package main

import (
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"strings"
	"time"

	"github.com/nlopes/slack"
	"github.com/unixvoid/glogger"
	"gopkg.in/gcfg.v1"
	"gopkg.in/redis.v5"
)

type Config struct {
	Lorebot struct {
		Loglevel       string
		BootstrapDelay time.Duration
		APIToken       string
	}
	Redis struct {
		Host     string
		Password string
	}
}

var (
	config = Config{}
)

func main() {
	// read in config file
	readConf()

	// initialize the logger with the configured loglevel
	initLogger(config.Lorebot.Loglevel)

	// initialize redis connection
	redisClient, err := initRedisConnection()
	if err != nil {
		glogger.Debug.Printf("redis conneciton cannot be made, trying again in %d seconds", config.Lorebot.BootstrapDelay)
		time.Sleep(config.Lorebot.BootstrapDelay * time.Second)
		redisClient, err = initRedisConnection()
		if err != nil {
			glogger.Error.Println("redis connection cannot be made.")
			os.Exit(1)
		}
	}
	glogger.Debug.Println("connection to redis succeeded.")
	glogger.Info.Println("link to redis on", config.Redis.Host)

	api := slack.New(config.Lorebot.APIToken)
	//api.SetDebug(true)

	rtm := api.NewRTM()
	go rtm.ManageConnection()

Loop:
	for {
		select {
		case msg := <-rtm.IncomingEvents:
			switch ev := msg.Data.(type) {
			case *slack.MessageEvent:
				if ev.Type == "message" {
					glogger.Debug.Printf("processing: %s", ev.Text)
					// see if the message begins with '.', it could be a command
					if len(ev.Text) == 0 {
						// nil message, dont print
						//glogger.Debug.Println("breaking on blank message")
						break
					} else {
						comm := fmt.Sprintf("%c", ev.Text[0])
						if comm == "." {
							if strings.Count(ev.Text, " ") == 0 {
								// no spaces, its a static command
								staticCommandHandler(rtm, ev, redisClient)
							} else {
								// spaces, dynamic handler
								dynamicCommandHandler(rtm, ev, redisClient)
							}
						}
					}
				}
			case *slack.RTMError:
				fmt.Printf("Error: %s\n", ev.Error())
			case *slack.InvalidAuthEvent:
				fmt.Printf("Invalid credentials")
				break Loop
			default:
				// ignore all other events
				//fmt.Printf("Unknown error")
				//fmt.Printf("%v\n", msg.Data)
			}
		}
	}
}

func readConf() {
	// init config file
	err := gcfg.ReadFileInto(&config, "config.gcfg")
	if err != nil {
		panic(fmt.Sprintf("Could not load config.gcfg, error: %s\n", err))
	}
}

func initLogger(logLevel string) {
	// init logger
	if logLevel == "debug" {
		glogger.LogInit(os.Stdout, os.Stdout, os.Stdout, os.Stderr)
	} else if logLevel == "cluster" {
		glogger.LogInit(os.Stdout, os.Stdout, ioutil.Discard, os.Stderr)
	} else if logLevel == "info" {
		glogger.LogInit(os.Stdout, ioutil.Discard, ioutil.Discard, os.Stderr)
	} else {
		glogger.LogInit(ioutil.Discard, ioutil.Discard, ioutil.Discard, os.Stderr)
	}
}

func initRedisConnection() (*redis.Client, error) {
	// init redis connection
	redisClient := redis.NewClient(&redis.Options{
		Addr:     config.Redis.Host,
		Password: config.Redis.Password,
		DB:       0,
	})

	_, redisErr := redisClient.Ping().Result()
	return redisClient, redisErr
}

func dynamicCommandHandler(rtm *slack.RTM, ev *slack.MessageEvent, redisClient *redis.Client) {
	message := ev.Text
	if strings.Count(message, " ") < 1 {
		glogger.Debug.Println("not proper syntax")
	}

