// SPDX-License-Identifier: Apache-2.0

package main

import (
	"encoding/json"
	"strings"

	cli "git.ipng.ch/ipng/golang-cli"
)

// formatError returns a user-friendly error string. gRPC status errors are
// unwrapped to show only the server's message (no "rpc error: code = ..."
// boilerplate). In JSON mode it returns the message as a {"error": "..."}
// document (so failures are machine-readable, matching the data/`{}` a success
// prints); otherwise it wraps the message in red when color is enabled.
// App.FormatError prints the result.
func formatError(err error) string {
	msg := err.Error()
	// google.golang.org/grpc/status errors format as:
	//   rpc error: code = <Code> desc = <message>
	if i := strings.Index(msg, " desc = "); i >= 0 {
		msg = msg[i+len(" desc = "):]
	}
	if cli.IsJSON() {
		b, _ := json.Marshal(map[string]string{"error": msg})
		return string(b)
	}
	if cli.ColorEnabled() {
		return cli.Red + msg + cli.Reset
	}
	return msg
}