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#!/usr/bin/env python3
# MiniPOS - A self-hosted, 0-confirmation Bitcoin Cash point-of-sale server
# Author: Simon Volpert <simon@simonvolpert.com>
# Project page: https://simonvolpert.com/minipos/
# This program is free software, released under the Apache License, Version 2.0. See the LICENSE file for more information
# Consult the README file for usage instructions and other helpful hints

import os
import sys
from wsgiref.simple_server import make_server
import urllib.parse
import datetime
import qrcode
import io
import random
import base64
import threading
import logging

# Local library files
import bch
import sendmail
import tridenticon

# Useful constants
NORMAL_FEE = 1.0
LOW_FEE = 0.5

usage = '''Usage: minipos [DATA_DIRECTORY]
See the README file for more information.'''
config = {
	'addresses': [],
	'lock': {
		'@': None,
	},
	'cache': [],
}
binary_extensions = ['png', 'jpg', 'gif', 'ico']
mime_types = {
	'txt': 'text/plain',
	'css': 'text/css',
	'js': 'text/javascript',
	'png': 'image/png',
	'jpg': 'image/jpeg',
	'gif': 'image/gif',
	'svg': 'image/svg+xml',
	'ico': 'image/x-icon',
}
# A list of files which will always be served regardless of access control settings
file_whitelist = ['style.css', 'logo.svg', 'logo.png', 'logo.gif', 'logo.jpg', 'favicon.png', 'favicon.ico']

# Set up logging
logger = logging.getLogger()
handler = logging.StreamHandler(sys.stdout)
handler.setLevel(logging.DEBUG)
handler.setFormatter(logging.Formatter('%(asctime)s [%(levelname)s] %(message)s'))
logger.addHandler(handler)
logger.setLevel(logging.INFO)

# Look for the directory containing the configuration files
lib_dir = os.path.dirname(os.path.abspath(__file__))
data_dir_locations = [
	os.path.join(os.path.expanduser('~'), '.minipos'),
	os.path.join(os.path.expanduser('~'), '.config', 'minipos'),
	lib_dir,
	os.getcwd()
]
if len(sys.argv) > 1:
	if sys.argv[1] == '-h' or sys.argv[1] == '--help':
		print(usage)
		sys.exit(0)
	else:
		data_dir_locations.insert(0, os.path.abspath(sys.argv[1]))
		if not os.path.isdir(data_dir_locations[0]):
			print('No such directory: ' + data_dir_locations[0])
for data_dir in data_dir_locations:
	try:
		os.chdir(data_dir)
	except (OSError, NotADirectoryError):
		continue
	if os.path.isfile('minipos.cfg'):
		logging.info('Using {} as data directory'.format(data_dir))
		break
# Load the config file
try:
	with open('minipos.cfg', 'r') as f:
		lines = f.readlines()
except (IOError, OSError, FileNotFoundError, PermissionError) as error:
	logging.warning('Could not open configuration file, using default settings ({})'.format(error))
	lines = []
for line in lines:
	# Skip blank lines and comments
	if line.strip() == '' or line.startswith('#'):
		continue
	# Split to key and value pairs
	words = line.strip().split('=')
	key = words[0].strip()
	value = '='.join(words[1:]).strip()
	# Skip empty values
	if value == '':
		continue
	elif key in ['sightings', 'index']:
		logging.warning('The "{}" option is depreciated'.format(key))
		continue
	if key == 'address':
		config['addresses'].append(value)
	else:
		config[key] = value
# Read the auxillary address list, if present
try:
	with open('address.list', 'r') as f:
		lines = f.readlines()
except (IOError, OSError, FileNotFoundError, PermissionError):
	lines = []
for line in lines:
	_addr = line.strip()
	if _addr == '':
		continue
	elif _addr in config['addresses']:
		logging.warning('Discarding duplicate address {}'.format(_addr))
		continue
	config['addresses'].append(_addr)


# Utility config parsing functions
def cast_config_type(key, _type, default):
	try:
		config[key] = _type(config[key])
	except (KeyError, ValueError):
		config[key] = default


def clamp_config_value(_name, _min=None, _max=None, default=0):
	if _min is not None and config[_name] < _min:
		logging.warning('Invalid "{}" value, falling back to {}'.format(_name, default))
		config[_name] = default
	elif _max is not None and config[_name] > _max:
		logging.warning('Invalid "{}" value, falling back to {}'.format(_name, default))
		config[_name] = default


def split_config_key(key, default):
	if key not in config:
		config[key] = [default]
	else:
		config[key] = config[key].split(',')


def pick_config_list(key, value_list):
	if key not in config:
		config[key] = value_list[0]
	else:
		if config[key] not in value_list:
			logging.warning('Invalid "{}" value, falling back to "{}"'.format(key, value_list[0]))
			config[key] = value_list[0]


