#!/usr/bin/env python3
# vim: set expandtab shiftwidth=4:
# -*- Mode: python; coding: utf-8; indent-tabs-mode: nil -*- */
#
# Copyright © 2020 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 libevdev
    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 DeviceError(Exception):
    pass


class Point:
    def __init__(self, x=None, y=None):
        self.x = x
        self.y = y


class Touchpad(object):
    def __init__(self, evdev):
        x = evdev.absinfo[libevdev.EV_ABS.ABS_X]
        y = evdev.absinfo[libevdev.EV_ABS.ABS_Y]
        if not x or not y:
            raise DeviceError('Device does not have an x or axis')

        if not x.resolution or not y.resolution:
            print('Device does not have resolutions.', file=sys.stderr)
            x.resolution = 1
            y.resolution = 1

        self.xrange = (x.maximum - x.minimum)
        self.yrange = (y.maximum - y.minimum)
        self.width = self.xrange / x.resolution
        self.height = self.yrange / y.resolution

        self._x = x
        self._y = y

        # We try to make the touchpad at least look proportional. The
        # terminal character space is (guesswork) ca 2.3 times as high as
        # wide.
        self.columns = 30
        self.rows = int(self.columns * (self.yrange // y.resolution) // (self.xrange // x.resolution) / 2.3)
        self.pos = Point(0, 0)
        self.min = Point()
        self.max = Point()

    @property
    def x(self):
        return self._x

    @property
    def y(self):
        return self._y

    @x.setter
    def x(self, x):
        self._x.minimum = min(self.x.minimum, x)
        self._x.maximum = max(self.x.maximum, x)
        self.min.x = min(x, self.min.x or 0xffffffff)
        self.max.x = max(x, self.max.x or -0xffffffff)
        # we calculate the position based on the original range.
        # this means on devices with a narrower range than advertised, not
        # all corners may be reachable in the touchpad drawing.
        self.pos.x = min(0.99, (x - self._x.minimum) / self.xrange)

    @y.setter
    def y(self, y):
        self._y.minimum = min(self.y.minimum, y)
        self._y.maximum = max(self.y.maximum, y)
        self.min.y = min(y, self.min.y or 0xffffffff)
        self.max.y = max(y, self.max.y or -0xffffffff)
        # we calculate the position based on the original range.
        # this means on devices with a narrower range than advertised, not
        # all corners may be reachable in the touchpad drawing.
        self.pos.y = min(0.99, (y - self._y.minimum) / self.yrange)

    def update_from_data(self):
        if None in [self.min.x, self.min.y, self.max.x, self.max.y]:
            raise DeviceError('Insufficient data to continue')
        self._x.minimum = self.min.x
        self._x.maximum = self.max.x
        self._y.minimum = self.min.y
        self._y.maximum = self.max.y

    def draw(self):
        print('Detected axis range: x [{:4d}..{:4d}], y [{:4d}..{:4d}]'.format(
              self.min.x if self.min.x is not None else 0,
              self.max.x if self.max.x is not None else 0,
              self.min.y if self.min.y is not None else 0,
              self.max.y if self.max.y is not None else 0))

        print()
        print('Move one finger along all edges of the touchpad'.center(self.columns))
        print('until the detected axis range stops changing.'.center(self.columns))

        top = int(self.pos.y * self.rows)

        print('+{}+'.format(''.ljust(self.columns, '-')))
        for row in range(0, top):
            print('|{}|'.format(''.ljust(self.columns)))

        left = int(self.pos.x * self.columns)
        right = max(0, self.columns - 1 - left)
        print('|{}{}{}|'.format(
            ''.ljust(left),
            'O',
            ''.ljust(right)))

        for row in range(top + 1, self.rows):
            print('|{}|'.format(''.ljust(self.columns)))

        print('+{}+'.format(''.ljust(self.columns, '-')))

        print('Press Ctrl+C to stop'.center(self.columns))

        print('\033[{}A'.format(self.rows + 8), flush=True)

        self.rows_printed = self.rows + 8

    def erase(self):
        # Erase all previous lines so we're not left with rubbish
        for row in range(self.rows_printed):
            print('\033[K')
        print('\033[{}A'.format(self.rows_printed))


def dimension(string):
    try:
        ts = string.split('x')
        t = tuple([int(x) for x in ts])
        if len(t) == 2:
            return t
    except: # noqa
        pass

    msg = "{} is not in format WxH".format(string)
    raise argparse.ArgumentTypeError(msg)


def between(v1, v2, deviation):
    return v1 - deviation < v2 < v1 + deviation


def dmi_modalias_match(modalias):
    modalias = modalias.split(':')
    dmi = {'svn': None, 'pvr': None, 'pn': None}
    for m in modalias:
        for key in dmi:
            if m.startswith(key):
                dmi[key] = m[len(key):]

    # Based on the current 60-evdev.hwdb, Lenovo uses pvr and everyone else
    # uses pn to provide a human-identifiable match
    if dmi['svn'] == 'LENOVO':
        return 'dmi:*svn{}:*pvr{}*'.format(dmi['svn'], dmi['pvr'])
    else:
        return 'dmi:*svn{}:*pn{}*'.format(dmi['svn'], dmi['pn'])


def main(args):
    parser = argparse.ArgumentParser(
        description="Measure the touchpad size"
    )
    parser.add_argument(
        'size', metavar='WxH', type=dimension,
        help='Touchpad size (width by height) in mm',
    )
    parser.add_argument(
        'path', metavar='/dev/input/event0', nargs='?', type=str,
        help='Path to device (optional)'
    )
    context = pyudev.Context()

