#include "Tileset_engine.h"

void SDL_RenderDrawGrid(SDL_Renderer* r, int w, int h, int gps)
{
	SDL_SetRenderDrawColor(r, 50, 50, 50, 255);
	SDL_Rect Grid{ 0, 0, w, h };
	SDL_RenderDrawRect(r, &Grid);
	for (int horz = 0; horz < h; horz += gps) SDL_RenderDrawLine(r, 0, horz, w, horz);
	for (int vert = 0; vert < w; vert += gps) SDL_RenderDrawLine(r, vert, 0, vert, h);
}

void MovePlayer(SDL_Rect& Player, std::vector<SDL_Rect>& Additionals, const int gps, int direction, int win_w, int win_h)
{
	SDL_Rect PlayerLastPos = Player;
	std::vector<SDL_Rect>NewPos;
	NewPos.resize(Additionals.size());
	switch (direction)
	{
	case 1:
		if (Player.y > 0)
		{
			if (Additionals.size() > 0)
			{
				for (unsigned int p = 0; p < Additionals.size(); p++) NewPos[p] = Additionals[p]; // put the tail in newpos
				for (unsigned int p = 0; p < Additionals.size(); p++) Additionals[p] = NewPos[p + 1]; // every element of the tail is put 1 next
				Additionals[0] = PlayerLastPos; // the part before the head is the last position of the player
			}
			Player.y -= gps;
		} break; // up

	case 2:
		if (Player.y < (win_h - gps))
		{
			if (Additionals.size() > 0)
			{
				for (unsigned int p = 0; p < Additionals.size(); p++) NewPos[p] = Additionals[p]; // put the tail in newpos
				for (unsigned int p = 0; p < Additionals.size(); p++) Additionals[p] = NewPos[p + 1]; // every element of the tail is put 1 next
				Additionals[0] = PlayerLastPos; // the part before the head is the last position of the player
			}
			Player.y += gps;
		} break; // down

	case 3:
		if (Player.x > 0)
		{
			if (Additionals.size() > 0)
			{
				for (unsigned int p = 0; p < Additionals.size(); p++) NewPos[p] = Additionals[p]; // put the tail in newpos
				for (unsigned int p = 0; p < Additionals.size(); p++) Additionals[p] = NewPos[p + 1]; // every element of the tail is put 1 next
				Additionals[0] = PlayerLastPos; // the part before the head is the last position of the player
			}
			Player.x -= gps;
		} break; // left

	case 4:
		if (Player.x < (win_w - gps))
		{
			if (Additionals.size() > 0)
			{
				for (unsigned int p = 0; p < Additionals.size(); p++) NewPos[p] = Additionals[p]; // put the tail in newpos
				for (unsigned int p = 0; p < Additionals.size(); p++) Additionals[p] = NewPos[p + 1]; // every element of the tail is put 1 next
				Additionals[0] = PlayerLastPos; // the part before the head is the last position of the player
			}
			Player.x += gps;
		} break; // right
	}
}

int main(int args, char* argc[])
{
	std::cout << "this code can be updated into a snake game!\n";
begin:
	// before SDL init
	const int WinW{ 700 }; const int WinH{ 700 };

	// SDL init
	Init();
	SDL_Window* win{ SDL_CreateWindow("SDL TRON-STYLE 2D COLLISION DEMO", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, WinW, WinH, SDL_WINDOW_SHOWN) };
	SDL_Renderer* ren{ SDL_CreateRenderer(win, -1, SDL_RENDERER_INIT) };

	const int GridPointSize{ 5 }; int Score{ 0 };

	// player variables
	SDL_Rect Player{ randomWithinRange(WinW / GridPointSize) * GridPointSize, randomWithinRange(WinH / GridPointSize) * GridPointSize, GridPointSize, GridPointSize };
	std::vector<SDL_Rect> PlayerPlacements{}; uint32_t pSteps = 0; int dir{};

	// object variables
	SDL_Rect Object{ randomWithinRange(WinW / GridPointSize) * GridPointSize, randomWithinRange(WinH / GridPointSize) * GridPointSize, GridPointSize, GridPointSize };

	// other variables
	SDL_Event e; bool q{ false }; bool restart{ false };

	// main loop
	while (!q)
	{
		SDL_SetRenderDrawColor(ren, 0, 0, 0, 255);
		SDL_RenderClear(ren);

		SDL_RenderDrawGrid(ren, WinW, WinH, GridPointSize); // draw grid

		// draw player
		SDL_SetRenderDrawColor(ren, 20, 0, 255, 255);
		SDL_RenderFillRect(ren, &Player);
		if (PlayerPlacements.size() > 0) SDL_RenderFillRects(ren, PlayerPlacements.data(), PlayerPlacements.size());

		// draw object
		SDL_SetRenderDrawColor(ren, 255, 50, 0, 255);
		SDL_RenderFillRect(ren, &Object);

		SDL_RenderPresent(ren);
		while (SDL_PollEvent(&e))
		{
			if (e.type == SDL_QUIT) q = true;
			else if (e.type == SDL_KEYDOWN)
			{
				switch (e.key.keysym.sym)
				{
				case SDLK_w: if (dir != 2) dir = 1; break; // move up if not moving down
				case SDLK_s: if (dir != 1) dir = 2; break; // move down if not moving up
				case SDLK_a: if (dir != 4) dir = 3; break; // move left if not moving right
				case SDLK_d: if (dir != 3) dir = 4; break; // move right if not moving left
				case SDLK_p: restart = true; q = true; break; // force restart
				case SDLKES: q = true; break; // quit
				}
			}
		}
		for (unsigned int pp = 0; pp < PlayerPlacements.size(); pp++) { if (SDL_HasIntersection(&Player, &PlayerPlacements[pp])) { restart = true; q = true; } } // self eat
		if (SDL_HasIntersection(&Player, &Object))
		{
			Score += 1; pSteps += 1; PlayerPlacements.resize(pSteps);
			Object.x = (randomWithinRange(WinW / GridPointSize) * GridPointSize); Object.y = (randomWithinRange(WinH / GridPointSize) * GridPointSize);
		}
		MovePlayer(Player, PlayerPlacements, GridPointSize, dir, WinW, WinH);
		SDL_Delay(50);
	}

	// exit code
	SDL_Window* windows[]{ win }; int numwin{ std::size(windows) };
	SDL_Renderer* renderers[]{ ren }; int numren{ std::size(renderers) };
	QuitSDL(windows, numwin, renderers, numren);
	if (restart) goto begin;
	return 0;
}