# Sanitize the config file
cast_config_type('taxrate', float, 0)
cast_config_type('port', int, 8080)
cast_config_type('propagation', int, 60)
clamp_config_value('propagation', 0, 100, 60)
cast_config_type('welcome_timeout', int, 120)
clamp_config_value('welcome_timeout', 0, None, 120)
split_config_key('currencies', 'USD')
split_config_key('allowed_ips', '127.0.0.1')
pick_config_list('unit', ['native', 'bits', 'cash', 'satoshi'])
pick_config_list('payment_return', ['request', 'welcome'])
pick_config_list('log_order', ['ascending', 'descending'])
if 'week_start' not in config or config['week_start'] == 'monday':
	config['week_start'] = 0
elif config['week_start'] == 'sunday':
	config['week_start'] = 1
else:
	logging.warning('Invalid "week_start" value, falling back to "monday"')
	config['week_start'] = 0
if 'label' not in config or config['label'] == '':
	config['label'] = 'MiniPOS'
exchange_list = []
for e in bch.exchanges:
	exchange_list.append(e['name'])
if 'price_source' not in config or config['price_source'] not in exchange_list:
	logging.info('Using default exchange rate source "{}"'.format(exchange_list[0]))
	config['price_source'] = exchange_list[0]
if 'custom_unit_satoshi' in config:
	config['custom_unit_satoshi'] = True if config['custom_unit_satoshi'].lower() in ['1', 'yes', 'on', 'true'] else False
config['auto_cents'] = True if 'auto_cents' in config and config['auto_cents'].lower() in ['1', 'yes', 'on', 'true'] else False
config['fingerprinting'] = True if 'fingerprinting' in config and config['fingerprinting'].lower() in ['1', 'yes', 'on', 'true'] else False
config['receive_notify'] = True if 'receive_notify' in config and config['receive_notify'].lower() in ['1', 'yes', 'on', 'true'] else False
# Prune meaningless values from configuration
config['allowed_ips'] = set(config['allowed_ips'])
if '127.0.0.1' in config['allowed_ips']:
	config['allowed_ips'].remove('127.0.0.1')
# Try to set up a custom block explorer
custom_explorer = None
try:
	custom_explorer = {
		'name': '.'.join(config['custom_explorer_url'].split('/')[2].split('.')[-2:]),
		'url': config['custom_explorer_url'],
		'tx_url': config['custom_tx_url'],
		'balance_key': config['custom_balance_key'],
		'confirmed_key': config['custom_confirmed_key'],
		'unconfirmed_key': config['custom_unconfirmed_key'],
		'last_tx_key': config['custom_last_tx_key'],
		'tx_time_key': config['custom_tx_time_key'],
		'tx_inputs_key': config['custom_tx_inputs_key'],
		'tx_in_double_spend_key': config['custom_tx_in_double_spend_key'],
		'tx_outputs_key': config['custom_tx_outputs_key'],
		'tx_out_value_key': config['custom_tx_out_value_key'],
		'tx_out_address_key': config['custom_tx_out_address_key'],
		'tx_double_spend_key': config['custom_tx_double_spend_key'],
		'tx_fee_key': config['custom_tx_fee_key'],
		'tx_size_key': config['custom_tx_size_key'],
		'unit_satoshi': config['custom_unit_satoshi'],
		'prefixes': config['custom_prefixes'],
	}
	for key in custom_explorer:
		if custom_explorer[key].lower() == 'none':
			custom_explorer[key] = None
	bch.explorers.insert(0, custom_explorer)
	custom_explorer = custom_explorer['name']
	logging.info('Using custom explorer definition: {}'.format(custom_explorer))
except KeyError as error:
	if str(error) != "'custom_explorer_url'":
		logging.warning('Missing key in custom explorer definition: {}'.format(error))


# Write cached address list to address.list
def write_address_list():
	address_list = []
	# Free receiving addresses
	for entry in config['addresses']:
		if type(entry) is tuple:
			address_list.append('{} {}'.format(*entry))
		else:
			address_list.append(entry)
	# Locked receiving addresses
	for entry in config['lock'].values():
		if type(entry) is dict:
			if 'index' in entry:
				address_list.append('{} {}'.format(entry['address'], entry['index']))
			else:
				address_list.append(entry['address'])
	# Perform the write
	try:
		with open(os.path.join(data_dir, 'address.list'), 'w') as f:
			f.write('\n'.join(address_list) + '\n')
	except (IOError, OSError, PermissionError) as error:
		logging.error('Could not write address.list: {}'.format(error))


# Utility wrapper function
def load_file(filename, override=False, null=False):
	extension = filename.split('.')[-1]
	file_mode = 'rb' if extension in binary_extensions else 'r'
	if extension == 'html':
		directory = 'templates'
	elif extension == 'log':
		directory = 'logs'
	else:
		directory = 'assets'
	if override or directory == 'logs':
		try:
			with open(os.path.join(data_dir, directory, filename), file_mode) as src:
				return src.read()
		except (IOError, OSError, PermissionError):
			pass
	try:
		with open(os.path.join(lib_dir, directory, filename), file_mode) as src:
			return src.read()
	except (IOError, OSError, PermissionError):
		if null:
			return ''
		raise


