hyperdb-api-core 1.0.0-rc.4

// Copyright (c) 2026, Salesforce, Inc. All rights reserved.
// SPDX-License-Identifier: Apache-2.0 OR MIT

//! gRPC-specific error types.
//!
//! This module handles conversion from gRPC status codes and Hyper's structured
//! error details to the common [`crate::Error`] type.

use std::fmt;

use tonic::Status;

use crate::client::error::Error;

/// Which [`Error`] variant a gRPC status code or SQLSTATE maps to.
///
/// gRPC is the one place in the crate where the variant is chosen at
/// runtime from a wire code rather than being known at the call site, so
/// the decision needs a name it can be carried around under. It stays
/// private to this module — [`Error`] itself is flat and has no `kind`.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum Variant {
    Authentication,
    Cancelled,
    Connection,
    FeatureNotSupported,
    Other,
    Query,
    Timeout,
}

impl Variant {
    /// Builds the corresponding [`Error`], attaching the server's
    /// diagnostics to the variants that carry them.
    ///
    /// `Query`, `Connection`, and `Cancelled` have fields for the pieces
    /// they can use. The rest have only a message, so any `detail` is
    /// folded into it rather than dropped — that keeps the rendered text
    /// identical to what the previous struct-shaped error produced.
    fn build(
        self,
        message: String,
        detail: Option<String>,
        hint: Option<String>,
        sqlstate: Option<String>,
    ) -> Error {
        match self {
            Variant::Query => Error::Query {
                message,
                sqlstate,
                detail,
                hint,
            },
            Variant::Connection => Error::Connection {
                message: fold_detail(message, detail.as_deref()),
                sqlstate,
            },
            Variant::Cancelled => Error::Cancelled {
                message: fold_detail(message, detail.as_deref()),
                sqlstate,
            },
            Variant::Authentication => {
                Error::authentication(fold_detail(message, detail.as_deref()))
            }
            Variant::FeatureNotSupported => {
                Error::feature_not_supported(fold_detail(message, detail.as_deref()))
            }
            Variant::Timeout => Error::timeout(fold_detail(message, detail.as_deref())),
            Variant::Other => Error::other(fold_detail(message, detail.as_deref())),
        }
    }
}

/// Appends `": {detail}"` unless `message` already contains it, matching
/// what `Error`'s `Display` does for the variants that keep a `detail`
/// field.
fn fold_detail(message: String, detail: Option<&str>) -> String {
    match detail {
        Some(detail) if !message.contains(detail) => format!("{message}: {detail}"),
        _ => message,
    }
}

/// gRPC-specific error information.
///
/// This wraps additional error details from Hyper's gRPC error responses,
/// including SQLSTATE codes, hints, and detailed error messages.
#[derive(Debug, Clone)]
pub struct GrpcError {
    /// The SQLSTATE error code (e.g., "42703" for undefined column)
    pub sqlstate: Option<String>,
    /// The primary error message
    pub message: String,
    /// Additional detail about the error
    pub detail: Option<String>,
    /// A hint for how to resolve the error
    pub hint: Option<String>,
    /// The error source ("User" or "System")
    pub error_source: Option<String>,
}

impl fmt::Display for GrpcError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.message)?;
        if let Some(ref detail) = self.detail {
            write!(f, ": {detail}")?;
        }
        Ok(())
    }
}

impl std::error::Error for GrpcError {}

#[expect(
    clippy::needless_pass_by_value,
    reason = "call-site ergonomics: function consumes logically-owned parameters, refactoring signatures is not worth per-site churn"
)]
/// Converts a tonic gRPC Status to our Error type.
///
/// This function attempts to parse Hyper's structured error details from the
/// gRPC status. If that fails, it falls back to parsing XML error format,
/// and finally to using the raw gRPC error message.
pub(super) fn from_grpc_status(status: Status) -> Error {
    // First, try to parse structured error details (ErrorInfo proto)
    if let Some(error_info) = parse_error_info(&status) {
        return grpc_code_to_variant(status.code()).build(
            error_info.message,
            error_info.detail,
            error_info.hint,
            error_info.sqlstate,
        );
    }

    // Fall back to parsing XML error format from the message
    if let Some(error) = parse_xml_error(status.message()) {
        return error;
    }

    // Last resort: use the raw gRPC error message
    grpc_code_to_variant(status.code()).build(status.message().to_string(), None, None, None)
}

/// Attempts to parse `ErrorInfo` from the gRPC status details.
fn parse_error_info(status: &Status) -> Option<GrpcError> {
    // The error details are in the status metadata as a serialized google.rpc.Status
    // containing salesforce.hyperdb.grpc.v1.ErrorInfo
    //
    // For now, we'll implement a simplified version that extracts from the status
    // details bytes. A full implementation would use prost to decode the Any types.

