import sys, os, time, hashlib, uuid, threading, atexit, flask, \
	configparser as cp, magic
from flask import Flask, render_template, url_for, request, session, \
	send_from_directory, send_file, redirect, abort, Response
from flask_pymongo import PyMongo, ObjectId
from apscheduler.schedulers.background import BackgroundScheduler
from pytz import utc

FILTERS = {
	'name': 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz' +
				'0123456789_',
	'path': ['../', './']
}

def apply_config():
	config = cp.ConfigParser()
	config.read('config.ini')
	for k,v in config['Settings'].items():
		k = k.upper()
		if k == 'KEY_FILE':
			app.secret_key = open(v, 'rb').read()
		elif k == 'DEFAULT_VIRTUAL_SIZE':
			app.config[k] = int(v)
		else:
			app.config[k] = v

def expire():
	links = LINKS.find()
	for l in links:
		if l['expiry'] < time.time():
			print(l['expiry'])
			print(time.time())
			print("deleted")
			LINKS.delete_one({'_id': l['_id']})



os.chdir(os.path.dirname(__file__))

app = Flask(__name__)
apply_config()
mongo = PyMongo(app)

scheduler = BackgroundScheduler(timezone=utc)
scheduler.add_job(expire, 'interval', seconds=20)
scheduler.start()
atexit.register(lambda: scheduler.shutdown())

USERS, DRIVES, LINKS = mongo.db['users'], mongo.db['drives'], \
		mongo.db['links']


@app.route('/')
def index():
	if 'username' in session:
		return render_template('pre_main.html')
	else:
		return render_template('index.html')


@app.route('/main/<method>')
def main(method):
	return render_template(method+'.html')


@app.route('/login', methods=['POST'])
def login():
	error = None
	u, p = request.form['username'], request.form['password']
	success = validate_login(u, p)
	if success:
		session['username'] = u
		return flask.jsonify(True)
	else:
		return flask.jsonify(False)


@app.route('/logout')
def logout():
	session.pop('username', None)
	return redirect(url_for('index'))


@app.route('/mydrives')
def mydrives():
	if 'username' not in session:
		return redirect(url_for('index'))

	user_id = get_user(session)['_id']
	owned = DRIVES.find({'owner': user_id})
	shared = DRIVES.find({'shared_read': {'$in': [user_id]}})

	info = {'owned': [], 'shared': []}

	for drive in owned:
		drive_info = {
			'_id': str(drive['_id']),
			'name': drive['name'],
			'size': drive['size'],
			'public_read': drive['public_read'],
			'public_write': drive['public_write'],
			'shared_read': [str(i) for i in drive['shared_read']],
			'shared_write': [str(i) for i in drive['shared_write']]
		}
		info['owned'].append(drive_info)

	for drive in shared:
		drive_info = {
 			'_id': str(drive['_id']),
			'name': drive['name'],
			'size': drive['size']
		}
		info['shared'].append(drive_info)

	return flask.jsonify(info)


@app.route('/files/<method>', methods=['POST'])
def files(method):
	err_msgs = {
		'list': 'Error: This directory does not exist.',
		'zip': 'Error: Folder downloading not supported.'
	}
	check = verify_data('files', request.form, session)
	if not check[0]: return check[1], 400
	form = check[1]

	if method == 'list':
		if not form['is_fol']: return err_msgs['list']
		info = dir_info(form['path'], form['drive']['type'], \
				form['drive']['_id'])
		return flask.jsonify(info)

	elif method == 'download' or method == 'stream':
		if form['is_fol']:
			return err_msgs['zip']
		else:
			link_uuid = str(uuid.uuid4()).replace("-","")
			if method == 'download':
				expire = -1
			else:
				expire = time.time() + 20*60 # 20 minutes

			if form['drive']['type'] == 'real':
				link = LINKS.insert_one({
					'path': form['path'],
					'uuid': link_uuid,
					'name': form['path'].split("/")[-1],
					'shared': [get_user(session)['_id']],\
					'expiry': expire
				})
			elif form['drive']['type'] == 'virtual':
				r_path = form['drive']['path'] + '/' \
							+ form['real_file']
				link = LINKS.insert_one({
					'path': r_path,
					'uuid': link_uuid,
					'name': form['path'].split("/")[-1],
					'shared': [get_user(session)['_id']],
					'expiry': expire
				})
			else:
				raise Exception('Drive not real or virtual.')
			return link_uuid
	else:
		return redirect(url_for('index'))