# Cast amount into preferred units
def format_amount(amount):
	token = 'BCH' if config['unit'] == 'native' else config['unit']
	if config['unit'] in ['bits', 'cash']:
		amount = bch.bits(float(amount))
	elif config['unit'] == 'satoshi':
		amount = str(int(float(amount) * 100000000))
	return amount, token


# Generate a new receiving address and add it in the cache
def generate_new_address():
	address = bch.generate_address(config['xpub'], config['index'])
	logging.debug('Generated new address {} with derivation index {}'.format(address, config['index']))
	config['addresses'].append((address, config['index']))
	config['index'] += 1


# Create a payment request QR page
def create_invoice(parameters):
	if 'currency' not in parameters:
		parameters['currency'] = config['currencies']
	currency = parameters['currency'][0]
	divider = 100 if config['auto_cents'] else 1
	fiat = float(parameters['amount'][0]) / divider
	if fiat <= 0.0:
		raise ValueError('Requested amount must be positive')
	# Check for address lock timeouts
	for k in list(config['lock']):
		if k != '@' and check_lock_timeout(k):
			logging.info('Payment request {} timed out'.format(k))
			unlock_address(k)
	# Use the next available address
	if config['addresses'] == []:
		if 'xpub' in config:
			generate_new_address()
			write_address_list()
		else:
			return load_file('noaddrs.html')
	address = config['addresses'].pop(0)
	# Generate a lock tag
	tag = ''
	for i in range(7):
		tag += random.choice('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ')
	# Lock the address
	lock_address(tag)
	request = config['lock'][tag]
	if type(address) is tuple:
		request['address'], request['index'] = address
		address = request['address']
	else:
		request['address'] = address
	# Get the exchange rate
	try:
		price = bch.get_price(currency, exchange=config['price_source'])
	except KeyboardInterrupt:
		raise
	except:
		logging.error(sys.exc_info()[1])
		return load_file('timeout.html')
	# Calculate amount
	amount = bch.btc(fiat / price)
	if float(amount) > 20999950:
		raise ValueError('Requested amount is greater than logically possible')
	# Get current address state
	try:
		txid = bch.get_last_txid(address, explorer=custom_explorer)
	except KeyboardInterrupt:
		raise
	except:
		logging.error(sys.exc_info()[1])
		unlock_address(tag)
		return load_file('timeout.html')
	request['seen_txids'] = [] if txid is None else [txid]
	request['amount'] = amount
	request['fiat'] = bch.fiat(fiat)
	request['currency'] = currency
	# Generate the invoice URI and QR code
	logging.info('New invoice {tag}: {amount} BCH ({fiat} {currency}) to {address}'.format(tag=tag, **request))
	label = urllib.parse.quote('%s ID:%s' % (config['label'], tag))
	data = 'bitcoincash:{addr}?amount={amt}&message={label}'.format(addr=address, amt=amount, label=label)
	image = qrcode.make(data, box_size=7, error_correction=qrcode.constants.ERROR_CORRECT_L)
	# Overlay a visual fingerprint over the QR code
	if 'hash' in config:
		icon = config['hash']
		image = image.get_image().convert('RGB')
		image_width, image_height = image.size
		icon_width, icon_height = icon.size
		image.paste(icon, (image_width // 2 - icon_width // 2, image_height // 2 - icon_height // 2))
	# Convert QR code into text data
	output = io.BytesIO()
	image.save(output, format='PNG')
	output = base64.b64encode(output.getvalue()).decode('UTF-8')
	amt, token = format_amount(amount)
	filler = {
		'addr': address,
		'amt': amt,
		'token': token,
		'qr': output,
		'request': data,
		'fiat': bch.fiat(fiat),
		'cur': currency,
		'price': bch.fiat(price),
		'tag': tag,
		'return': config['payment_return'],
		'label': config['label'],
	}
	# Load user template override
	invoice_text = load_file('invoice_text.html', override=True)
	if '<script' in invoice_text.lower():
		logging.warning('Script detected in user invoice_text.html, override rejected')
		invoice_text = load_file('invoice_text.html')
	filler['text'] = invoice_text.format_map(filler)
	page = load_file('invoice.html').format_map(filler)
	return page


