#!/usr/bin/env python3

# This script requires i3ipc-python package (install it from a system package manager
# or pip).
# It makes inactive windows transparent. Use `transparency_val` variable to control
# transparency strength in range of 0…1 or use the command line argument -o.

import argparse
import i3ipc
import signal
import sys
import os
import time
from pathlib import Path
from functools import partial

def on_window_focus(opacity, ipc, event):
    if os.path.exists(flag):
        return
    global prev_focused
    global prev_workspace

    focused_workspace = ipc.get_tree().find_focused()

    if focused_workspace == None:
        return

    focused = event.container
    workspace = focused_workspace.workspace().num

    if focused.id != prev_focused.id:  # https://github.com/swaywm/sway/issues/2859
        focused.command("opacity 1")
        if workspace == prev_workspace:
            prev_focused.command("opacity " + opacity)
        prev_focused = focused
        prev_workspace = workspace

def show_hide(ipc, opacity):
    global flag
    if os.path.exists(flag):
        os.remove(flag)
    else:
        opacity = 0
        Path(flag).touch()
    for workspace in ipc.get_tree().workspaces():
        for w in workspace:
            if w.focused and opacity != 0:
                w.command("opacity 1")
            else:
                w.command("opacity "+str(opacity))

def fade(ipc, opacity):
    global flag
    if os.path.exists(flag):
        show_hide(ipc, opacity)
        return
    for i in range(1,100):
        for workspace in ipc.get_tree().workspaces():
            for w in workspace:
                if w.focused:
                    w.command("opacity "+str(1-(i/100)))
                elif float(opacity) >= (i/100):
                    w.command("opacity "+str(float(opacity)-(i/100)))
        time.sleep(0.005)
    Path(flag).touch()

def remove_opacity(ipc):
    global pid
    global flag
    for workspace in ipc.get_tree().workspaces():
        for w in workspace:
            w.command("opacity 1")
    for file in [pid, flag]:
        if os.path.exists(file):
            os.remove(file)
    ipc.main_quit()
    sys.exit(0)

def set_all(ipc,opacity):
    for window in ipc.get_tree():
        window.command("opacity " + opacity)

flag = os.environ["HOME"]+"/.spool/sway-hidden"
pid = os.environ["HOME"]+"/.spool/sway-transparency"
opacity = "0.8"

if __name__ == "__main__":
    f = open(pid, "w")
    try:
        f.write(str(os.getpid()))
    except AssertionError as error:
        print("Failed to write PID to file "+pid+": "+error)
        sys.exit(0)
    f.close()

    parser = argparse.ArgumentParser(
        description="This script allows you to set the transparency of unfocused windows in sway."
    )
    parser.add_argument(
        "--opacity",
        "-o",
        type=str,
        default=opacity,
        help="set opacity value in range 0...1",
    )
    args = parser.parse_args()

    ipc = i3ipc.Connection()
    prev_focused = None
    prev_workspace = ipc.get_tree().find_focused().workspace().num

    for window in ipc.get_tree():
        if window.focused:
            prev_focused = window
        else:
            window.command("opacity " + args.opacity)
    for sig in [signal.SIGINT, signal.SIGTERM]:
        signal.signal(sig, lambda signal, frame: remove_opacity(ipc))
    signal.signal(signal.SIGUSR1, lambda signal, frame: show_hide(ipc, opacity))
    signal.signal(signal.SIGUSR2, lambda signal, frame: fade(ipc, opacity))
    ipc.on("window::focus", partial(on_window_focus, args.opacity))
    ipc.main()