use std::env;

#[derive(Debug, Clone)]
pub struct Config {
    pub api_key: String,
    pub base_url: String,
    pub model: String,
}

impl Config {
    /// Resolve from environment. Prefers GROKBOY_*, then XAI_*, then OPENAI_*.
    pub fn from_env() -> Result<Self, String> {
        let api_key = env::var("GROKBOY_API_KEY")
            .or_else(|_| env::var("XAI_API_KEY"))
            .or_else(|_| env::var("OPENAI_API_KEY"))
            .map_err(|_| {
                "missing API key: set GROKBOY_API_KEY (or XAI_API_KEY / OPENAI_API_KEY)".to_string()
            })?;
        if api_key.trim().is_empty() {
            return Err("API key is empty".into());
        }
        let base_url = env::var("GROKBOY_BASE_URL")
            .or_else(|_| env::var("OPENAI_BASE_URL"))
            .unwrap_or_else(|_| "https://api.x.ai/v1".into());
        let model = env::var("GROKBOY_MODEL").unwrap_or_else(|_| "grok-4.6".into());
        Ok(Self {
            api_key,
            base_url: base_url.trim_end_matches('/').to_string(),
            model,
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn default_model_is_grok_4_6() {
        let cfg = Config {
            api_key: "x".into(),
            base_url: "https://api.x.ai/v1".into(),
            model: "grok-4.6".into(),
        };
        assert_eq!(cfg.model, "grok-4.6");
    }

    #[test]
    fn rejects_missing_key() {
        let _ = Config {
            api_key: "x".into(),
            base_url: "https://api.x.ai/v1".into(),
            model: "grok-4.6".into(),
        };
    }
}