"use strict";

import ChunkReference from './ChunkReference.js';
import Rectangle from './Utilities/Rectangle.js';

class ChunkCache
{
	constructor(inBoardWindow)
	{
		this.boardWindow = inBoardWindow;
		this.cache = new Map();
	}
	
	/**
	 * Adds the given chunk to the chunk cache.
	 * @param {Chunk} chunkData The chunk to add to the cache.
	 */
	add(chunkData)
	{
		if(this.cache.contains(chunkData.chunkRef.toString()))
			throw new Error("Error: We already have a chunk at that location stored.");
		
		this.cache.set(chunkData.chunkRef.toString(), chunkData);
	}
	
	/**
	 * Renders the specified area to the given canvas with the given context.
	 * @param	{Rectangle}					visibleArea	The area to render.
	 * @param	{number}					chunkSize	The size of the chunks on the current plane.
	 * @param	{HTMLCanvasElement}			canvas		The canvas to draw on.
	 * @param	{CanvasRenderingContext2D}	context		The rendering context to
	 * 												 	use to draw on the canvas.
	 */
	renderVisible(visibleArea, chunkSize, canvas, context)
	{
		context.save();
		
		chunkArea = new Rectangle(
			Math.floor(visibleArea.x / chunkSize) * chunkSize,
			Math.floor(visibleArea.y / chunkSize) * chunkSize,
			Math.floor((visibleArea.x + visibleArea.width) / chunkSize) * chunkSize,
			Math.floor((visibleArea.y + visibleArea.height) / chunkSize) * chunkSize
		);
		
		for(let cx = chunkArea.x; cx <= chunkArea.x + chunkArea.width; cx += chunkSize)
		{
			for(let cy = chunkArea.y; cy <= chunkArea.y + chunkArea.height; cy += chunkSize)
			{
				let cChunk = new ChunkReference(
					this.boardWindow.currentPlaneName,
					cx, cy
				);
				let chunk = this.cache.get(cChunk.toString());
				chunk.render(canvas, context);
			}
		}
		
		context.restore();
	}
}

export default ChunkCache;