tecthulhu.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"time"

	"github.com/TeamNorCal/mawt/model"
	"github.com/go-stack/stack"
	"github.com/karlmutch/errors"
)

// This module implements a module to handle communications
// with the tecthulhu device.  These devices can provide a WiFi
// like capability, however the original documentation appears
// to indicate a serial like communications peripheral
//
// The following json shows example output from a tecthulhu used
// for the 2018 season
//
//{
//    "result": {
//        "controllingFaction": "Resistance",
//        "level": 6,
//        "health": 99,
//        "owner": "puntila",
//        "title": "Crab Mosaic",
//        "description": null,
//        "coverImageUrl": "http://lh3.ggpht.com/rF4RNr3xmVnLep_3WmJPCcnzBtKl3z74vc2mlaHpF0K9bVieZb_61w0fygAGUCduYzB47sRXbcajUk8-5bxmVg",
//        "attribution": "PennIsMightier",
//        "mods": [
//            {
//                "type": "Portal Shield",
//                "rarity": "Common",
//                "owner": "dorkus",
//                "slot": 1
//            },
//            {
//                "type": "Turret",
//                "rarity": "Rare",
//                "owner": "slackfarmer",
//                "slot": 3
//            },
//            {
//                "type": "Portal Shield",
//                "rarity": "Common",
//                "owner": "dorkus",
//                "slot": 4
//            }
//        ],
//        "resonators": [
//            {
//                "level": 6,
//                "health": 98,
//                "owner": "NumberSix",
//                "position": "E"
//            },
//            {
//                "level": 7,
//                "health": 100,
//                "owner": "NumberSix",
//                "position": "NE"
//            },
//            {
//                "level": 8,
//                "health": 100,
//                "owner": "NumberSix",
//                "position": "N"
//            },
//            {
//                "level": 6,
//                "health": 100,
//                "owner": "NumberSix",
//                "position": "NW"
//            },
//            {
//                "level": 7,
//                "health": 100,
//                "owner": "dorkus",
//                "position": "W"
//            },
//            {
//                "level": 8,
//                "health": 99,
//                "owner": "dorkus",
//                "position": "SW"
//            },
//            {
//                "level": 5,
//                "health": 99,
//                "owner": "NumberSix",
//                "position": "S"
//            },
//            {
//                "level": 5,
//                "health": 95,
//                "owner": "NumberSix",
//                "position": "SE"
//            }
//        ]
//    },
//    "message": null,
//    "code": "OK",
//    "fieldErrors": null
//}
//

type tResonator struct {
	Position string `json:"position"`
	Level    int    `json:"level"`
	Health   int    `json:"health"`
	Owner    string `json:"owner"`
}

type tMod struct {
	Type   string `json:"type"`
	Rarity string `json:"rarity"`
	Owner  string `json:"owner"`
	Slot   int    `json:"slot"`
}

type tStatus struct {
	Title      string       `json:"title"`
	Owner      string       `json:"owner"`
	Level      int          `json:"level"`
	Health     int          `json:"health"`
	Faction    string       `json:"controllingFaction"`
	Mods       []tMod       `json:"mods"`
	Resonators []tResonator `json:"resonators"`
}

type tPortalStatus struct {
	State tStatus `json:"result"`
	Code  string  `json:"code"`
}

type PortalMon interface {
	Run(quitC <-chan struct{})
}

type tecthulhu struct {
	url     url.URL
	home    bool
	statusC chan<- *model.PortalMsg
	errorC  chan<- errors.Error
}

func NewTecthulu(url url.URL, home bool, statusC chan<- *model.PortalMsg, errorC chan<- errors.Error) (tec *tecthulhu) {
	return &tecthulhu{
		url:     url,
		home:    home,
		statusC: statusC,
		errorC:  errorC,
	}
}

