#include <sokol/sokol_app.h>
#include <sokol/sokol_gfx.h>
#include <sokol/sokol_log.h>
#include <sokol/sokol_glue.h>
#include <math.h>

#include <shaders/shader.glsl.h>

static struct {
    sg_pipeline pip;
    sg_bindings bind;
    sg_pass_action pass_action;
} state;

typedef struct {
    float x, y, z;
    int16_t u, v;
} vertex_t;

static void init(void) {
    sg_setup(&(sg_desc){
        .environment = sglue_environment(),
        .logger.func = slog_func,
    });

    vertex_t vertices[] = {
        {  0.5f,  0.5f, 0.0f, 1.0f * 32767, 1.0f * 32767 },   // top right
        {  0.5f, -0.5f, 0.0f, 1.0f * 32767, 0.0f * 32767 },  // bottom right
        { -0.5f, -0.5f, 0.0f, 0.0f * 32767, 0.0f * 32767 },  // bottom left
        { -0.5f,  0.5f, 0.0f, 0.0f * 32767, 1.0f * 32767 }  // top left 
    };

    unsigned int indices[] = {  // note that we start from 0!
        0, 1, 3,   // first triangle
        1, 2, 3    // second triangle
    };

    state.bind.vertex_buffers[0] = sg_make_buffer(&(sg_buffer_desc){
        .data = SG_RANGE(vertices),
        .label = "triangle-vertices"
    });

    state.bind.index_buffer = sg_make_buffer(&(sg_buffer_desc){
        .type = SG_BUFFERTYPE_INDEXBUFFER,
        .data = SG_RANGE(indices),
        .label = "triangle-indices"
    });

     uint32_t pixels[4*4] = {
        0xFF000000, 0xFFFF00FF, 0xFF000000, 0xFFFF00FF,
        0xFFFF00FF, 0xFF000000, 0xFFFF00FF, 0xFF000000,
        0xFF000000, 0xFFFF00FF, 0xFF000000, 0xFFFF00FF,
        0xFFFF00FF, 0xFF000000, 0xFFFF00FF, 0xFF000000,
    };

    state.bind.fs.images[SLOT_tex] = sg_make_image(&(sg_image_desc){
        .width = 4,
        .height = 4,
        .data.subimage[0][0] = SG_RANGE(pixels),
        .label = "triangle-texture",
        .pixel_format = SG_PIXELFORMAT_RGBA8,
    });

    state.bind.fs.samplers[SLOT_smp] = sg_make_sampler(&(sg_sampler_desc){
        .label = "triangle-sampler"
    });

    sg_shader shd = sg_make_shader(triangle_shader_desc(sg_query_backend()));

    state.pip = sg_make_pipeline(&(sg_pipeline_desc){
        .shader = shd,
        .layout = {
            .attrs = {
                [ATTR_vs_position].format = SG_VERTEXFORMAT_FLOAT3,
                [ATTR_vs_texcoord0].format = SG_VERTEXFORMAT_SHORT2N,
            }
        },
        .label = "triangle-pipeline",
        .index_type = SG_INDEXTYPE_UINT32,
        .cull_mode = SG_CULLMODE_BACK,
        .sample_count = 1,
    });

    state.pass_action = (sg_pass_action) {
        .colors[0] = { .load_action=SG_LOADACTION_CLEAR, .clear_value={0.2f, 0.4f, 0.3f, 1.0f } }
    };
}

void frame(void) {
    sg_begin_pass(&(sg_pass){ .action = state.pass_action, .swapchain = sglue_swapchain() });
    sg_apply_pipeline(state.pip);
    sg_apply_bindings(&state.bind);
    sg_draw(0, 6, 1);
    sg_end_pass();
    sg_commit();
}

void cleanup(void) {
    sg_shutdown();
}

sapp_desc sokol_main(int argc, char* argv[]) {
    (void)argc; (void)argv;
    return (sapp_desc){
        .init_cb = init,
        .frame_cb = frame,
        .cleanup_cb = cleanup,
        .width = 640,
        .height = 480,
        .window_title = "Gear",
        .icon.sokol_default = true,
        .logger.func = slog_func,
    };
}