"""JSON-RPC error envelope helpers for the Muse MCP server (§KD-5a.0)."""

from __future__ import annotations

from typing import Any

from muse.core.validation import sanitize_display

# JSON-RPC 2.0 standard codes
PARSE_ERROR = -32700
INVALID_REQUEST = -32600
METHOD_NOT_FOUND = -32601
INVALID_PARAMS = -32602
INTERNAL_ERROR = -32603

# Application-level tool error (result carries reason in data)
TOOL_ERROR = -32001


class MCPApplicationError(Exception):
    """Structured tool/resource error with a stable ``reason`` token."""

    def __init__(
        self,
        reason: str,
        message: str,
        *,
        detail: str | None = None,
    ) -> None:
        self.reason = reason
        self.message = sanitize_display(message)
        self.detail = sanitize_display(detail) if detail else None
        super().__init__(message)

    def to_data(self) -> dict[str, str]:
        data: dict[str, str] = {"reason": self.reason}
        if self.detail:
            data["detail"] = self.detail
        return data


def error_response(
    req_id: str | int | None,
    code: int,
    message: str,
    *,
    data: dict[str, Any] | None = None,
) -> dict[str, Any]:
    """Build a JSON-RPC 2.0 error object."""
    payload: dict[str, Any] = {
        "jsonrpc": "2.0",
        "id": req_id,
        "error": {
            "code": code,
            "message": sanitize_display(message),
        },
    }
    if data:
        payload["error"]["data"] = data
    return payload


def success_response(req_id: str | int | None, result: Any) -> dict[str, Any]:
    """Build a JSON-RPC 2.0 success object."""
    return {"jsonrpc": "2.0", "id": req_id, "result": result}