebuffers(1, &tex_gl->fbo);

        p->gl->DeleteTextures(1, &tex_gl->texture);
    }
    gl_pbo_upload_uninit(&tex_gl->pbo);
    talloc_free(tex_gl);
    talloc_free(tex);
}

static struct ra_tex *gl_tex_create(struct ra *ra,
                                    const struct ra_tex_params *params)
{
    struct ra_gl *p = ra->priv;
    GL *gl = p->gl;

    struct ra_tex *tex = talloc_zero(NULL, struct ra_tex);
    tex->params = *params;
    struct ra_tex_gl *tex_gl = tex->priv = talloc_zero(NULL, struct ra_tex_gl);

    const struct gl_format *fmt = params->format->priv;
    tex_gl->own_objects = true;
    tex_gl->internal_format = fmt->internal_format;
    tex_gl->format = fmt->format;
    tex_gl->type = fmt->type;
    switch (params->dimensions) {
    case 1: tex_gl->target = GL_TEXTURE_1D; break;
    case 2: tex_gl->target = GL_TEXTURE_2D; break;
    case 3: tex_gl->target = GL_TEXTURE_3D; break;
    default: abort();
    }
    if (params->non_normalized) {
        assert(params->dimensions == 2);
        tex_gl->target = GL_TEXTURE_RECTANGLE;
    }

    gl->GenTextures(1, &tex_gl->texture);
    gl->BindTexture(tex_gl->target, tex_gl->texture);

    GLint filter = params->src_linear ? GL_LINEAR : GL_NEAREST;
    GLint wrap = params->src_repeat ? GL_REPEAT : GL_CLAMP_TO_EDGE;
    gl->TexParameteri(tex_gl->target, GL_TEXTURE_MIN_FILTER, filter);
    gl->TexParameteri(tex_gl->target, GL_TEXTURE_MAG_FILTER, filter);
    gl->TexParameteri(tex_gl->target, GL_TEXTURE_WRAP_S, wrap);
    if (params->dimensions > 1)
        gl->TexParameteri(tex_gl->target, GL_TEXTURE_WRAP_T, wrap);
    if (params->dimensions > 2)
        gl->TexParameteri(tex_gl->target, GL_TEXTURE_WRAP_R, wrap);

    gl->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
    switch (params->dimensions) {
    case 1:
        gl->TexImage1D(tex_gl->target, 0, tex_gl->internal_format, params->w,
                       0, tex_gl->format, tex_gl->type, params->initial_data);
        break;
    case 2:
        gl->TexImage2D(tex_gl->target, 0, tex_gl->internal_format, params->w,
                       params->h, 0, tex_gl->format, tex_gl->type,
                       params->initial_data);
        break;
    case 3:
        gl->TexImage3D(tex_gl->target, 0, tex_gl->internal_format, params->w,
                       params->h, params->d, 0, tex_gl->format, tex_gl->type,
                       params->initial_data);
        break;
    }
    gl->PixelStorei(GL_UNPACK_ALIGNMENT, 4);

    gl->BindTexture(tex_gl->target, 0);

    tex->params.initial_data = NULL;

    gl_check_error(gl, ra->log, "after creating texture");

    if (tex->params.render_dst) {
        if (!tex->params.format->renderable) {
            MP_ERR(ra, "Trying to create renderable texture with unsupported "
                   "format.\n");
            ra_tex_free(ra, &tex);
            return NULL;
        }

        assert(gl->mpgl_caps & MPGL_CAP_FB);

        gl->GenFramebuffers(1, &tex_gl->fbo);
        gl->BindFramebuffer(GL_FRAMEBUFFER, tex_gl->fbo);
        gl->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                GL_TEXTURE_2D, tex_gl->texture, 0);
        GLenum err = gl->CheckFramebufferStatus(GL_FRAMEBUFFER);
        gl->BindFramebuffer(GL_FRAMEBUFFER, 0);

        if (err != GL_FRAMEBUFFER_COMPLETE) {
            MP_ERR(ra, "Error: framebuffer completeness check failed (error=%d).\n",
                   (int)err);
            ra_tex_free(ra, &tex);
            return NULL;
        }


        gl_check_error(gl, ra->log, "after creating framebuffer");
    }

    return tex;
}

static const struct ra_format fbo_dummy_format = {
    .name = "unknown_fbo",
    .priv = (void *)&(const struct gl_format){
        .name = "unknown",
        .format = GL_RGBA,
        .flags = F_CR,
    },
    .renderable = true,
};

static const struct ra_format tex_dummy_format = {
    .name = "unknown_tex",
    .priv = (void *)&(const struct gl_format){
        .name = "unknown",
        .format = GL_RGBA,
        .flags = F_TF,
    },
    .renderable = true,
    .linear_filter = true,
};

