//! PrismNET network management server binary

use anyhow::anyhow;
use chainfire_client::Client as ChainFireClient;
use clap::Parser;
use iam_service_auth::AuthService;
use metrics_exporter_prometheus::PrometheusBuilder;
use prismnet_api::{
    ipam_service_server::IpamServiceServer, port_service_server::PortServiceServer,
    security_group_service_server::SecurityGroupServiceServer,
    subnet_service_server::SubnetServiceServer, vpc_service_server::VpcServiceServer,
};
use prismnet_server::{
    config::MetadataBackend,
    IpamServiceImpl, NetworkMetadataStore, OvnClient, PortServiceImpl, SecurityGroupServiceImpl,
    ServerConfig, SubnetServiceImpl, VpcServiceImpl,
};
use std::net::SocketAddr;
use std::path::PathBuf;
use std::sync::Arc;
use std::time::{SystemTime, UNIX_EPOCH};
use tonic::transport::{Certificate, Identity, Server, ServerTlsConfig};
use tonic::{Request, Status};
use tonic_health::server::health_reporter;
use tracing_subscriber::EnvFilter;

/// PrismNET network management server
#[derive(Parser, Debug)]
#[command(author, version, about, long_about = None)]
struct Args {
    /// Configuration file path
    #[arg(short, long, default_value = "prismnet.toml")]
    config: PathBuf,

    /// gRPC API address (overrides config)
    #[arg(long)]
    grpc_addr: Option<String>,

    /// ChainFire endpoint for cluster coordination (optional)
    #[arg(long)]
    chainfire_endpoint: Option<String>,

    /// FlareDB endpoint for metadata and tenant data storage
    #[arg(long)]
    flaredb_endpoint: Option<String>,

    /// Metadata backend (flaredb, postgres, sqlite)
    #[arg(long)]
    metadata_backend: Option<String>,

    /// SQL database URL for metadata (required for postgres/sqlite backend)
    #[arg(long)]
    metadata_database_url: Option<String>,

    /// Run in single-node mode (required when metadata backend is SQLite)
    #[arg(long)]
    single_node: bool,

    /// Log level (overrides config)
    #[arg(short, long)]
    log_level: Option<String>,

    /// Metrics port for Prometheus scraping
    #[arg(long, default_value = "9096")]
    metrics_port: u16,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let args = Args::parse();

    // Load configuration from file or use defaults
    let mut config = if args.config.exists() {
        let contents = tokio::fs::read_to_string(&args.config).await?;
        toml::from_str(&contents)?
    } else {
        tracing::info!(
            "Config file not found: {}, using defaults",
            args.config.display()
        );
        ServerConfig::default()
    };

    // Apply command line overrides
    if let Some(grpc_addr_str) = args.grpc_addr {
        config.grpc_addr = grpc_addr_str.parse()?;
    }
    if let Some(log_level) = args.log_level {
        config.log_level = log_level;
    }
    if let Some(chainfire_endpoint) = args.chainfire_endpoint {
        config.chainfire_endpoint = Some(chainfire_endpoint);
    }
    if let Some(flaredb_endpoint) = args.flaredb_endpoint {
        config.flaredb_endpoint = Some(flaredb_endpoint);
    }
    if let Some(metadata_backend) = args.metadata_backend {
        config.metadata_backend = parse_metadata_backend(&metadata_backend)?;
    }
    if let Some(metadata_database_url) = args.metadata_database_url {
        config.metadata_database_url = Some(metadata_database_url);
    }
    if args.single_node {
        config.single_node = true;
    }
    if config.chainfire_endpoint.is_none() {
        if let Ok(chainfire_endpoint) = std::env::var("PRISMNET_CHAINFIRE_ENDPOINT") {
            let trimmed = chainfire_endpoint.trim();
            if !trimmed.is_empty() {
                config.chainfire_endpoint = Some(trimmed.to_string());
            }
        }
    }
    if config.flaredb_endpoint.is_none() {
        if let Ok(flaredb_endpoint) = std::env::var("PRISMNET_FLAREDB_ENDPOINT") {
            let trimmed = flaredb_endpoint.trim();
            if !trimmed.is_empty() {
                config.flaredb_endpoint = Some(trimmed.to_string());
            }
        }
    }
    if let Ok(metadata_backend) = std::env::var("PRISMNET_METADATA_BACKEND") {
        let trimmed = metadata_backend.trim();
        if !trimmed.is_empty() {
            config.metadata_backend = parse_metadata_backend(trimmed)?;
        }
    }
    if config.metadata_database_url.is_none() {
        if let Ok(metadata_database_url) = std::env::var("PRISMNET_METADATA_DATABASE_URL") {
            let trimmed = metadata_database_url.trim();
            if !trimmed.is_empty() {
                config.metadata_database_url = Some(trimmed.to_string());
            }
        }
    }
    if !config.single_node {
        if let Ok(single_node) = std::env::var("PRISMNET_SINGLE_NODE") {
            let parsed = single_node.trim().to_ascii_lowercase();
            config.single_node = matches!(parsed.as_str(), "1" | "true" | "yes" | "on");
        }
    }

