#!/usr/bin/env python3
# vim: set expandtab shiftwidth=4:
# -*- Mode: python; coding: utf-8; indent-tabs-mode: nil -*- */
#
# Copyright © 2017 Red Hat, Inc.
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice (including the next
# paragraph) shall be included in all copies or substantial portions of the
# Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
#

import sys
import argparse
try:
    import evdev
    import evdev.ecodes
    import pyudev
except ModuleNotFoundError as e:
    print('Error: {}'.format(str(e)), file=sys.stderr)
    print('One or more python modules are missing. Please install those '
          'modules and re-run this tool.')
    sys.exit(1)


class Range(object):
    """Class to keep a min/max of a value around"""
    def __init__(self):
        self.min = float('inf')
        self.max = float('-inf')

    def update(self, value):
        self.min = min(self.min, value)
        self.max = max(self.max, value)


class Touch(object):
    """A single data point of a sequence (i.e. one event frame)"""

    def __init__(self, major=None, minor=None, orientation=None):
        self._major = major
        self._minor = minor
        self._orientation = orientation
        self.dirty = False

    @property
    def major(self):
        return self._major

    @major.setter
    def major(self, major):
        self._major = major
        self.dirty = True

    @property
    def minor(self):
        return self._minor

    @minor.setter
    def minor(self, minor):
        self._minor = minor
        self.dirty = True

    @property
    def orientation(self):
        return self._orientation

    @orientation.setter
    def orientation(self, orientation):
        self._orientation = orientation
        self.dirty = True

    def __str__(self):
        s = "Touch: major {:3d}".format(self.major)
        if self.minor is not None:
                s += ", minor {:3d}".format(self.minor)
        if self.orientation is not None:
                s += ", orientation {:+3d}".format(self.orientation)
        return s


class TouchSequence(object):
    """A touch sequence from beginning to end"""

    def __init__(self, device, tracking_id):
        self.device = device
        self.tracking_id = tracking_id
        self.points = []

        self.is_active = True

        self.is_down = False
        self.was_down = False
        self.is_palm = False
        self.was_palm = False

        self.major_range = Range()
        self.minor_range = Range()

    def append(self, touch):
        """Add a Touch to the sequence"""
        self.points.append(touch)
        self.major_range.update(touch.major)
        self.minor_range.update(touch.minor)

        if touch.major < self.device.up or \
           touch.minor < self.device.up:
                self.is_down = False
        elif touch.major > self.device.down or \
                touch.minor > self.device.down:
            self.is_down = True
            self.was_down = True

        self.is_palm = touch.major > self.device.palm
        if self.is_palm:
                self.was_palm = True

    def finalize(self):
        """Mark the TouchSequence as complete (finger is up)"""
        self.is_active = False

    def avg(self):
        """Average pressure value of this sequence"""
        return int(sum([p.pressure for p in self.points])/len(self.points))

    def median(self):
        """Median pressure value of this sequence"""
        ps = sorted([p.pressure for p in self.points])
        idx = int(len(self.points)/2)
        return ps[idx]

    def __str__(self):
        return self._str_state() if self.is_active else self._str_summary()

    def _str_summary(self):
        if not self.points:
                return "Sequence: no major/minor values recorded"

        s = "Sequence: major: [{:3d}..{:3d}] ".format(
                self.major_range.min, self.major_range.max
        )
        if self.device.has_minor:
                s += "minor: [{:3d}..{:3d}] ".format(
                        self.minor_range.min, self.minor_range.max
                     )
        if self.was_down:
                s += " down"
        if self.was_palm:
                s += " palm"

        return s

    def _str_state(self):
        touch = self.points[-1]
        s = "{}, tags: {} {}".format(
                                touch,
                                "down" if self.is_down else "    ",
                                "palm" if self.is_palm else "     "
                                )
        return s


class InvalidDeviceError(Exception):
    pass


class Device(object):
    def __init__(self, path):
        if path is None:
            self.path = self.find_touch_device()
        else:
            self.path = path

        self.device = evdev.InputDevice(self.path)

        print("Using {}: {}\n".format(self.device.name, self.path))

