//! Everything that talks to something outside this process: the chain's
//! JSON-RPC, the substrate-telemetry feed, and Postgres.
//!
//! The split is deliberate. `blackbeard-core` decodes and tallies with no I/O
//! at all and is exercised entirely by unit tests; this crate does the talking
//! and holds the retry, reconnect and schema concerns. `blackbeard-api` wires
//! the two together.

#![deny(missing_docs)]

pub mod rpc;
pub mod store;
pub mod telemetry;

/// Failures reaching a node, the telemetry feed, or the database.
#[derive(Debug, thiserror::Error)]
pub enum DataError {
    /// The node answered with a JSON-RPC error, or an unusable result.
    #[error("rpc {method}: {message}")]
    Rpc {
        /// Which method.
        method: String,
        /// What the node said.
        message: String,
    },

    /// The HTTP request itself failed — connection refused, timeout, TLS.
    #[error("http transport: {0}")]
    Http(#[from] reqwest::Error),

    /// A WebSocket connection failed or dropped.
    ///
    /// Boxed: tungstenite's error is by far the largest variant here, and an
    /// unboxed copy would be paid for on the stack by every `Result` in this
    /// crate — including the RPC calls made several times a second.
    #[error("websocket: {0}")]
    WebSocket(#[from] Box<tokio_tungstenite::tungstenite::Error>),

    /// A response did not have the shape we expected.
    #[error("decoding a response: {0}")]
    Decode(#[from] serde_json::Error),

    /// A node answered with something that was not a JSON-RPC response at all.
    ///
    /// Distinct from [`Self::Rpc`], which is the node answering *correctly*
    /// with an error. This one is a host misbehaving, and so is worth trying
    /// another endpoint for — the difference is what keeps a caller's own
    /// mistake from walking the whole endpoint list.
    #[error("malformed response to {method}: {message}")]
    Malformed {
        /// Which method.
        method: String,
        /// What was wrong with it.
        message: String,
    },

    /// A database query failed.
    #[error("database: {0}")]
    Database(#[from] sqlx::Error),

    /// A migration failed to apply.
    #[error("migration: {0}")]
    Migration(#[from] sqlx::migrate::MigrateError),
}

impl From<tokio_tungstenite::tungstenite::Error> for DataError {
    fn from(e: tokio_tungstenite::tungstenite::Error) -> Self {
        DataError::WebSocket(Box::new(e))
    }
}