@app.route('/d/<uuid>')
def download(uuid):
	if 'username' not in session:
		return redirect(url_for('index'))

	uuid = uuid.split('.')[0]
	try:
		link = LINKS.find_one({'uuid': uuid})
	except:
		return redirect(url_for('index'))

	if link == None: return redirect(url_for('index'))
	if get_user(session)['_id'] not in link['shared']:
		return redirect(url_for('index'))

	if link['expiry'] == -1:
		LINKS.delete_one({'uuid': uuid})
	else:
		LINKS.update_one({'uuid': uuid}, {
			'$set': {'expiry': time.time() + 20*60}
			})

	if 'pdf' in magic.from_file(link['path'], mime=True):
		r = send_file(link['path'])
		header = 'inline; filename=\"' + link['name'] + '\"'
		r.headers['Content-Disposition'] = header
		return r
	else:
		return send_file(link['path'], as_attachment=True,
							attachment_filename=link['name'],
							conditional=True)


@app.route('/changepass', methods=['POST'])
def changepass():
	## FIX LATER
	check = verify_data('changepass', request.form, session)
	if not check[0]: return check[1], 400
	form = check[1]

	salt = uuid.uuid4().hex
	to_hash = (form['password'] + salt).encode('utf-8')
	USERS.update_one({'username': form['username']},
		{'$set': {
			'password': hashlib.sha512(to_hash).digest(),
			'salt': salt
		}
	})
	return 'Operation completed'


@app.route('/users/<method>', methods=['POST'])
def users(method):
	if 'username' not in session:
		return redirect(url_for('index'))

	user = USERS.find_one({'username': session['username']})

	if method == 'create':
		check = verify_data('users.create', request.form, session)
		if not check[0]: return check[1], 400
		form = check[1]

		salt = uuid.uuid4().hex
		to_hash = (form['password'] + salt).encode('utf-8')
		user = USERS.insert_one({
			'username': form['username'],
			'password': hashlib.sha512(to_hash).digest(),
			'salt': salt,
		})

		create_drive('virtual', user.inserted_id)
		

	elif method == 'delete':
		check = verify_data('users.delete', request.form, session)
		if not check[0]: return check[1], 400
		form = check[1]
		USERS.delete_one({'username': form['username']})

	elif method == 'modify':
		pass
	return 'Operation completed'


@app.route('/drive/<drive_id>/<path:path>')
def drive_path():
	pass


@app.errorhandler(404)
def page_not_found(e):
	return render_template('404.html'), 404


# Temporary for development:
@app.route('/css/<path:path>')
def css(path):
	return send_from_directory('css', path)

@app.route('/js/<path:path>')
def js(path):
	return send_from_directory('js', path)

@app.route('/assets/<path:path>')
def assets(path):
	return send_from_directory('assets', path)

@app.route('/test/<path:path>')
def test(path):
	return send_from_directory('test', path)

# End temporary

def get_user(sess):
	return USERS.find_one({'username': session['username']})


def validate_login(u, p):
	user = USERS.find_one({'username': u})
	if user == None:
		return False
	else:
		to_hash = (p + user['salt']).encode('utf-8')
		return hashlib.sha512(to_hash).digest() == user['password']


def sizeof_fmt(num, suffix='B'):
	for unit in ['','K','M','G','T','P','E','Z']:
		if abs(num) < 1024.0:
			return '%3.1f%s%s' % (num, unit, suffix)
		num /= 1024.0
	return '%.1f%s%s' % (num, 'Y', suffix)


def dir_info(path, t, drive_id):
	def info_dict(item, stats, is_fol, filetype):
		if is_fol:
			my_item = ({
				'folder': True,
				'name': item
			})
		else:
			my_item = ({
				'name': item,
				'date': time.strftime('%Y-%m-%d %H:%M:%S UTC', \
						time.gmtime(stats[8])),
				'size': sizeof_fmt(stats[6]),
				'real_size': stats[6],
				'filetype': filetype
			})
		return my_item
	full_items = []

	if t == 'real':
		items = os.listdir(path)
		for item in items:
			f_path = path + '/' + item
			stats = list(os.stat(f_path))
			is_fol = os.path.isdir(f_path)
			if not is_fol:
				kind = magic.from_file(f_path, mime=True)
			else:
				kind = None

			full_items.append(info_dict(item, stats, is_fol, kind))

	elif t == 'virtual':
		drives = DRIVES.find_one({'_id': drive_id})
		tree = drives['tree']
		path = path.replace('.',':').split("/")[1:]
		if path != []:
			for sub in path: tree = tree[sub]

		for k,v in tree.items():
			is_fol = type(v).__name__ != 'str'
			if is_fol:
				stats, kind = None, None
			else:
				stats = list(os.stat(drives['path'] + '/' + v))
				kind = magic.from_file(drives['path'] + '/' + v,
						mime=True)

			full_items.append(info_dict(k.replace(':','.'), \
										stats, is_fol, kind))

	return full_items


def exists(data, need):
	try:
		[i in data for i in need].index(False)
		return False
	except ValueError:
		return True


def sanitize(d):
	if 'username' in d:
		s = ''
		for c in d['username']: s += c if c in FILTERS['name'] else ''
		d['username'] = s

	if 'path' in d:
		for s in FILTERS['path']:
			if s in d['path']:
				d['path'] = ''


