theme: add live theming for chromium-based browsers (#103)

* theme: add live theming for chromium-based browsers

Writes the surface colour as an RGB triplet to chromium.theme and
applies it as a managed browser policy for chromium, brave, and
google-chrome-stable using the --refresh-platform-policy flag
(introduced in Chrome 142+).

Also fixes write_file to set 0644 permissions so browser processes
can read the policy files.

* feat: use sudo tee not chmod

* chore: update readme

---------

Co-authored-by: 2 * r + 2 * t <61896496+soramanew@users.noreply.github.com>

README.md

@@ -18,35 +18,6 @@ The main control script for the Caelestia dotfiles.
 
 </details>
 
-<details><summary id="optional-dependencies">Optional dependencies</summary>
-
-- [`papirus-folders`](https://github.com/PapirusDevelopmentTeam/papirus-folders) - automatic folder icon color syncing with theme
-
-> [!NOTE]
-> For automatic Papirus folder icon color syncing, `papirus-folders` needs to be able to run with `sudo` without a password prompt.
->
-> **Recommended** - Create a sudoers file:
->
-> ```fish
-> # Fish shell
-> echo "$USER ALL=(ALL) NOPASSWD: "(which papirus-folders) | sudo tee /etc/sudoers.d/papirus-folders
-> sudo chmod 440 /etc/sudoers.d/papirus-folders
-> ```
->
-> ```sh
-> # Bash/other shells
-> echo "$USER ALL=(ALL) NOPASSWD: $(which papirus-folders)" | sudo tee /etc/sudoers.d/papirus-folders
-> sudo chmod 440 /etc/sudoers.d/papirus-folders
-> ```
->
-> **Alternatively** - Edit the main sudoers file by running `sudo visudo` and adding at the end:
->
-> ```
-> your_username ALL=(ALL) NOPASSWD: /usr/bin/papirus-folders
-> ```
-
-</details>
-
 ## Installation
 
 ### Arch linux
@@ -122,6 +93,45 @@ sudo python -m installer dist/*.whl
 sudo cp completions/caelestia.fish /usr/share/fish/vendor_completions.d/caelestia.fish
 ```
 
+### Additional steps
+
+#### Auto folder colour theming
+
+For automatic Papirus folder icon colour syncing, you must have [`papirus-folders`](https://github.com/PapirusDevelopmentTeam/papirus-folders)
+installed, and `papirus-folders` must to be able to run with `sudo` without a password prompt.
+
+You can allow this by creating a sudoers file:
+
+```sh
+echo "$USER ALL=(ALL) NOPASSWD: $(which papirus-folders)" | sudo tee /etc/sudoers.d/papirus-folders
+sudo chmod 440 /etc/sudoers.d/papirus-folders
+```
+
+#### Chromium-based browser theming
+
+For live Chromium-based browser theming, the CLI must be allowed to create certain directories in `/etc`
+and write to them via `sudo` without a password prompt.
+
+You can allow this by creating a sudoers file:
+
+```fish
+# Fish shell
+for dir in /etc/chromium/policies/managed /etc/brave/policies/managed /etc/opt/chrome/policies/managed
+    echo "$USER ALL=(ALL) NOPASSWD: $(which mkdir) -p $dir" | sudo tee -a /etc/sudoers.d/caelestia-chromium
+    echo "$USER ALL=(ALL) NOPASSWD: $(which tee) $dir/caelestia.json" | sudo tee -a /etc/sudoers.d/caelestia-chromium
+end
+sudo chmod 440 /etc/sudoers.d/caelestia-chromium
+```
+
+```sh
+# Bash/other shells
+for dir in /etc/chromium/policies/managed /etc/brave/policies/managed /etc/opt/chrome/policies/managed; do
+    echo "$USER ALL=(ALL) NOPASSWD: $(which mkdir) -p $dir" | sudo tee -a /etc/sudoers.d/caelestia-chromium
+    echo "$USER ALL=(ALL) NOPASSWD: $(which tee) $dir/caelestia.json" | sudo tee -a /etc/sudoers.d/caelestia-chromium
+done
+sudo chmod 440 /etc/sudoers.d/caelestia-chromium
+```
+
 ## Usage
 
 All subcommands/options can be explored via the help flag.
@@ -151,7 +161,7 @@ subcommands:
     resizer      window resizer daemon
 ```
 
-### User Templates
+### User templates
 
 Custom user templates can be defined in `~/.config/caelestia/templates/`.
 

src/caelestia/utils/theme.py

@@ -4,8 +4,6 @@ import re
 import shutil
 import subprocess
 import tempfile
-import shutil
-import fcntl
 from pathlib import Path
 
 from caelestia.utils.colour import get_dynamic_colours
@@ -340,6 +338,39 @@ def apply_warp(colours: dict[str, str], mode: str) -> None:
 
 
 @log_exception
+def apply_chromium(colours: dict[str, str]) -> None:
+    surface_hex = colours["surface"]
+    theme_color = f"#{surface_hex}"
+    browsers = [
+        ("chromium", Path("/etc/chromium/policies/managed")),
+        ("brave", Path("/etc/brave/policies/managed")),
+        ("google-chrome-stable", Path("/etc/opt/chrome/policies/managed")),
+    ]
+
+    for cmd, policy_dir in browsers:
+        if shutil.which(cmd) is None:
+            continue
+        if not policy_dir.is_dir():
+            subprocess.run(["sudo", "-n", "mkdir", "-p", str(policy_dir)], stderr=subprocess.DEVNULL)
+        if not policy_dir.is_dir():
+            print(f"Unable to create {policy_dir} directory")
+            continue
+
+        # Use tee instead of write_file cause we need sudo
+        subprocess.run(
+            ["sudo", "-n", "tee", str(policy_dir / "caelestia.json")],
+            input=json.dumps({"BrowserThemeColor": theme_color, "BrowserColorScheme": "device"}),
+            text=True,
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+        )
+        subprocess.run(
+            [cmd, "--refresh-platform-policy", "--no-startup-window"],
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+        )
+
+
 def apply_zed(colours: dict[str, str], mode: str) -> None:
     theme_path = config_dir / "zed/themes/caelestia.json"
     # Zed's file watcher does not detect changes through symlinks,
@@ -413,6 +444,8 @@ def apply_colours(colours: dict[str, str], mode: str) -> None:
                 apply_qt(colours, mode)
             if check("enableWarp"):
                 apply_warp(colours, mode)
+            if check("enableChromium"):
+                apply_chromium(colours)
             if check("enableZed"):
                 apply_zed(colours, mode)
             if check("enableCava"):