// Package chanutil exports helper functions for working with channels and
// framing defined by the github.com/creachadair/jrpc2/channel package.
package chanutil

import (
	"strings"

	"github.com/creachadair/jrpc2/channel"
)

// Framing returns a channel.Framing described by the specified name, or nil if
// the name is unknown. The framing types currently understood are:
//
//    header:t -- corresponds to channel.Header(t)
//    strict:t -- corresponds to channel.StrictHeader(t)
//    line     -- corresponds to channel.Line
//    lsp      -- corresponds to channel.LSP
//    raw      -- corresponds to channel.RawJSON
//    varint   -- corresponds to channel.Varint
//
func Framing(name string) channel.Framing {
	if t := strings.TrimPrefix(name, "header:"); t != name {
		return channel.Header(t)
	}
	if t := strings.TrimPrefix(name, "strict:"); t != name {
		return channel.StrictHeader(t)
	}
	return framings[name]
}

var framings = map[string]channel.Framing{
	"line":   channel.Line,
	"lsp":    channel.LSP,
	"raw":    channel.RawJSON,
	"varint": channel.Varint,
}