def sess_is_user(sess, name):
	return sess['username'] == name


def sess_is_admin(sess):
	return get_user(sess)['perm_level'] == 100


def copy_dict(form):
	new_form = {}
	for k,v in form.items(): new_form[k] = v
	return new_form


def verify_data(method, form, sess):
	'''
	Verifies permissions and format and sanitizes user input.
	For each method, 1) Check for malformed data. 3) Check permissions
	for operation based on session. 3) Sanitize data. 4) Check
	operation specific requirements.
	'''

	err_msgs = {
		'data': 'malformed data',
		'permission': 'insufficient permissions',
		'userexists': 'username already in use',
		'usernotexist': 'user does not exist',
		'driveperm': 'the drive is not shared with you',
		'pathinvalid': 'not a valid path'
	}

	errors = []
	data = copy_dict(form)
	if method == 'users.create':
		has_items = exists(data, ['username', 'password'])
		if not has_items: errors.append('data')
		if not sess_is_admin(sess): errors.append('permission')

		sanitize(data)

		try:
			if USERS.find_one({'username': data['username']}) != None:
				errors.append('userexists')
		except KeyError:
			pass

	elif method == 'users.delete':
		has_items = exists(data, ['username'])
		if not has_items: errors.append('data')
		if not sess_is_admin(sess) and \
			not sess_is_user(sess, data['username']):
			return errors.append('permission')

		sanitize(data)

	elif method == 'users.modify':
		pass

	elif method == 'changepass':
		### REIMPLEMENT LATER
		has_items = exists(data, ['username', 'password'])
		if not has_items: errors.append('data')

		sanitize(data)

		try:
			if USERS.find_one({'username': data['username']}) == None:
				errors.append('usernotexist')
		except KeyError:
			pass

	elif method == 'files':
		has_items = exists(data, ['drive_id', 'path'])
		if not has_items: errors.append('data')

		drive = DRIVES.find_one({'_id': ObjectId(data['drive_id'])})
		if drive == None: errors.append('driveinvalid')

		if not drive['public_read']:
			user_id = get_user(sess)['_id']
			if user_id != drive['owner'] and \
				user_id not in drive['shared_read']:
				errors.append('driveperm')

		sanitize(data)

		if drive['type'] == 'real':
			if not os.path.exists(drive['path'] + data['path']):
				errors.append('pathinvalid')
			data['is_fol'] = os.path.isdir(drive['path'] + \
												data['path'])

			# For real drives, the path is kept as the full real path.
			data['path'] = drive['path']+data['path']
		elif drive['type'] == 'virtual':
			tree = drive['tree']
			path = data['path'].replace('.',':').split('/')[1:]
			if path != []:
				folder, f = path[:-1], path[-1]
				try:
					for sub in folder: tree = tree[sub]
					data['is_fol'] = type(tree[f]).__name__ != 'str'
					data['real_file'] = tree[f]
				except KeyError:
					errors.append('pathinvalid')
			else:
				data['is_fol'] = True

			# For virtual drives, the path is just the user request.

		data['drive'] = drive
	else:
		raise Exception('Invalid data verification method.')

	if len(errors) == 0: return [True, data]

	msg = 'Error: '
	for i,e in enumerate(errors):
		if len(errors) == 1:
			msg += err_msgs[e][0].upper() + err_msgs[e][1:]
		elif i == 0:
			msg += err_msgs[e][0].upper() + err_msgs[e][1:] + ', '
		elif i == len(errors)-1:
			msg += 'and ' + err_msgs[e]
		else:
			msg += err_msgs[e] + ', '
	msg += '.'

	if len(errors) <= 2: msg = msg.replace(',', '')

	return [False, msg]


def create_drive(method, owner, form=None):
	if method == 'real':
		DRIVES.insert_one({
			'name': form['name'],
			'path': form['path'],
			'type': 'real',
			'owner': owner,
			'public_read': False,
			'public_write': False,
			'shared_read': [],
			'shared_write': []
		})
	elif method == 'virtual':
		vir_path = app.config['VIRTUAL_DB_PATH'] + "/" + str(owner)
		name = str(uuid.uuid4())+str(uuid.uuid4())
		DRIVES.insert_one({
			'name': 'My Drive',
			'path': vir_path,
			'tree': {
				'Welcome:txt': name
			},
			'type': 'virtual',
			'size': app.config['DEFAULT_VIRTUAL_SIZE'],
			'owner': owner,
			'public_read': False,
			'public_write': False,
			'shared_read': [],
			'shared_write': []
		})

		os.mkdir(vir_path)
		file = open(vir_path+'/'+name, 'w')
		file.write(app.config['WELCOME_MSG'])
		file.close()

	else:
		raise Exception('Invalid drive creation method.')

	return 'Operation completed.'


if __name__ == '__main__':
	app.run(debug=True)