#include "teensy_context.h"

#include <math.h>
#include <stdarg.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <time.h>
#endif

#include "teensy_platform.h"
#include "teensy_renderer.h"

ty_Ctx ctx;

bool is_init(void)
{
    int scr_size = ctx.hints.scr_width * ctx.hints.scr_height;
    return scr_size > 0;
}

void ty_init(ty_Hints hints)
{
    ty_init_mem();

    ctx.hints = hints;
    ctx.ticrate = 1.0 / hints.ticrate;
    ctx.prev_tic_ts = 0;

    ty_platform_init(&ctx);
    ty_init_renderer();
}

void ty_deinit(void)
{
    assert(is_init());
    ty_platform_deinit();
    ty_deinit_renderer();
    ty_deinit_mem();
}

bool ty_button_down(ty_Button btn)
{
    assert(btn < TY_BTN_COUNT);
    return ctx.down[btn];
}

bool ty_button_pressed(ty_Button btn)
{
    assert(btn < TY_BTN_COUNT);
    return ctx.pressed[btn];
}

ty_Vec2i ty_mouse_pos(void)
{
    return ty_platform_get_mouse();
}

bool ty_is_game_running(void)
{
    assert(is_init());
    return !ty_platform_os_wants_quit();
}

double ty_get_time(void)
{
    assert(is_init());
    return ty_platform_get_time();
}

static
void update_buttons(void)
{
    for (int btn = 0; btn < TY_BTN_COUNT; btn++) {
        bool down = ty_platform_is_button_down(btn); 
        ctx.pressed[btn] = down && !ctx.down[btn];
        ctx.down[btn] = down;
    }
}

int ty_tick(void)
{
    assert(is_init());

    double current_time   = ty_get_time();
    double time_since_tic = current_time - ctx.prev_tic_ts;

    int tics = (int)(time_since_tic / ctx.ticrate);
    if (tics > 0) {
        update_buttons();
        ctx.prev_tic_ts = current_time;
        ty_platform_frame(r.screen);
    }
    return tics;
}

// TODO: Find a better place for this
void ty_sleep(uint64_t ms)
{
    assert(is_init());

#ifdef _WIN32
    Sleep((DWORD)ms);
#else
    struct timespec ts;
    ts.tv_sec = ms / 1000;
    ts.tv_nsec = (ms % 1000) * 1000000;
    nanosleep(&ts, NULL);
#endif
}

char *ty_format_args(const char *fmt, va_list list)
{
    va_list args;
    va_copy(args, list);
    int len = vsnprintf(NULL, 0, fmt, args);
    char *text = ty_talloc(sizeof(char) * (len + 1));
    va_end(args);

    va_copy(args, list);
    vsnprintf(text, len + 1, fmt, args);
    va_end(args);

    return text;
}

char *ty_format(const char *fmt, ...)
{
    va_list args;
    va_start(args, fmt);
    char *text = ty_format_args(fmt, args);
    va_end(args);
    return text;
}