package ezhandler

import (
	"io"
	"net/http"
)

// Handler is similar to [http.Handler], but also may return an error.
type Handler interface {
	ServeHTTP(w http.ResponseWriter, r *http.Request) error
}

// HandlerFunc is similar to [http.HandlerFunc] but it can also return an error.
type HandlerFunc func(w http.ResponseWriter, r *http.Request) error

var _ Handler = HandlerFunc(nil)

func (fn HandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
	return fn(w, r)
}

// ResponseHandler is similar to HandlerFunc but returns a [ResponseHelper], instead of passing an [http.ResponseWriter].
type ResponseHandler func(r *http.Request) (resp ResponseHelper, err error)

var _ Handler = ResponseHandler(nil)

func (fn ResponseHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
	resp, err := fn(r)
	if err != nil {
		return err
	}
	w.WriteHeader(resp.Status())
	for key, values := range resp.Headers() {
		for _, val := range values {
			w.Header().Add(key, val)
		}
	}
	body, err := resp.Body()
	if err != nil {
		return err
	}
	_, err = io.Copy(w, body)
	return err
}