refactor: split Rust backend into sub-modules — git, theme, github, frontmatter, commands

- git.rs (1907 lines) → 7 files: mod, history, status, commit, remote, conflict, pulse
- theme.rs (1075 lines) → 4 files: mod, defaults, seed, create
- github.rs (886 lines) → 4 files: mod, api, auth, clone
- frontmatter.rs (827 lines) → 3 files: mod, yaml, ops
- lib.rs (772 lines) → lib.rs (160) + commands.rs (650)

484 tests pass, clippy clean, rustfmt clean, coverage 85.42%

src-tauri/src/theme/mod.rs

@@ -0,0 +1,268 @@
+mod create;
+pub mod defaults;
+mod seed;
+
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+use std::fs;
+use std::path::Path;
+
+pub use create::{create_theme, create_vault_theme};
+pub use defaults::*;
+pub use seed::{
+    ensure_vault_themes, restore_default_themes, seed_default_themes, seed_vault_themes,
+};
+
+/// A theme file parsed from _themes/*.json in the vault.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ThemeFile {
+    /// Filename stem (e.g. "default" for _themes/default.json)
+    #[serde(default)]
+    pub id: String,
+    pub name: String,
+    #[serde(default)]
+    pub description: String,
+    #[serde(default)]
+    pub colors: HashMap<String, String>,
+    #[serde(default)]
+    pub typography: HashMap<String, String>,
+    #[serde(default)]
+    pub spacing: HashMap<String, String>,
+}
+
+/// Vault-level settings stored in .laputa/settings.json (git-tracked).
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct VaultSettings {
+    #[serde(default)]
+    pub theme: Option<String>,
+}
+
+/// List all theme files in _themes/ directory of the vault.
+/// Seeds built-in themes if the directory is missing.
+pub fn list_themes(vault_path: &str) -> Result<Vec<ThemeFile>, String> {
+    let themes_dir = Path::new(vault_path).join("_themes");
+    if !themes_dir.is_dir() {
+        seed_default_themes(vault_path);
+    }
+    if !themes_dir.is_dir() {
+        return Ok(Vec::new());
+    }
+
+    let mut themes = Vec::new();
+    let entries =
+        fs::read_dir(&themes_dir).map_err(|e| format!("Failed to read _themes directory: {e}"))?;
+
+    for entry in entries.flatten() {
+        let path = entry.path();
+        if path.extension().and_then(|e| e.to_str()) != Some("json") {
+            continue;
+        }
+        match parse_theme_file(&path) {
+            Ok(theme) => themes.push(theme),
+            Err(e) => log::warn!("Skipping theme file {}: {e}", path.display()),
+        }
+    }
+
+    themes.sort_by(|a, b| a.name.cmp(&b.name));
+    Ok(themes)
+}
+
+/// Parse a single theme JSON file.
+fn parse_theme_file(path: &Path) -> Result<ThemeFile, String> {
+    let id = path
+        .file_stem()
+        .and_then(|s| s.to_str())
+        .map(|s| s.to_string())
+        .ok_or_else(|| "Invalid theme filename".to_string())?;
+
+    let content =
+        fs::read_to_string(path).map_err(|e| format!("Failed to read {}: {e}", path.display()))?;
+
+    let mut theme: ThemeFile = serde_json::from_str(&content)
+        .map_err(|e| format!("Failed to parse {}: {e}", path.display()))?;
+
+    theme.id = id;
+    Ok(theme)
+}
+
+/// Read vault-level settings from .laputa/settings.json.
+pub fn get_vault_settings(vault_path: &str) -> Result<VaultSettings, String> {
+    let settings_path = Path::new(vault_path).join(".laputa").join("settings.json");
+    if !settings_path.exists() {
+        return Ok(VaultSettings::default());
+    }
+    let content = fs::read_to_string(&settings_path)
+        .map_err(|e| format!("Failed to read vault settings: {e}"))?;
+    serde_json::from_str(&content).map_err(|e| format!("Failed to parse vault settings: {e}"))
+}
+
+/// Save vault-level settings to .laputa/settings.json.
+pub fn save_vault_settings(vault_path: &str, settings: VaultSettings) -> Result<(), String> {
+    let laputa_dir = Path::new(vault_path).join(".laputa");
+    fs::create_dir_all(&laputa_dir)
+        .map_err(|e| format!("Failed to create .laputa directory: {e}"))?;
+
+    let json = serde_json::to_string_pretty(&settings)
+        .map_err(|e| format!("Failed to serialize vault settings: {e}"))?;
+    fs::write(laputa_dir.join("settings.json"), json)
+        .map_err(|e| format!("Failed to write vault settings: {e}"))
+}
+
+/// Set the active theme in vault settings. Pass `None` to clear.
+pub fn set_active_theme(vault_path: &str, theme_id: Option<&str>) -> Result<(), String> {
+    let mut settings = get_vault_settings(vault_path)?;
+    settings.theme = theme_id.map(|s| s.to_string());
+    save_vault_settings(vault_path, settings)
+}
+
+/// Read a single theme file by ID from the vault's _themes/ directory.
+pub fn get_theme(vault_path: &str, theme_id: &str) -> Result<ThemeFile, String> {
+    let path = Path::new(vault_path)
+        .join("_themes")
+        .join(format!("{theme_id}.json"));
+    if !path.exists() {
+        return Err(format!("Theme not found: {theme_id}"));
+    }
