use std::fmt;

use jsonrpc_core::{Error as JsonRpcError, ErrorCode};
use serde_json::error::Error as SerdeJsonError;

use peach_stats::StatsError;

/// Custom error type encapsulating all possible errors for a JSON-RPC server
/// and associated methods.
#[derive(Debug)]
pub enum JsonRpcServerError {
    /// Failed to serialize a string from a data structure.
    Serde(SerdeJsonError),
    /// An error returned from the `peach-stats` library.
    Stats(StatsError),
    /// An expected JSON-RPC method parameter was not provided.
    MissingParameter(JsonRpcError),
    /// Failed to parse a provided JSON-RPC method parameter.
    ParseParameter(JsonRpcError),
}

impl fmt::Display for JsonRpcServerError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            JsonRpcServerError::ParseParameter(ref source) => {
                write!(f, "Failed to parse parameter: {}", source)
            }
            JsonRpcServerError::MissingParameter(ref source) => {
                write!(f, "Missing expected parameter: {}", source)
            }
            JsonRpcServerError::Serde(ref source) => {
                write!(f, "{}", source)
            }
            JsonRpcServerError::Stats(ref source) => {
                write!(f, "{}", source)
            }
        }
    }
}

impl From<JsonRpcServerError> for JsonRpcError {
    fn from(err: JsonRpcServerError) -> Self {
        match &err {
            JsonRpcServerError::Serde(source) => JsonRpcError {
                code: ErrorCode::ServerError(-32002),
                message: format!("{}", source),
                data: None,
            },
            JsonRpcServerError::Stats(source) => JsonRpcError {
                code: ErrorCode::ServerError(-32001),
                message: format!("{}", source),
                data: None,
            },
            JsonRpcServerError::MissingParameter(source) => source.clone(),
            JsonRpcServerError::ParseParameter(source) => source.clone(),
        }
    }
}