package main

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"flag"
	"image"
	_ "image/gif"
	_ "image/jpeg"
	_ "image/png"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"os"
	"strings"
	"time"

	"git.sr.ht/~thrrgilag/woodstock"
	"github.com/gabriel-vasile/mimetype"
	"github.com/gorilla/websocket"
	"github.com/mitchellh/go-wordwrap"
	"gopkg.in/ini.v1"
)

var cfgfile *string

var done chan interface{}
var interrupt chan os.Signal

type Config struct {
	PnutAccessToken string `ini:"pnut_access_token"`
	PnutUsername    string `ini:"pnut_username"`
	MbUrl           string `ini:"matterbridge_url"`
	MbToken         string `ini:"matterbridge_token"`
	Rooms           []Room
}

type Room struct {
	ChannelID string `ini:"pnut_channel"`
	Gateway   string `ini:"gateway"`
}

type Meta struct {
	Timestamp       int      `json:"timestamp"`
	Id              string   `json:"id"`
	ChannelType     string   `json:"channel_type"`
	SubscriptionIds []string `json:"subscription_ids"`
	Stream          Stream   `json:"stream"`
	ConnectionId    string   `json:"connection_id"`
}

type Stream struct {
	Endpoint string `json:"endpoint"`
}

type Msg struct {
	Meta Meta `json:"meta"`
}

type Messages struct {
	Meta Meta                `json:"meta"`
	Data []woodstock.Message `json:"data"`
}

type MbMessage struct {
	Text      string  `json:"text"`
	Channel   string  `json:"channel"`
	Username  string  `json:"username"`
	UserID    string  `json:"userid"`
	Avatar    string  `json:"avatar"`
	Account   string  `json:"account"`
	Event     string  `json:"event"`
	Protocol  string  `json:"protocol"`
	Gateway   string  `json:"gateway"`
	ParentID  string  `json:"parent_id"`
	Timestamp string  `json:"timestamp"`
	ID        string  `json:"id"`
	Extra     MbExtra `json"extra"`
}

type MbExtra struct {
	File []MbFile `json:"file"`
}

type MbFile struct {
	Name    string `json:"name"`
	Data    string `json:"data"`
	Comment string `json:"comment"`
	URL     string `json:"url"`
	Size    int    `json:"size"`
	Avatar  bool   `json:"avatar"`
	SHA     string `json:"sha"`
}

type MbOutMsg struct {
	Text     string `json:"text"`
	Username string `json:"username"`
	Gateway  string `json:"gateway"`
}

type PnutOembed struct {
	Version string `json:"version"`
	Type    string `json:"type"`
	Title   string `json:"title"`
	Url     string `json:"url"`
	Width   int    `json:"width"`
	Height  int    `json:"height"`
}

func subscribe(connection_id string, access_token string, rooms []Room) {
	params := url.Values{}
	params.Set("connection_id", connection_id)
	for _, _room := range rooms {
		log.Printf(">> connecting channel %s ...", _room.ChannelID)
		url := "https://api.pnut.io/v1/channels/" + _room.ChannelID + "/messages?" + params.Encode()
		req, err := http.NewRequest("GET", url, nil)
		if err != nil {
			log.Println("!! unable to create request", err)
		}
		req.Header.Set("User-Agent", "pnut-bridge")
		req.Header.Add("Authorization", "Bearer "+access_token)
		client := &http.Client{}
		resp, err := client.Do(req)
		if err != nil {
			log.Println("!! error on reponse", err)
		}
		defer resp.Body.Close()
		log.Printf("<< %s", resp.Status)
	}
}

func receiveHandler(connection *websocket.Conn, conf *Config) {
	defer close(done)
	for {
		_, msg, err := connection.ReadMessage()
		if err != nil {
			log.Println("!! error in websocket receive:", err)
			return
		}
		log.Printf("<< received: %s", msg)
		var m Msg
		if err := json.Unmarshal(msg, &m); err != nil {
			log.Println("!! error unmarshaling msg", err)
		}
		if len(m.Meta.ConnectionId) > 0 {
			log.Println("<< connection", m.Meta.ConnectionId)
			subscribe(m.Meta.ConnectionId, conf.PnutAccessToken, conf.Rooms)
			continue
		}
		switch m.Meta.ChannelType {
		case "io.pnut.core.chat":
			var messages Messages
			if err := json.Unmarshal(msg, &messages); err != nil {
				log.Println("!! error unmarshaling message objects", err)
			}
			for _, _message := range messages.Data {
				pnutMsgHandler(conf, _message)
			}
		default:
		}
	}
}

func pnutMsgHandler(conf *Config, msg woodstock.Message) {
	gateway := getRoomGateway(conf.Rooms, msg.ChannelID)
	if len(gateway) < 1 {
		return
	}
	if msg.User.Username == conf.PnutUsername {
		return
	}
	log.Printf(">> sending message from channel %s to %s ...", msg.ChannelID, gateway)
	data := MbOutMsg{
		Text:     msg.Content.Text,
		Username: msg.User.Username,
		Gateway:  gateway,
	}
	jsonStr, err := json.Marshal(data)
	if err != nil {
		log.Println("!! there is a problem creating json string", err)
		return
	}
	url := conf.MbUrl + "/api/message"
	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonStr))
	if err != nil {
		log.Println("!! unable to create request", err)
	}
	req.Header.Set("User-Agent", "pnut-bridge")
	req.Header.Set("Content-Type", "application/json; charset=UTF-8")
	req.Header.Add("Authorization", "Bearer "+conf.MbToken)
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		log.Println("!! error on reponse", err)
	}
	defer resp.Body.Close()
	log.Printf("<< %s", resp.Status)
}

