#include "gles2_debayer.h"

#include "camera.h"
#include "gl_util.h"
#include <stdlib.h>

#define VERTEX_ATTRIBUTE 0
#define TEX_COORD_ATTRIBUTE 1

struct _GLES2Debayer {
        int format;

        GLuint frame_buffer;
        GLuint program;
        GLuint uniform_transform;
        GLuint uniform_pixel_size;
        GLuint uniform_padding_ratio;
        GLuint uniform_texture;
        GLuint uniform_color_matrix;
        GLuint uniform_row_length;

        GLuint quad;
};

GLES2Debayer *
gles2_debayer_new(int format)
{
        uint32_t pixfmt = libmegapixels_format_to_v4l_pixfmt(format);
        if (pixfmt != V4L2_PIX_FMT_SBGGR8 && pixfmt != V4L2_PIX_FMT_SGBRG8 &&
            pixfmt != V4L2_PIX_FMT_SGRBG8 && pixfmt != V4L2_PIX_FMT_SRGGB8 &&
            pixfmt != V4L2_PIX_FMT_SBGGR10P && pixfmt != V4L2_PIX_FMT_SGBRG10P &&
            pixfmt != V4L2_PIX_FMT_SGRBG10P && pixfmt != V4L2_PIX_FMT_SRGGB10P) {
                return NULL;
        }

        GLuint frame_buffer;
        glGenFramebuffers(1, &frame_buffer);
        check_gl();

        char format_def[64];
        snprintf(format_def,
                 64,
                 "#define CFA_%s\n#define BITS_%d\n",
                 libmegapixels_format_cfa_pattern(format),
                 libmegapixels_format_bits_per_pixel(format));

        const GLchar *def[1] = { format_def };

        GLuint shaders[] = {
                gl_util_load_shader("/org/postmarketos/Megapixels/debayer.vert",
                                    GL_VERTEX_SHADER,
                                    NULL,
                                    0),
                gl_util_load_shader("/org/postmarketos/Megapixels/debayer.frag",
                                    GL_FRAGMENT_SHADER,
                                    def,
                                    1),
        };

        GLuint program = gl_util_link_program(shaders, 2);
        glBindAttribLocation(program, VERTEX_ATTRIBUTE, "vert");
        glBindAttribLocation(program, TEX_COORD_ATTRIBUTE, "tex_coord");
        check_gl();

        GLES2Debayer *self = malloc(sizeof(GLES2Debayer));
        self->format = format;

        self->frame_buffer = frame_buffer;
        self->program = program;

        self->uniform_transform = glGetUniformLocation(self->program, "transform");
        self->uniform_pixel_size = glGetUniformLocation(self->program, "pixel_size");
        self->uniform_padding_ratio =
                glGetUniformLocation(self->program, "padding_ratio");
        self->uniform_texture = glGetUniformLocation(self->program, "texture");
        self->uniform_color_matrix =
                glGetUniformLocation(self->program, "color_matrix");
        if (libmegapixels_format_bits_per_pixel(self->format) == 10)
                self->uniform_row_length =
                        glGetUniformLocation(self->program, "row_length");
        check_gl();

        self->quad = gl_util_new_quad();

        return self;
}

void
gles2_debayer_free(GLES2Debayer *self)
{
        glDeleteFramebuffers(1, &self->frame_buffer);

        glDeleteProgram(self->program);

        free(self);
}

void
gles2_debayer_use(GLES2Debayer *self)
{
        assert(self != NULL);
        glUseProgram(self->program);
        check_gl();

        gl_util_bind_quad(self->quad);
}

void
gles2_debayer_configure(GLES2Debayer *self,
                        const uint32_t dst_width,
                        const uint32_t dst_height,
                        const uint32_t src_width,
                        const uint32_t src_height,
                        const uint32_t rotation,
                        const bool mirrored,
                        const float *colormatrix,
                        const uint8_t blacklevel)
{
        glViewport(0, 0, (int)dst_width, (int)dst_height);
        check_gl();

        GLfloat rotation_list[4] = { 0, -1, 0, 1 };
        int rotation_index = 4 - (int)rotation / 90;

        GLfloat sin_rot = rotation_list[rotation_index];
        GLfloat cos_rot = rotation_list[(rotation_index + 1) % 4];
        GLfloat scale_x = mirrored ? 1 : -1;
        GLfloat matrix[9] = {
                // clang-format off
		cos_rot * scale_x,  sin_rot, 0,
		-sin_rot * scale_x, cos_rot, 0,
		0,                        0, 1,
                // clang-format on
        };
        glUniformMatrix3fv(self->uniform_transform, 1, GL_FALSE, matrix);
        check_gl();

        GLfloat pixel_size_x = 1.0f / src_width;
        GLfloat pixel_size_y = 1.0f / src_height;
        glUniform2f(self->uniform_pixel_size, pixel_size_x, pixel_size_y);
        check_gl();

        if (colormatrix) {
                GLfloat transposed[9];
                for (int i = 0; i < 3; ++i)
                        for (int j = 0; j < 3; ++j)
                                transposed[i + j * 3] = colormatrix[j + i * 3];

                glUniformMatrix3fv(
                        self->uniform_color_matrix, 1, GL_FALSE, transposed);
        } else {
                static const GLfloat identity[9] = {
                        // clang-format off
			1, 0, 0,
			0, 1, 0,
			0, 0, 1,
                        // clang-format on
                };
                glUniformMatrix3fv(
                        self->uniform_color_matrix, 1, GL_FALSE, identity);
        }
        check_gl();

        GLuint row_length =
                libmegapixels_mode_width_to_bytes(self->format, src_width);
        if (libmegapixels_format_bits_per_pixel(self->format) == 10) {
                assert(src_width % 4 == 0);
                glUniform1f(self->uniform_row_length, row_length);
                check_gl();
        }

        GLuint padding_bytes =
                libmegapixels_mode_width_to_padding(self->format, src_width);
        GLfloat padding_ratio = (float)row_length / (row_length + padding_bytes);
        glUniform1f(self->uniform_padding_ratio, padding_ratio);
}

void
gles2_debayer_process(GLES2Debayer *self, GLuint dst_id, GLuint source_id)
{
        glBindFramebuffer(GL_FRAMEBUFFER, self->frame_buffer);
        glBindTexture(GL_TEXTURE_2D, dst_id);
        glFramebufferTexture2D(
                GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, dst_id, 0);
        check_gl();

        assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, source_id);
        glUniform1i(self->uniform_texture, 0);
        check_gl();

        gl_util_draw_quad(self->quad);
}