//! Connection options shared by [`crate::client::GatewayClient`] and
//! [`crate::galaxy::GalaxyClient`]. Build with [`ClientOptions::new`] and a
//! chain of `with_*` setters; the `Debug` impl redacts the API key.

use std::fmt;
use std::path::PathBuf;
use std::time::Duration;

use crate::auth::ApiKey;

const DEFAULT_MAX_GRPC_MESSAGE_BYTES: usize = 16 * 1024 * 1024;

/// Configuration for connecting to a gateway endpoint.
///
/// Defaults are 10s connect timeout, 30s call timeout, no streaming timeout,
/// and plaintext (h2c) transport. Set [`ClientOptions::with_plaintext`] to
/// `false` and supply [`ClientOptions::with_ca_file`] / a server-name override
/// for TLS deployments.
#[derive(Clone)]
pub struct ClientOptions {
    endpoint: String,
    api_key: Option<ApiKey>,
    plaintext: bool,
    ca_file: Option<PathBuf>,
    server_name_override: Option<String>,
    connect_timeout: Duration,
    call_timeout: Duration,
    stream_timeout: Option<Duration>,
    max_grpc_message_bytes: usize,
}

impl ClientOptions {
    /// Build options for the supplied gateway endpoint URL (for example,
    /// `http://127.0.0.1:5000`). Other settings take their defaults.
    pub fn new(endpoint: impl Into<String>) -> Self {
        Self {
            endpoint: endpoint.into(),
            api_key: None,
            plaintext: true,
            ca_file: None,
            server_name_override: None,
            connect_timeout: Duration::from_secs(10),
            call_timeout: Duration::from_secs(30),
            stream_timeout: None,
            max_grpc_message_bytes: DEFAULT_MAX_GRPC_MESSAGE_BYTES,
        }
    }

    /// Attach an API key. The key flows through [`crate::auth::AuthInterceptor`]
    /// as the Bearer token on every request.
    pub fn with_api_key(mut self, api_key: ApiKey) -> Self {
        self.api_key = Some(api_key);
        self
    }

    /// Toggle h2c (plaintext) vs TLS. `true` (the default) skips the TLS
    /// handshake and is suitable for loopback development.
    pub fn with_plaintext(mut self, plaintext: bool) -> Self {
        self.plaintext = plaintext;
        self
    }

    /// Trust roots PEM bundle for TLS connections. Ignored when
    /// `plaintext` is `true`.
    pub fn with_ca_file(mut self, ca_file: impl Into<PathBuf>) -> Self {
        self.ca_file = Some(ca_file.into());
        self
    }

    /// Override the SNI/server name used during the TLS handshake. Useful
    /// when the dial-target host name does not match the certificate.
    pub fn with_server_name_override(mut self, server_name_override: impl Into<String>) -> Self {
        self.server_name_override = Some(server_name_override.into());
        self
    }

    /// Maximum time the transport waits for the initial TCP/TLS connection.
    pub fn with_connect_timeout(mut self, connect_timeout: Duration) -> Self {
        self.connect_timeout = connect_timeout;
        self
    }

    /// Per-call deadline applied to every unary RPC. Streaming RPCs use
    /// [`ClientOptions::with_stream_timeout`] instead.
    pub fn with_call_timeout(mut self, call_timeout: Duration) -> Self {
        self.call_timeout = call_timeout;
        self
    }

    /// Optional deadline applied to streaming RPCs (for example,
    /// `StreamEvents`). Without a stream timeout the stream lives until the
    /// caller drops it or the server closes it.
    pub fn with_stream_timeout(mut self, stream_timeout: Duration) -> Self {
        self.stream_timeout = Some(stream_timeout);
        self
    }

    /// Maximum encoded/decoded gRPC message size in bytes (default 16 MiB).
    pub fn with_max_grpc_message_bytes(mut self, max_grpc_message_bytes: usize) -> Self {
        self.max_grpc_message_bytes = max_grpc_message_bytes;
        self
    }

    /// Configured endpoint URL.
    pub fn endpoint(&self) -> &str {
        &self.endpoint
    }

    /// Configured API key, if any.
    pub fn api_key(&self) -> Option<&ApiKey> {
        self.api_key.as_ref()
    }

    /// Whether the transport runs in plaintext (h2c) mode.
    pub fn plaintext(&self) -> bool {
        self.plaintext
    }

    /// Optional CA bundle path used to validate the server certificate.
    pub fn ca_file(&self) -> Option<&PathBuf> {
        self.ca_file.as_ref()
    }

    /// Optional SNI / server-name override for TLS handshakes.
    pub fn server_name_override(&self) -> Option<&str> {
        self.server_name_override.as_deref()
    }

    /// Connect timeout used during transport setup.
    pub fn connect_timeout(&self) -> Duration {
        self.connect_timeout
    }

    /// Per-call timeout for unary RPCs.
    pub fn call_timeout(&self) -> Duration {
        self.call_timeout
    }

    /// Optional per-call timeout for streaming RPCs.
    pub fn stream_timeout(&self) -> Option<Duration> {
        self.stream_timeout
    }

    /// Configured maximum encoded/decoded gRPC message size in bytes.
    pub fn max_grpc_message_bytes(&self) -> usize {
        self.max_grpc_message_bytes
    }
}

impl Default for ClientOptions {
    fn default() -> Self {
        Self::new("http://127.0.0.1:5000")
    }
}

impl fmt::Debug for ClientOptions {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        formatter
            .debug_struct("ClientOptions")
            .field("endpoint", &self.endpoint)
            .field("api_key", &self.api_key.as_ref().map(|_| "<redacted>"))
            .field("plaintext", &self.plaintext)
            .field("ca_file", &self.ca_file)
            .field("server_name_override", &self.server_name_override)
            .field("connect_timeout", &self.connect_timeout)
            .field("call_timeout", &self.call_timeout)
            .field("stream_timeout", &self.stream_timeout)
            .field("max_grpc_message_bytes", &self.max_grpc_message_bytes)
            .finish()
    }
}

#[cfg(test)]
mod tests {
    use super::ClientOptions;
    use crate::auth::ApiKey;

    #[test]
    fn debug_redacts_api_key() {
        let options =
            ClientOptions::new("http://localhost:5000").with_api_key(ApiKey::new("mxgw_secret"));

        let debug = format!("{options:?}");

        assert!(debug.contains("<redacted>"));
        assert!(!debug.contains("mxgw_secret"));
    }
}