# API check if a payment was received
def check_payment(parameters):
	# Responses:
	# 0 - not yet received
	# 1 - payment detected (with txid)
	# 2 - payment request timed out
	# 3 - server connection error
	# 4 - client connection error
	# 5 - double spend detected (with txid)
	# 6 - low fee (with txid)
	tag = parameters['id'][0]
	if tag not in config['lock']:
		return '2'
	# Update address lock
	if check_lock_timeout(tag):
		logging.info('Payment request {} timed out'.format(tag))
		unlock_address(tag)
		return '2'
	lock_address(tag)
	# Check address state
	request = config['lock'][tag]
	address = request['address']
	amount = float(request['amount'])
	# No previously detected transaction
	if 'txid' not in request:
		try:
			txid = bch.get_last_txid(address)
		except KeyboardInterrupt:
			raise
		except:
			logging.warning('Could not fetch address info: {}'.format(sys.exc_info()[1]))
			return '3'
		# No new transactions
		if txid is None:
			return '0'
		# Previously seen transaction
		elif txid in request['seen_txids']:
			return '0'
		elif txid in config['cache']:
			return '0'
		# New transaction
		try:
			tx = bch.TxInfo(txid, explorer=bch.explorers[-1]['name'])
		except KeyboardInterrupt:
			raise
		except bch.TxNotFoundError:
			logging.warning('Anomalous event: tx not found on reporting explorer')
			return '0' # TODO anomaly!
		except:
			logging.warning('Could not fetch address info: {}'.format(sys.exc_info()[1]))
			return '3'
		# Transaction is known-old
		if tx.time < request['ctime']:
			logging.info('Ignoring old tx {}'.format(txid))
			request['seen_txids'].append(txid)
			return '0'
		elif address not in tx.outputs:
			logging.info('Ignoring mis-addressed tx {}'.format(txid)) # TODO anomaly!
			request['seen_txids'].append(txid)
			return '0'
		# Wrong transaction amount
		elif tx.outputs[address] != amount:
			logging.info('Ignoring tx with wrong amount {}'.format(txid))
			request['seen_txids'].append(txid)
			return '0'
		# All checks passed make note of the transaction
		request['txid'] = txid
		logging.info('Payment {} detected'.format(tag))
		# Double spend check
		if tx.double_spend:
			logging.warning('Double spend detected, waiting for confitmation')
			request['wait_confirm'] = True
			return '5 ' + txid
		# Check transaction fee
		if tx.fee_per_byte >= NORMAL_FEE:
			logging.debug('Tx has sufficient fee ({:.3f}), skipping propagation check'.format(tx.fee_per_byte))
		else:
			if tx.fee_per_byte < LOW_FEE:
				logging.debug('Tx has low fee ({:.3f})'.format(tx.fee_per_byte))
				request['low_fee'] = True
			# Propagation check needed, defer processing
			if config['propagation'] > 0:
				return '0'
			logging.debug('Skipping propagation check by user config')
	# Previously detected transaction
	else:
		# Currently waiting for confirmation
		if 'wait_confirm' in request:
			try:
				tx = bch.TxInfo(txid)
			except KeyboardInterrupt:
				raise
			except:
				logging.warning('Could not get transaction info: {}'.format(sys.exc_info()[1]))
				return '3'
			if tx.confirmations == 0:
				if tx.double_spend:
					return '5 ' + txid
				return '0'
		# Not currently waiting for confirmation
		else:
			txid = request['txid']
			try:
				propagation, double_spend = bch.get_tx_propagation(txid, threshold=config['propagation'], stop_on_double_spend=True)
			except KeyboardInterrupt:
				raise
			except:
				logging.warning('Could not get propagation information: {}'.format(sys.exc_info()[1]))
				return '3'
			# Is double spend
			if double_spend:
				request['wait_confirm'] = True
				return '5 ' + txid
			# Low propagation
			elif propagation < config['propagation']:
				if 'low_fee' in request:
					return '6 ' + txid
				return '0'
	# Record the payment
	record_payment(tag)
	config['cache'].append(txid)
	unlock_address(tag)
	# Remove this address from future use if generated
	if 'xpub' in config:
		config['addresses'].remove((address, request['index']))
		logging.debug('Removing used address {}'.format(address))
		# Generate a new address if on the last derivation index to keep the index saved
		if request['index'] + 1 == config['index']:
			generate_new_address()
		write_address_list()
	return '1 ' + txid


# Write the details of the payment to a log file
def record_payment(tag):
	logging.info('Payment {} received'.format(tag))
	request = config['lock'][tag]
	log_dir = os.path.join(data_dir, 'logs')
	if not os.path.isdir(log_dir):
		os.mkdir(log_dir)
	logfile = os.path.join(log_dir, datetime.date.today().isoformat() + '.log')
	with log_lock:
		with open(logfile, 'a') as log:
			log.write('{date}	{address}	{amount}	{fiat} {currency}	{tag}	{txid}\n'.format(date=datetime.datetime.now().isoformat(), tag=tag, **request))
	# Send a notification
	if config['receive_notify'] and 'email' in config:
		subject = '[MiniPOS] New payment received, ID: {}'.format(tag)
		_amount, token = format_amount(request['amount'])
		body = '''Date and time: {date}
Address: {address}
Amount: {amt} {token}
Amount (fiat): {fiat} {currency}
TxID: https://bch.btc.com/{txid}'''.format(date=datetime.datetime.now().isoformat().split('.')[0].replace('T', ' '), token=token, amt=_amount, **request)
		sendmail.background_send(config, config['email'], subject, body)