    // Try to decode the details
    let details = status.details();
    if details.is_empty() {
        return None;
    }

    // Try to parse as google.rpc.Status containing ErrorInfo
    // This is a simplified implementation - we look for known field patterns
    parse_error_info_from_bytes(details)
}

/// Parses `ErrorInfo` from raw bytes.
///
/// This is a simplified parser that looks for the `ErrorInfo` fields in the
/// serialized protobuf data.
fn parse_error_info_from_bytes(data: &[u8]) -> Option<GrpcError> {
    // Try to decode using prost
    use prost::Message;

    // The details are wrapped in google.rpc.Status
    // which contains a repeated Any field with ErrorInfo
    #[derive(Clone, PartialEq, Message)]
    struct GoogleRpcStatus {
        #[prost(int32, tag = "1")]
        code: i32,
        #[prost(string, tag = "2")]
        message: String,
        #[prost(message, repeated, tag = "3")]
        details: Vec<prost_types::Any>,
    }

    if let Ok(rpc_status) = GoogleRpcStatus::decode(data) {
        for detail in rpc_status.details {
            // Check if this is an ErrorInfo
            if detail
                .type_url
                .ends_with("salesforce.hyperdb.grpc.v1.ErrorInfo")
            {
                // Try to decode the ErrorInfo
                if let Some(error_info) = decode_error_info(&detail.value) {
                    return Some(error_info);
                }
            }
        }
    }

    None
}

/// Decodes `ErrorInfo` from its serialized form.
fn decode_error_info(data: &[u8]) -> Option<GrpcError> {
    use prost::Message;

    // ErrorInfo proto fields:
    // 1: primary_message (string)
    // 2: sqlstate (string)
    // 3: customer_hint (string)
    // 4: customer_detail (string)
    // 5: system_detail (string)
    // 6: position (message)
    // 7: error_source (string)
    #[derive(Clone, PartialEq, Message)]
    struct ErrorInfo {
        #[prost(string, tag = "1")]
        primary_message: String,
        #[prost(string, tag = "2")]
        sqlstate: String,
        #[prost(string, tag = "3")]
        customer_hint: String,
        #[prost(string, tag = "4")]
        customer_detail: String,
        #[prost(string, tag = "5")]
        system_detail: String,
        // Skipping position (tag 6) for now
        #[prost(string, tag = "7")]
        error_source: String,
    }

    if let Ok(info) = ErrorInfo::decode(data) {
        // Build error message combining primary_message and customer_detail
        let message = if info.customer_detail.is_empty() {
            info.primary_message.clone()
        } else {
            format!("{}: {}", info.primary_message, info.customer_detail)
        };

        return Some(GrpcError {
            sqlstate: if info.sqlstate.is_empty() {
                None
            } else {
                Some(info.sqlstate)
            },
            message,
            detail: if info.customer_detail.is_empty() {
                None
            } else {
                Some(info.customer_detail)
            },
            hint: if info.customer_hint.is_empty() {
                None
            } else {
                Some(info.customer_hint)
            },
            error_source: if info.error_source.is_empty() {
                None
            } else {
                Some(info.error_source)
            },
        });
    }

    None
}

/// Parses XML-format error message (legacy Hyper error format).
///
/// Example: `<sqlstate>42703</sqlstate><primary>column not found</primary><detail>...</detail>`
fn parse_xml_error(message: &str) -> Option<Error> {
    // Quick check if this looks like XML
    if !message.contains("<sqlstate>") && !message.contains("<primary>") {
        return None;
    }

    let sqlstate = extract_xml_tag(message, "sqlstate");
    let primary = extract_xml_tag(message, "primary");
    let detail = extract_xml_tag(message, "detail");
    let hint = extract_xml_tag(message, "hint");

    // Build the error message
    let error_message = match (&primary, &detail) {
        (Some(p), Some(d)) => format!("{p}: {d}"),
        (Some(p), None) => p.clone(),
        (None, Some(d)) => d.clone(),
        (None, None) => message.to_string(),
    };

    // Determine the variant from SQLSTATE
    let variant = sqlstate
        .as_ref()
        .map_or(Variant::Query, |s| sqlstate_to_variant(s));

    Some(variant.build(error_message, detail, hint, sqlstate))
}

/// Extracts content from an XML tag like `<tag>content</tag>`.
fn extract_xml_tag(text: &str, tag: &str) -> Option<String> {
    let start_tag = format!("<{tag}>");
    let end_tag = format!("</{tag}>");

    let start = text.find(&start_tag)? + start_tag.len();
    let end = text[start..].find(&end_tag)? + start;

