Initial commit

src-tauri/src/config/mod.rs

@@ -0,0 +1,279 @@
+//! Configuration types for Brittle.
+//!
+//! Two levels of config exist:
+//! - [`GlobalConfig`] — stored at `~/.config/brittle/config.toml`; applies to all projects.
+//! - [`ProjectConfig`] — stored at `{repo}/.brittle/config.toml`; overrides globals per project.
+//!
+//! Use [`MergedConfig::merge`] to produce the effective config the app should use.
+
+mod global;
+mod project;
+
+pub use global::GlobalConfig;
+pub use project::ProjectConfig;
+
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+
+// ── Shared types ──────────────────────────────────────────────────────────────
+
+/// Application colour theme.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, Default)]
+#[serde(rename_all = "lowercase")]
+pub enum Theme {
+    #[default]
+    Dark,
+    Light,
+}
+
+/// Appearance settings (font size, theme).
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(default)]
+pub struct AppearanceConfig {
+    pub theme: Theme,
+    pub font_size: u32,
+}
+
+impl Default for AppearanceConfig {
+    fn default() -> Self {
+        Self {
+            theme: Theme::Dark,
+            font_size: 14,
+        }
+    }
+}
+
+/// Partial appearance override from a project config.
+/// Only `Some` fields replace the global value.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
+#[serde(default)]
+pub struct AppearanceOverride {
+    pub theme: Option<Theme>,
+    pub font_size: Option<u32>,
+}
+
+/// Pane layout proportions (fractions of the window width, 0..1).
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(default)]
+pub struct LayoutConfig {
+    pub left_pane_fraction: f32,
+    pub right_pane_fraction: f32,
+}
+
+impl Default for LayoutConfig {
+    fn default() -> Self {
+        Self {
+            left_pane_fraction: 0.20,
+            right_pane_fraction: 0.35,
+        }
+    }
+}
+
+/// Keybinding overrides — maps action name to key combo string.
+///
+/// Only actions the user wants to rebind need an entry here; everything else
+/// falls back to the built-in defaults defined in `keymap`.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
+pub struct KeybindingsConfig(pub HashMap<String, String>);
+
+// ── Merged config ─────────────────────────────────────────────────────────────
+
+/// The effective config the application uses at runtime, produced by merging
+/// global defaults with per-project overrides.
+#[derive(Debug, Clone)]
+#[allow(dead_code)] // consumed in Phase 3 when AppState is wired up
+pub struct MergedConfig {
+    pub appearance: AppearanceConfig,
+    pub layout: LayoutConfig,
+    pub keybindings: KeybindingsConfig,
+    /// Reference IDs of tabs that should be restored on launch.
+    pub open_tabs: Vec<String>,
+}
+
+impl MergedConfig {
+    #[allow(dead_code)] // consumed in Phase 3 when AppState is wired up
+    /// Merge `global` with an optional `project` override.
+    ///
+    /// Project values take precedence for appearance; layout and keybindings
+    /// are always taken from the global config (per-project overrides for those
+    /// are intentionally not supported — it would be confusing).
+    pub fn merge(global: &GlobalConfig, project: Option<&ProjectConfig>) -> Self {
+        let appearance = match project.and_then(|p| p.appearance.as_ref()) {
+            Some(ov) => AppearanceConfig {
+                theme: ov
+                    .theme
+                    .clone()
+                    .unwrap_or_else(|| global.appearance.theme.clone()),
+                font_size: ov.font_size.unwrap_or(global.appearance.font_size),
+            },
+            None => global.appearance.clone(),
+        };
+
+        Self {
+            appearance,
+            layout: global.layout.clone(),
+            keybindings: global.keybindings.clone(),
+            open_tabs: project
+                .map(|p| p.session.open_tabs.clone())
+                .unwrap_or_default(),
+        }
+    }
+}
+
+// ── Error type ────────────────────────────────────────────────────────────────
+
+#[derive(Debug, thiserror::Error)]
+pub enum ConfigError {
+    #[error("no config directory found on this platform")]
+    NoConfigDir,
+    #[error("I/O error: {0}")]
+    Io(#[from] std::io::Error),
+    #[error("TOML parse error: {0}")]
+    Parse(#[from] toml::de::Error),
+    #[error("TOML serialize error: {0}")]
+    Serialize(#[from] toml::ser::Error),
+}
+
+// ── Tests ─────────────────────────────────────────────────────────────────────
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::config::project::SessionConfig;
+
+    // ── AppearanceConfig ──────────────────────────────────────────────────────
+
+    #[test]
+    fn appearance_defaults_are_dark_14pt() {
+        let a = AppearanceConfig::default();
+        assert_eq!(a.theme, Theme::Dark);
+        assert_eq!(a.font_size, 14);
+    }
+
+    #[test]
+    fn appearance_round_trips() {
+        let original = AppearanceConfig {
+            theme: Theme::Light,
+            font_size: 16,
+        };
+        let s = toml::to_string_pretty(&original).unwrap();
+        let parsed: AppearanceConfig = toml::from_str(&s).unwrap();
+        assert_eq!(parsed, original);
+    }
+
+    #[test]
+    fn appearance_missing_fields_use_defaults() {
+        // Only theme specified; font_size should fall back to 14.
