package jsonrpc

import (
	"net/http"
	"reflect"

	"github.com/alecthomas/jsonschema"
	"github.com/intel-go/fastjson"
)

// A MethodReference is a reference of JSON-RPC method.
type MethodReference struct {
	Name    string             `json:"name"`
	Handler string             `json:"handler"`
	Params  *jsonschema.Schema `json:"params,omitempty"`
	Result  *jsonschema.Schema `json:"result,omitempty"`
}

// ServeDebug views registered method list.
func (mr *MethodRepository) ServeDebug(w http.ResponseWriter, r *http.Request) {
	ms := mr.Methods()
	if len(ms) == 0 {
		w.WriteHeader(http.StatusNotFound)
		return
	}
	l := make([]*MethodReference, 0, len(ms))
	for k, md := range ms {
		l = append(l, makeMethodReference(k, md))
	}
	w.Header().Set(contentTypeKey, contentTypeValue)
	if err := fastjson.NewEncoder(w).Encode(l); err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
}

func makeMethodReference(k string, md Metadata) *MethodReference {
	mr := &MethodReference{
		Name: k,
	}
	tv := reflect.TypeOf(md.Handler)
	if tv.Kind() == reflect.Ptr {
		tv = tv.Elem()
	}
	mr.Handler = tv.Name()
	if md.Params != nil {
		mr.Params = jsonschema.Reflect(md.Params)
	}
	if md.Result != nil {
		mr.Result = jsonschema.Reflect(md.Result)
	}
	return mr
}