#!/usr/bin/env python
"""
#  Copyright (C) 2008 Michael Buesch <mb@bu3sch.de>
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License version 3
#  as published by the Free Software Foundation.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""

import getopt
import sys
from serial.serialposix import *

from PyQt4.QtCore import *
from PyQt4.QtGui import *


# Serial communication port configuration
CONFIG_BAUDRATE			= 9600
CONFIG_BYTESIZE			= 8
CONFIG_PARITY			= PARITY_EVEN
CONFIG_STOPBITS			= 2

# The size of one message
MSG_SIZE			= 38
MSG_PAYLOAD_SIZE		= 32
# Message IDs
MSG_INVALID			= 0
MSG_ERROR			= 1
MSG_LOGMESSAGE			= 2
MSG_PING			= 3
MSG_PONG			= 4
MSG_GET_CURRENT_PRESSURE	= 5
MSG_CURRENT_PRESSURE		= 6
MSG_GET_DESIRED_PRESSURE	= 7
MSG_DESIRED_PRESSURE		= 8
MSG_SET_DESIRED_PRESSURE	= 9
MSG_GET_HYSTERESIS		= 10
MSG_HYSTERESIS			= 11
MSG_SET_HYSTERESIS		= 12
MSG_GET_CONFIG_FLAGS		= 13
MSG_CONFIG_FLAGS		= 14
MSG_SET_CONFIG_FLAGS		= 15
# Message error codes
MSG_ERR_NONE			= 0
MSG_ERR_CHKSUM			= 1
MSG_ERR_NOREPLY			= -1 # internal. Not sent over wire.
# Config flags
CFG_FLAG_AUTOADJUST_ENABLE	= 0


def usage():
	print "Pressure control - remote configuration"
	print ""
	print "Copyright (C) 2008 Michael Buesch <mb@bu3sch.de>"
	print "Licensed under the GNU/GPL version 3"
	print ""
	print "Usage: pctl-remote [OPTIONS] /dev/ttyS0"
	print ""
	print "-h|--help            Print this help text"

def parseArgs():
	global opt_ttyfile

	if len(sys.argv) < 2:
		usage()
		sys.exit(1)

	opt_ttyfile = sys.argv[-1]

	try:
		(opts, args) = getopt.getopt(sys.argv[1:-1],
			"h",
			[ "help" ])
	except getopt.GetoptError:
		usage()
		sys.exit(1)

	for (o, v) in opts:
		if o in ("-h", "--help"):
			usage()
			sys.exit(0)

class RemoteProtocol(QObject):
	def __init__(self, ttyfile):
		QObject.__init__(self)

		self.serial = Serial(ttyfile, CONFIG_BAUDRATE,
				     CONFIG_BYTESIZE, CONFIG_PARITY,
				     CONFIG_STOPBITS)

		self.pollTimer = QTimer(self)
		self.connect(self.pollTimer, SIGNAL("timeout()"), self.poll)
		self.pollTimer.start(50)

		reply = self.sendMessageSyncReply(MSG_PING, "", MSG_PONG)
		if not reply:
			print "Communication with device failed. No reply to PING request."
			sys.exit(1)
		mainwnd.centralWidget().log.addText("PING->PONG success. Device is alife.\n")

	def poll(self):
		if self.serial.inWaiting() < MSG_SIZE:
			return
		self.parseMessage(self.serial.read(MSG_SIZE))

	def checksumMessage(self, msg):
		calc_crc = self.__crc16_update_buffer(0xFFFF, msg[0:-2])
		calc_crc ^= 0xFFFF
		want_crc = (ord(msg[-2]) | (ord(msg[-1]) << 8))
		if calc_crc != want_crc:
			text = self.tr("ERROR: message CRC mismatch\n")
			mainwnd.centralWidget().log.addText(text)
			self.serial.flushInput()
			return False
		return True

	def parseMessage(self, msg):
		if not self.checksumMessage(msg):
			return
		id = ord(msg[0])
		if (id == MSG_LOGMESSAGE):
			str = self.getPayload(msg).rstrip('\0')
			mainwnd.centralWidget().log.addText(str)
		if (id == MSG_PING):
			sendMessage(MSG_PING, [])
		if (id == MSG_CURRENT_PRESSURE):
			mainwnd.centralWidget().parseCurrentPressureMsg(msg)

	def getPayload(self, msg):
		return msg[4:-2]