+        let parsed: AppearanceConfig = toml::from_str("theme = \"light\"").unwrap();
+        assert_eq!(parsed.theme, Theme::Light);
+        assert_eq!(parsed.font_size, 14);
+    }
+
+    // ── LayoutConfig ─────────────────────────────────────────────────────────
+
+    #[test]
+    fn layout_defaults() {
+        let l = LayoutConfig::default();
+        assert!((l.left_pane_fraction - 0.20).abs() < f32::EPSILON);
+        assert!((l.right_pane_fraction - 0.35).abs() < f32::EPSILON);
+    }
+
+    #[test]
+    fn layout_round_trips() {
+        let original = LayoutConfig {
+            left_pane_fraction: 0.25,
+            right_pane_fraction: 0.40,
+        };
+        let s = toml::to_string_pretty(&original).unwrap();
+        let parsed: LayoutConfig = toml::from_str(&s).unwrap();
+        assert_eq!(parsed, original);
+    }
+
+    // ── MergedConfig ─────────────────────────────────────────────────────────
+
+    #[test]
+    fn merge_without_project_uses_globals() {
+        let global = GlobalConfig {
+            appearance: AppearanceConfig {
+                theme: Theme::Light,
+                font_size: 16,
+            },
+            ..Default::default()
+        };
+        let merged = MergedConfig::merge(&global, None);
+        assert_eq!(merged.appearance.theme, Theme::Light);
+        assert_eq!(merged.appearance.font_size, 16);
+        assert!(merged.open_tabs.is_empty());
+    }
+
+    #[test]
+    fn merge_project_overrides_theme() {
+        let global = GlobalConfig {
+            appearance: AppearanceConfig {
+                theme: Theme::Dark,
+                font_size: 14,
+            },
+            ..Default::default()
+        };
+        let project = ProjectConfig {
+            appearance: Some(AppearanceOverride {
+                theme: Some(Theme::Light),
+                font_size: None,
+            }),
+            ..Default::default()
+        };
+        let merged = MergedConfig::merge(&global, Some(&project));
+        assert_eq!(merged.appearance.theme, Theme::Light);
+        // font_size not overridden — inherits from global
+        assert_eq!(merged.appearance.font_size, 14);
+    }
+
+    #[test]
+    fn merge_project_overrides_font_size_only() {
+        let global = GlobalConfig {
+            appearance: AppearanceConfig {
+                theme: Theme::Dark,
+                font_size: 14,
+            },
+            ..Default::default()
+        };
+        let project = ProjectConfig {
+            appearance: Some(AppearanceOverride {
+                theme: None,
+                font_size: Some(18),
+            }),
+            ..Default::default()
+        };
+        let merged = MergedConfig::merge(&global, Some(&project));
+        assert_eq!(merged.appearance.theme, Theme::Dark);
+        assert_eq!(merged.appearance.font_size, 18);
+    }
+
+    #[test]
+    fn merge_project_open_tabs_are_included() {
+        let global = GlobalConfig::default();
+        let project = ProjectConfig {
+            session: SessionConfig {
+                open_tabs: vec!["tab-a".to_string(), "tab-b".to_string()],
+            },
+            ..Default::default()
+        };
+        let merged = MergedConfig::merge(&global, Some(&project));
+        assert_eq!(merged.open_tabs, ["tab-a", "tab-b"]);
+    }
+
+    #[test]
+    fn merge_layout_always_from_global() {
+        let global = GlobalConfig {
+            layout: LayoutConfig {
+                left_pane_fraction: 0.30,
+                right_pane_fraction: 0.40,
+            },
+            ..Default::default()
+        };
+        // Project config has no layout override capability.
+        let merged = MergedConfig::merge(&global, None);
+        assert!((merged.layout.left_pane_fraction - 0.30).abs() < f32::EPSILON);
+    }
+}