# Lock an address to prevent concurrent access
def lock_address(tag):
	if tag not in config['lock']:
		config['lock'][tag] = {
			'ctime': datetime.datetime.now()
		}
	config['lock'][tag]['time'] = datetime.datetime.now()


# Free address lock
def unlock_address(tag):
	if tag in config['lock']:
		request = config['lock'][tag]
		if 'index' in request:
			config['addresses'].append((request['address'], request['index']))
		else:
			config['addresses'].append(request['address'])
		del(config['lock'][tag])


# Check address lock timeout
def check_lock_timeout(tag):
	if tag not in config['lock']:
		return True
	delta = datetime.datetime.now() - config['lock'][tag]['time']
	if delta >= datetime.timedelta(seconds=60):
		return True
	return False


# Parse a log file and add its contents to the table
def read_log_file(filename, plaintext=False, txids=False, reverse_order=False):
	if plaintext and txids:
		raise RuntimeError('read_log_file: the "plaintext" and "txids" parameters are incompatible')
	table = [] if txids else ''
	totals = {}
	try:
		logfile = open(os.path.join(data_dir, filename), 'r')
	except:
		if sys.exc_info()[0] not in [IOError, OSError, FileNotFoundError, PermissionError]:
			logging.warning(sys.exc_info()[1])
		return totals, table
	try:
		for line in logfile.readlines():
			line = line.strip().split('	')
			while len(line) < 6:
				line.append('')
			date, address, amount, fiat, tag, txid = line
			amount, token = format_amount(amount)
			fiat, currency = fiat.split(' ')
			if currency not in totals:
				totals[currency] = 0
			totals[currency] += float(fiat)
			date = date.split('.')[0].replace('T', ' ')
			if txids:
				if txid != '':
					table.append(txid)
			elif plaintext:
				line = '{date}  {amt}  {fiat} {cur}  {tag}\n  Address: {addr}\n  TxID: {txid}\n'.format(date=date, addr=address, amt=str(amount).rjust(17 + len(token)), fiat=str(fiat).rjust(15), cur=currency, tag=tag, txid=txid)
				if reverse_order:
					table = line + table
				else:
					table += line
			else:
				line = '''<tr class="%STYLE%">
<td><a id="toggle%ROW%" href="javascript:toggleRow(%ROW%);">+</a></td>
<td>{date}</td><td>{fiat} {cur}</td><td>{tag}</td>
</tr>
<tr class="%STYLE% expand" id="row%ROW%">
<td colspan="4"><strong>Address:</strong> <a href="https://bch.btc.com/{addr}" class="address" target="_blank"><img class="icon" src="icon.svg" alt="">{addr}</a><br>
<strong>Amount:</strong> <span>{amt} {token}</span><br>
<strong>TxID:</strong> <span class="txid"><a href="https://bch.btc.com/{txid}" target="_blank">{txid}</a></span></td></tr>\n'''.format(date=date, amt=amount, fiat=fiat, cur=currency, tag=tag, token=token, addr=address, txid=txid)
				if reverse_order:
					table = line + table
				else:
					table += line
	except:
		logging.warning('Log file is corrupted: {file} ({error})'.format(file=filename, error=sys.exc_info()[1]))
		msg = 'The log file for {file} is corrupted!'.format(file=filename.split('/')[1].split('.')[0])
		if not plaintext:
			msg = '<tr class="%STYLE%"><td colspan="5" class="error">' + msg + '</td></tr>'
		if txids:
			pass
		else:
			if reverse_order:
				table = msg + table
			else:
				table += msg
	logfile.close()
	return totals, table


