ferro_theme/
loader.rs

1use std::path::Path;
2
3use crate::error::ThemeError;
4use crate::template::ThemeTemplates;
5
6const DEFAULT_THEME_CSS: &str = include_str!("../assets/default.css");
7
8/// A loaded theme: CSS tokens and optional intent template overrides.
9///
10/// Two construction paths:
11/// - [`Theme::default_theme()`] — always available, embedded at compile time.
12/// - [`Theme::from_path()`] — loads from a filesystem directory.
13#[derive(Debug, Clone)]
14pub struct Theme {
15    /// CSS content using Tailwind v4 `@theme` syntax.
16    pub css: String,
17
18    /// Optional intent template overrides; all-`None` means built-in layouts apply.
19    pub templates: ThemeTemplates,
20}
21
22impl Theme {
23    /// Returns the embedded default theme.
24    ///
25    /// The CSS uses Tailwind v4 `@theme` with 23 semantic token slots (light + dark).
26    /// Templates are all-`None` — built-in intent layouts apply unchanged.
27    pub fn default_theme() -> Self {
28        Self {
29            css: DEFAULT_THEME_CSS.to_string(),
30            templates: ThemeTemplates::default(),
31        }
32    }
33
34    /// Loads a theme from a directory on the filesystem.
35    ///
36    /// Expects `tokens.css` to exist in the directory.
37    /// `theme.json` is optional — if absent, templates default to empty (`ThemeTemplates::default()`).
38    ///
39    /// # Errors
40    ///
41    /// - [`ThemeError::NotFound`] — directory does not exist.
42    /// - [`ThemeError::Io`] — `tokens.css` cannot be read.
43    /// - [`ThemeError::Json`] — `theme.json` exists but cannot be parsed.
44    pub fn from_path(path: &str) -> Result<Self, ThemeError> {
45        let dir = Path::new(path);
46        if !dir.exists() {
47            return Err(ThemeError::NotFound(path.to_string()));
48        }
49
50        let css_path = dir.join("tokens.css");
51        let css = std::fs::read_to_string(css_path)?;
52
53        let templates_path = dir.join("theme.json");
54        let templates = if templates_path.exists() {
55            let json = std::fs::read_to_string(&templates_path)?;
56            serde_json::from_str(&json)?
57        } else {
58            ThemeTemplates::default()
59        };
60
61        Ok(Self { css, templates })
62    }
63}
64
65#[cfg(test)]
66mod tests {
67    use super::*;
68
69    #[test]
70    fn default_theme_returns_non_empty_css_with_color_primary() {
71        let theme = Theme::default_theme();
72        assert!(!theme.css.is_empty());
73        assert!(theme.css.contains("--color-primary"));
74    }
75
76    #[test]
77    fn default_theme_returns_all_none_templates() {
78        let theme = Theme::default_theme();
79        assert!(theme.templates.browse.is_none());
80        assert!(theme.templates.focus.is_none());
81        assert!(theme.templates.collect.is_none());
82        assert!(theme.templates.process.is_none());
83        assert!(theme.templates.summarize.is_none());
84        assert!(theme.templates.analyze.is_none());
85        assert!(theme.templates.track.is_none());
86    }
87
88    #[test]
89    fn from_path_loads_tokens_css_and_theme_json() {
90        let dir = tempfile::tempdir().unwrap();
91        let css_content = "@theme { --color-primary: oklch(55% 0.2 250); }";
92        let json_content = r#"{"browse": {"display": {"slots": ["title", "fields"]}}}"#;
93        std::fs::write(dir.path().join("tokens.css"), css_content).unwrap();
94        std::fs::write(dir.path().join("theme.json"), json_content).unwrap();
95
96        let theme = Theme::from_path(dir.path().to_str().unwrap()).unwrap();
97        assert_eq!(theme.css, css_content);
98        assert!(theme.templates.browse.is_some());
99        let browse = theme.templates.browse.unwrap();
100        assert_eq!(browse.display.slots, vec!["title", "fields"]);
101    }
102
103    #[test]
104    fn from_path_works_without_theme_json() {
105        let dir = tempfile::tempdir().unwrap();
106        let css_content = "@theme { --color-primary: oklch(55% 0.2 250); }";
107        std::fs::write(dir.path().join("tokens.css"), css_content).unwrap();
108
109        let theme = Theme::from_path(dir.path().to_str().unwrap()).unwrap();
110        assert_eq!(theme.css, css_content);
111        assert!(theme.templates.browse.is_none());
112    }
113
114    #[test]
115    fn from_path_returns_not_found_for_nonexistent_directory() {
116        let result = Theme::from_path("/nonexistent/path/that/does/not/exist");
117        assert!(matches!(result, Err(ThemeError::NotFound(_))));
118    }
119
120    #[test]
121    fn from_path_returns_json_error_for_invalid_theme_json() {
122        let dir = tempfile::tempdir().unwrap();
123        std::fs::write(dir.path().join("tokens.css"), "@theme {}").unwrap();
124        std::fs::write(dir.path().join("theme.json"), "not valid json{{").unwrap();
125
126        let result = Theme::from_path(dir.path().to_str().unwrap());
127        assert!(matches!(result, Err(ThemeError::Json(_))));
128    }
129
130    #[test]
131    fn from_path_returns_io_error_when_tokens_css_missing() {
132        let dir = tempfile::tempdir().unwrap();
133        // Only create theme.json, not tokens.css
134        std::fs::write(dir.path().join("theme.json"), "{}").unwrap();
135
136        let result = Theme::from_path(dir.path().to_str().unwrap());
137        assert!(matches!(result, Err(ThemeError::Io(_))));
138    }
139}
ferro_theme/loader.rs

ferro_theme/
loader.rs
