#include "mandel.h"


static void	st_zoom(State *state, bool zoom_in);
static void	st_move_horizontal(State *state, bool move_right);
static void	st_move_vertical(State *state, bool move_down);
static void	st_set_key(SDL_Keycode sym, bool value);
static void	st_apply_keys(State *state);

static bool	g_key_states[] = {
	[KEY_UP] = false,
	[KEY_DOWN] = false,
	[KEY_RIGHT] = false,
	[KEY_LEFT] = false,

	[KEY_INC_ITERATIONS] = false,
	[KEY_DEC_ITERATIONS] = false,

	[KEY_ZOOM_IN] = false,
	[KEY_ZOOM_OUT] = false,
};

void 		event_handle(State *state)
{
    SDL_Event	e;

    while (SDL_PollEvent(&e))
    {
        switch (e.type)
        {
            case SDL_QUIT:
                state->running = false;
                break;

            case SDL_KEYDOWN:
				if (e.key.keysym.sym == SDLK_i)
					state->info = !state->info;
				else
					st_set_key(e.key.keysym.sym, true);
                break;

            case SDL_KEYUP:
				st_set_key(e.key.keysym.sym, false);
                break;

            case SDL_MOUSEWHEEL:
                if (e.wheel.y == -1)
					st_zoom(state, true);
                else if (e.wheel.y == 1)
					st_zoom(state, false);
                break;

			case SDL_WINDOWEVENT:
				if (e.window.event == SDL_WINDOWEVENT_RESIZED)
				{
					int width;
					int height;
					SDL_QueryTexture(state->texture, NULL, NULL, &width, &height);

					double w_ratio = (double)width / (double)e.window.data1;
					double h_ratio = (double)height / (double)e.window.data2;

					state->real_start /= w_ratio;
					state->real_end /= w_ratio;
					state->imag_start /= h_ratio;
					state->imag_end /= h_ratio;

					SDL_DestroyTexture(state->texture);
					SDL_CALL(state->texture = SDL_CreateTexture(
						state->renderer,
						SDL_PIXELFORMAT_RGB888,
						SDL_TEXTUREACCESS_STREAMING,
						e.window.data1,
						e.window.data2
					));
				}
				break;
        }
    }
	st_apply_keys(state);
}

static void	st_set_key(SDL_Keycode sym, bool value)
{
	switch (sym)
	{
		case SDLK_r: g_key_states[KEY_INC_ITERATIONS] = value; break;
		case SDLK_e: g_key_states[KEY_DEC_ITERATIONS] = value; break;

		case SDLK_UP:
		case SDLK_k:
			g_key_states[KEY_UP] = value;
			break;
		case SDLK_DOWN:
		case SDLK_j:
			g_key_states[KEY_DOWN] = value;
			break;
		case SDLK_LEFT:
		case SDLK_h:
			g_key_states[KEY_LEFT] = value;
			break;
		case SDLK_RIGHT:
		case SDLK_l:
			g_key_states[KEY_RIGHT] = value;
			break;

		case SDLK_EQUALS:
		case SDLK_f:
			g_key_states[KEY_ZOOM_IN] = value;
			break;
		case SDLK_MINUS:
		case SDLK_d:
			g_key_states[KEY_ZOOM_OUT] = value;
			break;
	}
}

#define MANDEL_ITERATIONS_DELTA 1

#define EVENT_TEXTURE_CENTER_UPDATE(state) \
	TEXT_TEXTURE_UPDATE(state, state->texture_center, "center: %.3ei + %.3e", \
			state->imag_start + (state->imag_end - state->imag_start) / 2.0, \
			state->real_start + (state->real_end - state->real_start) / 2.0)


static void	st_apply_keys(State *state)
{
	if (g_key_states[KEY_INC_ITERATIONS])
	{
		state->iterations += MANDEL_ITERATIONS_DELTA;
		state->palette = color_palette_new(state->palette, state->iterations);
		TEXT_TEXTURE_UPDATE(state, state->texture_iterations, "iterations: %d", state->iterations);
	}
	if (g_key_states[KEY_DEC_ITERATIONS])
	{
		state->iterations -= MANDEL_ITERATIONS_DELTA;
		if (state->iterations <= 0)
			state->iterations = 1;
		state->palette = color_palette_new(state->palette, state->iterations);
		TEXT_TEXTURE_UPDATE(state, state->texture_iterations, "iterations: %d", state->iterations);
	}

	if (g_key_states[KEY_UP])
	{
		st_move_vertical(state, false);
		EVENT_TEXTURE_CENTER_UPDATE(state);
	}
	if (g_key_states[KEY_DOWN])
	{
		st_move_vertical(state, true);
		EVENT_TEXTURE_CENTER_UPDATE(state);
	}
	if (g_key_states[KEY_LEFT])
	{
		st_move_horizontal(state, false);
		EVENT_TEXTURE_CENTER_UPDATE(state);
	}
	if (g_key_states[KEY_RIGHT])
	{
		st_move_horizontal(state, true);
		EVENT_TEXTURE_CENTER_UPDATE(state);
	}

	if (g_key_states[KEY_ZOOM_IN])
		st_zoom(state, true);
	if (g_key_states[KEY_ZOOM_OUT])
		st_zoom(state, false);
}

#define MANDEL_ZOOM_RATIO 64

static void	st_zoom(State *state, bool zoom_in)
{
	double factor = zoom_in ? 1 : -1;
	double real_change = (state->real_end - state->real_start) / MANDEL_ZOOM_RATIO;
	double imag_change = (state->imag_end - state->imag_start) / MANDEL_ZOOM_RATIO;
	state->real_start += factor * real_change;
	state->real_end -= factor * real_change;
	state->imag_start += factor * imag_change;
	state->imag_end -= factor * imag_change;
}

#define MANDEL_MOVE_RATIO 64

static void	st_move_horizontal(State *state, bool move_right)
{
	double factor = move_right ? 1 : -1;
	double real_change = (state->real_end - state->real_start) / MANDEL_MOVE_RATIO;
	state->real_start += factor * real_change;
	state->real_end += factor * real_change;
}

static void	st_move_vertical(State *state, bool move_down)
{
	double factor = move_down ? 1 : -1;
	double imag_change = (state->imag_end - state->imag_start) / MANDEL_MOVE_RATIO;
	state->imag_start += factor * imag_change;
	state->imag_end += factor * imag_change;
}