#!/usr/bin/env python3
# vim: set expandtab shiftwidth=4:
# -*- Mode: python; coding: utf-8; indent-tabs-mode: nil -*- */
#
# Copyright © 2018 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 os
import sys
import time
import multiprocessing
import argparse

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


SUPPORTED_FILE_VERSION = 1


def error(msg, **kwargs):
    print(msg, **kwargs, file=sys.stderr)


class YamlException(Exception):
    pass


def fetch(yaml, key):
    '''Helper function to avoid confusing a YAML error with a
    normal KeyError bug'''
    try:
        return yaml[key]
    except KeyError:
        raise YamlException('Failed to get \'{}\' from recording.'.format(key))


def create(device):
    evdev = fetch(device, 'evdev')

    d = libevdev.Device()
    d.name = fetch(evdev, 'name')

    ids = fetch(evdev, 'id')
    if len(ids) != 4:
        raise YamlException('Invalid ID format: {}'.format(ids))
    d.id = dict(zip(['bustype', 'vendor', 'product', 'version'], ids))

    codes = fetch(evdev, 'codes')
    for evtype, evcodes in codes.items():
        for code in evcodes:
            data = None
            if evtype == libevdev.EV_ABS.value:
                values = fetch(evdev, 'absinfo')[code]
                absinfo = libevdev.InputAbsInfo(minimum=values[0],
                                                maximum=values[1],
                                                fuzz=values[2],
                                                flat=values[3],
                                                resolution=values[4])
                data = absinfo
            elif evtype == libevdev.EV_REP.value:
                if code == libevdev.EV_REP.REP_DELAY.value:
                    data = 500
                elif code == libevdev.EV_REP.REP_PERIOD.value:
                    data = 20
            d.enable(libevdev.evbit(evtype, code), data=data)

    uinput = d.create_uinput_device()
    return uinput


def print_events(devnode, indent, evs):
    devnode = os.path.basename(devnode)
    for e in evs:
        print("{}: {}{:06d}.{:06d} {} / {:<20s} {:4d}".format(
            devnode, ' ' * (indent * 8), e.sec, e.usec, e.type.name, e.code.name, e.value))


def replay(device, verbose):
    events = fetch(device, 'events')
    if events is None:
        return
    uinput = device['__uinput']

    offset = time.time()
    handled_first_event = False

    # each 'evdev' set contains one SYN_REPORT so we only need to check for
    # the time offset once per event
    for event in events:
        try:
            evdev = fetch(event, 'evdev')
        except YamlException:
            continue

        (sec, usec, evtype, evcode, value) = evdev[0]

        # The first event may have a nonzero offset but we want to replay
        # immediately regardless.
        if not handled_first_event:
            offset -= sec + usec/1.e6
            handled_first_event = True

        evtime = sec + usec/1e6 + offset
        now = time.time()

        if evtime - now > 150/1e6:  # 150 µs error margin
            time.sleep(evtime - now - 150/1e6)

        evs = [libevdev.InputEvent(libevdev.evbit(e[2], e[3]), value=e[4], sec=e[0], usec=e[1]) for e in evdev]
        uinput.send_events(evs)
        if verbose:
            print_events(uinput.devnode, device['__index'], evs)


def wrap(func, *args):
    try:
        func(*args)
    except KeyboardInterrupt:
        pass


def loop(args, recording):
    version = fetch(recording, 'version')
    if version != SUPPORTED_FILE_VERSION:
        raise YamlException('Invalid file format: {}, expected {}'.format(version, SUPPORTED_FILE_VERSION))

    ndevices = fetch(recording, 'ndevices')
    devices = fetch(recording, 'devices')
    if ndevices != len(devices):
        error('WARNING: truncated file, expected {} devices, got {}'.format(ndevices, len(devices)))

    for idx, d in enumerate(devices):
        uinput = create(d)
        print('{}: {}'.format(uinput.devnode, uinput.name))
        d['__uinput'] = uinput  # cheaper to hide it in the dict then work around it
        d['__index'] = idx

    stop = False
    while not stop:
        input('Hit enter to start replaying')

        processes = []
        for d in devices:
            p = multiprocessing.Process(target=wrap, args=(replay, d, args.verbose))
            processes.append(p)

        for p in processes:
            p.start()

        for p in processes:
            p.join()

        del processes


def main():
    parser = argparse.ArgumentParser(
            description='Replay a device recording'
    )
    parser.add_argument('recording', metavar='recorded-file.yaml',
                        type=str, help='Path to device recording')
    parser.add_argument('--verbose', action='store_true')
    args = parser.parse_args()

    try:
        with open(args.recording) as f:
            y = yaml.safe_load(f)
            loop(args, y)
    except KeyboardInterrupt:
        pass
    except (PermissionError, OSError) as e:
        error('Error: failed to open device: {}'.format(e))
    except YamlException as e:
        error('Error: failed to parse recording: {}'.format(e))


if __name__ == '__main__':
    main()