//! Server deployment configuration.
//!
//! Reads from environment variables to select adapter (local/redis/nats)
//! and WebTransport settings.

use std::env;

/// Adapter + message bus configuration for multi-node scale-out.
#[derive(Debug, Clone)]
pub struct DeployConfig {
    /// "local" | "redis" | "nats"
    pub adapter_mode: String,
    /// Redis cluster nodes, comma-separated host:port pairs.
    /// Example: "redis1:6379,redis2:6379,redis3:6379"
    pub redis_cluster_nodes: String,
    /// Redis password (optional).
    pub redis_password: String,
    /// NATS connection URL (used when adapter_mode = "nats").
    pub nats_url: String,
    /// Unique server ID for this node.
    pub server_id: String,
    /// Enable WebTransport server.
    pub webtransport_enabled: bool,
    /// WebTransport listen port.
    pub webtransport_port: u16,
    /// TLS certificate path (required for WebTransport).
    pub cert_path: String,
    /// TLS key path (required for WebTransport).
    pub key_path: String,
}

impl DeployConfig {
    pub fn from_env() -> Self {
        let server_id = env::var("IMKS_SERVER_ID").unwrap_or_else(|_| hostname());

        Self {
            adapter_mode: env::var("IMKS_ADAPTER").unwrap_or_else(|_| "local".into()),
            redis_cluster_nodes: env::var("IMKS_REDIS_CLUSTER_NODES")
                .unwrap_or_else(|_| "localhost:6379,localhost:6380,localhost:6381".into()),
            redis_password: env::var("IMKS_REDIS_PASSWORD").unwrap_or_default(),
            nats_url: env::var("IMKS_NATS_URL").unwrap_or_else(|_| "nats://localhost:4222".into()),
            server_id,
            webtransport_enabled: env::var("IMKS_WT_ENABLED")
                .map(|v| v == "true" || v == "1")
                .unwrap_or(false),
            webtransport_port: env::var("IMKS_WT_PORT")
                .ok()
                .and_then(|v| v.parse().ok())
                .unwrap_or(3001),
            cert_path: env::var("IMKS_WT_CERT_PATH").unwrap_or_default(),
            key_path: env::var("IMKS_WT_KEY_PATH").unwrap_or_default(),
        }
    }

    /// Build a redis-cluster URL from cluster_nodes and optional password.
    /// Format: redis-cluster://[:password@]host1:port1,host2:port2,...
    pub fn redis_cluster_url(&self) -> String {
        let auth = if self.redis_password.is_empty() {
            String::new()
        } else {
            format!(":{}@", self.redis_password)
        };
        format!("redis-cluster://{}{}", auth, self.redis_cluster_nodes)
    }
}

impl Default for DeployConfig {
    fn default() -> Self {
        Self::from_env()
    }
}

fn hostname() -> String {
    env::var("HOSTNAME")
        .or_else(|_| env::var("HOST"))
        .unwrap_or_else(|_| "imks-node-1".into())
}