package bot

import (
	"os"
	"os/signal"
	"regexp"
	"strings"

	"github.com/mattermost/mattermost-server/v5/model"
)

type Bot struct {
	APIURL               string
	AccountEmail         string
	AccountFirstname     string
	AccountLastname      string
	AccountPassword      string
	AccountUsername      string
	BotName              string
	Buildarch            string
	DebuggingChannelName string
	TeamName             string
	Version              string
	WebsocketURL         string
	client               *model.Client4
	webSocketClient      *model.WebSocketClient
	botUser              *model.User
	botTeam              *model.Team
	debuggingChannel     *model.Channel
}

func New(options ...func(s *Bot)) *Bot {
	b := new(Bot)
	for _, opt := range options {
		opt(b)
	}
	return b
}

func (b *Bot) Main() int {
	println(b.BotName)

	b.SetupGracefulShutdown()

	b.client = model.NewAPIv4Client(b.APIURL)

	// Lets test to see if the mattermost server is up and running
	b.MakeSureServerIsRunning()

	// lets attempt to login to the Mattermost server as the bot user
	// This will set the token required for all future calls
	// You can get this token with client.AuthToken
	b.LoginAsTheBotUser()

	// If the bot user doesn't have the correct information lets update his profile
	b.UpdateTheBotUserIfNeeded()

	// Lets find our bot team
	b.FindBotTeam()

	// This is an important step.  Lets make sure we use the botTeam
	// for all future web service requests that require a team.
	//client.SetTeamId(botTeam.Id)

	// Lets create a bot channel for logging debug messages into
	b.CreateBotDebuggingChannelIfNeeded()
	b.SendMsgToDebuggingChannel("_"+b.BotName+" has **started** running_", "")

	// Lets start listening to some channels via the websocket!
	var err *model.AppError
	b.webSocketClient, err = model.NewWebSocketClient4(b.WebsocketURL, b.client.AuthToken)
	if err != nil {
		println("We failed to connect to the web socket")
		PrintError(err)
	}

	b.webSocketClient.Listen()

	go func() {
		for {
			select {
			case resp := <-b.webSocketClient.EventChannel:
				b.HandleWebSocketResponse(resp)
			}
		}
	}()

	// You can block forever with
	select {}
	return 0
}

func (b *Bot) MakeSureServerIsRunning() {
	if props, resp := b.client.GetOldClientConfig(""); resp.Error != nil {
		println("There was a problem pinging the Mattermost server.  Are you sure it's running?")
		PrintError(resp.Error)
		os.Exit(1)
	} else {
		println("Server detected and is running version " + props["Version"])
	}
}

func (b *Bot) LoginAsTheBotUser() {
	if user, resp := b.client.Login(b.AccountEmail, b.AccountPassword); resp.Error != nil {
		println("There was a problem logging into the Mattermost server.  Are you sure ran the setup steps from the README.md?")
		PrintError(resp.Error)
		os.Exit(1)
	} else {
		b.botUser = user
	}
}

func (b *Bot) UpdateTheBotUserIfNeeded() {
	if b.botUser.FirstName != b.AccountFirstname || b.botUser.LastName != b.AccountLastname || b.botUser.Username != b.AccountUsername {
		b.botUser.FirstName = b.AccountFirstname
		b.botUser.LastName = b.AccountLastname
		b.botUser.Username = b.AccountUsername

		if user, resp := b.client.UpdateUser(b.botUser); resp.Error != nil {
			println("We failed to update the Bot user account")
			PrintError(resp.Error)
			os.Exit(1)
		} else {
			b.botUser = user
			println("Looks like this might be the first run so we've updated the bots account settings")
		}
	}
}

func (b *Bot) FindBotTeam() {
	if team, resp := b.client.GetTeamByName(b.TeamName, ""); resp.Error != nil {
		println("We failed to get the initial load")
		println("or we do not appear to be a member of the team '" + b.TeamName + "'")
		PrintError(resp.Error)
		os.Exit(1)
	} else {
		b.botTeam = team
	}
}

func (b *Bot) CreateBotDebuggingChannelIfNeeded() {
	if rchannel, resp := b.client.GetChannelByName(b.DebuggingChannelName, b.botTeam.Id, ""); resp.Error != nil {
		println("We failed to get the channels")
		PrintError(resp.Error)
	} else {
		b.debuggingChannel = rchannel
		return
	}

