Add swayidle to make the screen go dark

---

### Step 1: Install `swayidle`

Open your terminal and install `swayidle` from the official Arch repositories. It's good practice to also install a screen locker like `swaylock` at the same time, as you'll likely want to lock your screen before it turns off.

```bash
sudo pacman -S swayidle swaylock
```

### Step 2: Create the Idle Management Script

It's cleanest to manage this with a small shell script. Let's create one in niri's configuration directory.

1.  Create the file:
    ```bash
    mkdir -p ~/.config/niri
    nano ~/.config/niri/idle.sh
    ```

2.  Paste the following content into the file. This configuration will do two things:
    *   **After 10 minutes (600s):** Lock the screen with `swaylock`.
    *   **After 15 minutes (900s):** Turn the display off (DPMS off).
    *   **On resume (mouse/keyboard activity):** Turn the display back on (DPMS on).

    ```sh
    #!/bin/sh

    # This script is a simple wrapper for swayidle.
    # It locks the screen after 10 minutes of inactivity,
    # and turns off the display after 15 minutes.

    swayidle -w \
         timeout 600 'swaylock -f' \
         timeout 900 'niri msg output "*" dpms off' \
         resume 'niri msg output "*" dpms on'
    ```

    *   `swayidle -w`: Starts the daemon and waits (doesn't exit).
    *   `timeout 600 'swaylock -f'`: After 600 seconds (10 minutes) of inactivity, run `swaylock -f` to lock the screen.
    *   `timeout 900 'niri msg output "*" dpms off'`: After 900 seconds (15 minutes), run the command to turn off all outputs (`*`). The command `niri msg` is how you control niri from the command line.
    *   `resume 'niri msg output "*" dpms on'`: When activity is detected again (mouse move, key press), run the command to turn all outputs back on.

3.  Save the file and exit `nano` (Ctrl+O, Enter, Ctrl+X).

4.  Make the script executable:
    ```bash
    chmod +x ~/.config/niri/idle.sh
    ```

### Step 3: Autostart the Script with Niri

Now, we need to tell niri to run this script every time it starts.

1.  Open your niri configuration file. If it doesn't exist, niri uses its defaults, but you can create it.
    ```bash
    nano ~/.config/niri/config.kdl
    ```

2.  Add the `startup-commands` block if it doesn't exist, and add an `exec-on-startup` command to run your script. Make sure to use the full path.

    ```kdl
    // Your other niri configurations might be here...

    startup-commands {
        // Add this line to run your idle script
        exec-on-startup "~/.config/niri/idle.sh"

        // You might have other startup commands here, for example:
        // exec-on-startup "waybar"
        // exec-on-startup "mako"
    }

    // More of your niri config...
    ```

    **Note:** The `~` shortcut for your home directory works in the niri config.

3.  Save and close the file.

### Step 4: Apply the Changes

Log out of your niri session and log back in. The `idle.sh` script will now be running in the background. Your screen will lock after 10 minutes and turn off after 15 minutes of inactivity. Moving your mouse or pressing a key will wake the screen up to the `swaylock` prompt.

---

### Customization

*   **To only turn off the screen (no lock):**
    If you *only* want the screen to go black after 15 minutes and don't want to lock it, modify your `~/.config/niri/idle.sh` script to remove the `swaylock` timeout:

    ```sh
    #!/bin/sh

    swayidle -w \
         timeout 900 'niri msg output "*" dpms off' \
         resume 'niri msg output "*" dpms on'
    ```
    This directly addresses your original request.

*   **Changing the time:**
    Simply change the number of seconds in the script. For example, for a 5-minute screen-off time, change `900` to `300`.

*   **Customizing swaylock:**
    You can make `swaylock` look nicer. For example, to set a solid color:
    `swaylock -f -c 000000` (for black).
    You can edit this command directly in your `idle.sh` script. Check `man swaylock` for all options.