import { WASM_MEMORY_PAGE_SIZE, appGlobals } from './globals.js'
import { loadWasmModule, wasmPntrToJsString, wasmPntrAndLengthToJsString } from './wasm_functions.js'
import { jsStdFunctions } from './std_functions.js'
import { jsGlFunctions } from './gl_functions.js'
import { jsMiscFunctions } from './misc_functions.js'

function AcquireCanvas(canvasWidth, canvasHeight)
{
	var canvas = document.getElementsByTagName("canvas")[0];
	// console.log(canvas);
	
	// set the display size of the canvas.
	canvas.style.width = canvasWidth + "px";
	canvas.style.height = canvasHeight + "px";
	
	// set the size of the drawingBuffer
	var devicePixelRatio = window.devicePixelRatio || 1;
	canvas.width = canvasWidth * devicePixelRatio;
	canvas.height = canvasHeight * devicePixelRatio;
	
	// canvasContainer = document.getElementById("canvas_container");
	// console.assert(canvasContainer != null, "Couldn't find canvas container DOM element!");
	appGlobals.canvas = canvas;
}

async function MainLoop()
{
	appGlobals.textDecoder = new TextDecoder("utf-8");
	appGlobals.textEncoder = new TextEncoder("utf-8");
	
	console.log("Initializing WebGL Canvas...");
	AcquireCanvas(600, 400);
	
	var canvasContextGl = appGlobals.canvas.getContext("webgl2");
	if (canvasContextGl === null) { console.error("Unable to initialize WebGL render context. Your browser or machine may not support it :("); return; }
	// console.dir(canvasContextGl);
	appGlobals.glContext = canvasContextGl;
	
	console.log("Loading WASM Module...");
	appGlobals.wasmModule = await loadWasmModule("app.wasm", { ...jsStdFunctions, ...jsGlFunctions, ...jsMiscFunctions });
	appGlobals.memDataView = new DataView(new Uint8Array(appGlobals.wasmModule.exports.memory.buffer).buffer);
	
	let initSuccess = appGlobals.wasmModule.exports.App_Initialize();
	
	if (initSuccess)
	{
		var resourcePaths = [];
		var resourceIndex = 0;
		while (true)
		{
			let resourcePathPntr = appGlobals.wasmModule.exports.App_GetResourcePath(resourceIndex);
			if (resourcePathPntr == 0) { break; }
			let resourcePathStr = wasmPntrToJsString(resourcePathPntr);
			resourcePaths.push(resourcePathStr);
			resourceIndex++;
		}
		
		console.log("Running!");
		function renderFrame(currentTime)
		{
			let shouldContinue = appGlobals.wasmModule.exports.App_UpdateAndRender(currentTime);
			if (shouldContinue) { window.requestAnimationFrame(renderFrame); }
			else { appGlobals.wasmModule.exports.App_Close(); }
		}
		window.requestAnimationFrame(renderFrame);
		
		if (resourcePaths.length > 0)
		{
			console.log("Loading " + resourcePaths.length + " Resource" + (resourcePaths.length == 1 ? "" : "s") + "...");
			// console.dir(resourcePaths);
			for (var rIndex = 0; rIndex < resourcePaths.length; rIndex++)
			{
				const file = await fetch(resourcePaths[rIndex]);
				if (file.ok)
				{
					const fileBytes = await file.arrayBuffer();
					// console.log(fileBytes);
					var fileBytesPntr = 0;
					var scratchArenaPntr = 0;
					var scratchArenaMark = 0;
					if (fileBytes.byteLength > 0)
					{
						scratchArenaPntr = appGlobals.wasmModule.exports.cGetScratchArenaPntr(0);
						scratchArenaMark = appGlobals.wasmModule.exports.cGetScratchArenaMark(0);
						fileBytesPntr = appGlobals.wasmModule.exports.cAllocMem(scratchArenaPntr, fileBytes.byteLength);
						if (fileBytesPntr != 0)
						{
							const writeArray = new Uint8Array(appGlobals.wasmModule.exports.memory.buffer);
							writeArray.set(new Uint8Array(fileBytes), fileBytesPntr);
						}
						else { console.error("Failed to allocate " + fileBytes.byteLength + " byte resource[" + rIndex + "] from \"" + resourcePaths[rIndex] + "\""); }
					}
					appGlobals.wasmModule.exports.App_ResourceLoaded(rIndex, fileBytes.byteLength, fileBytesPntr);
					if (fileBytes.byteLength > 0 && fileBytesPntr != 0) { appGlobals.wasmModule.exports.cEndScratchArena(scratchArenaPntr, scratchArenaMark); }
				}
				else
				{
					console.error("Failed to fetch resource[" + rIndex + "] from \"" + resourcePaths[rIndex] + "\"");
					appGlobals.wasmModule.exports.App_ResourceLoaded(rIndex, 0, 0);
				}
			}
		}
	}
	else
	{
		console.error("Initialization failed!");
	}
}

MainLoop();