	// Looks like we need to create the logging channel
	channel := &model.Channel{}
	channel.Name = b.DebuggingChannelName
	channel.DisplayName = "Debugging For Bot"
	channel.Purpose = "This is used as a test channel for logging bot debug messages"
	channel.Type = model.CHANNEL_OPEN
	channel.TeamId = b.botTeam.Id
	if rchannel, resp := b.client.CreateChannel(channel); resp.Error != nil {
		println("We failed to create the channel " + b.DebuggingChannelName)
		PrintError(resp.Error)
	} else {
		b.debuggingChannel = rchannel
		println("Looks like this might be the first run so we've created the channel " + b.DebuggingChannelName)
	}
}

func (b *Bot) SendMsgToDebuggingChannel(msg string, replyToId string) {
	post := &model.Post{}
	post.ChannelId = b.debuggingChannel.Id
	post.Message = msg

	post.RootId = replyToId

	if _, resp := b.client.CreatePost(post); resp.Error != nil {
		println("We failed to send a message to the logging channel")
		PrintError(resp.Error)
	}
}

func (b *Bot) HandleWebSocketResponse(event *model.WebSocketEvent) {
	b.HandleMsgFromDebuggingChannel(event)
}

func (b *Bot) HandleMsgFromDebuggingChannel(event *model.WebSocketEvent) {
	// If this isn't the debugging channel then lets ingore it
	if event.Broadcast.ChannelId != b.debuggingChannel.Id {
		return
	}

	// Lets only reponded to messaged posted events
	if event.Event != model.WEBSOCKET_EVENT_POSTED {
		return
	}

	println("responding to debugging channel msg")

	post := model.PostFromJson(strings.NewReader(event.Data["post"].(string)))
	if post != nil {

		// ignore my events
		if post.UserId == b.botUser.Id {
			return
		}

		// if you see any word matching 'alive' then respond
		if matched, _ := regexp.MatchString(`(?:^|\W)alive(?:$|\W)`, post.Message); matched {
			b.SendMsgToDebuggingChannel("Yes I'm running", post.Id)
			return
		}

		// if you see any word matching 'up' then respond
		if matched, _ := regexp.MatchString(`(?:^|\W)up(?:$|\W)`, post.Message); matched {
			b.SendMsgToDebuggingChannel("Yes I'm running", post.Id)
			return
		}

		// if you see any word matching 'running' then respond
		if matched, _ := regexp.MatchString(`(?:^|\W)running(?:$|\W)`, post.Message); matched {
			b.SendMsgToDebuggingChannel("Yes I'm running", post.Id)
			return
		}

		// if you see any word matching 'hello' then respond
		if matched, _ := regexp.MatchString(`(?:^|\W)hello(?:$|\W)`, post.Message); matched {
			b.SendMsgToDebuggingChannel("Yes I'm running", post.Id)
			return
		}
	}

	b.SendMsgToDebuggingChannel("I did not understand you!", post.Id)
}

func PrintError(err *model.AppError) {
	println("\tError Details:")
	println("\t\t" + err.Message)
	println("\t\t" + err.Id)
	println("\t\t" + err.DetailedError)
}

func (b *Bot) SetupGracefulShutdown() {
	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)
	go func() {
		for _ = range c {
			if b.webSocketClient != nil {
				b.webSocketClient.Close()
			}

			b.SendMsgToDebuggingChannel("_"+b.BotName+" has **stopped** running_", "")
			os.Exit(0)
		}
	}()
}