    // Initialize tracing
    tracing_subscriber::fmt()
        .with_env_filter(
            EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new(&config.log_level)),
        )
        .init();

    tracing::info!("Starting PrismNET server");
    tracing::info!("  gRPC: {}", config.grpc_addr);

    // Initialize Prometheus metrics exporter
    let metrics_addr = format!("0.0.0.0:{}", args.metrics_port);
    let builder = PrometheusBuilder::new();
    builder
        .with_http_listener(metrics_addr.parse::<std::net::SocketAddr>()?)
        .install()
        .expect("Failed to install Prometheus metrics exporter");

    tracing::info!(
        "Prometheus metrics available at http://{}/metrics",
        metrics_addr
    );

    if let Some(endpoint) = &config.chainfire_endpoint {
        tracing::info!("  Cluster coordination: ChainFire @ {}", endpoint);
        let endpoint = endpoint.clone();
        let addr = config.grpc_addr.to_string();
        tokio::spawn(async move {
            if let Err(error) = register_chainfire_membership(&endpoint, "prismnet", addr).await {
                tracing::warn!(error = %error, "Failed to register ChainFire membership");
            }
        });
    }

    // Create metadata store from explicitly selected backend.
    let metadata = match config.metadata_backend {
        MetadataBackend::FlareDb => {
            if let Some(endpoint) = &config.flaredb_endpoint {
                tracing::info!("  Metadata backend: FlareDB @ {}", endpoint);
            } else {
                tracing::info!("  Metadata backend: FlareDB");
            }
            Arc::new(
                NetworkMetadataStore::new_flaredb_with_pd(
                    config.flaredb_endpoint.clone(),
                    config.chainfire_endpoint.clone(),
                )
                    .await
                    .map_err(|e| anyhow!("Failed to init FlareDB metadata store: {}", e))?,
            )
        }
        MetadataBackend::Postgres | MetadataBackend::Sqlite => {
            let database_url = config
                .metadata_database_url
                .as_deref()
                .ok_or_else(|| {
                    anyhow!(
                        "metadata_database_url is required when metadata_backend={} (env: PRISMNET_METADATA_DATABASE_URL)",
                        metadata_backend_name(config.metadata_backend)
                    )
                })?;
            ensure_sql_backend_matches_url(config.metadata_backend, database_url)?;
            tracing::info!(
                "  Metadata backend: {} @ {}",
                metadata_backend_name(config.metadata_backend),
                database_url
            );
            Arc::new(
                NetworkMetadataStore::new_sql(database_url, config.single_node)
                    .await
                    .map_err(|e| anyhow!("Failed to init SQL metadata store: {}", e))?,
            )
        }
    };

    // Initialize OVN client (default: mock)
    let ovn =
        Arc::new(OvnClient::from_env().map_err(|e| anyhow!("Failed to init OVN client: {}", e))?);

