/*
This file is part of Minitrem.

Minitrem is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.

Minitrem is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Minitrem.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "game.hpp"
#include <iomanip>

namespace interface {

using namespace game; // FIXME

state_t::state_t(sf::RenderWindow *window_, game::state_t *game_)
{
	window = window_;
	game = game_;
}

static sf::Vector2f compute_pan(sf::RenderWindow *window, sf::Vector2f pan_ref)
{
	sf::Vector2i mouse = sf::Mouse::getPosition(*window);
	sf::Vector2f vmouse = window->mapPixelToCoords(mouse);
	return -(vmouse - pan_ref);
}

void state_t::start_following(void)
{
	camera.following = true;
	camera.zero_point_s = camera.center;
	camera.center = v2f_t(0, 0);
	print(text::get(text::FOLLOWING_ON));
}

void state_t::stop_following(void)
{
	camera.following = false;
	camera.center += camera.zero_point_s;
	camera.zero_point_s = v2f_t(0, 0);
	print(text::get(text::FOLLOWING_OFF));
}

void state_t::tick(double dt)
{
	vec_t<int, 2> window_size;
	sf::Event event;

	v2f_t view_size;
	v2f_t follow_center(0, 0), view_center, pan_delta;
	float view_scale;
	v2f_t wmouse; // Mouse position in world space;

	window_size = window->getSize();

	expfade<float>(&camera.zoom_s, camera.zoom, 15, dt);
	view_scale = 4.5 * exp(camera.zoom_s * 0.12);
	if (window_size[0] < window_size[1]) {
		view_size[1] = view_scale;
		view_size[0] = view_scale * window_size[0] / window_size[1];
	} else {
		view_size[0] = view_scale;
		view_size[1] = view_scale * window_size[1] / window_size[0];
	}

	if (!game->selected_units.size() && camera.following)
		stop_following();

	if (camera.following) {
		float limit;

		for (entity_t *ent : game->selected_units)
			follow_center += ent->render_bounds.center();
		follow_center /= game->selected_units.size();

		expfade<float, 2>(&camera.zero_point_s, follow_center, 15, dt);

		limit = view_scale * 0.2f;
		if (camera.center.len() > limit * 2.0f)
			stop_following();
		else if (camera.center.len() > limit)
			expfade<float, 2>(&camera.center, camera.center.norm() * limit, 3, dt);
	}

	view_center = camera.zero_point_s + camera.center;
	window->setView(sf::View(view_center, view_size));

	if (camera.panning) {
		pan_delta = compute_pan(window, camera.pan_ref);
		view_center += compute_pan(window, camera.pan_ref);
		window->setView(sf::View(view_center, view_size));
	}

	wmouse = window->mapPixelToCoords(sf::Mouse::getPosition(*window));

	while (window->pollEvent(event)) {
		// FIXME: refactor this nested switch clusterfuck
		switch (event.type)  {
		case sf::Event::Closed:
			window->close();
			return;

		case sf::Event::MouseButtonPressed:
			switch (event.mouseButton.button) {
			case sf::Mouse::Button::Left:
				select.selecting = true;
				select.rect[0] = wmouse;
				select.rect[1] = wmouse;
				break;

			case sf::Mouse::Button::Right:
				game->command(wmouse);
				break;

			case sf::Mouse::Button::Middle:
				camera.panning = true;
				camera.pan_ref = wmouse;
				break;

			default:;
			}
			break;

		case sf::Event::MouseButtonReleased:
			switch (event.mouseButton.button) {
			case sf::Mouse::Button::Left:
				if (select.selecting)
					game->select(select.rect);
				select.selecting = false;
				break;

			case sf::Mouse::Button::Middle:
				if (camera.panning)
					camera.center += pan_delta;
				camera.panning = false;
				break;

			default:;
			}
			break;

		case sf::Event::MouseWheelScrolled:
			camera.zoom -= event.mouseWheelScroll.delta;
			if (camera.zoom < 0)
				camera.zoom = 0;
			if (camera.zoom > 17)
				camera.zoom = 17;
			break;

		case sf::Event::KeyPressed:
			switch (event.key.code) {
			case sf::Keyboard::Key::Space:
				game->paused ^= 1;
				if (game->paused)
					print(text::get(text::PAUSED));
				else
					print(text::get(text::UNPAUSED));
				break;

			case sf::Keyboard::Key::F:
				if (camera.following)
					stop_following();
				else
					start_following();
				break;

			case sf::Keyboard::Key::H:
				game->spawn_soldier(wmouse);
				break;

			case sf::Keyboard::Key::F1:
				debug_draw_cmodels ^= 1;
				print("debug_draw_cmodels = " + std::to_string(debug_draw_cmodels));
				break;

			case sf::Keyboard::Key::F2:
				debug_draw_paths ^= 1;
				print("debug_draw_paths = " + std::to_string(debug_draw_paths));
				break;

			case sf::Keyboard::Key::F3:
				debug_draw_tile_coords ^= 1;
				print("debug_draw_tile_coords = " + std::to_string(debug_draw_tile_coords));
				break;

			case sf::Keyboard::Key::F4:
				debug_AI ^= 1;
				print("debug_AI = " + std::to_string(debug_AI));
				break;
			default:;
			}
		default:;
		}
	}

	if (select.selecting)
		select.rect[1] = wmouse;
}

void state_t::print(std::string str)
{
	log.push_back((log_entry_t){game->now, str});
	std::cout << str << std::endl;
}

void state_t::render_to(render::state_t *render)
{
	size_t w = window->getSize().x, h = window->getSize().y;
	v2f_t x;
	std::stringstream ss;
	double fps;

	if (select.selecting)
		render->render_hlrect(select.rect, sf::Color(60, 60, 150));

	window->setView(sf::View(sf::FloatRect(0, 0, w, h)));
	em = std::max(w, h) * 0.017;

	for (auto i = log.begin(); i != log.end(); ) {
		if (i->time + 3 < game->now)
			i = log.erase(i);
		else
			i++;
	}

	x = v2f_t(0.0f, 0.0f);
	for (log_entry_t &entry : log) {
		render->render_text(x, em, entry.text, render::ALIGN_LEFT_TOP, sf::Color::White);
		x[1] += em;
	}
	
	x = v2f_t(0.0f, h - em * 4.5);
	ss << "World S/T:";
	ss << game->world.stats.sectors << "/";
	ss << game->world.stats.tiles;
	render->render_text(x, em, ss.str(), render::ALIGN_LEFT_TOP, sf::Color::White);

	x[1] += em;
	ss.str(std::string());
	ss << "Awake: " << game->awake_entities.size() << "/" << game->world.stats.entities;
	render->render_text(x, em, ss.str(), render::ALIGN_LEFT_TOP, sf::Color::White);

	x[1] += em;
	ss.str(std::string());
	ss << "View S/T/E: ";
	ss << render->stats.sectors << "/";
	ss << render->stats.tiles << "/";
	ss << render->stats.entities;
	render->render_text(x, em, ss.str(), render::ALIGN_LEFT_TOP, sf::Color::White);

	perf_hist_index = (perf_hist_index + 1) % COUNT(perf_hist);
	perf_hist[perf_hist_index] = 1.0 / render->dt;

	fps = 0.0;
	for (size_t i = 0; i < COUNT(perf_hist); i++)
		fps += perf_hist[i];
	fps /= COUNT(perf_hist);

	x[1] += em;
	ss.str(std::string());
	ss << std::fixed << std::setprecision(1);
	ss << "FPS: " << fps;
	render->render_text(x, em, ss.str(), render::ALIGN_LEFT_TOP, sf::Color::White);
}

} // namespace interface