        # capabilities returns a dict with the EV_* codes as key,
        # each of which is a list of tuples of (code, AbsInfo)
        #
        # Get the abs list first (or empty list if missing),
        # then extract the pressure absinfo from that
        caps = self.device.capabilities(absinfo=True).get(
                evdev.ecodes.EV_ABS, []
               )
        codes = [cap[0] for cap in caps]

        if evdev.ecodes.ABS_MT_TOUCH_MAJOR not in codes:
            raise InvalidDeviceError("device does not have ABS_MT_TOUCH_MAJOR")

        self.has_minor = evdev.ecodes.ABS_MT_TOUCH_MINOR in codes
        self.has_orientation = evdev.ecodes.ABS_MT_ORIENTATION in codes

        self.up = 0
        self.down = 0
        self.palm = 0

        self._init_thresholds_from_udev()
        self.sequences = []
        self.touch = Touch(0, 0)

    def find_touch_device(self):
        context = pyudev.Context()
        for device in context.list_devices(subsystem='input'):
            if not device.get('ID_INPUT_TOUCHPAD', 0) and \
               not device.get('ID_INPUT_TOUCHSCREEN', 0):
                continue

            if not device.device_node or \
                    not device.device_node.startswith('/dev/input/event'):
                continue

            return device.device_node

        print("Unable to find a touch device.", file=sys.stderr)
        sys.exit(1)

    def _init_thresholds_from_udev(self):
        context = pyudev.Context()
        ud = pyudev.Devices.from_device_file(context, self.path)
        v = ud.get('LIBINPUT_ATTR_TOUCH_SIZE_RANGE')
        if v:
            self.up, self.down = colon_tuple(v)

        v = ud.get('LIBINPUT_ATTR_PALM_SIZE_THRESHOLD')
        if v:
            self.palm = int(v)

    def start_new_sequence(self, tracking_id):
        self.sequences.append(TouchSequence(self, tracking_id))

    def current_sequence(self):
        return self.sequences[-1]

    def handle_key(self, event):
        tapcodes = [evdev.ecodes.BTN_TOOL_DOUBLETAP,
                    evdev.ecodes.BTN_TOOL_TRIPLETAP,
                    evdev.ecodes.BTN_TOOL_QUADTAP,
                    evdev.ecodes.BTN_TOOL_QUINTTAP]
        if event.code in tapcodes and event.value > 0:
                print("\rThis tool cannot handle multiple fingers, "
                      "output will be invalid", file=sys.stderr)

    def handle_abs(self, event):
        if event.code == evdev.ecodes.ABS_MT_TRACKING_ID:
                if event.value > -1:
                    self.start_new_sequence(event.value)
                else:
                    s = self.current_sequence()
                    s.finalize()
                    print("\r{}".format(s))
        elif event.code == evdev.ecodes.ABS_MT_TOUCH_MAJOR:
                self.touch.major = event.value
        elif event.code == evdev.ecodes.ABS_MT_TOUCH_MINOR:
                self.touch.minor = event.value
        elif event.code == evdev.ecodes.ABS_MT_ORIENTATION:
                self.touch.orientation = event.value

    def handle_syn(self, event):
        if self.touch.dirty:
            self.current_sequence().append(self.touch)
            print("\r{}".format(self.current_sequence()), end="")
            self.touch = Touch(major=self.touch.major,
                               minor=self.touch.minor,
                               orientation=self.touch.orientation)

    def handle_event(self, event):
        if event.type == evdev.ecodes.EV_ABS:
            self.handle_abs(event)
        elif event.type == evdev.ecodes.EV_KEY:
            self.handle_key(event)
        elif event.type == evdev.ecodes.EV_SYN:
            self.handle_syn(event)

    def read_events(self):
        print("Ready for recording data.")
        print("Touch sizes used: {}:{}".format(self.down, self.up))
        print("Palm size used: {}".format(self.palm))
        print("Place a single finger on the device to measure touch size.\n"
              "Ctrl+C to exit\n")

        for event in self.device.read_loop():
            self.handle_event(event)


def colon_tuple(string):
    try:
        ts = string.split(':')
        t = tuple([int(x) for x in ts])
        if len(t) == 2 and t[0] >= t[1]:
            return t
    except:
        pass

    msg = "{} is not in format N:M (N >= M)".format(string)
    raise argparse.ArgumentTypeError(msg)


def main(args):
    parser = argparse.ArgumentParser(
            description="Measure touch size and orientation"
    )
    parser.add_argument('path', metavar='/dev/input/event0',
                        nargs='?', type=str, help='Path to device (optional)')
    parser.add_argument('--touch-thresholds', metavar='down:up',
                        type=colon_tuple,
                        help='Thresholds when a touch is logically down or up')
    parser.add_argument('--palm-threshold', metavar='t',
                        type=int, help='Threshold when a touch is a palm')
    args = parser.parse_args()

    try:
        device = Device(args.path)

        if args.touch_thresholds is not None:
            device.down, device.up = args.touch_thresholds

        if args.palm_threshold is not None:
            device.palm = args.palm_threshold

        device.read_events()
    except KeyboardInterrupt:
        pass
    except (PermissionError, OSError):
        print("Error: failed to open device")
    except InvalidDeviceError as e:
        print("Error: {}".format(e))

if __name__ == "__main__":
    main(sys.argv)
