# srec: A simple GUI for screen recording
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, version 3.

from __future__ import annotations

from dataclasses import dataclass
from datetime import datetime
import os
import subprocess
import sys
from typing import Any, Callable

import gi
gi.require_version("Gtk", "4.0")
gi.require_version("GLib", "2.0")

from gi.repository import Gtk   # nopep8 pylint: disable=wrong-import-position
from gi.repository import GLib  # nopep8 pylint: disable=wrong-import-position


@dataclass
class Stream:
    process: subprocess.Popen[bytes]

    @staticmethod
    def start(command: list[str]) -> Stream:
        # pylint: disable=consider-using-with
        return Stream(process=subprocess.Popen(command, stdin=subprocess.PIPE))

    def stop(self) -> None:
        stdin = self.process.stdin
        assert stdin is not None
        try:
            stdin.write(b'q')
            stdin.flush()
        except BrokenPipeError:
            print("Stream already stopped?", file=sys.stderr)
        self.process.wait()


recording: Stream | None = None


def make_filename() -> str:
    directory = os.environ.get(
        'XDG_VIDEOS_DIR',
        os.path.expanduser('~/Videos/SRec'))
    os.makedirs(directory, exist_ok=True)
    timestamp = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
    return os.path.join(directory, f'srec {timestamp}.mkv')


def video_source(stack: Gtk.Stack) -> list[str]:
    if stack.get_child_by_name('not_recording').get_first_child().get_active():
        return ['-f', 'x11grab', '-i', ':0.0+0,0']
    return ['-f', 'v4l2', '-i', '/dev/video0']


def find_size_display(stack: Gtk.Stack) -> Gtk.Label:
    return stack.get_child_by_name(
        'recording').get_first_child().get_next_sibling()


def summarize_size(n: int) -> str:
    if n > 100_000_000:
        m = int(n / (1024 * 1024))
        return f'{m}M'
    if n > 100_000:
        k = int(n / 1024)
        return f'{k}K'
    return str(n)


def on_start_recording(_: Gtk.Button, stack: Gtk.Stack) -> None:
    global recording  # pylint: disable=global-statement
    assert recording is None

    filename = make_filename()
    size_display = find_size_display(stack)

    def update_size_display() -> Any:
        try:
            size = summarize_size(os.stat(filename).st_size)
        except FileNotFoundError:
            size = '--'
        size_display.set_label(f'<big>{size}</big>')
        return GLib.SOURCE_REMOVE if recording is None else GLib.SOURCE_CONTINUE
    GLib.timeout_add_seconds(1, update_size_display)

    recording = Stream.start(
        ['ffmpeg', '-framerate', '25'] + video_source(stack) +
        ['-f', 'pulse', '-ac', '2', '-i', 'default', filename])
    stack.set_visible_child_name("recording")


def on_stop_recording(_: Gtk.Button, stack: Gtk.Stack) -> None:
    global recording  # pylint: disable=global-statement
    assert recording is not None
    recording.stop()
    recording = None
    stack.set_visible_child_name("not_recording")


def make_button(label: str, action: Callable[[
                Gtk.Button, Gtk.Stack], None], stack: Gtk.Stack) -> Gtk.Button:
    button = Gtk.Button(label=label)
    button.connect('clicked', action, stack)
    button.set_margin_top(10)
    button.set_margin_start(10)
    button.set_margin_end(10)
    button.set_margin_bottom(10)
    return button


def make_share_control() -> Gtk.CheckButton:
    can_share = os.path.exists('/sys/module/v4l2loopback')
    control = Gtk.CheckButton(
        label='Share Webcam', sensitive=can_share, active=can_share)
    control.set_margin_start(20)
    return control


def on_activate(app: Gtk.Application) -> None:
    win = Gtk.ApplicationWindow(application=app)
    win.set_title('SRec')
    win.set_icon_name('srec')

    stack = Gtk.Stack()

    nr_box = Gtk.Box()
    nr_box.set_orientation(Gtk.Orientation.VERTICAL)
    screen = Gtk.CheckButton(label='Screen')
    nr_box.append(screen)
    nr_box.append(Gtk.CheckButton(label='Webcam', active=True, group=screen))
    nr_box.append(make_share_control())
    nr_box.append(make_button("Start Recording", on_start_recording, stack))
    stack.add_named(nr_box, "not_recording")

    r_box = Gtk.Box()
    r_box.set_orientation(Gtk.Orientation.VERTICAL)
    r_box.append(make_button("Stop Recording", on_stop_recording, stack))
    r_box.append(Gtk.Label(use_markup=True, justify=Gtk.Justification.CENTER))
    stack.add_named(r_box, "recording")

    win.set_child(stack)
    win.present()


def main() -> None:
    app = Gtk.Application(application_id='net.chkno.srec')
    app.connect('activate', on_activate)
    app.run(None)


if __name__ == '__main__':
    main()