#!/bin/env python
"""Sets the monitor temperature based on the current time using Hyprsunset"""
from argparse import ArgumentParser, Namespace
from datetime import datetime
from os import environ
from pathlib import Path
from socket import AF_UNIX, SOCK_STREAM, socket
from typing import cast


type Range = tuple[float, float]


def lerped_amount(x: float, edges: Range) -> float:
	"""How far `x` is between `values`"""
	return (x - edges[0]) / (edges[1] - edges[0])


def smoothstep(x: float, edges: Range) -> float:
	"""Smoothly interpolates between the `edges` based on `x`"""
	# Technically I should bounds check but whatever
	return (x * x * (3.0 - 2.0 * x)) * (edges[1] - edges[0]) + edges[0]


def day_elapsed(hours: int = 0, minutes: int = 0, seconds: int = 0) -> float:
	"""Converts (H, M, S) into [0, 1] representing how far through the day it is"""
	return ((((hours * 60) + minutes) * 60) + seconds) / 86400


def now_elapsed() -> float:
	"""How far through the day it is"""
	now = datetime.now()
	return day_elapsed(now.hour, now.minute, now.second)

def calculate_temperature(sunrise: Range, sunset: Range, temperature_range: Range) -> float:
	"""What temperature the monitor should be"""
	elapsed = now_elapsed()

	if elapsed <= sunrise[0]:
		return temperature_range[0]
	elif elapsed < sunrise[1]:
		return smoothstep(lerped_amount(elapsed, sunrise), temperature_range)
	elif elapsed <= sunset[0]:
		return temperature_range[1]
	elif elapsed < sunset[1]:
		return smoothstep(lerped_amount(elapsed, sunset), (temperature_range[1], temperature_range[0]))
	else:
		return temperature_range[0]


def setup_socket() -> socket:
	"""Connects to the Hyprsunset socket"""
	hyprsunset = socket(AF_UNIX, SOCK_STREAM)
	# In theory I should use $XDG_RUNTIME_DIR, but for me it's always `/run/user/1000/`
	hyprsunset.connect(f"{environ["XDG_RUNTIME_DIR"]}/hypr/{environ["HYPRLAND_INSTANCE_SIGNATURE"]}/.hyprsunset.sock")
	return hyprsunset


def get_temperature(hyprsunset: socket) -> int:
	"""Retrieves the current screen temperature"""
	# In theory the message might not send in one go, but in practice it does so I won't bother handling the error
	_ = hyprsunset.send(b"temperature")
	# 4 bytes should be enough but why not 8 for comfort
	# Just raise an error if it's not a number, nothing special to do here
	return int(hyprsunset.recv(8))


def set_temperature(hyprsunset: socket, temperature: float, /, instant: bool = False) -> None:
	# In theory the message might not send in one go, but in practice it does so I won't bother handling the error
	_ = hyprsunset.send(f"temperature {temperature:.1f}".encode())
	if instant:
		# Setting the temperature twice in quick succession sometimes skips the transition period
		set_temperature(hyprsunset, temperature, instant=False)


def on_steam() -> bool:
	"""Whether the Steam PID is in use"""
	pid_file = Path("~/.steampid").expanduser().resolve(strict=True)
	pid = pid_file.read_text().strip()
	pid_dir = Path("/proc") / pid
	return pid_dir.is_dir()


def main(sunrise: Range, sunset: Range, temperature_range: Range, /, check_steam: bool = False, instant: bool = False) -> None:
	"""Adjusts the monitor temperature based on the current time"""
	hyprsunset = setup_socket()
	temperature = int(calculate_temperature(sunrise, sunset, temperature_range))
	if temperature != get_temperature(hyprsunset):
		if check_steam and on_steam():
			return
		set_temperature(hyprsunset, temperature, instant=instant)


class Arguments(Namespace):
	check_steam: bool = False
	instant: bool = False

if __name__ == "__main__":
	parser = ArgumentParser(description="Adjusts the temperature of your screen based on the time of day")
	_ = parser.add_argument("-s", "--check-steam", action="store_true", help="Don't adjust temperature if Steam is active")
	_ = parser.add_argument("-i", "--instant", action="store_true", help="Try to instantly change temperature")
	args = cast(Arguments, parser.parse_args())
	main(
		(day_elapsed(5), day_elapsed(7)),
		(day_elapsed(21), day_elapsed(23)),
		(2500.0, 6000.0),
		check_steam=args.check_steam,
		instant=args.instant
	)