+    parse_theme_file(&path)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs;
+    use tempfile::TempDir;
+
+    fn setup_vault_with_themes(dir: &TempDir) -> String {
+        let vault = dir.path().join("vault");
+        let themes_dir = vault.join("_themes");
+        fs::create_dir_all(&themes_dir).unwrap();
+        fs::write(themes_dir.join("default.json"), DEFAULT_THEME).unwrap();
+        fs::write(themes_dir.join("dark.json"), DARK_THEME).unwrap();
+        vault.to_string_lossy().to_string()
+    }
+
+    #[test]
+    fn test_list_themes_returns_sorted_list() {
+        let dir = TempDir::new().unwrap();
+        let vault = setup_vault_with_themes(&dir);
+        let themes = list_themes(&vault).unwrap();
+        assert_eq!(themes.len(), 2);
+        assert_eq!(themes[0].id, "dark");
+        assert_eq!(themes[1].id, "default");
+    }
+
+    #[test]
+    fn test_list_themes_seeds_defaults_when_no_dir() {
+        let dir = TempDir::new().unwrap();
+        let vault = dir.path().join("empty-vault");
+        fs::create_dir_all(&vault).unwrap();
+        let themes = list_themes(vault.to_str().unwrap()).unwrap();
+        assert_eq!(themes.len(), 3);
+        let names: Vec<&str> = themes.iter().map(|t| t.name.as_str()).collect();
+        assert!(names.contains(&"Default"));
+        assert!(names.contains(&"Dark"));
+        assert!(names.contains(&"Minimal"));
+    }
+
+    #[test]
+    fn test_get_theme_by_id() {
+        let dir = TempDir::new().unwrap();
+        let vault = setup_vault_with_themes(&dir);
+        let theme = get_theme(&vault, "default").unwrap();
+        assert_eq!(theme.name, "Default");
+        assert!(!theme.colors.is_empty());
+    }
+
+    #[test]
+    fn test_get_theme_not_found() {
+        let dir = TempDir::new().unwrap();
+        let vault = setup_vault_with_themes(&dir);
+        let result = get_theme(&vault, "nonexistent");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_vault_settings_roundtrip() {
+        let dir = TempDir::new().unwrap();
+        let vault = dir.path().join("vault");
+        fs::create_dir_all(&vault).unwrap();
+        let vp = vault.to_str().unwrap();
+
+        let settings = get_vault_settings(vp).unwrap();
+        assert!(settings.theme.is_none());
+
+        set_active_theme(vp, Some("dark")).unwrap();
+        let settings = get_vault_settings(vp).unwrap();
+        assert_eq!(settings.theme.as_deref(), Some("dark"));
+
+        set_active_theme(vp, None).unwrap();
+        let settings = get_vault_settings(vp).unwrap();
+        assert_eq!(settings.theme, None);
+    }
+
+    #[test]
+    fn test_vault_settings_creates_laputa_dir() {
+        let dir = TempDir::new().unwrap();
+        let vault = dir.path().join("vault");
+        fs::create_dir_all(&vault).unwrap();
+        let vp = vault.to_str().unwrap();
+
+        assert!(!vault.join(".laputa").exists());
+        save_vault_settings(
+            vp,
+            VaultSettings {
+                theme: Some("light".into()),
+            },
+        )
+        .unwrap();
+        assert!(vault.join(".laputa").join("settings.json").exists());
+    }
+
+    #[test]
+    fn test_parse_all_builtin_themes() {
+        for (name, content) in [
+            ("default", DEFAULT_THEME),
+            ("dark", DARK_THEME),
+            ("minimal", MINIMAL_THEME),
+        ] {
+            let theme: ThemeFile = serde_json::from_str(content)
+                .unwrap_or_else(|e| panic!("Failed to parse {name} theme: {e}"));
+            assert!(!theme.name.is_empty(), "{name} theme should have a name");
+            assert!(!theme.colors.is_empty(), "{name} theme should have colors");
+        }
+    }
+
+    #[test]
+    fn test_list_themes_ignores_non_json_files() {
+        let dir = TempDir::new().unwrap();
+        let vault = setup_vault_with_themes(&dir);
+        let themes_dir = Path::new(&vault).join("_themes");
+        fs::write(themes_dir.join("readme.txt"), "not a theme").unwrap();
+        fs::write(themes_dir.join(".DS_Store"), "").unwrap();
+
+        let themes = list_themes(&vault).unwrap();
+        assert_eq!(themes.len(), 2);
+    }
+
+    #[test]
+    fn test_list_themes_skips_malformed_json() {
+        let dir = TempDir::new().unwrap();
+        let vault = setup_vault_with_themes(&dir);
+        let themes_dir = Path::new(&vault).join("_themes");
+        fs::write(themes_dir.join("broken.json"), "not valid json{{{").unwrap();
+
+        let themes = list_themes(&vault).unwrap();
+        assert_eq!(themes.len(), 2);
+    }
+
+    #[test]
+    fn test_vault_theme_content_contains_all_vars() {
+        let content = DEFAULT_VAULT_THEME;
+        assert!(content.contains("background:"));
+        assert!(content.contains("primary:"));
+        assert!(content.contains("sidebar:"));
+        assert!(content.contains("text-primary:"));
+        assert!(content.contains("accent-blue:"));
+        assert!(content.contains("editor-font-size:"));
+    }
+}