func getRoomGateway(rooms []Room, chan_id string) string {
	for _, v := range rooms {
		if v.ChannelID == chan_id {
			return v.Gateway
		}
	}
	return ""
}

func bridgeMsgHandler(conf *Config, msg MbMessage) {
	client := woodstock.NewClient("", "")
	client.SetAccessToken(conf.PnutAccessToken)
	channel_id := getPnutChannel(conf.Rooms, msg.Gateway)

	text := msg.Text
	var raw []woodstock.Raw
	for _, file := range msg.Extra.File {
		fdata, err := base64.StdEncoding.DecodeString(file.Data)
		if err != nil {
			log.Println("!! error decoding file", err)
		}
		mtype := mimetype.Detect(fdata)
		ir := bytes.NewReader(fdata)
		im, _, err := image.DecodeConfig(ir)
		if err != nil {
			log.Println("Couldn't decode image?", err)
		}
		if strings.HasPrefix(mtype.String(), "image") {
			oembed := PnutOembed{
				Version: "1.0",
				Type:    "photo",
				Title:   file.Name,
				Url:     file.URL,
				Width:   im.Width,
				Height:  im.Height,
			}
			raw = append(raw, woodstock.Raw{Type: "io.pnut.core.oembed", Value: oembed})
		} else {
			text = text + "\n" + file.URL
		}
	}

	maxlen := 2048
	prelen := len(msg.Username) + 1
	wrapped := wordwrap.WrapString(text, uint(maxlen-prelen))
	lines := strings.Split(wrapped, "\n")
	for _, line := range lines {
		line := msg.Username + " " + line
		log.Printf(">> sending message from %s to channel %s ...", msg.Gateway, channel_id)
		newmessage := woodstock.NewMessage{Text: line, Raw: raw}
		_, err := client.CreateMessage(channel_id, newmessage)
		if err != nil {
			log.Println("!! problem posting message to pnut.io", err)
		}
		log.Println("<< ok")
		raw = nil
	}
}

func getPnutChannel(rooms []Room, gateway string) string {
	for _, v := range rooms {
		if v.Gateway == gateway {
			return v.ChannelID
		}
	}
	return ""
}

func init() {
	cfgfile = flag.String("c", "config.ini", "config file")
}

func main() {
	flag.Parse()

	done = make(chan interface{})
	interrupt = make(chan os.Signal)

	conf := new(Config)
	file, err := ini.Load(*cfgfile)
	if err != nil {
		log.Printf("!! there was a problem loading the config: %v", err)
		os.Exit(1)
	}
	var rooms []Room
	for _, _sec := range file.SectionStrings() {
		if _sec == "DEFAULT" {
			err = file.Section("DEFAULT").MapTo(conf)
			if err != nil {
				log.Println("!! unable to map default config section", err)
			}
		} else {
			room := new(Room)
			err = file.Section(_sec).MapTo(room)
			if err != nil {
				log.Printf("!! unable to map config section %s: %v", _sec, err)
			}
			rooms = append(rooms, *room)
		}
	}
	conf.Rooms = rooms

	params := url.Values{}
	params.Set("access_token", conf.PnutAccessToken)

	socketUrl := "wss://stream.pnut.io/v1/user?" + params.Encode()
	conn, _, err := websocket.DefaultDialer.Dial(socketUrl, nil)
	if err != nil {
		log.Fatal("!! error connectiong to pnut.io:", err)
	}
	defer conn.Close()
	go receiveHandler(conn, conf)

	for {
		select {
		case <-time.After(time.Duration(1) * time.Millisecond * 1000):
			err := conn.WriteMessage(websocket.TextMessage, []byte("."))
			if err != nil {
				log.Fatal("!! error during write to websocket:", err)
			}

			url := conf.MbUrl + "/api/messages"
			req, err := http.NewRequest("GET", url, nil)
			if err != nil {
				log.Println("!! unable to create request", err)
			}
			req.Header.Set("User-Agent", "pnut-bridge")
			req.Header.Add("Authorization", "Bearer "+conf.MbToken)
			client := &http.Client{
				Timeout: 10 * time.Second,
			}
			resp, err := client.Do(req)
			if err != nil {
				log.Println(">> error on reponse", err)
			}
			body, _ := ioutil.ReadAll(resp.Body)
			resp.Body.Close()
			//log.Println("<< ", string([]byte(body)))
			var m []MbMessage
			jerr := json.Unmarshal(body, &m)
			if jerr != nil {
				log.Println("Error unmarshaling msg", jerr)
			}
			if len(m) > 0 {
				for _, _m := range m {
					bridgeMsgHandler(conf, _m)
				}
			}

		case <-interrupt:
			log.Println("Received SIGINT.")

			err := conn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
			if err != nil {
				log.Println("Error during closing websocket:", err)
				return
			}

			select {
			case <-done:
				log.Println("Receiver Channel Closed! Exiting...")
			case <-time.After(time.Duration(1) * time.Second):
				log.Println("Timeout in closing receiving channel. Exiting...")
			}
			return
		}
	}
}