    Some(text[start..end].to_string())
}

/// Converts a gRPC status code to the [`Error`] variant it maps to.
fn grpc_code_to_variant(code: tonic::Code) -> Variant {
    match code {
        tonic::Code::Ok => Variant::Other, // Shouldn't happen for errors
        tonic::Code::Cancelled => Variant::Cancelled,
        tonic::Code::Unknown => Variant::Query,
        tonic::Code::InvalidArgument => Variant::Query,
        tonic::Code::DeadlineExceeded => Variant::Timeout,
        tonic::Code::NotFound => Variant::Query,
        tonic::Code::AlreadyExists => Variant::Query,
        tonic::Code::PermissionDenied => Variant::Authentication,
        tonic::Code::ResourceExhausted => Variant::Query,
        tonic::Code::FailedPrecondition => Variant::Query,
        tonic::Code::Aborted => Variant::Query,
        tonic::Code::OutOfRange => Variant::Query,
        tonic::Code::Unimplemented => Variant::FeatureNotSupported,
        tonic::Code::Internal => Variant::Query,
        tonic::Code::Unavailable => Variant::Connection,
        tonic::Code::DataLoss => Variant::Query,
        tonic::Code::Unauthenticated => Variant::Authentication,
    }
}

/// Converts a SQLSTATE code to the [`Error`] variant it maps to.
fn sqlstate_to_variant(sqlstate: &str) -> Variant {
    match sqlstate {
        // Query canceled
        "57014" => Variant::Cancelled,
        // Authentication errors (28xxx)
        s if s.starts_with("28") => Variant::Authentication,
        // Connection errors (08xxx)
        s if s.starts_with("08") => Variant::Connection,
        // Feature not supported (0A000)
        "0A000" => Variant::FeatureNotSupported,
        // Everything else is a query error
        _ => Variant::Query,
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_parse_xml_error() {
        let msg = "<sqlstate>42703</sqlstate><primary>column not found</primary><detail>column \"foo\" does not exist</detail>";
        let error = parse_xml_error(msg).unwrap();
        assert!(error.to_string().contains("column not found"));
    }

    #[test]
    fn test_extract_xml_tag() {
        assert_eq!(
            extract_xml_tag("<foo>bar</foo>", "foo"),
            Some("bar".to_string())
        );
        assert_eq!(
            extract_xml_tag("<a>1</a><b>2</b>", "b"),
            Some("2".to_string())
        );
        assert_eq!(extract_xml_tag("<a>1</a>", "c"), None);
    }

    #[test]
    fn test_grpc_code_mapping() {
        assert_eq!(
            grpc_code_to_variant(tonic::Code::Cancelled),
            Variant::Cancelled
        );
        assert_eq!(
            grpc_code_to_variant(tonic::Code::Unauthenticated),
            Variant::Authentication
        );
        assert_eq!(
            grpc_code_to_variant(tonic::Code::Unavailable),
            Variant::Connection
        );
    }

    /// A SQLSTATE-selected variant must keep the code on the variants that
    /// have a field for it — the public `hyperdb_api::Error` mapping reads
    /// `sqlstate()` for `Cancelled` and `Connection`, not just `Query`.
    #[test]
    fn test_sqlstate_survives_variant_selection() {
        let err = sqlstate_to_variant("57014").build(
            "canceled".to_string(),
            None,
            None,
            Some("57014".to_string()),
        );
        assert!(matches!(err, Error::Cancelled { .. }));
        assert_eq!(err.sqlstate(), Some("57014"));

        let err = sqlstate_to_variant("08006").build(
            "connection failure".to_string(),
            None,
            None,
            Some("08006".to_string()),
        );
        assert!(matches!(err, Error::Connection { .. }));
        assert_eq!(err.sqlstate(), Some("08006"));
    }

    /// The variants with no `detail` field must fold it into the message
    /// rather than dropping it, so the rendered text is unchanged.
    #[test]
    fn test_detail_folded_into_message_when_no_field() {
        let err = Variant::Timeout.build(
            "deadline exceeded".to_string(),
            Some("waited 30s".to_string()),
            None,
            None,
        );
        assert_eq!(err.to_string(), "deadline exceeded: waited 30s");

        // Already contained → not repeated.
        let err = Variant::Timeout.build(
            "deadline exceeded: waited 30s".to_string(),
            Some("waited 30s".to_string()),
            None,
            None,
        );
        assert_eq!(err.to_string(), "deadline exceeded: waited 30s");
    }
}