	def sendMessage(self, id, payload):
		"""Send a message"""
		assert(len(payload) <= MSG_PAYLOAD_SIZE)
		# Create the header
		msg = "%c\0\0\0" % id
		# Add the payload
		msg += payload
		# Pad the payload up to the constant size
		i = MSG_PAYLOAD_SIZE - len(payload)
		while i:
			msg += '\0'
			i -= 1
		# Calculate the CRC
		crc = self.__crc16_update_buffer(0xFFFF, msg)
		crc ^= 0xFFFF
		# Add the CRC to the message
		msg += "%c%c" % ((crc & 0xFF), ((crc >> 8) & 0xFF))
		# Send the message
		assert(len(msg) == MSG_SIZE)
		self.serial.write(msg)

	def sendMessageSyncReply(self, id, payload, replyId):
		"""Send a message and synchronously wait for the reply."""
		self.pollTimer.stop()
		self.sendMessage(id, payload)
		timeout = QDateTime.currentDateTime().addSecs(2)
		while True:
			if QDateTime.currentDateTime() >= timeout:
				msg = None
				break
			if self.serial.inWaiting() < MSG_SIZE:
				app.processEvents()
				QThread.msleep(50)
				continue
			msg = self.serial.read(MSG_SIZE)
			if not self.checksumMessage(msg):
				continue
			msgid = ord(msg[0])
			if msgid == replyId:
				break
			# This is not a reply to our message.
			self.parseMessage(msg)
		self.pollTimer.start()
		return msg

	def sendMessageSyncError(self, id, payload):
		"""Sends a message and synchronously waits for the MSG_ERROR reply."""
		reply = self.sendMessageSyncReply(id, payload, MSG_ERROR)
		if not reply:
			return MSG_ERR_NOREPLY
		return ord(self.getPayload(reply)[0])

	def __crc16_update_buffer(self, crc, buf):
		for c in buf:
			crc ^= ord(c)
			for i in range(0, 8):
				if crc & 1:
					crc = (crc >> 1) ^ 0xA001
				else:
					crc = (crc >> 1)
		return crc

class StatusBar(QStatusBar):
	def showMessage(self, msg):
		QStatusBar.showMessage(self, msg, 10000)

class LogBrowser(QTextEdit):
	def __init__(self, parent=None):
		QTextBrowser.__init__(self, parent)

		self.needTimeStamp = True
		self.setReadOnly(1)
		self.addText(self.tr("Pressure Control logging started\n"));

	def addText(self, text):
		if self.needTimeStamp:
			date = QDateTime.currentDateTime()
			text = date.toString("[hh:mm:ss] ") + text
		self.textCursor().setPosition(len(self.toPlainText()))
		self.insertPlainText(text)
		self.needTimeStamp = (text[-1] in QString("\r\n"))

class MainWidget(QWidget):
	def __init__(self, parent=None):
		QWidget.__init__(self, parent)
		self.initialized = False

		layout = QVBoxLayout()

		h = QHBoxLayout()
		label = QLabel(self.tr("Current pressure:"), self)
		h.addWidget(label)
		self.curPressure = QLCDNumber(self)
		self.curPressure.setSegmentStyle(QLCDNumber.Flat)
		self.curPressure.display(5.1)
		h.addWidget(self.curPressure)
		label = QLabel(self.tr("Bar"), self)
		h.addWidget(label)
		h.addStretch()
		layout.addLayout(h)

		self.autoCheckbox = QCheckBox(self.tr("Automatically adjust pressure"), self)
		layout.addWidget(self.autoCheckbox)

		h = QHBoxLayout()
		label = QLabel(self.tr("Desired pressure:"), self)
		h.addStretch()
		h.addWidget(label)
		self.pressureSpin = QDoubleSpinBox(self)
		self.pressureSpin.setMinimum(1)
		self.pressureSpin.setMaximum(8)
		self.pressureSpin.setSingleStep(0.1)
		self.pressureSpin.setSuffix(self.tr(" Bar"))
		self.connect(self.pressureSpin, SIGNAL("valueChanged(double)"),
			     self.desiredPressureChanged)
		h.addWidget(self.pressureSpin)
		layout.addLayout(h)

		h = QHBoxLayout()
		label = QLabel(self.tr("Hysteresis:"), self)
		h.addStretch()
		h.addWidget(label)
		self.hystSpin = QDoubleSpinBox(self)
		self.hystSpin.setMinimum(0.1)
		self.hystSpin.setMaximum(8)
		self.hystSpin.setSingleStep(0.1)
		self.hystSpin.setSuffix(self.tr(" Bar"))
		self.connect(self.hystSpin, SIGNAL("valueChanged(double)"),
			     self.desiredHysteresisChanged)
		h.addWidget(self.hystSpin)
		layout.addLayout(h)

		self.log = LogBrowser(self)
		layout.addWidget(self.log)

		self.setLayout(layout)

	def initializeState(self):
		# Get the current pressure
		reply = remote.sendMessageSyncReply(MSG_GET_CURRENT_PRESSURE, "",
						    MSG_CURRENT_PRESSURE)
		if not reply:
			print "Failed to fetch current pressure. No reply."
			sys.exit(1)
		self.parseCurrentPressureMsg(reply)

