package mcp

import "encoding/json"

// JSON-RPC application-defined error codes (range -32000 to -32099 per spec).
// Tool handlers return one of these from tools/call to signal a typed failure.
const (
	// CodePermissionDenied: caller authenticated but lacks permission for this
	// resource (e.g. owner not in the allowlist).
	CodePermissionDenied = -32001

	// CodeNotFound: target repo, file, branch, PR, issue, or workflow run does
	// not exist.
	CodeNotFound = -32002

	// CodeConflict: write attempted on stale state (branch already exists,
	// non-fast-forward push, file modified concurrently).
	CodeConflict = -32003

	// CodeValidation: arguments failed input validation (bad regex, oversized
	// payload, missing required field).
	CodeValidation = -32004

	// CodeUpstreamGitea: Gitea API returned an error this server could not map
	// to one of the codes above. The original status is in error.data.
	CodeUpstreamGitea = -32005
)

type Request struct {
	JSONRPC string          `json:"jsonrpc"`
	ID      any             `json:"id,omitempty"`
	Method  string          `json:"method"`
	Params  json.RawMessage `json:"params,omitempty"`
}

type Response struct {
	JSONRPC string    `json:"jsonrpc"`
	ID      any       `json:"id,omitempty"`
	Result  any       `json:"result,omitempty"`
	Error   *RPCError `json:"error,omitempty"`
}

type RPCError struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
	Data    any    `json:"data,omitempty"`
}

func NewResponse(id any, result any) Response {
	return Response{JSONRPC: "2.0", ID: id, Result: result}
}

func NewErrorResponse(id any, code int, msg string, data any) Response {
	return Response{
		JSONRPC: "2.0",
		ID:      id,
		Error:   &RPCError{Code: code, Message: msg, Data: data},
	}
}