import * as Dom from UnitJS.Dom;
import {color, tool} from Toolbox;

var grid = {
	element: null,
	data: null
};
var down = false;

return {
	init: init
};

function init(size, elementId) {
	grid.element = document.getElementById(elementId || 'grid');
	for(var row = 0; row < size; row++) {
		grid.element.appendChild(
			makeRow({tag: 'td', attributes: bodyAttributes, row: row, size: size})
		);
	}
	grid.data = emptyGrid(size);
	grid.element.addEventListener('mouseleave', function() {
		down = false;
	});
}

function emptyGrid(size) {
	var result = {};
	for(var i = 0; i < size; i++) {
		result[i] = {};
	}
	return result;
}

function makeRow(config) {
	var cells = [];
	for(var column = 0; column < config.size; column++) {
		cells.push(Dom.make(config.tag, config.attributes(config.row, column)));
	}
	return Dom.make('tr', {}, cells);
}

function bodyAttributes(i, j) {
	return {
		onMousedown: function(e) {
			down = true;
			if(tool() == 'draw') {
				colorize(i, j, e.target);
			}
		},
		onMouseup: function(e) {
			down = false;
			if(tool() == 'paint') {
				paint(i, j);
			}
		},
		onMouseenter: function(e) {
			if(down && tool() == 'draw') {
				colorize(i, j, e.target);
			}
		}
	};
}

function colorize(i, j, element) {
	grid.data[i][j] = color();
	element.className = grid.data[i][j];
}

function paint(i0, j0) {
	var originColor = grid.data[i0][j0];
	var size = grid.element.children.length;
	var done = emptyGrid(size);
	var queue = [{i: i0, j: j0}];
	while(queue.length > 0) {
		var p0 = queue[0];
		colorize(p0.i, p0.j, grid.element.children[p0.i].children[p0.j]);
		done[p0.i][p0.j] = true;
		for(var d = -1; d < 2; d += 2) {
			[{i: p0.i + d, j: p0.j}, {i: p0.i, j: p0.j + d}].forEach(function(p1) {
				if(p1.i >= 0 && p1.i < size && p1.j >= 0 && p1.j < size
					&& !done[p1.i][p1.j]
					&& grid.data[p1.i][p1.j] == originColor) {
					queue.push(p1);
				}
			});
		}
		queue.shift();
	}
}