    args = parser.parse_args()
    if not args.path:
        for device in context.list_devices(subsystem='input'):
            if (device.get('ID_INPUT_TOUCHPAD', 0) and
                    (device.device_node or '').startswith('/dev/input/event')):
                args.path = device.device_node
                name = 'unknown'
                parent = device
                while parent is not None:
                    n = parent.get('NAME', None)
                    if n:
                        name = n
                        break
                    parent = parent.parent

                print('Using {}: {}'.format(name, device.device_node))
                break
        else:
            print('Unable to find a touchpad device.', file=sys.stderr)
            return 1

    dev = pyudev.Devices.from_device_file(context, args.path)
    overrides = [p for p in dev.properties if p.startswith('EVDEV_ABS')]
    if overrides:
        print()
        print('********************************************************************')
        print('WARNING: axis overrides already in place for this device:')
        for prop in overrides:
            print('  {}={}'.format(prop, dev.properties[prop]))
        print('The systemd hwdb already overrides the axis ranges and/or resolution.')
        print('This tool is not needed unless you want to verify the axis overrides.')
        print('********************************************************************')
        print()

    try:
        fd = open(args.path, 'rb')
        evdev = libevdev.Device(fd)
        touchpad = Touchpad(evdev)
        print('Kernel specified touchpad size: {:.1f}x{:.1f}mm'.format(touchpad.width, touchpad.height))
        print('User specified touchpad size:   {:.1f}x{:.1f}mm'.format(*args.size))

        print()
        print('Kernel axis range:   x [{:4d}..{:4d}], y [{:4d}..{:4d}]'.format(
              touchpad.x.minimum, touchpad.x.maximum,
              touchpad.y.minimum, touchpad.y.maximum))

        print('Put your finger on the touchpad to start\033[1A')

        try:
            touchpad.draw()
            while True:
                for event in evdev.events():
                    if event.matches(libevdev.EV_ABS.ABS_X):
                        touchpad.x = event.value
                    elif event.matches(libevdev.EV_ABS.ABS_Y):
                        touchpad.y = event.value
                    elif event.matches(libevdev.EV_SYN.SYN_REPORT):
                        touchpad.draw()
        except KeyboardInterrupt:
            touchpad.erase()
            touchpad.update_from_data()

        print('Detected axis range: x [{:4d}..{:4d}], y [{:4d}..{:4d}]'.format(
              touchpad.x.minimum, touchpad.x.maximum,
              touchpad.y.minimum, touchpad.y.maximum))

        touchpad.x.resolution = round((touchpad.x.maximum - touchpad.x.minimum) / args.size[0])
        touchpad.y.resolution = round((touchpad.y.maximum - touchpad.y.minimum) / args.size[1])

        print('Resolutions calculated based on user-specified size: x {}, y {} units/mm'.format(
              touchpad.x.resolution, touchpad.y.resolution))

        # If both x/y are within some acceptable deviation, we skip the axis
        # overrides and only override the resolution
        xorig = evdev.absinfo[libevdev.EV_ABS.ABS_X]
        yorig = evdev.absinfo[libevdev.EV_ABS.ABS_Y]
        deviation = 1.5 * touchpad.x.resolution  # 1.5 mm rounding on each side
        skip = between(xorig.minimum, touchpad.x.minimum, deviation)
        skip = skip and between(xorig.maximum, touchpad.x.maximum, deviation)
        deviation = 1.5 * touchpad.y.resolution  # 1.5 mm rounding on each side
        skip = skip and between(yorig.minimum, touchpad.y.minimum, deviation)
        skip = skip and between(yorig.maximum, touchpad.y.maximum, deviation)

        if skip:
            print()
            print('Note: Axis ranges within acceptable deviation, skipping min/max override')
            print()

        print()
        print('Suggested hwdb entry:')

        use_dmi = evdev.id['bustype'] not in [0x03, 0x05]  # USB, Bluetooth
        if use_dmi:
            modalias = open('/sys/class/dmi/id/modalias').read().strip()
            print('Note: the dmi modalias match is a guess based on your machine\'s modalias:')
            print(' ', modalias)
            print('Please verify that this is the most sensible match and adjust if necessary.')

        print('-8<--------------------------')
        print('# Laptop model description (e.g. Lenovo X1 Carbon 5th)')
        if use_dmi:
            print('evdev:name:{}:{}*'.format(evdev.name, dmi_modalias_match(modalias)))
        else:
            print('evdev:input:b{:04X}v{:04X}p{:04X}*'.format(
                  evdev.id['bustype'], evdev.id['vendor'], evdev.id['product']))
        print(' EVDEV_ABS_00={}:{}:{}'.format(
              touchpad.x.minimum if not skip else '',
              touchpad.x.maximum if not skip else '',
              touchpad.x.resolution))
        print(' EVDEV_ABS_01={}:{}:{}'.format(
              touchpad.y.minimum if not skip else '',
              touchpad.y.maximum if not skip else '',
              touchpad.y.resolution))
        if evdev.absinfo[libevdev.EV_ABS.ABS_MT_POSITION_X]:
            print(' EVDEV_ABS_35={}:{}:{}'.format(
                  touchpad.x.minimum if not skip else '',
                  touchpad.x.maximum if not skip else '',
                  touchpad.x.resolution))
            print(' EVDEV_ABS_36={}:{}:{}'.format(
                  touchpad.y.minimum if not skip else '',
                  touchpad.y.maximum if not skip else '',
                  touchpad.y.resolution))
        print('-8<--------------------------')
        print('Instructions on what to do with this snippet are in /usr/lib/udev/hwdb.d/60-evdev.hwdb')
    except DeviceError as e:
        print('Error: {}'.format(e), file=sys.stderr)
        return 1
    except PermissionError:
        print('Unable to open device. Please run me as root', file=sys.stderr)
        return 1

    return 0


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