gb_wasm_export char wasm_temp_buff1[128] = {[127] = 0x13};
gb_wasm_export i32  wasm_temp_buff1_len  = 127;
gb_wasm_export char wasm_temp_buff2[128] = {[127] = 0x13};
gb_wasm_export i32  wasm_temp_buff2_len  = 127;

gb f32         wasm_dpr;
gb f32         wasm_delta_time;
gb f32         wasm_time;
gb f32         wasm_last_time;
gb app_frame_t wasm_frame;
gb u64         wasm_frame_counter;
gb u64         wasm_event_ids;

typedef struct wasm_cached_t wasm_cached_t;
struct wasm_cached_t {
    v2f32_t mouse_pos;
    v2f32_t mouse_delta;
    b8 ctrl, alt, shift;
} wasm_cached;

fn b32  app_update(app_frame_t *frame);
fn void app_init(f32 dpr);

fn void wasm_add_event(app_event_t event) {
    app_event_t *ev = ma_push_type(tcx.temp, app_event_t);
    *ev = event;
    ev->id = ++wasm_event_ids;
    ev->alt = wasm_cached.alt;
    ev->ctrl = wasm_cached.ctrl;
    ev->shift = wasm_cached.shift;
    ev->mouse_pos = wasm_cached.mouse_pos;
    ev->mouse_delta = wasm_cached.mouse_delta;
    SLLQ_APPEND(wasm_frame.first_event, wasm_frame.last_event, ev);
    wasm_frame.event_count += 1;
}

fn void wasm_set_cached_mouse(v2f32_t p) {
    p = v2f32_muls(p, wasm_dpr);
    wasm_cached.mouse_delta = v2f32_sub(p, wasm_cached.mouse_pos);
    wasm_cached.mouse_pos = p;
}

fn void wasm_set_cached_buttons(b32 ctrl, b32 shift, b32 alt) {
    wasm_cached.ctrl = ctrl;
    wasm_cached.alt = alt;
    wasm_cached.shift = shift;
}

fn_wasm_export void wasm_mouse_move(f32 x, f32 y, b32 ctrl, b32 shift, b32 alt, b32 meta) {
    wasm_set_cached_mouse((v2f32_t){x, y});
    wasm_set_cached_buttons(ctrl, shift, alt);
}

fn_wasm_export void wasm_mouse_down(f32 x, f32 y, i32 button, b32 ctrl, b32 shift, b32 alt, b32 meta) {
    button += 1;
    assert(button >= app_mouse_button_left && button <= app_mouse_button_right);
    wasm_set_cached_buttons(ctrl, shift, alt);
    wasm_set_cached_mouse((v2f32_t){x, y});
    wasm_add_event((app_event_t){
        .kind = app_event_kind_mouse_down,
        .mouse_button = button,
    });
}

fn_wasm_export void wasm_mouse_up(f32 x, f32 y, i32 button, b32 ctrl, b32 shift, b32 alt, b32 meta) {
    button += 1;
    assert(button >= app_mouse_button_left && button <= app_mouse_button_right);
    wasm_set_cached_buttons(ctrl, shift, alt);
    wasm_set_cached_mouse((v2f32_t){x, y});
    wasm_add_event((app_event_t){
        .kind = app_event_kind_mouse_up,
        .mouse_button = button,
    });
}

fn_wasm_export void wasm_mouse_wheel(f32 x, f32 y, f32 delta_x, f32 delta_y, f32 delta_z, b32 ctrl, b32 shift, b32 alt, b32 meta) {
    wasm_set_cached_mouse((v2f32_t){x, y});
    wasm_set_cached_buttons(ctrl, shift, alt);
    wasm_add_event((app_event_t){
        .kind = app_event_kind_mouse_wheel,
        .mouse_wheel_delta = {delta_x, -delta_y, delta_z},
    });
}

fn_wasm_export void wasm_key_down(char *key, b32 ctrl, b32 shift, b32 alt, b32 meta) {
    wasm_set_cached_buttons(ctrl, shift, alt);
    assert(wasm_temp_buff1[127] == 0x13); // make sure we didn't overwrite memory in JS
    assert(wasm_temp_buff2[127] == 0x13);
    s8_t key8 = s8_from_char(key);
    wasm_key_map_t map = wasm_map_key_string_to_app_key(key8);
    if (map.key != app_key_null) {
        wasm_add_event((app_event_t){
            .kind = app_event_kind_key_down,
            .key = map.key,
        });
    }

    if (map.filter_out) {
        return;
    }

    s8_t text = s8_copy(tcx.temp, key8);
    wasm_add_event((app_event_t){
        .kind = app_event_kind_text,
        .text = text,
    });
}

fn_wasm_export void wasm_key_up(char *key, b32 ctrl, b32 shift, b32 alt, b32 meta) {
    wasm_set_cached_buttons(ctrl, shift, alt);
    assert(wasm_temp_buff1[127] == 0x13); // make sure we didn't overwrite memory in JS
    assert(wasm_temp_buff2[127] == 0x13);
    s8_t key8 = s8_from_char(key);

    wasm_key_map_t map = wasm_map_key_string_to_app_key(key8);
    if (map.key != app_key_null) {
        wasm_add_event((app_event_t){
            .kind = app_event_kind_key_up,
            .key = map.key,
        });
    }
}

fn_wasm_export b32 wasm_update(f64 time, f32 width, f32 height, f32 dpr) {
    wasm_time = time;
    wasm_delta_time = wasm_time - wasm_last_time;
    wasm_dpr = dpr;

    if (wasm_frame.first_event == NULL) wasm_add_event((app_event_t){.kind = app_event_kind_update});
    wasm_frame.window_size = (v2f32_t){width, height};
    wasm_frame.dpr = wasm_dpr;
    wasm_frame.mouse_pos = wasm_frame.last_event->mouse_pos;
    wasm_frame.delta = wasm_delta_time;
    wasm_frame.frame = wasm_frame_counter;
    b32 animating = app_update(&wasm_frame);

    ma_set0(tcx.temp);
    zero_struct(&wasm_frame);
    wasm_last_time = wasm_time;
    wasm_frame_counter += 1;

    return animating;
}

fn_wasm_export void wasm_init(f32 dpr) {
    core_init();
    app_init(dpr);
}