		# Get the desired pressure
		reply = remote.sendMessageSyncReply(MSG_GET_DESIRED_PRESSURE, "",
						    MSG_DESIRED_PRESSURE)
		if not reply:
			print "Failed to fetch desired pressure. No reply."
			sys.exit(1)
		reply = remote.getPayload(reply)
		mbar = ord(reply[0]) | (ord(reply[1]) << 8)
		self.pressureSpin.setValue(float(mbar) / 1000)

		# Get the hysteresis
		reply = remote.sendMessageSyncReply(MSG_GET_HYSTERESIS, "",
						    MSG_HYSTERESIS)
		if not reply:
			print "Failed to fetch hysteresis. No reply."
			sys.exit(1)
		reply = remote.getPayload(reply)
		mbar = ord(reply[0]) | (ord(reply[1]) << 8)
		self.hystSpin.setValue(float(mbar) / 1000)

		# Get the config flags
		reply = remote.sendMessageSyncReply(MSG_GET_CONFIG_FLAGS, "",
						    MSG_CONFIG_FLAGS)
		if not reply:
			print "Failed to fetch config flags. No reply."
			sys.exit(1)
		reply = remote.getPayload(reply)
		flags = ord(reply[0]) | (ord(reply[1]) << 8) | \
			(ord(reply[2]) << 16) | (ord(reply[3]) << 24)
		if flags & (1 << CFG_FLAG_AUTOADJUST_ENABLE):
			self.autoCheckbox.setCheckState(Qt.Checked)
		#TODO

		self.initialized = True

	def parseCurrentPressureMsg(self, msg):
		msg = remote.getPayload(msg)
		mbar = ord(msg[0]) | (ord(msg[1]) << 8)
		self.curPressure.display(float(mbar) / 1000)

	def desiredPressureChanged(self):
		if not self.initialized:
			return
		mbar = int(self.pressureSpin.value() * 1000)
		data = "%c%c" % ((mbar & 0xFF), ((mbar >> 8) & 0xFF))
		err = remote.sendMessageSyncError(MSG_SET_DESIRED_PRESSURE, data)
		if err != MSG_ERR_NONE:
			self.log.addText(self.tr("Failed to change pressure. Error=%u\n" % err))

	def desiredHysteresisChanged(self):
		if not self.initialized:
			return
		mbar = int(self.hystSpin.value() * 1000)
		data = "%c%c" % ((mbar & 0xFF), ((mbar >> 8) & 0xFF))
		err = remote.sendMessageSyncError(MSG_SET_HYSTERESIS, data)
		if err != MSG_ERR_NONE:
			self.log.addText(self.tr("Failed to change hysteresis. Error=%u\n" % err))

class MainWindow(QMainWindow):
	def __init__(self, parent=None):
		QMainWindow.__init__(self, parent)
		self.setWindowTitle(self.tr("Pneumatic pressure control"))

		mb = QMenuBar(self)
		ctlmen = QMenu(self.tr("Control"), mb)
		ctlmen.addAction(self.tr("Exit"), self.close)
		mb.addMenu(ctlmen)
		helpmen = QMenu(self.tr("Help"), mb)
		helpmen.addAction(self.tr("About"), self.about)
		mb.addMenu(helpmen)
		self.setMenuBar(mb)

		self.setStatusBar(StatusBar())
		self.setCentralWidget(MainWidget())

		self.resize(400, 500)

	def initializeState(self):
		self.centralWidget().initializeState()

	def about(self):
		QMessageBox.information(self, self.tr("About"),
					self.tr("Pneumatic pressure control\n"
						"Copyright (c) 2008 Michael Buesch"))

def main():
	global remote
	global mainwnd
	global app

	mainwnd = None

	app = QApplication(sys.argv)
	parseArgs()

	mainwnd = MainWindow()
	remote = RemoteProtocol(opt_ttyfile)

	mainwnd.initializeState()
	mainwnd.show()
	exit(app.exec_())

if __name__ == "__main__":
	try:
		main()
	except SerialException, e:
		print "[Serial error]  %s" % e.message