#!/usr/bin/env python3
import json
import logging
import os
import sys
import time
from argparse import ArgumentParser
from subprocess import Popen

import evdev

INPUTDEV_BASEDIR = "/dev/input/"

# TODO: handle sighup
# TODO: prevent event to do other things


def listall():
    for f in os.listdir(INPUTDEV_BASEDIR):
        try:
            print(f, evdev.InputDevice(os.path.join(INPUTDEV_BASEDIR, f)))
        except:
            pass


def find_dev_by_name(name):
    for f in os.listdir(INPUTDEV_BASEDIR):
        try:
            ev = evdev.InputDevice(os.path.join(INPUTDEV_BASEDIR, f))
        except Exception:
            continue
        if ev.name == name:
            return os.path.join(INPUTDEV_BASEDIR, f)
    raise ValueError("device with such name not found")


class KeymapTable:
    def __init__(self):
        self.table = {}

    @classmethod
    def from_config_file(cls, data):
        kt = cls()
        kt.table = {int(key): value for key, value in data.items()}
        kt.validate()
        return kt

    def validate(self):
        errors = 0
        for key in self.table:
            if type(key) is not int:
                logging.error("Keycode %r is not of valid type", key)
                errors += 1
            if type(self.table[key]) is str:
                # Autofixing key key
                self.table[key] = {
                    "short": self.table[key],
                    "long": self.table[key],
                }
            if type(self.table[key]) is not dict:
                logging.error("Keycode %r is not of valid type", key)
                errors += 1
        if errors:
            raise ValueError("%d validation errors found" % errors)

    def __contains__(self, x):
        code, pressure_type = x
        return code in self.table and pressure_type in self.table[code]

    def __getitem__(self, x):
        code, pressure_type = x
        return self.table[code][pressure_type]


def loop(device, args):
    pressed = None
    for event in device.read_loop():
        if event.type != evdev.ecodes.EV_KEY:
            continue
        # for attr in dir(event):
        #    if not attr.startswith("_"):
        #        logging.debug("   ", attr, str(getattr(event, attr)))
        logging.debug("received %s", str(evdev.categorize(event)))
        if event.value == 1:  # keydown
            pressed = {"code": event.code, "ts": event.timestamp()}
        if event.value == 0 and pressed is not None:
            pressure_time = event.timestamp() - pressed["ts"]
            if pressure_time * 1000 <= args.short_threshold:
                pressure_type = "short"
            else:
                pressure_type = "long"
            yield (pressed["code"], pressure_type)


def main():
    p = ArgumentParser()
    p.add_argument("--config", type=open)
    input_p = p.add_argument_group("input device options")
    input_p.add_argument("-d", "--device")
    input_p.add_argument(
        "-n", "--name", help="Look at `xinput list` to have an idea"
    )
    input_p.add_argument(
        "--short-threshold",
        default=300,
        help="Threshold to distinguish a short and a long press, "
        "in milliseconds",
    )
    output_p = p.add_argument_group("output options")
    output_p.add_argument(
        "-v",
        "--verbose",
        dest="logging_level",
        action="store_const",
        const=logging.INFO,
    )
    output_p.add_argument(
        "--debug",
        dest="logging_level",
        action="store_const",
        const=logging.DEBUG,
    )
    args = p.parse_args()

    logging.basicConfig(level=args.logging_level)
    if args.config:
        config = json.load(args.config)
    else:
        config = {}

    keymaps = KeymapTable.from_config_file(config.get("keys", {}))

    if args.name:
        if args.device:
            print("Cannot specify both -d and -n", file=sys.stderr)
            sys.exit(1)
        while True:
            try:
                args.device = find_dev_by_name(args.name)
            except ValueError:
                logging.debug("Could not find device; trying again")
                time.sleep(2)
                continue
            else:
                logging.info("Found device: %s", args.device)
                break

    device = evdev.InputDevice(args.device)
    logging.debug("%s", device)
    logging.info("start loop")
    for highlevel_event in loop(device, args):
        logging.debug(highlevel_event)
        if highlevel_event not in keymaps:
            continue

        cmd = keymaps[highlevel_event]
        if type(cmd) is str:
            cmd = cmd.split()
        cmd[0] = os.path.expanduser(cmd[0])
        try:
            Popen(cmd)
        except Exception as exc:
            logging.error("Error running %s: %s" % (cmd, str(exc)))


if __name__ == "__main__":
    # listall()
    main()