fn_wasm_import void wasm_clear(void);
fn_wasm_import void wasm_draw_text(isize str, i32 len, f64 x, f64 y, isize font_str, i32 font_len, i32 font_size, f32 r, f32 g, f32 b, f32 a);
fn_wasm_import void wasm_draw_rect(f64 x, f64 y, f64 w, f64 h, f32 r, f32 g, f32 b, f32 a);
fn_wasm_import f64  wasm_measure_text(isize str, i32 len, isize font_str, i32 font_len, i32 font_size);
fn_wasm_import f64  wasm_get_font_height(isize font_str, i32 font_len, i32 font_size);
fn_wasm_import void wasm_set_clip(f64 x, f64 y, f64 w, f64 h);

global s8_t font_face = s8_const_lit("open_sans_regular");


fn void set_clip(r2f64_t rect) {
    wasm_set_clip(wasm_dpr * rect.min.x, wasm_dpr * rect.min.y, wasm_dpr * (rect.max.x - rect.min.x), wasm_dpr * (rect.max.y - rect.min.y));
}

fn f64 get_font_height(void) {
    return wasm_get_font_height((isize) font_face.str, font_face.len, 20*wasm_dpr) / wasm_dpr;
}

fn f64 measure_text_ex(char *str, i32 len) {
    return wasm_measure_text((isize)str, len, (isize) font_face.str, font_face.len, 20*wasm_dpr) / wasm_dpr;
}

fn f64 measure_text(char *str) {
    return measure_text_ex(str, str_len(str));
}

fn void draw_text(v2f64_t pos, v4f32_t color, s8_t string) {
    wasm_draw_text((isize)string.str, string.len, wasm_dpr * pos.x, wasm_dpr * pos.y, (isize) font_face.str, font_face.len, 20*wasm_dpr, color.r * 255.f, color.g * 255.f, color.b * 255.f, color.a);
}

fn void draw_textf(v2f64_t pos, char *str, ...) {
    char    buff[1024];
    va_list args;
    va_start(args, str);
    i32 len = stbsp_vsnprintf(buff, sizeof(buff), str, args);
    va_end(args);

    wasm_draw_text((isize)buff, len, wasm_dpr * pos.x, wasm_dpr * pos.y, (isize) font_face.str, font_face.len, 20*wasm_dpr, 0, 0, 0, 1);
}

fn void draw_rect(r2f64_t rect, v4f32_t color) {
    wasm_draw_rect(wasm_dpr * rect.min.x, wasm_dpr * rect.min.y, wasm_dpr * (rect.max.x - rect.min.x), wasm_dpr * (rect.max.y - rect.min.y), color.r * 255.f, color.g * 255.f, color.b * 255.f, color.a);
}

typedef enum {
    gfx2d_kind_null,
    gfx2d_kind_clear,
    gfx2d_kind_draw_rect,
    gfx2d_kind_draw_text,
    gfx2d_kind_set_clip,
} gfx2d_kind_t;

typedef struct gfx2d_cmd_t gfx2d_cmd_t;
struct gfx2d_cmd_t {
    gfx2d_cmd_t *next;
    gfx2d_kind_t kind;
    r2f64_t      rect;
    v4f32_t      color;
    s8_t         text;
};

typedef struct gfx2d_t gfx2d_t;
struct gfx2d_t {
    gfx2d_cmd_t *first;
    gfx2d_cmd_t *last;
    app_event_t *ev;
};

void gfx2d_begin(gfx2d_t *gfx, app_event_t *ev) {
    gfx->ev = ev;
}

void gfx2d_end(gfx2d_t *gfx) {
    app_event_t *ev = gfx->ev;
    r2f64_t window = (r2f64_t){0, 0, ev->window_size.x, ev->window_size.y};
    for (gfx2d_cmd_t *cmd = gfx->first; cmd; cmd = cmd->next) {
        if (cmd->kind == gfx2d_kind_clear) {
            wasm_clear();
            draw_rect(window, cmd->color);
        } else if (cmd->kind == gfx2d_kind_draw_rect) {
            draw_rect(cmd->rect, cmd->color);
        } else if (cmd->kind == gfx2d_kind_draw_text) {
            draw_text(cmd->rect.min, cmd->color, cmd->text);
        } else if (cmd->kind == gfx2d_kind_set_clip) {
            set_clip(cmd->rect);
        } else {
            invalid_codepath;
        }
    }

    gfx->first = gfx->last = NULL;
}

void gfx2d_add_cmd(gfx2d_t *gfx, gfx2d_cmd_t cmd) {
    gfx2d_cmd_t *c = ma_push_type(tcx.temp, gfx2d_cmd_t);
    *c = cmd;
    SLLQ_APPEND(gfx->first, gfx->last, c);
}

void gfx2d_clear(gfx2d_t *gfx, v4f32_t color) {
    gfx2d_add_cmd(gfx, (gfx2d_cmd_t){
        .kind = gfx2d_kind_clear,
        .color = color,
    });
}

void gfx2d_rect(gfx2d_t *gfx, r2f64_t rect, v4f32_t color) {
    gfx2d_add_cmd(gfx, (gfx2d_cmd_t){
        .kind = gfx2d_kind_draw_rect,
        .color = color,
        .rect = rect,
    });
}

void gfx2d_set_clip(gfx2d_t *gfx, r2f64_t rect) {
    gfx2d_add_cmd(gfx, (gfx2d_cmd_t){
        .kind = gfx2d_kind_set_clip,
        .rect = rect,
    });
}

void gfx2d_text(gfx2d_t *gfx, v2f64_t pos, v4f32_t color, s8_t string) {
    gfx2d_add_cmd(gfx, (gfx2d_cmd_t){
        .kind = gfx2d_kind_draw_text,
        .text = s8_copy(tcx.temp, string),
        .color = color,
        .rect.min = pos,
    });
}
void gfx2d_textf(gfx2d_t *gfx, v2f64_t pos, v4f32_t color, char *str, ...) {
    S8_FMT(tcx.temp, str, text);
    gfx2d_add_cmd(gfx, (gfx2d_cmd_t){
        .kind = gfx2d_kind_draw_text,
        .text = text,
        .color = color,
        .rect.min = pos,
    });
}