/* Copyright Martin Dosch
Licensed under the "MIT License" */

package main

import (
	"log"
	"strings"

	"github.com/xmppo/go-xmpp"
)

func processStanzas(client *xmpp.Client, muc string, mucNick string, feeds []string, quiet bool, contact string) {
	for {
		// Receive stanzas.
		stanza, err := client.Recv()
		if err != nil {
			log.Fatal("Error: Failed receiving Stanzas:", err)
		}

		// Check stanzas, maybe we want to reply.
		switch v := stanza.(type) {
		// Reply to requests for source and feeds.
		case xmpp.Chat:
			var command string

			switch v.Type {
			// Check for room mention of the bots nick if the the message type is groupchat.
			case "groupchat":
				// Leave if option quiet is set.
				if quiet {
					break
				}
				// Get first word of the message and transform it to lower case.
				mention := strings.ToLower(strings.Split(v.Text, " ")[0])

				// If it is not the bots nick remove one trailing character as
				// a lot of clients append `:` or `,` to mentions.
				if mention != strings.ToLower(mucNick) {
					mentionLength := len(mention)
					// Leave if mentionLength is <= 0
					if mentionLength <= 0 {
						break
					}
					mention = mention[:mentionLength-1]
					// Leave if the message is not addressed to the bot.
					if mention != strings.ToLower(mucNick) {
						break
					}
				}
				// As the first word is the mention of the bots nickname, the command is
				// the second word in a groupchat message.
				command = strings.ToLower(strings.Split(v.Text, " ")[1])
				// If the message type is chat (e.g. private message), the command is the
				// first word.
			case "chat":
				command = strings.ToLower(strings.Split(v.Text, " ")[0])
			default:
				break
			}

			// Check for the command.
			switch command {

			// Reply with a short summary of available commands for `help`.
			case "help":

				reply := "The following commands are available:\n" +
					"\"contact\": Show contact for this bot.\n" +
					"\"feeds\": List feeds I'm following.\n" +
					"\"ping\": Sends back a pong.\n" +
					"\"source\": Show source code URL."

				if v.Type == "groupchat" {
					_, err = client.Send(xmpp.Chat{
						Remote: muc,
						Type:   "groupchat", Text: strings.Split(v.Remote, "/")[1] + ": " + reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to MUC:", err)
					}
				} else if v.Type == "chat" {
					_, err = client.Send(xmpp.Chat{
						Remote: v.Remote,
						Type:   "chat", Text: reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to ", v.Remote, ": ", err)
					}
				}

			// Reply with repo address for `source`.
			case "source":

				reply := "My source can be found at " +
					"https://salsa.debian.org/mdosch/feed-to-muc"

				if v.Type == "groupchat" {
					_, err = client.Send(xmpp.Chat{
						Remote: muc,
						Type:   "groupchat", Text: strings.Split(v.Remote, "/")[1] + ": " + reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to MUC:", err)
					}
				} else if v.Type == "chat" {
					_, err = client.Send(xmpp.Chat{
						Remote: v.Remote,
						Type:   "chat", Text: reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to ", v.Remote, ": ", err)
					}
				}
			// Reply with the list of monitored feeds for `feeds`.
			case "feeds":
				var feedList string
				for _, feed := range feeds {
					// Add next feed element and a newline.
					feedList = feedList + feed + "\n"
				}

				reply := "Feeds I'm following:\n" + feedList

				if v.Type == "groupchat" {
					_, err = client.Send(xmpp.Chat{
						Remote: muc,
						Type:   "groupchat", Text: strings.Split(v.Remote, "/")[1] + ": " + reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to MUC:", err)
					}
				} else if v.Type == "chat" {
					_, err = client.Send(xmpp.Chat{
						Remote: v.Remote,
						Type:   "chat", Text: reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to ", v.Remote, ": ", err)
					}
				}
			// Reply with pong to ping requests.
			case "ping", "bing":
				var reply string
				if command == "bing" {
					reply = "bong"
				} else {
					reply = "pong"
				}

				if v.Type == "groupchat" {
					_, err = client.Send(xmpp.Chat{
						Remote: muc,
						Type:   "groupchat", Text: strings.Split(v.Remote, "/")[1] + ": " + reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to MUC:", err)
					}
				} else if v.Type == "chat" {
					_, err = client.Send(xmpp.Chat{
						Remote: v.Remote,
						Type:   "chat", Text: reply,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to ", v.Remote, ": ", err)
					}
				}

			// Reply with contact address if set.
			case "contact":

				if contact == "" {
					contact = "Sorry, no contact information provided."
				}

				if v.Type == "groupchat" {
					_, err = client.Send(xmpp.Chat{
						Remote: muc,
						Type:   "groupchat", Text: strings.Split(v.Remote, "/")[1] + ": " + contact,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to MUC:", err)
					}
				} else if v.Type == "chat" {
					_, err = client.Send(xmpp.Chat{
						Remote: v.Remote,
						Type:   "chat", Text: contact,
					})
					if err != nil {
						log.Fatal("Error: Failed sending message to ", v.Remote, ": ", err)
					}
				}
			}

		// Reply to pings and disco queries.
		case xmpp.IQ:

			if (v.Type == "error") && (v.ID == ID) {
				log.Fatal("MUC not available. processStanza")
			}

			if (v.Type == "result") && (v.ID == ID) {
				pingReceived = true
			}

			if v.Type == "get" {
				// Reply to disco#info requests according to https://xmpp.org/extensions/xep-0030.html.
				switch {
				case strings.Contains(string(v.Query),
					"<query xmlns='http://jabber.org/protocol/disco#info'/>"):
					_, err := client.RawInformation(client.JID(), v.From, v.ID,
						"result", "<query xmlns='http://jabber.org/protocol/disco#info'>"+
							"<identity category='client' type='bot' name='feedbot'/>"+
							"<feature var='http://jabber.org/protocol/disco#info'/></query>")
					if err != nil {
						log.Fatal("Error: Failed to reply to disco#info:", err)
					}
				case strings.Contains(string(v.Query), "<ping xmlns='urn:xmpp:ping'/>"):
					// Reply to pings.
					_, err := client.RawInformation(client.JID(), v.From, v.ID, "result", "")
					if err != nil {
						log.Fatal("Error: Failed to reply to ping:", err)
					}
				default:
					// Send error replies for all other IQs.
					_, err := client.RawInformation(client.JID(), v.From, v.ID, "error",
						"<error type='cancel'><service-unavailable "+
							"xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/></error>")
					if err != nil {
						log.Fatal("Error: Failed to send error IQ:", err)
					}
				}
			}

		default:
			break
		}
	}
}