static const struct ra_format *find_similar_format(struct ra *ra,
                                                   GLint gl_iformat,
                                                   GLenum gl_format,
                                                   GLenum gl_type)
{
    if (gl_iformat || gl_format || gl_type) {
        for (int n = 0; n < ra->num_formats; n++) {
            const struct ra_format *fmt = ra->formats[n];
            const struct gl_format *gl_fmt = fmt->priv;
            if ((gl_fmt->internal_format == gl_iformat || !gl_iformat) &&
                (gl_fmt->format == gl_format || !gl_format) &&
                (gl_fmt->type == gl_type || !gl_type))
                return fmt;
        }
    }
    return NULL;
}

static struct ra_tex *wrap_tex_fbo(struct ra *ra, GLuint gl_obj, bool is_fbo,
                                   GLenum gl_target, GLint gl_iformat,
                                   GLenum gl_format, GLenum gl_type,
                                   int w, int h)
{
    const struct ra_format *format =
        find_similar_format(ra, gl_iformat, gl_format, gl_type);
    if (!format)
        format = is_fbo ? &fbo_dummy_format : &tex_dummy_format;

    struct ra_tex *tex = talloc_zero(ra, struct ra_tex);
    *tex = (struct ra_tex){
        .params = {
            .dimensions = 2,
            .w = w, .h = h, .d = 1,
            .format = format,
            .render_dst = is_fbo,
            .render_src = !is_fbo,
            .non_normalized = gl_target == GL_TEXTURE_RECTANGLE,
        },
    };

    struct ra_tex_gl *tex_gl = tex->priv = talloc_zero(NULL, struct ra_tex_gl);
    *tex_gl = (struct ra_tex_gl){
        .target = gl_target,
        .texture = is_fbo ? 0 : gl_obj,
        .fbo = is_fbo ? gl_obj : 0,
        .internal_format = gl_iformat,
        .format = gl_format,
        .type = gl_type,
    };

    return tex;
}

// Create a ra_tex that merely wraps an existing texture. gl_format and gl_type
// can be 0, in which case possibly nonsensical fallbacks are chosen.
// Works for 2D textures only. Integer textures are not supported.
// The returned object is freed with ra_tex_free(), but this will not delete
// the texture passed to this function.
struct ra_tex *ra_create_wrapped_texture(struct ra *ra, GLuint gl_texture,
                                         GLenum gl_target, GLint gl_iformat,
                                         GLenum gl_format, GLenum gl_type,
                                         int w, int h)
{
    return wrap_tex_fbo(ra, gl_texture, false, gl_target, gl_iformat, gl_format,
                        gl_type, w, h);
}

// Create a ra_tex that merely wraps an existing framebuffer. gl_fbo can be 0
// to wrap the default framebuffer.
// The returned object is freed with ra_tex_free(), but this will not delete
// the framebuffer object passed to this function.
struct ra_tex *ra_create_wrapped_fb(struct ra *ra, GLuint gl_fbo, int w, int h)
{
    return wrap_tex_fbo(ra, gl_fbo, true, 0, GL_RGBA, 0, 0, w, h);
}

static void gl_tex_upload(struct ra *ra, struct ra_tex *tex,
                         const void *src, ptrdiff_t stride,
                         struct ra_mapped_buffer *buf)
{
    struct ra_gl *p = ra->priv;
    GL *gl = p->gl;
    struct ra_tex_gl *tex_gl = tex->priv;
    struct ra_mapped_buffer_gl *buf_gl = NULL;

    if (buf) {
        buf_gl = buf->priv;
        gl->BindBuffer(GL_PIXEL_UNPACK_BUFFER, buf_gl->pbo);
        src = (void *)((uintptr_t)src - (uintptr_t)buf->data);
    }

    gl->BindTexture(tex_gl->target, tex_gl->texture);

    switch (tex->params.dimensions) {
    case 1:
        gl->TexImage1D(tex_gl->target, 0, tex_gl->internal_format,
                       tex->params.w, 0, tex_gl->format, tex_gl->type, src);
        break;
    case 2:
        gl_pbo_upload_tex(&tex_gl->pbo, gl, tex->use_pbo && !buf,
                          tex_gl->target, tex_gl->format, tex_gl->type,
                          tex->params.w, tex->params.h, src, stride,
                          0, 0, tex->params.w, tex->params.h);
        break;
    case 3:
        gl->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
        gl->TexImage3D(GL_TEXTURE_3D, 0, tex_gl->internal_format, tex->params.w,
                       tex->params.h, tex->params.d, 0, tex_gl->format,
                       tex_gl->type, src);
        gl->PixelStorei(GL_UNPACK_ALIGNMENT, 4);
        break;
    }

    gl->BindTexture(tex_gl->target, 0);

    if (buf) {
        gl->BindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
        // Make sure the PBO is not reused until GL is done with it. If a
        // previous operation is pending, "update" it by creating a new
        // fence that will cover the previous operation as well.
        gl->DeleteSync(buf_gl->fence);
        buf_gl->fence = gl->FenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
    }
}