# Display a log of recent transactions
def show_logs(parameters, plaintext=False):
	if 'date' not in parameters:
		date = datetime.date.today().isoformat()
	else:
		date = parameters['date'][0]
	# Process the current and calculate next and previous date
	days = []
	tally = False
	# Day scope
	if len(date) == 10:
		d = datetime.datetime.strptime(date, '%Y-%m-%d')
		delta = datetime.timedelta(1)
		next_date = (d + delta).date().isoformat()
		prev_date = (d - delta).date().isoformat()
		tag_s = 'W'
		scope_s = '%s-W%02d' % d.isocalendar()[0:2]
		tag_m = 'M'
		scope_m = '%s-%s' % (d.year, str(d.month).zfill(2))
		tag_l = 'Y'
		scope_l = str(d.year)
		days = [date]
	# Week scope
	elif len(date) == 8:
		# Convert ISO week to Python date
		_year = int(date[0:4])
		_week = int(date[6:8])
		ref_date = datetime.date(_year, 1, 4)
		ref_week, ref_day = ref_date.isocalendar()[1:3]
		d = (ref_date + datetime.timedelta(days=1-ref_day, weeks=_week-ref_week))
		# Calculate offsets
		delta = datetime.timedelta(7)
		next_date = '%s-W%02d' % (d + delta).isocalendar()[0:2]
		prev_date = '%s-W%02d' % (d - delta).isocalendar()[0:2]
		tag_s = 'D'
		scope_s = (d + datetime.timedelta(3)).isoformat()
		tag_m = 'M'
		scope_m = '%s-%s' % (d.year, str(d.month).zfill(2))
		tag_l = 'Y'
		scope_l = str(d.year)
		# Populate date list
		for i in range(7):
			days.append((d + datetime.timedelta(i - config['week_start'])).isoformat())
	# Month scope
	elif len(date) == 7:
		d = datetime.datetime.strptime(date, '%Y-%m')
		if d.month == 12:
			year, month = d.year + 1, 1
		else:
			year, month = d.year, d.month + 1
		next_date = '%s-%s' % (year, str(month).zfill(2))
		if d.month == 1:
			year, month = d.year - 1, 12
		else:
			year, month = d.year, d.month - 1
		prev_date = '%s-%s' % (year, str(month).zfill(2))
		tag_s = 'D'
		scope_s = '%s-%s-15' % (d.year, str(d.month).zfill(2))
		tag_m = 'W'
		scope_m = '%s-W%02d' % (d + datetime.timedelta(15)).isocalendar()[0:2]
		tag_l = 'Y'
		scope_l = str(d.year)
		# Populate date list
		_date = datetime.date(d.year, d.month, 1)
		while _date.month == d.month:
			days.append(_date.isoformat())
			_date += datetime.timedelta(1)
		tally = True
	# Year scope
	elif len(date) == 4:
		d = datetime.datetime.strptime(date, '%Y')
		next_date = str(d.year + 1)
		prev_date = str(d.year - 1)
		tag_s = 'D'
		scope_s = '%s-06-15' % d.year
		tag_m = 'W'
		scope_m = '%s-W26' % d.year
		tag_l = 'M'
		scope_l = '%s-06' % d.year
		# Populate date list
		_date = datetime.date(d.year, 1, 1)
		while _date.year == d.year:
			days.append(_date.isoformat())
			_date += datetime.timedelta(1)
		tally = True
	else:
		raise ValueError
	# Create a transaction table and calculate totals
	if plaintext:
		page = '===== Summary for {date} ====='.format(date=date)
	else:
		page = load_file('logs.html')
	table = ''
	table_head = ''
	table_foot = ''
	summary = ''
	totals = {}
	# Compile transaction table and calculate date totals
	reverse_order = config['log_order'] == 'descending'
	if reverse_order:
		days.reverse()
	for _date in days:
		_totals, _table = read_log_file(os.path.join('logs', _date + '.log'), plaintext=plaintext, reverse_order=reverse_order)
		if tally:
			_amounts = []
			for k, v in _totals.items():
				_amounts.append('{} {}'.format(bch.fiat(v), k))
			if plaintext:
				_amounts = ', '.join(_amounts)
				tx_count = _table.count('TxID:')
			else:
				_amounts = '<br>'.join(_amounts)
				tx_count = _table.count('javascript:toggleRow(')
			if tx_count > 0:
				plural = ' ' if str(tx_count).endswith('1') else 's'
				if plaintext:
					chunk = '{} transaction{}'.format(tx_count, plural)
					table += '{}  {:>17}  {}\n'.format(_date, chunk, _amounts)
				else:
					table += '<tr class="%STYLE%"><td><a href="logs?date={date}">{date}</a></td><td>{count} transaction{plural}</td><td>{amounts}</td></tr>\n'.format(date=_date, count=tx_count, plural=plural, amounts=_amounts)
		else:
			table += _table
		for k in _totals.keys():
			if k in totals:
				totals[k] += _totals[k]
			else:
				totals[k] = _totals[k]
	for sign in totals.keys():
		if totals[sign] != 0:
			if plaintext:
				chunk = '{fiat} {cur}\n'
			else:
				chunk = '<p>{fiat} {cur}</p>\n'
			summary += chunk.format(fiat=bch.fiat(totals[sign]), cur=sign)
	# Format and return the logs page
	if table != '':
		if plaintext:
			_, token = format_amount(0)
			if tally:
				table_head = '== Date ==||===== Count =====||===== Amount (fiat) ====='
			else:
				table_head = '=== Date & Time ===||=== Amount ({token}) ===||== Amount (fiat) ==||== ID =='.format(token=token)
		else:
			if tally:
				table_head = '<h2>Transactions:</h2>\n<table class="listing">\n<tr><th>Date</th><th>Count</th><th>Amount (fiat)</tr></tr>\n'
			else:
				table_head = '<h2>Transactions:</h2>\n<table class="listing">\n<tr><th></th><th>Date and time</th><th>Amount</th><th>ID</th></tr>\n'
			table_foot = '</table>\n'
	else:
		if plaintext:
			summary = 'No transactions.'
		else:
			summary = '<p>No transactions.</p>'
	if plaintext:
		return '\n'.join([page, summary, table_head, table])
	else:
		# Load print header and footer
		header = load_file('log_header.html', override=True, null=True)
		footer = load_file('log_footer.html', override=True, null=True)
		row_count = 1
		style = 'odd'
		if tally:
			while '%STYLE%' in table:
				table = table.replace('%STYLE%', style, 1)
				style = 'even' if style == 'odd' else 'odd'
		else:
			while '%ROW%' in table:
				table = table.replace('%ROW%', str(row_count), 3)
				table = table.replace('%STYLE%', style, 2)
				style = 'even' if style == 'odd' else 'odd'
				row_count += 1
		table = table_head + table + table_foot
		# Pack the above variables into a filler dict
		label = config['label']
		params = {}
		_names = ['date', 'prev_date', 'tag_s', 'scope_s', 'tag_m', 'scope_m', 'tag_l', 'scope_l', 'next_date', 'header', 'summary', 'table', 'footer', 'label']
		for n in _names:
			params[n] = locals()[n]
		return page.format_map(params)


