rpi-cli 0.1.3

//! `~/.rpi/agent/settings.json` — saved user defaults. Mirrors the slice of
//! pi's `Settings` interface (`packages/coding-agent/src/core/settings-manager.ts`)
//! that rpi honors: `defaultProvider` / `defaultModel` / `defaultThinkingLevel`
//! (consumed by `provider::resolve` as pi's `findInitialModel` step 3 — the
//! saved default, when authed, wins over the built-in fallback) and `theme`.
//!
//! pi's `Settings` carries ~40 fields; rpi reads the 4 it uses and drops the
//! rest (serde `default` ignores unknown fields), so a copied pi `settings.json`
//! parses clean.

use crate::config::{self, strip_line_comments, ConfigError};

/// The honored subset of pi's `Settings`. Unknown fields are ignored.
#[derive(serde::Deserialize, Default, Clone, Debug)]
#[serde(rename_all = "camelCase")]
pub struct Settings {
    /// Saved default provider id (v1 honors only `"anthropic"`; an absent or
    /// anthropic value allows the saved default-model lookup).
    #[serde(default)]
    pub default_provider: Option<String>,
    /// Saved default model id. When present and the model is authed,
    /// `provider::resolve` selects it (pi `findInitialModel` step 3).
    #[serde(default)]
    pub default_model: Option<String>,
    /// Saved default thinking level (a level-name string: off/minimal/low/medium/
    /// high/xhigh/max). Parsed by the caller via `args::parse_thinking_level`.
    #[serde(default)]
    pub default_thinking_level: Option<String>,
    /// Saved theme name. Surfaced for best-effort TUI theme application.
    #[serde(default)]
    pub theme: Option<String>,
}

/// Load `~/.rpi/agent/settings.json`. Missing file ⇒ `Settings::default()`
/// (not an error). Malformed JSON ⇒ `ConfigError::Json`. Tolerates `//` line
/// comments (a copied pi settings.json may contain them).
pub fn load_settings() -> Result<Settings, ConfigError> {
    let path = config::settings_path()?;
    match std::fs::read_to_string(&path) {
        Ok(text) => parse_settings(&text).map_err(|e| ConfigError::Json {
            path: path.clone(),
            source: e,
        }),
        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(Settings::default()),
        Err(e) => Err(ConfigError::Read { path, source: e }),
    }
}

fn parse_settings(text: &str) -> Result<Settings, serde_json::Error> {
    match serde_json::from_str(text) {
        Ok(s) => Ok(s),
        Err(first) => {
            let stripped = strip_line_comments(text);
            serde_json::from_str(&stripped).map_err(|_| first)
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::config::test_support::env_lock;

    /// Point `RPI_CODING_AGENT_DIR` at a fresh temp dir for this test.
    struct TempConfig {
        _guard: std::sync::MutexGuard<'static, ()>,
        _tmp: tempfile::TempDir,
        prev: Option<std::ffi::OsString>,
    }
    impl TempConfig {
        fn new() -> Self {
            let guard = env_lock().lock().unwrap();
            let prev = std::env::var_os(config::CONFIG_DIR_ENV);
            let tmp = tempfile::TempDir::new().unwrap();
            std::env::set_var(config::CONFIG_DIR_ENV, tmp.path());
            Self { _guard: guard, _tmp: tmp, prev }
        }
    }
    impl Drop for TempConfig {
        fn drop(&mut self) {
            match self.prev.take() {
                Some(v) => std::env::set_var(config::CONFIG_DIR_ENV, v),
                None => std::env::remove_var(config::CONFIG_DIR_ENV),
            }
        }
    }

    #[test]
    fn missing_settings_is_default() {
        let _cfg = TempConfig::new();
        let s = load_settings().unwrap();
        assert!(s.default_provider.is_none());
        assert!(s.default_model.is_none());
        assert!(s.default_thinking_level.is_none());
        assert!(s.theme.is_none());
    }

    #[test]
    fn reads_honored_fields_and_ignores_unknown() {
        let _cfg = TempConfig::new();
        let path = config::settings_path().unwrap();
        std::fs::create_dir_all(path.parent().unwrap()).unwrap();
        // A pi-style settings.json with many unknown fields + the 4 we honor.
        std::fs::write(
            &path,
            r#"{
                "lastChangelogVersion": "1.0.0",
                "defaultProvider": "anthropic",
                "defaultModel": "claude-sonnet-5",
                "defaultThinkingLevel": "high",
                "theme": "dark",
                "hideThinkingBlock": true,
                "compaction": { "threshold": 100 },
                "packages": ["some-pkg"]
            }"#,
        )
        .unwrap();
        let s = load_settings().unwrap();
        assert_eq!(s.default_provider.as_deref(), Some("anthropic"));
        assert_eq!(s.default_model.as_deref(), Some("claude-sonnet-5"));
        assert_eq!(s.default_thinking_level.as_deref(), Some("high"));
        assert_eq!(s.theme.as_deref(), Some("dark"));
    }

    #[test]
    fn tolerates_line_comments() {
        let _cfg = TempConfig::new();
        let path = config::settings_path().unwrap();
        std::fs::create_dir_all(path.parent().unwrap()).unwrap();
        std::fs::write(
            &path,
            "{\n  // my default\n  \"defaultModel\": \"glm-5\",\n  \"theme\": \"light\"\n}\n",
        )
        .unwrap();
        let s = load_settings().unwrap();
        assert_eq!(s.default_model.as_deref(), Some("glm-5"));
        assert_eq!(s.theme.as_deref(), Some("light"));
    }

    #[test]
    fn malformed_is_error() {
        let _cfg = TempConfig::new();
        let path = config::settings_path().unwrap();
        std::fs::create_dir_all(path.parent().unwrap()).unwrap();
        std::fs::write(&path, "{ not json").unwrap();
        assert!(matches!(load_settings(), Err(ConfigError::Json { .. })));
    }
}