#!/usr/bin/env python3
"""
volume_remapper.py
------------------
Listen for Volume‑Up key events and emit a different key code
(“Ctrl+Shift+M” by default) so the focused application receives it.

Dependencies: python‑evdev (pip install evdev)
"""

import sys
import os
import argparse
from evdev import InputDevice, categorize, ecodes, UInput, list_devices
import time

# ------------------------------------------------------------------ #
# Helpers
# ------------------------------------------------------------------ #

def find_device(name_substr="volume"):
    """Return the first InputDevice that contains a KEY_VOLUMEUP event."""
    for dev_path in [d.path for d in list_devices()]:
        dev = InputDevice(dev_path)
        caps = dev.capabilities()
        if ecodes.EV_KEY in caps and ecodes.KEY_VOLUMEUP in caps[ecodes.EV_KEY]:
            if name_substr.lower() in dev.name.lower():
                return dev
    return None

# ------------------------------------------------------------------ #
# Core logic
# ------------------------------------------------------------------ #

def main(remap_keys, device=None):
    """
    :param remap_keys: tuple of ecodes.KEY_* codes to emit (e.g. (ecodes.KEY_LCTRL, ecodes.KEY_LSHIFT, ecodes.KEY_M))
    :param device: path to /dev/input/eventX or None to auto‑detect
    """
    if device is None:
        dev = find_device()
        if dev is None:
            print("⚠️  No device with a Volume‑Up key found.", file=sys.stderr)
            sys.exit(1)
    else:
        dev = InputDevice(device)

    print(f"[INFO] Listening on {dev.path} ({dev.name}) ...")
    print(f"[INFO] Remapping to: {', '.join(ecodes.KEY.get(k) for k in remap_keys)}")

    # Create a virtual keyboard (uinput)
    ui = UInput(events=[
        ecodes.EV_KEY,  # only key events
        ecodes.EV_SYN
    ], name='volume‑remapper')

    try:
        for event in dev.read_loop():
            if event.type == ecodes.EV_KEY:
                if event.code == ecodes.KEY_VOLUMEUP and event.value == 1:  # key_down
                    # Emit the mapped key sequence
                    for key in remap_keys:
                        ui.write(ecodes.EV_KEY, key, 1)  # key down
                        ui.write(ecodes.EV_KEY, key, 0)  # key up
                    ui.syn()
                    print(f"✅  Mapped Volume‑Up → {', '.join(ecodes.KEY.get(k) for k in remap_keys)}")
    except KeyboardInterrupt:
        print("\n[INFO] Stopping …")
    finally:
        ui.close()


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Remap Volume‑Up to any key combo.")
    parser.add_argument("--device", help="Optional /dev/input/eventX path to listen on.")
    parser.add_argument("--to", nargs="+", default=["KEY_LCTRL", "KEY_LSHIFT", "KEY_M"],
                        help="Space‑separated key names to emit.  Default: Ctrl+Shift+M")
    args = parser.parse_args()

    # Convert key names to ecodes
    remap = [ecodes.KEY[code.upper()] for code in args.to]
    main(remap_keys=remap, device=args.device)