    // Initialize IAM authentication service
    tracing::info!(
        "Connecting to IAM server at {}",
        config.auth.iam_server_addr
    );
    let auth_service = AuthService::new(&config.auth.iam_server_addr)
        .await
        .map_err(|e| anyhow!("Failed to connect to IAM server: {}", e))?;
    let auth_service = Arc::new(auth_service);

    // Dedicated runtime for auth interceptors to avoid blocking the main async runtime
    let auth_runtime = Arc::new(tokio::runtime::Runtime::new()?);
    let make_interceptor = |auth: Arc<AuthService>| {
        let rt = auth_runtime.clone();
        move |mut req: Request<()>| -> Result<Request<()>, Status> {
            let auth = auth.clone();
            tokio::task::block_in_place(|| {
                rt.block_on(async move {
                    let tenant_context = auth.authenticate_request(&req).await?;
                    req.extensions_mut().insert(tenant_context);
                    Ok(req)
                })
            })
        }
    };

    // Create gRPC services
    let vpc_service = Arc::new(VpcServiceImpl::new(
        metadata.clone(),
        ovn.clone(),
        auth_service.clone(),
    ));
    let subnet_service = Arc::new(SubnetServiceImpl::new(
        metadata.clone(),
        auth_service.clone(),
    ));
    let port_service = Arc::new(PortServiceImpl::new(
        metadata.clone(),
        ovn.clone(),
        auth_service.clone(),
    ));
    let sg_service = Arc::new(SecurityGroupServiceImpl::new(
        metadata.clone(),
        ovn.clone(),
        auth_service.clone(),
    ));
    let ipam_service = Arc::new(IpamServiceImpl::new(metadata.clone(), auth_service.clone()));

    // Setup health service
    let (mut health_reporter, health_service) = health_reporter();
    health_reporter
        .set_serving::<VpcServiceServer<VpcServiceImpl>>()
        .await;
    health_reporter
        .set_serving::<SubnetServiceServer<SubnetServiceImpl>>()
        .await;
    health_reporter
        .set_serving::<PortServiceServer<PortServiceImpl>>()
        .await;
    health_reporter
        .set_serving::<SecurityGroupServiceServer<SecurityGroupServiceImpl>>()
        .await;
    health_reporter
        .set_serving::<IpamServiceServer<IpamServiceImpl>>()
        .await;

    // Parse address
    let grpc_addr: SocketAddr = config.grpc_addr;

    // Configure TLS if enabled
    let mut server = Server::builder();

    if let Some(tls_config) = &config.tls {
        tracing::info!("TLS enabled, loading certificates...");
        let cert = tokio::fs::read(&tls_config.cert_file).await?;
        let key = tokio::fs::read(&tls_config.key_file).await?;
        let server_identity = Identity::from_pem(cert, key);

        let tls = if tls_config.require_client_cert {
            tracing::info!("mTLS enabled");
            let ca_cert = tokio::fs::read(
                tls_config
                    .ca_file
                    .as_ref()
                    .ok_or("ca_file required for mTLS")?,
            )
            .await?;
            let ca = Certificate::from_pem(ca_cert);
            ServerTlsConfig::new()
                .identity(server_identity)
                .client_ca_root(ca)
        } else {
            ServerTlsConfig::new().identity(server_identity)
        };

        server = server.tls_config(tls)?;
    }

    // Start gRPC server
    tracing::info!("gRPC server listening on {}", grpc_addr);
    let grpc_server = server
        .add_service(health_service)
        .add_service(tonic::codegen::InterceptedService::new(
            VpcServiceServer::new(vpc_service.as_ref().clone()),
            make_interceptor(auth_service.clone()),
        ))
        .add_service(tonic::codegen::InterceptedService::new(
            SubnetServiceServer::new(subnet_service.as_ref().clone()),
            make_interceptor(auth_service.clone()),
        ))
        .add_service(tonic::codegen::InterceptedService::new(
            PortServiceServer::new(port_service.as_ref().clone()),
            make_interceptor(auth_service.clone()),
        ))
        .add_service(tonic::codegen::InterceptedService::new(
            SecurityGroupServiceServer::new(sg_service.as_ref().clone()),
            make_interceptor(auth_service.clone()),
        ))
        .add_service(tonic::codegen::InterceptedService::new(
            IpamServiceServer::new(ipam_service.as_ref().clone()),
            make_interceptor(auth_service.clone()),
        ))
        .serve(grpc_addr);

