/// Environment-based configuration for all upstream services and the gateway itself.

#[derive(Debug, Clone)]
pub struct AppConfig {
    pub host: String,
    pub port: u16,
    /// Public-facing URL of this backend, used to rewrite tile URLs in style.json.
    /// Set via PUBLIC_URL env var, defaults to http://localhost:8080.
    pub public_url: String,
    pub martin_url: String,
    pub photon_url: String,
    pub osrm_driving_url: String,
    pub osrm_walking_url: String,
    pub osrm_cycling_url: String,
    pub database_url: String,
    pub redis_url: String,
    pub offline_data_dir: String,
}

impl AppConfig {
    /// Load configuration from environment variables with sensible defaults
    /// for docker-compose deployment.
    pub fn from_env() -> Self {
        Self {
            host: std::env::var("HOST").unwrap_or_else(|_| "0.0.0.0".into()),
            port: std::env::var("PORT")
                .ok()
                .and_then(|v| v.parse().ok())
                .unwrap_or(8080),
            public_url: std::env::var("PUBLIC_URL")
                .unwrap_or_else(|_| "http://localhost:8080".into()),
            martin_url: std::env::var("MARTIN_URL")
                .unwrap_or_else(|_| "http://martin:3000".into()),
            photon_url: std::env::var("PHOTON_URL")
                .unwrap_or_else(|_| "http://photon:2322".into()),
            osrm_driving_url: std::env::var("OSRM_DRIVING_URL")
                .unwrap_or_else(|_| "http://osrm-driving:5000".into()),
            osrm_walking_url: std::env::var("OSRM_WALKING_URL")
                .unwrap_or_else(|_| "http://osrm-walking:5000".into()),
            osrm_cycling_url: std::env::var("OSRM_CYCLING_URL")
                .unwrap_or_else(|_| "http://osrm-cycling:5000".into()),
            database_url: std::env::var("DATABASE_URL")
                .unwrap_or_else(|_| "postgres://maps:maps@postgis:5432/maps".into()),
            redis_url: std::env::var("REDIS_URL")
                .unwrap_or_else(|_| "redis://redis:6379".into()),
            offline_data_dir: std::env::var("OFFLINE_DATA_DIR")
                .unwrap_or_else(|_| "/data/offline".into()),
        }
    }

    /// Return the OSRM base URL for a given routing profile.
    pub fn osrm_url_for_profile(&self, profile: &str) -> Option<&str> {
        match profile {
            "driving" => Some(&self.osrm_driving_url),
            "walking" => Some(&self.osrm_walking_url),
            "cycling" => Some(&self.osrm_cycling_url),
            _ => None,
        }
    }
}