# Serve a static file or return a 404
def serve_static_file(request):
	status = '200 OK'
	headers = [('Content-type', 'text/html; charset=UTF-8')]
	# Handle specific content-types
	extension = request.split('.')[-1]
	if extension in mime_types:
		headers = [('Content-Type', mime_types[extension])]
	override = False if request.split('.') == 'js' else True
	# Try to load the requested file
	try:
		page = load_file(request, override=override)
	except:
		headers = [('Content-type', 'text/html; charset=UTF-8')]
		status = '404 Not Found'
		page = load_file('error.html').format(err=status)
		logging.warning(sys.exc_info()[1])
	return status, headers, page


# Set the log mailing return status
def email_sent(success):
	config['lock']['@'] = success


# Main webapp function
def minipos(environ, start_response):
	headers = [('Content-type', 'text/html; charset=UTF-8')]
	status = '200 OK'
	page = ''
	filler = ()
	if 'HTTP_X_REAL_IP' in environ:
		ip_addr = environ['HTTP_X_REAL_IP']
	else:
		ip_addr = environ['REMOTE_ADDR']
	subnet = '.'.join(ip_addr.split('.')[0:3]) + '.0'
	request = environ['PATH_INFO'].lstrip('/').split('/')[-1]
	if ip_addr != '127.0.0.1' and '0.0.0.0' not in config['allowed_ips'] and ip_addr not in config['allowed_ips'] and subnet not in config['allowed_ips'] and request not in file_whitelist:
		status = '403 Not Allowed'
		page = load_file('error.html').format(err=status)
		start_response(status, headers)
		return [bytes(page, 'UTF-8')]
	parameters = urllib.parse.parse_qs(environ['QUERY_STRING'])
	# Handle specific app pages
	if request == 'invoice':
		try:
			page = create_invoice(parameters)
		except ValueError:
			status = '303 See Other\nLocation: request'
			page = 'Redirecting...'
		except:
			if sys.exc_info()[0] is KeyError:
				logging.error('Missing required GET argument: {}'.format(sys.exc_info()[1]))
			else:
				logging.error(sys.exc_info()[1])
			status = '400 Bad Request'
			page = load_file('error.html').format(err=status)
	elif request == 'check':
		if 'id' not in parameters:
			status = '400 Bad Request'
			page = load_file('error.html').format(err=status)
		else:
			tag = parameters['id'][0]
		# Welcome page JavaScript check
		if tag == '0':
			page = '2'
		# Email sending check
		elif tag == '@':
			sent = config['lock']['@']
			page = '-1' if sent is None else '1' if sent else '2'
		# Payment received check
		else:
			page = check_payment(parameters)
		headers = [('Content-type', 'text/plain')]
	elif request == 'cancel':
		try:
			tag = parameters['id'][0]
			if tag:
				logging.info('Payment {} cancelled'.format(tag))
				unlock_address(tag)
		except:
			if sys.exc_info()[0] is KeyError:
				logging.error('Missing required GET argument: {}'.format(sys.exc_info()[1]))
			else:
				logging.error(sys.exc_info()[1])
		status = '303 See Other\nLocation: {}'.format(config['payment_return'])
		page = 'Redirecting...'
	elif request == 'logs':
		try:
			page = show_logs(parameters)
		except:
			logging.error(sys.exc_info()[1])
			status = '400 Bad Request'
			page = load_file('error.html').format(err=status)
	elif request == 'email':
		headers = [('Content-type', 'text/plain')]
		if 'email' not in config:
			logging.error('Sendmail failed: Email address is not set')
			page = '0'
		else:
			# Unset previous status
			config['lock']['@'] = None
			# Assemble message parts
			if 'date' not in parameters:
				date = datetime.date.today().isoformat()
			else:
				date = parameters['date'][0]
			listing = show_logs(parameters, plaintext=True)
			subject = '[MiniPOS] Transaction listing for {}'.format(date)
			# Send an email in a background thread
			sendmail.background_send(config, config['email'], subject, listing, callback=email_sent)
			page = '-1'
	elif request == 'welcome':
		footer = load_file('welcome_footer.html', override=True, null=True)
		page = load_file('welcome.html').format(label=config['label'], welcome_footer=footer)
	elif request == 'request':
		tax = 'Discount' if config['taxrate'] < 0 else 'Tax'
		filler = {
			'currencies': repr(config['currencies']),
			'timeout': config['welcome_timeout'],
			'cur': config['currencies'][0],
			'tax': tax,
			'taxrate': config['taxrate'],
			'label': config['label'],
			'centkey': '00' if config['auto_cents'] else '.',
		}
		filler['currency_disabled'] = 'disabled' if len(config['currencies']) == 1 else ''
		filler['tax_disabled'] = 'disabled' if config['taxrate'] == 0 else ''
		page = load_file('request.html').format_map(filler)
	# Redirect blank request to main page
	elif request == '':
		if config['welcome_timeout'] > 0:
			status = '303 See Other \nLocation: welcome'
		else:
			status = '303 See Other \nLocation: request'
		page = 'Redirecting...'
	# Load non-generated files from disk
	if page == '':
		status, headers, page = serve_static_file(request)
	# Serve the page
	start_response(status, headers)
	if type(page) is bytes:
		return [page]
	return [bytes(page, 'UTF-8')]


