Switch iTerm2 color preset automatic base on macOS dark mode.

iterm2_switch_automatic.md

1. Add switch_automatic.py to ~/Library/ApplicationSupport/iTerm2/Scripts/AutoLaunch with:

#!/usr/bin/env python3

import asyncio
import iterm2

async def main(connection):
    async with iterm2.VariableMonitor(connection, iterm2.VariableScopes.APP, "effectiveTheme", None) as mon:
        while True:
            # Block until theme changes
            theme = await mon.async_get()

            # 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, "Dark Background")
            else:
                preset = await iterm2.ColorPreset.async_get(connection, "Light Background")

            # 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)

iterm2.run_forever(main)

Change Dark Background and Light Background to color presets you like.

2. Enabled switch_automatic.py from Scripts menu.

Change OSX theme dynamically with a button or based on screen brightness: https://apollozhu.github.io/Dynamic-Dark-Mode/
Change vscode theme dynamically based on OSX theme: https://marketplace.visualstudio.com/items?itemName=LinusU.auto-dark-mode&ssr=false