	// verify syntax
	s := strings.SplitN(message, " ", 2)
	command, content := s[0], s[1]
	trimmedPrefix := strings.TrimPrefix(command, ".")

	switch trimmedPrefix {
	case "lore":
		s := strings.SplitN(string(ev.Text), " ", 2)
		lorehandler(redisClient, rtm, ev, s[1])
	case "newlore":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
		println(content)
	case "rmlore":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "rek":
		s := strings.SplitN(string(ev.Text), " ", 2)
		rekhandler(redisClient, rtm, ev, s[1])
	case "gnu":
		s := strings.SplitN(string(ev.Text), " ", 2)
		gnuhandler(redisClient, rtm, ev, s[1])
	case "created":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "owner":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "removedby":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "removed":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	}
}

func staticCommandHandler(rtm *slack.RTM, ev *slack.MessageEvent, redisClient *redis.Client) {
	s := strings.SplitN(ev.Text, " ", 2)
	command := s[0]
	trimmedPrefix := strings.TrimPrefix(command, ".")

	switch trimmedPrefix {
	case "help":
		helpmsg(rtm, ev)
	case "help2":
		advancedhelpmsg(rtm, ev)
	case "rng":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "version":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "lorelist":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "removedlore":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	case "lorestatus":
		rtm.SendMessage(rtm.NewOutgoingMessage("command not yet supported", ev.Channel))
	}
}

func helpmsg(rtm *slack.RTM, ev *slack.MessageEvent) {
	help1 := "I am the lore archival bot, I support the following commands:\n" +
		"```" +
		".lore:         view lore\n" +
		".newlore:      add new lore\n" +
		".rmlore:       remove lore\n" +
		".lorelist:     view lore database\n" +
		"use '.help2' to see advanced lookup commands." +
		"```"

	rtm.SendMessage(rtm.NewOutgoingMessage(help1, ev.Channel))
}

func advancedhelpmsg(rtm *slack.RTM, ev *slack.MessageEvent) {
	help2 := "```" +
		".created       view creation timestamp\n" +
		".owner:        who created the lore\n" +
		".removed:      view removal timestamp\n" +
		".removedby:    who removed the lore" +
		"```"

	rtm.SendMessage(rtm.NewOutgoingMessage(help2, ev.Channel))
}

func lorehandler(redisClient *redis.Client, rtm *slack.RTM, ev *slack.MessageEvent, rawMessage string) {
	loreTerm := strings.Replace(rawMessage, ".lore", "", -1)
	println("searching for:", loreTerm)
	//rtm.SendMessage(rtm.NewOutgoingMessage(fmt.Sprintf("searching for '%s'\n", loreTerm), ev.Channel))

	content, err := checkLore(loreTerm, redisClient)
	if err == nil {
		// lore found, print it
		rtm.SendMessage(rtm.NewOutgoingMessage(content, ev.Channel))
	} else {
		// lore not found, print error
		rtm.SendMessage(rtm.NewOutgoingMessage(fmt.Sprintf("lore '%s' not found\n", loreTerm), ev.Channel))
	}
}

func rekhandler(redisClient *redis.Client, rtm *slack.RTM, ev *slack.MessageEvent, target string) {
	rektBit, _ := redisClient.SRandMember("index:rekt").Result()
	rekFmt := fmt.Sprintf("%s %s", target, rektBit)
	rtm.SendMessage(rtm.NewOutgoingMessage(rekFmt, ev.Channel))
}

func gnuhandler(redisClient *redis.Client, rtm *slack.RTM, ev *slack.MessageEvent, target string) {
	gnuFmt := fmt.Sprintf("slaps the nonfree software out of %s's hands", target)
	rtm.SendMessage(rtm.NewOutgoingMessage(gnuFmt, ev.Channel))
}

func checkLore(searchTerm string, redisClient *redis.Client) (string, error) {
	val, err := redisClient.Get(fmt.Sprintf("lore:%s:content", searchTerm)).Result()
	if err != nil {
		return "", errors.New("String not found.")
	} else {
		return val, nil
	}
	//return "", nil
}