// Copyright 2018 The Go Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package protocol

import (
	"context"
	"encoding/json"
	"log"

	"../jsonrpc2"
)

const (
	// RequestCancelledError should be used when a request is cancelled early.
	RequestCancelledError = -32800
)

type DocumentUri = string

type canceller struct{ jsonrpc2.EmptyHandler }

type clientHandler struct {
	canceller
	client Client
}

type serverHandler struct {
	canceller
	server Server
}

func (canceller) Request(ctx context.Context, conn *jsonrpc2.Conn, direction jsonrpc2.Direction, r *jsonrpc2.WireRequest) context.Context {
	if direction == jsonrpc2.Receive && r.Method == "$/cancelRequest" {
		var params CancelParams
		if err := json.Unmarshal(*r.Params, &params); err != nil {
			log.Printf("%v", err)
		} else {
			conn.Cancel(params.ID)
		}
	}
	return ctx
}

func (canceller) Cancel(ctx context.Context, conn *jsonrpc2.Conn, id jsonrpc2.ID, cancelled bool) bool {
	if cancelled {
		return false
	}
	conn.Notify(ctx, "$/cancelRequest", &CancelParams{ID: id})
	return true
}

func NewClient(ctx context.Context, stream jsonrpc2.Stream, client Client) (context.Context, *jsonrpc2.Conn, Server) {
	ctx = WithClient(ctx, client)
	conn := jsonrpc2.NewConn(stream)
	conn.AddHandler(&clientHandler{client: client})
	return ctx, conn, &serverDispatcher{Conn: conn}
}

func NewServer(ctx context.Context, stream jsonrpc2.Stream, server Server) (context.Context, *jsonrpc2.Conn, Client) {
	conn := jsonrpc2.NewConn(stream)
	client := &clientDispatcher{Conn: conn}
	ctx = WithClient(ctx, client)
	conn.AddHandler(&serverHandler{server: server})
	return ctx, conn, client
}

func sendParseError(ctx context.Context, req *jsonrpc2.Request, err error) {
	if _, ok := err.(*jsonrpc2.Error); !ok {
		err = jsonrpc2.NewErrorf(jsonrpc2.CodeParseError, "%v", err)
	}
	if err := req.Reply(ctx, nil, err); err != nil {
		log.Printf("%v", err)
	}
}