static void gl_destroy_mapped_buffer(struct ra *ra, struct ra_mapped_buffer *buf)
{
    struct ra_gl *p = ra->priv;
    GL *gl = p->gl;
    struct ra_mapped_buffer_gl *buf_gl = buf->priv;

    gl->DeleteSync(buf_gl->fence);
    gl->BindBuffer(GL_PIXEL_UNPACK_BUFFER, buf_gl->pbo);
    if (buf->data)
        gl->UnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
    gl->BindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
    gl->DeleteBuffers(1, &buf_gl->pbo);

    talloc_free(buf_gl);
    talloc_free(buf);
}

static struct ra_mapped_buffer *gl_create_mapped_buffer(struct ra *ra,
                                                        size_t size)
{
    struct ra_gl *p = ra->priv;
    GL *gl = p->gl;

    if (gl->version < 440)
        return NULL;

    struct ra_mapped_buffer *buf = talloc_zero(NULL, struct ra_mapped_buffer);
    buf->size = size;

    struct ra_mapped_buffer_gl *buf_gl = buf->priv =
        talloc_zero(NULL, struct ra_mapped_buffer_gl);

    unsigned flags = GL_MAP_READ_BIT | GL_MAP_WRITE_BIT | GL_MAP_PERSISTENT_BIT |
                     GL_MAP_COHERENT_BIT;

    gl->GenBuffers(1, &buf_gl->pbo);
    gl->BindBuffer(GL_PIXEL_UNPACK_BUFFER, buf_gl->pbo);
    gl->BufferStorage(GL_PIXEL_UNPACK_BUFFER, size, NULL, flags | GL_CLIENT_STORAGE_BIT);
    buf->data = gl->MapBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, buf->size, flags);
    gl->BindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
    if (!buf->data) {
        gl_check_error(gl, ra->log, "mapping buffer");
        gl_destroy_mapped_buffer(ra, buf);
        return NULL;
    }

    return buf;
}

static bool gl_poll_mapped_buffer(struct ra *ra, struct ra_mapped_buffer *buf)
{
    struct ra_gl *p = ra->priv;
    GL *gl = p->gl;
    struct ra_mapped_buffer_gl *buf_gl = buf->priv;

    if (buf_gl->fence) {
        GLenum res = gl->ClientWaitSync(buf_gl->fence, 0, 0); // non-blocking
        if (res == GL_ALREADY_SIGNALED) {
            gl->DeleteSync(buf_gl->fence);
            buf_gl->fence = NULL;
        }
    }

    return !buf_gl->fence;
}

static void gl_clear(struct ra *ra, struct ra_tex *dst, float color[4],
                     struct mp_rect *scissor)
{
    struct ra_gl *p = ra->priv;
    GL *gl = p->gl;

    assert(dst->params.render_dst);
    struct ra_tex_gl *dst_gl = dst->priv;

    gl->BindFramebuffer(GL_FRAMEBUFFER, dst_gl->fbo);

    gl->Scissor(scissor->x0, scissor->y0,
                scissor->x1 - scissor->x0,
                scissor->y1 - scissor->y0);

    gl->Enable(GL_SCISSOR_TEST);
    gl->ClearColor(color[0], color[1], color[2], color[3]);
    gl->Clear(GL_COLOR_BUFFER_BIT);
    gl->Disable(GL_SCISSOR_TEST);

    gl->BindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
}

static void gl_blit(struct ra *ra, struct ra_tex *dst, struct ra_tex *src,
                    int dst_x, int dst_y, struct mp_rect *src_rc)
{
    struct ra_gl *p = ra->priv;
    GL *gl = p->gl;

    assert(dst->params.render_dst);
    assert(src->params.render_dst); // even src must have a FBO

    struct ra_tex_gl *src_gl = src->priv;
    struct ra_tex_gl *dst_gl = dst->priv;

    int w = mp_rect_w(*src_rc);
    int h = mp_rect_h(*src_rc);

    gl->BindFramebuffer(GL_READ_FRAMEBUFFER, src_gl->fbo);
    gl->BindFramebuffer(GL_DRAW_FRAMEBUFFER, dst_gl->fbo);
    gl->BlitFramebuffer(src_rc->x0, src_rc->y0, src_rc->x1, src_rc->y1,
                        dst_x, dst_y, dst_x + w, dst_y + h,
                        GL_COLOR_BUFFER_BIT, GL_NEAREST);
    gl->BindFramebuffer(GL_READ_FRAMEBUFFER, 0);
    gl->BindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
}

static struct ra_fns ra_fns_gl = {
    .destroy                = gl_destroy,
    .tex_create             = gl_tex_create,
    .tex_destroy            = gl_tex_destroy,
    .tex_upload             = gl_tex_upload,
    .create_mapped_buffer   = gl_create_mapped_buffer,
    .destroy_mapped_buffer  = gl_destroy_mapped_buffer,
    .poll_mapped_buffer     = gl_poll_mapped_buffer,
    .clear                  = gl_clear,
    .blit                   = gl_blit,
};