Automatically switch theme on iTerm2

automatic_theme_switcher.py

#!/usr/bin/env python3

import asyncio
import iterm2

def log(string):
  print(string)

async def update(connection, theme):
  # Themes have space-delimited attributes, one of which will be light or dark.
  parts = theme.split(" ")
  if "dark" in parts:
    preset = await iterm2.ColorPreset.async_get(connection, "Tango Dark")
  else:
    preset = await iterm2.ColorPreset.async_get(connection, "Tango Light")

  # Update the list of all profiles and iterate over them.
  profiles = await iterm2.PartialProfile.async_query(connection)
  for partial in profiles:
    # Fetch the full profile and then set the color preset in it.
    profile = await partial.async_get_full_profile()
    await profile.async_set_color_preset(preset)

async def monitor_variable(connection):
  async with iterm2.VariableMonitor(connection, iterm2.VariableScopes.APP, "effectiveTheme", None) as mon:
    while True:
      theme = await mon.async_get()
      log("theme switched to " + theme)
      await update(connection, theme)

async def monitor_app(connection, monitor_variable_task):
  while True:
    log("monitor_app: falling asleep")
    await asyncio.sleep(5)
    log("monitor_app: waking up")

    app = await iterm2.async_get_app(connection, create_if_needed = False)

    if app is None:
      log("monitor_app: None")
      break
    else:
      log("monitor_app: App")


async def main():
  connection = await iterm2.Connection.async_create()

  # Initial theme update
  app = await iterm2.async_get_app(connection)
  await update(connection, await app.async_get_variable("effectiveTheme"))

  monitor_variable_task = asyncio.create_task(monitor_variable(connection))
  await monitor_app(connection, monitor_variable_task)

asyncio.run(main())