server/protocol.go

package main

import (
	"code.google.com/p/go.net/websocket"
	"errors"
	"log"
)

// > identify
type IdRequest struct {
	Type       string `json:"type"`
	AssignedID string `json:"id"`
}

func NewIdRequest(id string) *IdRequest {
	return &IdRequest{
		Type:       "idreq",
		AssignedID: id,
	}
}

// < [robot | spectator], name, client-type, game ID
type ClientID struct {
	Type      string `json:"type"`
	Name      string `json:"name"`
	Useragent string `json:"useragent"`
}

func (c *ClientID) Valid() (bool, string) {
	switch c.Type {
	case "robot", "spectator":
		return true, ""
	}
	return false, "usergent must be 'robot' or 'spectator'"
}

type BoardSize struct {
	Width  float64 `json:"width"`
	Height float64 `json:"height"`
}

type GameParam struct {
	BoardSize BoardSize `json:"boardsize"`
	Type      string    `json:"type"`
}

// > [OK | FULL | NOT AUTH], board size, game params
func NewGameParam(w, h float64) *GameParam {
	return &GameParam{
		BoardSize: BoardSize{
			Width:  w,
			Height: h,
		},
		Type: "gameparam",
	}
}

type Handshake struct {
	ID      string `json:"id"`
	Success bool   `json:"success"`
	Type    string `json:"type"`
}

func NewHandshake(id string, success bool) *Handshake {
	return &Handshake{
		ID:      id,
		Success: success,
		Type:    "handshake",
	}
}

type Failure struct {
	Reason string `json:"reason"`
	Type   string `json:"type"`
}

func NewFailure(reason string) *Failure {
	return &Failure{
		Reason: reason,
		Type:   "failure",
	}
}

func Negociate(ws *websocket.Conn, id string, width, height float64) (*Config, error) {
	var err error

	err = websocket.JSON.Send(ws, NewIdRequest(id))
	if err != nil {
		return nil, errors.New("generic servr error")
	}

	var clientid ClientID
	err = websocket.JSON.Receive(ws, &clientid)
	if err != nil {
		return nil, errors.New("could not parse id")
	}
	if v, msg := clientid.Valid(); !v {
		websocket.JSON.Send(
			ws,
			NewFailure(msg),
		)
		return nil, errors.New(msg)
	}

	gameParam := NewGameParam(width, height)
	err = websocket.JSON.Send(ws, gameParam)
	if err != nil {
		websocket.JSON.Send(ws, NewFailure("generic server error"))
		return nil, err
	}
	switch clientid.Type {
	case "robot":
		var conf Config
		for {
			err = websocket.JSON.Receive(ws, &conf)
			if err != nil {
				log.Print(err)
				return nil, err
			}
			if conf.Stats.valid() {
				_ = websocket.JSON.Send(ws, NewHandshake(id, true))
				break
			} else {
				_ = websocket.JSON.Send(ws, NewHandshake(id, false))
			}
		}
		return &conf, nil
	case "spectator":
		return nil, nil
	}
	return nil, nil
}