import standard;
import engine;
import node;
import math;


//constants for generating maps
var TILE_PIXEL_WIDTH: int const = 16;
var TILE_PIXEL_HEIGHT: int const = 16;

var ROOM_MIN_WIDTH: int const = 4; //minimum safe value 4
var ROOM_MIN_HEIGHT: int const = 4;

var ROOM_MAX_WIDTH: int const = 12;
var ROOM_MAX_HEIGHT: int const = 12;

var CELL_WIDTH: int const = 16; //minimum safe value ROOM_MAX_* + 4
var CELL_HEIGHT: int const = 16;

var CELL_COUNT_X: int const = 3;
var CELL_COUNT_Y: int const = 3;

var MAP_GRID_WIDTH: int const = CELL_WIDTH * CELL_COUNT_X;
var MAP_GRID_HEIGHT: int const = CELL_HEIGHT * CELL_COUNT_Y;


var tilemapCache = [];


//lifecycle functions
fn onLoad(node: opaque) {
	//load the atlas into this node
	node.loadNodeTexture("sprites:/tileset.png");

	//create a child as a render target
	var child: opaque = node.loadChildNode("scripts:/tilemap/renderer-child.toy");
	child.createNodeTexture(MAP_GRID_WIDTH * TILE_PIXEL_WIDTH, MAP_GRID_HEIGHT * TILE_PIXEL_HEIGHT);

	//generate a grid filled with only empty tiles, as a starting point
	for (var j: int = 0; j < MAP_GRID_HEIGHT; j++) {
		for (var i: int = 0; i < MAP_GRID_WIDTH; i++) {
			tilemapCache.push(-1); //x
			tilemapCache.push(-1); //y
			// tilemapCache.push(0); //collision
		}
	}
}

//lazily render
fn updateVisble(node: opaque, x: int, y: int, tilemap) {
	print clock() + " - start updateVisible()";
	var child: opaque = node.getChildNode(0);
	setRenderTarget(child);

	//divide the regions into octants & determine what is visible
	node.shadowCastOctant(x, y, 1, 1, 10, tilemap);
	node.shadowCastOctant(x, y, -1, 1, 10, tilemap);
	node.shadowCastOctant(x, y, 1, -1, 10, tilemap);
	node.shadowCastOctant(x, y, -1, -1, 10, tilemap);

	//reset the render target to the screen
	setRenderTarget(null);

	print clock() + " - end updateVisible()";
}

fn shadowCastOctant(node: opaque, x: int, y: int, dirX: int, dirY: int, depth: int, tilemap) {
	var shadows = [];

	//for each tile, cast its shadow, and see if its already obscured
	for (var j: int = 0; abs(j) < depth; j += dirY) {
		for (var i: int = 0; abs(i) < abs(j); i += dirX) {
			//make sure this tile can actually cast a shadow
			var CACHE_ITERATION: int const = (y + j) * MAP_GRID_WIDTH * 2 + (x + i) * 2;
			var ITERATION: int const = (y + j) * MAP_GRID_WIDTH * 3 + (x + i) * 3;

			//don't render empty tiles
			if (ITERATION < 0 || ITERATION >= MAP_GRID_WIDTH * MAP_GRID_HEIGHT * 3 || tilemap[ITERATION] < 0 || tilemap[ITERATION + 1] < 0) {
				continue; //break?
			}

			//don't re-render already drawn tiles
			if (tilemapCache[CACHE_ITERATION] == tilemap[ITERATION] && tilemapCache[CACHE_ITERATION + 1] == tilemap[ITERATION + 1]) {
				continue;
			}

			//cast the shadow
			var shadow = shadowCastTile(i + x, j + y, dirX, dirY, depth);

			if (shadow == null) {
				continue;
			}

			//merge shadows if needed
			var index: int = 0;

			//find the insertion point
			for (; index < shadows.length(); index++) {
				if (shadows[index][0] >= shadow[0]) break;
			}

			print shadows.toString() + " " + string index;

			//check to see if the tile should be rendered (prev iterations would have merged shadows)
			if (shadows.length() == 0 || (shadows.length() > index && (index == 0 || shadows[index-1][1] <= shadow[1])) || (shadows.length() > index && (shadows.length() == index + 1 || shadows[index][0] >= shadow[0]) )) {
				print "first bracket";
				tilemapCache[CACHE_ITERATION] = tilemap[ITERATION];
				tilemapCache[CACHE_ITERATION + 1] = tilemap[ITERATION + 1];

				//set the rect of the node on the tilesheet - the "tilemap" var is a single blob of data
				node.setNodeRect(
					tilemap[ITERATION]     * TILE_PIXEL_WIDTH,
					tilemap[ITERATION + 1] * TILE_PIXEL_HEIGHT,
					TILE_PIXEL_WIDTH, TILE_PIXEL_HEIGHT
				);

				print string((x + i) * TILE_PIXEL_WIDTH) + ", " + string((y + j) * TILE_PIXEL_HEIGHT);

				//draw to the screen
				node.drawNode(
					((x + i) * TILE_PIXEL_WIDTH),
					((y + j) * TILE_PIXEL_HEIGHT),
					TILE_PIXEL_WIDTH,
					TILE_PIXEL_HEIGHT
				);
			}

			var overlapping = false;

			//see if the new shadow overlaps the previous
			if (index > 0 && shadows.length() > index && shadows[index -1][1] > shadow[0]) {
				print "second bracket";
				overlapping = true;

				print "MARK one";

				shadows[index-1][1] = max(shadows[index-1][1], shadow[1]); //extend the prev shadow

				print "MARK two";

				//see if the newly extended prev overlaps the shadow at "index"
				if (shadows[index-1][1] >= shadows[index][0]) {
					//merge the two
					shadows[index-1][1] = max(shadows[index-1][1], shadows[index][1]);
					shadows = shadows.remove(index);
				}
			}

			//see if the new shadow overlaps the one at "index"
			else if (shadows.length() > index && shadows[index][1] <= shadow[0]) {
				print "third bracket";
				overlapping = true;
				//extend the next shadow
				shadows[index][0] = min(shadows[index][0], shadow[0]);
			}

			if (!overlapping) {
				print "fourth bracket";
				//insert at this position
				shadows = shadows.insert(index, shadow);
			}
		}
	}
}

fn shadowCastTile(x: int, y: int, dirX: int, dirY: int, depth: int) {
	//top-left corner & bottom-right corner forms a triangle with the player

	//top-left = x & y
	//bottom-right = x + sign(dirX) & y + sign(dirY)

	var start = abs(shadowCastPoint(x, y, depth));
	var end = abs(shadowCastPoint(x + sign(dirX), y + sign(dirY), depth));

	if (checkIsNaN(start) || checkIsNaN(end)) {
		return null;
	}

	if (start < end) {
		return [start, end];
	}
	else {
		return [end, start];
	}
}

fn shadowCastPoint(x: float, y: float, depth: int) {
	if (y == 0) {
		return NAN;
	}
	return sin(tan(x/y)) * depth;
}

//polyfill the insert function
fn insert(self, k, v) {
	//eew
	var tmp1 = v;
	var tmp2;
	for (var i = k; i < self.length(); i++) {
		tmp2 = self[i];
		self[i] = tmp1;
		tmp1 = tmp2;
	}

	self.push(tmp1);
	return self;
}

//polyfill the remove function
fn remove(self, k) {
	//double eew
	var result = [];

	for (var i = 0; i <= k - 1; i++) {
		result.push( self[i] );
	}

	for (var i = k + 1; i < self.length(); i++) {
		result.push( self[i] );
	}

	return result;
}