    // HTTP REST API server
    let http_addr = config.http_addr;
    let rest_state = prismnet_server::rest::RestApiState {
        vpc_service: vpc_service.clone(),
        subnet_service: subnet_service.clone(),
        auth_service: auth_service.clone(),
    };
    let rest_app = prismnet_server::rest::build_router(rest_state);
    let http_listener = tokio::net::TcpListener::bind(&http_addr).await?;

    tracing::info!("PrismNET HTTP REST API server starting on {}", http_addr);

    let http_server = async move {
        axum::serve(http_listener, rest_app)
            .await
            .map_err(|e| anyhow!("HTTP server error: {}", e))
    };

    // Run both servers concurrently
    tokio::select! {
        result = grpc_server => {
            result?;
        }
        result = http_server => {
            result?;
        }
    }

    Ok(())
}

fn parse_metadata_backend(value: &str) -> Result<MetadataBackend, Box<dyn std::error::Error>> {
    match value.trim().to_ascii_lowercase().as_str() {
        "flaredb" => Ok(MetadataBackend::FlareDb),
        "postgres" => Ok(MetadataBackend::Postgres),
        "sqlite" => Ok(MetadataBackend::Sqlite),
        other => Err(format!(
            "invalid metadata backend '{}'; expected one of: flaredb, postgres, sqlite",
            other
        )
        .into()),
    }
}

fn metadata_backend_name(backend: MetadataBackend) -> &'static str {
    match backend {
        MetadataBackend::FlareDb => "flaredb",
        MetadataBackend::Postgres => "postgres",
        MetadataBackend::Sqlite => "sqlite",
    }
}

fn ensure_sql_backend_matches_url(
    backend: MetadataBackend,
    database_url: &str,
) -> Result<(), Box<dyn std::error::Error>> {
    let normalized = database_url.trim().to_ascii_lowercase();
    match backend {
        MetadataBackend::Postgres => {
            if normalized.starts_with("postgres://") || normalized.starts_with("postgresql://") {
                Ok(())
            } else {
                Err("metadata_backend=postgres requires postgres:// or postgresql:// URL".into())
            }
        }
        MetadataBackend::Sqlite => {
            if normalized.starts_with("sqlite:") {
                Ok(())
            } else {
                Err("metadata_backend=sqlite requires sqlite: URL".into())
            }
        }
        MetadataBackend::FlareDb => Ok(()),
    }
}

async fn register_chainfire_membership(
    endpoint: &str,
    service: &str,
    addr: String,
) -> anyhow::Result<()> {
    let node_id =
        std::env::var("HOSTNAME").unwrap_or_else(|_| format!("{}-{}", service, std::process::id()));
    let ts = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap_or_default()
        .as_secs();
    let key = format!("/cluster/{}/members/{}", service, node_id);
    let value = format!(r#"{{"addr":"{}","ts":{}}}"#, addr, ts);
    let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(120);
    let mut attempt = 0usize;
    let mut last_error = String::new();

    loop {
        attempt += 1;
        match ChainFireClient::connect(endpoint).await {
            Ok(mut client) => match client.put_str(&key, &value).await {
                Ok(_) => return Ok(()),
                Err(error) => last_error = format!("put failed: {}", error),
            },
            Err(error) => last_error = format!("connect failed: {}", error),
        }

        if tokio::time::Instant::now() >= deadline {
            break;
        }

        tracing::warn!(
            attempt,
            endpoint,
            service,
            error = %last_error,
            "retrying ChainFire membership registration"
        );
        tokio::time::sleep(std::time::Duration::from_secs(2)).await;
    }

    anyhow::bail!(
        "failed to register ChainFire membership for {} via {} after {} attempts: {}",
        service,
        endpoint,
        attempt,
        last_error
    )
}