#include <engine.hpp>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <ncurses.h>
#include <ranges>
#include <iostream>
#include <thread>
#include <chrono>

void Window::draw_display() {
	for(int i : std::ranges::views::iota(0, ROW)) {
		for(int j : std::ranges::views::iota(0, COL)) {
			mvaddch(i, j * 2, view[i][j]);
		}
	}
	refresh();
}

void Window::update_display(vec2 &head, vec2 &fruit, std::vector<vec2> &buf) {
	for(auto& row : view) row.fill('.');
	view[head.y][head.x] = '*';
	view[fruit.y][fruit.x] = 'o';

	for(const auto& segment : buf) {
		if(segment.x < COL && segment.y < ROW) {
			view[segment.y][segment.x] = '~';
		}
	}
}

Engine::Engine() {
	std::srand(std::time(0));
	initscr();
	cbreak();
	noecho();
	curs_set(0);
	nodelay(stdscr, true);
}

Engine::~Engine() {
	endwin();
}

void Engine::run() {
	while (exit_summary() && process_input()) {
		add_tail_and_respawn_fruit();
		determine_index_zero_pos();
		move_tail_indicies();

		win.update_display(head, fruit, buf);
		win.draw_display();
		std::this_thread::sleep_for(std::chrono::milliseconds((int) (200)));
	}
}

bool Engine::process_input() {
	int ch;
	while((ch = getch()) != ERR) {
		if(ch == 'q') { return false; }
		else if(ch == 'w') { if(dir != Direction::DOWN)  dir = Direction::UP; }
		else if(ch == 's') { if(dir != Direction::UP)    dir = Direction::DOWN; }
		else if(ch == 'd') { if(dir != Direction::LEFT)  dir = Direction::RIGHT; }
		else if(ch == 'a') { if(dir != Direction::RIGHT) dir = Direction::LEFT; }
	}
	return true;
}

bool Engine::exit_summary() {
	if(buf.size() >= ROW * COL) {
		std::cout << "You filled the whole board and won! Score: " << m_score << "\n";
		std::this_thread::sleep_for(std::chrono::seconds(1));
		return false;
	}
	if(std::any_of(buf.begin(), buf.end(), [&](const vec2& segment) { return segment == head; })) {
		std::cout << "You collided with yourself and died! Score: " << m_score << "\n";
		std::this_thread::sleep_for(std::chrono::seconds(1));
		return false;
	}
	return true;
}

void Engine::determine_index_zero_pos() {
	prev_head.set(head.x, head.y);

	if(dir == Direction::LEFT) 	 { head.x = (head.x + COL - 1) % COL; }
	else if(dir == Direction::RIGHT) { head.x = (head.x + 1) % COL; }
	else if(dir == Direction::UP) 	 { head.y = (head.y + ROW - 1) % ROW; }
	else if(dir == Direction::DOWN)  { head.y = (head.y + 1) % ROW; }
}

void Engine::move_tail_indicies() {
	if(buf.empty()) return;
	buf.pop_back();
	buf.insert(buf.begin(), prev_head);
}

void Engine::add_tail_and_respawn_fruit() {
	if(fruit != head) return;
	vec2 new_pos { 0, 0 };
	do { new_pos.set((rand() % ROW), (rand() % COL)); }
	while (new_pos == head || std::any_of(buf.begin(), buf.end(), [&](const vec2& seg) { return seg == new_pos; }));
	fruit = new_pos;
	buf.insert(buf.begin(), vec2 { ROW, COL });
	m_score++;
}