package mapping

import (
	"net/http"
	"net/textproto"
)

const headerKey = "header"

var headerUnmarshaler = NewUnmarshaler(headerKey, WithStringValues(),
	WithCanonicalKeyFunc(textproto.CanonicalMIMEHeaderKey))

// ParseHeaders parses the headers request.
func ParseHeaders(header http.Header, v any) error {
	m := map[string]any{}
	for k, v := range header {
		if len(v) == 1 {
			m[k] = v[0]
		} else {
			m[k] = v
		}
	}

	return headerUnmarshaler.Unmarshal(m, v)
}