meifamily/ptt-alertor

package messenger

import (
    "fmt"
    "net/http"
    "os"
    "regexp"
    "strings"

    "encoding/json"

    log "github.com/Ptt-Alertor/logrus"
    "github.com/Ptt-Alertor/ptt-alertor/command"
    "github.com/Ptt-Alertor/ptt-alertor/myutil"
    "github.com/julienschmidt/httprouter"
)

const (
    sendAPIURL    = "https://graph.facebook.com/v9.0/me/messages?access_token="
    profileURL    = "https://graph.facebook.com/v9.0/me/messenger_profile?access_token="
    maxCharacters = 640
)

var (
    accessToken = os.Getenv("MESSENGER_ACCESSTOKEN")
    verifyToken = os.Getenv("MESSENGER_VERIFYTOKEN")
)

type Messenger struct {
    VerifyToken string
    AccessToken string
}

func New() Messenger {
    return Messenger{
        VerifyToken: verifyToken,
        AccessToken: accessToken,
    }
}

func (m *Messenger) Verify(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
    if r.FormValue("hub.mode") == "subscribe" && r.FormValue("hub.verify_token") == m.VerifyToken {
        log.Info("Validating webhook")
        resStr := r.FormValue("hub.challenge")
        fmt.Fprintln(w, resStr)
    } else {
        log.Info("Failed validation. Make sure the validation tokens match.")
        http.Error(w, http.StatusText(http.StatusForbidden), http.StatusForbidden)
    }
}

func (m *Messenger) Received(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
    data := Webhook{}
    json.NewDecoder(r.Body).Decode(&data)
    if data.Object == "page" {
        for _, entry := range data.Entry {
            for _, messaging := range entry.Messaging {
                id := messaging.Sender.ID
                if messaging.Message != nil {
                    text := messaging.Message.Text
                    if text != "" {
                        if match, _ := regexp.MatchString("^(刪除|刪除作者)+\\s.*\\*+", text); match {
                            m.SendConfirmation(id, text)
                            return
                        }
                        responseText := command.HandleCommand(text, id, true)
                        m.SendTextMessage(id, responseText)
                    }
                } else if messaging.Postback != nil {
                    payload := messaging.Postback.Payload
                    log.WithField("payload", payload).Info("Messenger Postback")
                    m.handlePostback(id, payload)
                }
            }
        }
    }
}

func (m *Messenger) handlePostback(id string, payload string) {
    var responseText string
    switch payload {
    case "GET_STARTED_PAYLOAD":
        err := command.HandleMessengerFollow(id)
        if err != nil {
            log.WithError(err).Error("Messenger Follow Error")
        }
        responseText = "歡迎使用 Ptt Alertor\n輸入「指令」查看相關功能。\n\n觀看Demo:\nhttps://media.giphy.com/media/NVW8loI65D0I9Numxu/giphy.gif"
    case "COMMANDS_PAYLOAD":
        // responseText = command.HandleCommand("指令", id)
        var str string
        commands := make(map[string]string)
        for cat, cmds := range command.Commands {
            if strings.EqualFold(cat, "進階應用") || strings.EqualFold(cat, "一般") {
                continue
            }
            for cmd, doc := range cmds {
                str += cmd
                if doc != "" {
                    str += "：" + doc
                }
                str += "\n"
            }
            commands[cat] = str
            str = ""
        }
        m.SendListMessage(id, commands)
    case "SUBSCRIPTIONS_PAYLOAD":
        responseText = command.HandleCommand("清單", id, true)
    case "TOP_PAYLOAD":
        responseText = command.HandleCommand("排行", id, true)
    case "COMMENTS_PAYLOAD":
        responseText = command.HandleCommand("推文清單", id, true)
    case "CANCEL":
        responseText = "取消"
    default:
        responseText = command.HandleCommand(payload, id, true)
    }
    m.SendTextMessage(id, responseText)
}

// Using message tag to send notification
// Reference: https://developers.facebook.com/docs/messenger-platform/send-messages/message-tags/
func (m *Messenger) SendTextMessage(id string, message string) {
    for _, msg := range myutil.SplitTextByLineBreak(message, maxCharacters) {
        body := Request{
            Recipient:   Recipient{id},
            Message:     Message{Text: msg},
            MessageType: "MESSAGE_TAG",
            Tag:         "CONFIRMED_EVENT_UPDATE",
        }
        if err := m.callSendAPI(body); err != nil {
            log.WithError(err).WithField("message", msg).Error("Messenger Send Text Message Failed")
        }
    }
}

func (m *Messenger) SendConfirmation(id string, cmd string) {
    attachment := &Attachment{
        Type: "template",
        Payload: ButtonPayload{
            TemplateType: "button",
            Text:         "確認" + cmd,
            Buttons: Buttons{
                Button{"postback", "是", cmd},
                Button{"postback", "否", "CANCEL"},
            },
        },
    }
    body := Request{}
    body.Recipient.ID = id
    body.Message.Attachment = attachment
    if err := m.callSendAPI(body); err != nil {
        log.WithError(err).Error("Messenger Send Confirmation Failed")
    }
}

func (m *Messenger) SendQuickReplies(id string, payload string) {
    qrs := QuickReplies{
        QuickReply{"text", "是", payload},
        QuickReply{"text", "否", "CANCEL"},
    }
    body := Request{
        Recipient{id},
        Message{Text: "確定" + payload, QuickReplies: &qrs},
        "",
        "",
    }
    if err := m.callSendAPI(body); err != nil {
        log.WithError(err).Error("Messenger Send Quick Replies Failed")
    }
}

func (m *Messenger) SendListMessage(id string, StringMap map[string]string) {
    elements := []Element{}
    for key, str := range StringMap {
        elements = append(elements, Element{
            Title:    key,
            Subtitle: str,
        })
    }
    attachment := &Attachment{
        Type: "template",
        Payload: ListPayload{
            TemplateType:    "list",
            TopElementStyle: "compact",
            Elements:        elements,
        },
    }
    body := Request{}
    body.Recipient.ID = id
    body.Message.Attachment = attachment
    if err := m.callSendAPI(body); err != nil {
        log.WithError(err).Error("Messenger Send List Message Failed")
    }
}

func (m *Messenger) callSendAPI(body Request) error {
    url := sendAPIURL + m.AccessToken
    return callAPI(url, body)
}