package http

import (
	"fmt"
	"io"
	"net/http"
	"strings"

	"git.loafle.net/commons_go/rpc"
)

type HTTPAdapter struct {
	registry rpc.Registry
}

func NewAdapter(registry rpc.Registry) *HTTPAdapter {
	return &HTTPAdapter{
		registry: registry,
	}
}

// ServeHTTP
func (a *HTTPAdapter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		writeError(w, 405, "rpc: POST method required, received "+r.Method)
		return
	}

	contentType := r.Header.Get("Content-Type")
	idx := strings.Index(contentType, ";")
	if idx != -1 {
		contentType = contentType[:idx]
	}

	err := a.registry.Invoke(contentType, r.Body, w, beforeWrite, afterWrite)
	r.Body.Close()

	if nil != err {
		writeError(w, 400, err.Error())
	}

}

func beforeWrite(w io.Writer) {
	writer := w.(http.ResponseWriter)
	writer.Header().Set("x-content-type-options", "nosniff")
	writer.Header().Set("Content-Type", "application/json; charset=utf-8")
}

func afterWrite(w io.Writer) {

}

func writeError(w http.ResponseWriter, status int, msg string) {
	w.WriteHeader(status)
	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
	fmt.Fprint(w, msg)
}