'use strict';

function onMountRequested(successCallback, errorCallback) {
	console.log("mount requested");
	getMountInfo(function(mountInfo) { mount(mountInfo, successCallback, errorCallback); });
}


function getMountInfo(callback) {
	let windowCallback = function(appWindow) {
		let listener = function(message) {
			if(message.senderId == appWindow.id) {
				callback(message.mountInfo);
			} else {
				console.log(message);
				console.log(appWindow);
				console.log(message.senderId);
				console.log(appWindow.id);
			}
			chrome.runtime.onMessage.removeListener(listener);
		};
		chrome.runtime.onMessage.addListener(listener);
	};

	let windowOptions = { outerBounds : { width: 800, height: 600 }, resizable : false, id: Date.now().toString() };
	chrome.app.window.create("mount-info.html", windowOptions, windowCallback);
}

function mount(mountInfo, successCallback, errorCallback) {
	console.log("mount()");
	let request = new XMLHttpRequest();
	request.open("GET", mountInfo.url);
	request.onreadystatechange = function() {
		if(request.readyState != XMLHttpRequest.DONE) return;

		try {
			JSON.parse(request.responseText);

			let options = { fileSystemId: mountInfo.url, displayName: mountInfo.name, writable: false };
			chrome.fileSystemProvider.mount(options);

			console.log("mount succeeded");
			successCallback();
		} catch(exception) {
			console.log(exception);
			console.log("mount failed");
			errorCallback();
			//TODO: Properly show error (e.g. notification)
		}
	};
	request.send();
}

function readDirectory(options, successCallback, errorCallback) {
	let request = new XMLHttpRequest();
	request.open("GET", options.fileSystemId + "/" + options.directoryPath);
	request.onreadystatechange = function() {
		if(request.readyState != XMLHttpRequest.DONE) return;

		try {
			let json = JSON.parse(request.responseText);
			let entries = json.map(function(item) {
				let entry = {};
				if(options.isDirectory) {
					entry.isDirectory = item.type == "directory";
				}
				if(options.name) {
					entry.name = item.name;
				}
				if(options.size) {
					entry.size = item.size;
				}
				if(options.modificationTime) {
					entry.modificationTime = new Date(item.mtime);
				}
				return entry;
			});

			successCallback(entries, false);
		} catch(exception) {
			console.log(exception);
			console.log("readDirectory failed");
			errorCallback("FAILED");
			//TODO: Properly show error (e.g. notification)
		}
	};
	request.send();
}

function getMetadata(options, successCallback, errorCallback) {
	if(options.entryPath == "/") {
		successCallback({ isDirectory: true, name: "", size: 0, modificationTime: new Date() });
	} else {
		let parentDirectory = options.entryPath.substring(0, options.entryPath.lastIndexOf('/') + 1);
		let baseName = options.entryPath.substr(options.entryPath.lastIndexOf('/') + 1);
		options.directoryPath = parentDirectory;
		let nameRequested = options.name;
		options.name = true;
		readDirectory(options, function(entries, more) {
			for(let entry of entries) {
				if(entry.name == baseName) {
					if(!nameRequested) {
						delete entry.name;
						options.name = false;
					}
					successCallback(entry);
					return;
				}
			}
			errorCallback("NOT_FOUND");
		}, errorCallback);
	}
}

let openFiles = {};

function openFile(options, successCallback, errorCallback) {
	//TODO: Check if file exists (through getMetadata, or by sending HEAD for the file)

	openFiles[options.requestId] = options.fileSystemId + options.filePath;
	successCallback();
}

function closeFile(options, successCallback, errorCallback) {
	if(options.openRequestId in openFiles) {
		delete openFiles[options.openRequestId];
		successCallback();
	} else {
		errorCallback("FAILED");
	}
}

function readFile(options, successCallback, errorCallback) {
	let url = openFiles[options.openRequestId];
	let start = options.offset;
	let end = start + options.length - 1;

	let request = new XMLHttpRequest();
	request.open("GET", url);
	request.setRequestHeader("Range", "bytes=" + start + "-" + end);
	request.responseType = "arraybuffer";
	request.onreadystatechange = function() {
		if(request.readyState != XMLHttpRequest.DONE) return;

		successCallback(request.response, false);
	}
	try {
		request.send();
	} catch(exception) {
		if(request.status == 404) {
			errorCallback("NOT_FOUND");
		} else {
			console.log("readFile failed");
			console.log(exception);
			errorCallback("FAILED");
		}
	}
}

chrome.fileSystemProvider.onMountRequested.addListener(onMountRequested);
chrome.fileSystemProvider.onReadDirectoryRequested.addListener(readDirectory);
chrome.fileSystemProvider.onGetMetadataRequested.addListener(getMetadata);
chrome.fileSystemProvider.onOpenFileRequested.addListener(openFile);
chrome.fileSystemProvider.onCloseFileRequested.addListener(closeFile);
chrome.fileSystemProvider.onReadFileRequested.addListener(readFile);