# Creating a Nomarchy Theme

This guide walks through creating a new theme for Nomarchy from scratch.

## Theme Directory Structure

Each theme lives in `themes/palettes/<theme-name>/` with the following structure:

```
themes/palettes/my-theme/
├── colors.toml              # REQUIRED - Color palette definition
├── icons.theme              # REQUIRED - GTK icon theme name (single line)
├── light.mode               # Optional - Empty marker file for light themes
├── preview.png              # Optional - Preview image for the theme selector
├── backgrounds/             # Optional - Wallpaper images
│   ├── 1-primary.jpg        # Numbered prefix controls default order
│   ├── 2-alternate.png
│   └── ...
└── apps/                    # Optional - App-specific themed configs
    ├── btop.theme            # btop color theme
    ├── neovim.lua            # Neovim colorscheme plugin spec
    ├── vscode.json           # VS Code theme extension reference
    └── hyprland.conf         # Hyprland visual overrides (colors, decorations, animations)
```

## Step 1: Create the Color Palette

Create `colors.toml` with all 24 required color fields. Every color must be a hex value with a `#` prefix.

```toml
# UI colors
accent = "#83b6af"
cursor = "#d3c6aa"
foreground = "#d3c6aa"
background = "#2d353b"
selection_foreground = "#d3c6aa"
selection_background = "#505a60"

# ANSI 16-color palette (color0-15)
# Normal colors
color0 = "#3c474d"    # Black
color1 = "#e68183"    # Red
color2 = "#a7c080"    # Green
color3 = "#d9bb80"    # Yellow
color4 = "#83b6af"    # Blue
color5 = "#d39bb6"    # Magenta
color6 = "#87c095"    # Cyan
color7 = "#868d80"    # White

# Bright colors
color8 = "#868d80"    # Bright Black
color9 = "#e68183"    # Bright Red
color10 = "#a7c080"   # Bright Green
color11 = "#d9bb80"   # Bright Yellow
color12 = "#83b6af"   # Bright Blue
color13 = "#d39bb6"   # Bright Magenta
color14 = "#87c095"   # Bright Cyan
color15 = "#868d80"   # Bright White
```

These colors are mapped to a Base16 palette automatically:

| Base16 Slot | Source Field  | Typical Role               |
|-------------|---------------|----------------------------|
| base00      | background    | Default background         |
| base01      | color0        | Lighter background         |
| base02      | color8        | Selection background       |
| base03      | color8        | Comments, invisibles       |
| base04      | color7        | Dark foreground            |
| base05      | foreground    | Default foreground         |
| base06      | color15       | Light foreground           |
| base07      | color15       | Lightest foreground        |
| base08      | color1        | Red (errors, deletions)    |
| base09      | color3        | Orange                     |
| base0A      | color3        | Yellow (warnings)          |
| base0B      | color2        | Green (success, additions) |
| base0C      | color6        | Cyan (info)                |
| base0D      | color4        | Blue (primary accent)      |
| base0E      | color5        | Magenta (keywords)         |
| base0F      | color1        | Brown (deprecated)         |

## Step 2: Set the Icon Theme

Create `icons.theme` with a single line containing the GTK icon theme name:

```
Yaru-blue
```

Common options from the `yaru-theme` package: `Yaru-blue`, `Yaru-purple`, `Yaru-red`, `Yaru-sage`, `Yaru-olive`, `Yaru-magenta`, `Yaru-yellow`, `Yaru-gray`, `Yaru-grey`, `Yaru-wartybrown`.

## Step 3: Add Backgrounds (Optional)

Place wallpaper images in a `backgrounds/` directory. Use numbered prefixes to control the default selection order -- the first file alphabetically becomes the default wallpaper.

```
backgrounds/
├── 1-main-wallpaper.jpg     # Default wallpaper (first alphabetically)
├── 2-alternate.png          # Additional option
└── 3-minimal.jpg            # Another option
```

Supported formats: `.jpg`, `.png`, `.jpeg`.

If no backgrounds are provided, the system falls back to the catppuccin default wallpaper.

## Step 4: Light Theme (Optional)

For light themes, create an empty `light.mode` marker file:

```bash
touch themes/palettes/my-theme/light.mode
```

This controls Stylix polarity (`light` vs `dark`) and affects GTK theming, browser color scheme, and other system-wide dark/light detection.

### Step 5: App-Specific Configs (Optional)

These theme-specific files are automatically picked up by the respective application modules in `features/apps/<app>/default.nix` during theme switching.

### `apps/btop.theme`

A btop color theme file. See existing themes for the format, or generate one from your palette colors.

### `apps/neovim.lua`

A lazy.nvim plugin spec for the matching Neovim colorscheme:

```lua
return {
  { "sainnhe/everforest" },
  {
    "LazyVim/LazyVim",
    opts = {
      colorscheme = "everforest",
    },
  },
}
```

### `apps/vscode.json`

VS Code theme extension reference:

```json
{
  "name": "Everforest Dark",
  "extension": "sainnhe.everforest"
}
```

### `apps/hyprland.conf`

Hyprland visual overrides for this theme. This can include custom border colors, gaps, decorations, blur, and animations. The file is sourced after the default settings, so values here override the defaults.

```conf
$activeBorderColor = rgb(d3c6aa)

general {
    col.active_border = $activeBorderColor
    gaps_in = 6
    gaps_out = 12
    border_size = 3
}

decoration {
    rounding = 10
    blur {
        enabled = true
        size = 5
        passes = 3
    }
}
```

## Step 6: Template Variables

Nomarchy has a template system that generates app configs from your `colors.toml`. Templates in `themes/templates/*.tpl` use placeholder syntax:

| Syntax              | Example Value | Description                    |
|---------------------|---------------|--------------------------------|
| `{{ background }}`  | `#2d353b`     | Color value as-is (with `#`)   |
| `{{ background_strip }}` | `2d353b` | Color value without `#`        |
| `{{ background_rgb }}` | `45,53,59`  | Color as decimal RGB           |

Every key from `colors.toml` is available as a template variable. Templates are processed automatically by `nomarchy-theme-set-templates` when switching themes.

To add custom templates, place `.tpl` files in `~/.config/nomarchy/themed/`. User templates take priority over built-in ones.

## Step 7: Preview Image (Optional)

Add a `preview.png` screenshot of the theme in action. This is displayed in the theme selector menu (`nomarchy-menu theme`).

## Applying Your Theme

### During development (runtime switch)

```bash
nomarchy-theme-set my-theme
```

This updates `~/.config/nomarchy/state.json`, processes templates, and triggers a Home Manager rebuild.

### Setting as default (Nix configuration)

In your `home.nix`:

```nix
{
  nomarchy.theme = "my-theme";
}
```

Then rebuild: `env-update` (or `sys-update` for system-wide changes).

## Theme Discovery

The system automatically discovers themes by scanning `themes/palettes/` for directories containing a `colors.toml` file. No registration step is needed -- just create the directory with a valid `colors.toml` and the theme is available.

## Checklist

- [ ] `colors.toml` with all 24 color fields
- [ ] `icons.theme` with a valid GTK icon theme name
- [ ] `backgrounds/` with at least one numbered wallpaper
- [ ] `light.mode` if it's a light theme
- [ ] `apps/neovim.lua` with colorscheme plugin spec
- [ ] `apps/vscode.json` with theme extension reference
- [ ] `apps/btop.theme` with terminal monitor colors
- [ ] `apps/hyprland.conf` if custom decorations/animations are desired
- [ ] `preview.png` for the theme selector