# Populate txid cache from recent log entries
_today = datetime.datetime.today().strftime('logs/%Y-%m-%d.log')
config['cache'] += read_log_file(_today, txids=True)[1]
_yesterday = (datetime.datetime.today() - datetime.timedelta(1)).strftime('logs/%Y-%m-%d.log')
config['cache'] += read_log_file(_yesterday, txids=True)[1]

# Make sure xpub works
if 'xpub' in config:
	try:
		if not bch.validate_key(config['xpub']):
			logging.warning('xpub is invalid, address generation unavailable')
			del(config['xpub'])
	except ImportError:
		logging.warning('pycoin is not installed, address generation unavailable')
		del(config['xpub'])
# Validate addresses
config['index'] = 0
for address in config['addresses'].copy():
	if address.startswith('xp'):
		logging.warning('Discarding extended key from address list')
		config['addresses'].remove(address)
		continue
	if 'xpub' in config:
		try:
			addr, idx = address.split(' ')
		except ValueError:
			logging.warning('Discarding address {} without derivation index'.format(address))
			config['addresses'].remove(address)
			continue
		try:
			idx = int(idx)
		except ValueError:
			logging.warning('Discarding address {} with invalid derivation index {}'.format(addr, idx))
			config['addresses'].remove(address)
			continue
		if not bch.validate_key(addr):
			logging.warning('Discarding invalid address {}'.format(addr))
			config['addresses'].remove(address)
			continue
		if addr[0] in 'qp':
			generated = bch.generate_address(config['xpub'], idx)
		else:
			generated = bch.generate_address(config['xpub'], idx, False)
		if addr != generated:
			logging.debug('Generated address: {}'.format(generated))
			logging.warning('Discarding address {} with mismatching derivation index {}'.format(addr, idx))
			config['addresses'].remove(address)
			continue
		# Replace the plaintext entry with a ready-to-use tuple
		config['addresses'][config['addresses'].index(address)] = (addr, idx)
		if idx >= config['index']:
			config['index'] = idx + 1
	else:
		try:
			addr, idx = address.split(' ')
		except ValueError:
			addr = address
		if not bch.validate_key(addr):
			logging.warning('Discarding invalid address {}'.format(addr))
			config['addresses'].remove(address)
			continue
		if addr != address:
			# Replace the plaintext entry with a ready-to-use tuple
			config['addresses'][config['addresses'].index(address)] = (addr, idx)
plural_addrs = 'es' if len(config['addresses']) > 1 else ''
logging.debug('{} receiving address{} loaded'.format(len(config['addresses']), plural_addrs))
if 'xpub' in config:
	logging.debug('Current derivation index set to {}'.format(config['index']))

# General initialization
random.seed()
log_lock = threading.Lock()
# Generate visual hash
if config['fingerprinting']:
	if 'xpub' in config:
		config['hash'] = tridenticon.generate(config['xpub'], scale=7)
	else:
		address_list = []
		for i, addr in enumerate(config['addresses']):
			if type(addr) is tuple:
				address_list.append(''.join(addr))
			else:
				address_list.append(addr)
		config['hash'] = tridenticon.generate(''.join(sorted(address_list)), scale=7)

# Start the web server
if __name__ == "__main__":
	if config['addresses'] == [] and 'xpub' not in config:
		logging.critical('No receiving addresses available. Please add some receiving addresses or an extended public key to your config file.')
		sys.exit(2)
	httpd = make_server('', config['port'], minipos)
	logging.info('Serving minipos on port {}...'.format(config['port']))
	try:
		httpd.serve_forever()
	except KeyboardInterrupt:
		logging.info('Server stopped.')