func (tec *tPortalStatus) status() (state *model.PortalStatus) {
	state = &model.PortalStatus{
		Status: model.Status{
			Title:      tec.State.Title,
			Owner:      tec.State.Owner,
			Level:      float32(tec.State.Level),
			Health:     float32(tec.State.Health),
			Faction:    tec.State.Faction,
			Mods:       []model.Mod{},
			Resonators: []model.Resonator{},
		},
	}
	for _, res := range tec.State.Resonators {
		state.Status.Resonators = append(state.Status.Resonators,
			model.Resonator{
				Position: res.Position,
				Level:    float32(res.Level),
				Health:   float32(res.Health),
				Owner:    res.Owner,
			})
	}
	state.Status.Faction = string(tec.State.Faction[0])
	for _, mod := range tec.State.Mods {
		newMod := model.Mod{
			Slot:   float32(mod.Slot),
			Type:   mod.Type,
			Owner:  mod.Owner,
			Rarity: mod.Rarity,
		}
		state.Status.Mods = append(state.Status.Mods, newMod)
	}
	return state
}

// checkPortal can be used to extract status information from the portal
//
func (tec *tecthulhu) checkPortal() (status *model.PortalStatus, err errors.Error) {

	body := []byte{}

	switch tec.url.Scheme {
	case "http":
		resp, errGo := http.Get(tec.url.String())
		if errGo != nil {
			return nil, errors.Wrap(errGo).With("url", tec.url).With("stack", stack.Trace().TrimRuntime())
		}

		body, errGo = ioutil.ReadAll(resp.Body)
		resp.Body.Close()
		if errGo != nil {
			return nil, errors.Wrap(errGo).With("url", tec.url).With("stack", stack.Trace().TrimRuntime())
		}

	case "serial":
		errGo := fmt.Errorf("Unknown scheme %s for the tecthulhu device is not yet implemented", tec.url.Scheme)
		return nil, errors.Wrap(errGo).With("url", tec.url).With("stack", stack.Trace().TrimRuntime())

	default:
		errGo := fmt.Errorf("Unknown scheme %s for the tecthulhu device URI", tec.url.Scheme)
		return nil, errors.Wrap(errGo).With("url", tec.url).With("stack", stack.Trace().TrimRuntime())
	}

	// Parse into the tecthulhu specific format and then convert to
	// the canonical format used by the concentrator which we assume
	// is a reference format for portal data and meta data
	//
	tecStatus := &tPortalStatus{}

	errGo := json.Unmarshal(body, &tecStatus)
	if errGo != nil {
		return nil, errors.Wrap(errGo).With("url", tec.url).With("body", string(body)).With("stack", stack.Trace().TrimRuntime())
	}
	status = tecStatus.status()
	return status, err
}

func (tec *tecthulhu) sendStatus() {
	// Perform a regular status check with the portal
	// and return the received results  to listeners using
	// the channel
	//
	// Use  a TCP and USB Serial handler function
	status, err := tec.checkPortal()

	if err != nil {
		go func(err errors.Error) {
			select {
			case tec.errorC <- err:
			case <-time.After(500 * time.Millisecond):
				fmt.Fprintf(os.Stderr, "could not send error for portal status update %s\n", err.Error())
			}
		}(err)
		return
	}

	msg := &model.PortalMsg{
		Status: status.Status,
		Home:   tec.home,
	}

	select {
	case tec.statusC <- msg:
	case <-time.After(750 * time.Millisecond):
		go func() {
			err := errors.New("portal status dropped").With("url", tec.url).With("stack", stack.Trace().TrimRuntime())
			select {
			case tec.errorC <- err:
			case <-time.After(2 * time.Second):
				fmt.Fprintf(os.Stderr, "could not send error for portal status update %s\n", err.Error())
			}
		}()
	}
}

// startPortal listens to a tecthulhu device and returns
// regular reports on the status of the portal with which it
// is associated
//
func (tec *tecthulhu) Run(quitC <-chan struct{}) {

	refresh := time.Duration(5 * time.Second)

	for {
		select {
		case <-time.After(refresh):
			tec.sendStatus()
		case <-quitC:
			return
		}
	}
}