package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"os/signal"
	"strings"
	"time"

	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
	"github.com/vilmibm/hermeticum/proto"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
)

var (
	tls                = flag.Bool("tls", false, "Connection uses TLS if true, else plain TCP")
	caFile             = flag.String("ca_file", "", "The file containing the CA root cert file")
	serverAddr         = flag.String("addr", "localhost:6666", "The server address in the format of host:port")
	serverHostOverride = flag.String("server_host_override", "x.test.example.com", "The server name used to verify the hostname returned by the TLS handshake")
)

type ClientState struct {
	App          *tview.Application
	Client       proto.GameWorldClient
	SessionInfo  *proto.SessionInfo
	MaxMessages  int
	messagesView *tview.TextView
	messages     []*proto.ClientMessage
	cmdStream    proto.GameWorld_CommandsClient
}

func (cs *ClientState) Messages() error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	stream, err := cs.Client.Messages(ctx, cs.SessionInfo)
	if err != nil {
		return err
	}

	for {
		msg, err := stream.Recv()
		if err == io.EOF {
			break
		}
		if err != nil {
			return err
		}
		cs.AddMessage(msg)
	}

	return nil
}

func (cs *ClientState) HandleSIGINT(sigC chan os.Signal) {
	for range sigC {
		cm := &proto.Command{
			SessionInfo: cs.SessionInfo,
			Verb:        "quit",
		}
		err := cs.cmdStream.Send(cm)
		if err != nil {
			fmt.Printf("failed to send quit verb to server: %s\n", err.Error())
		}
		_, err = cs.cmdStream.Recv()
		if err != nil {
			fmt.Printf("failed to receive an ACK from server: %s\n", err.Error())
		}

		cs.App.Stop()
	}
}

func (cs *ClientState) HandleInput(input string) error {
	var verb string
	rest := input
	if strings.HasPrefix(input, "/") {
		verb, rest, _ = strings.Cut(input[1:], " ")
	} else {
		verb = "say"
	}
	cmd := &proto.Command{
		SessionInfo: cs.SessionInfo,
		Verb:        verb,
		Rest:        rest,
	}
	// TODO I'm punting on handling CommandAcks for now but it will be a nice UX thing later for showing connectivity problems
	err := cs.cmdStream.Send(cmd)
	if err != nil {
		return err
	}
	_, err = cs.cmdStream.Recv()
	if err != nil {
		fmt.Printf("failed to receive an ACK from server: %s\n", err.Error())
	}
	if verb == "quit" || verb == "q" {
		cs.App.Stop()
	}
	return nil
}

func (cs *ClientState) InitCommandStream() error {
	ctx := context.Background()
	stream, err := cs.Client.Commands(ctx)
	if err != nil {
		return err
	}
	cs.cmdStream = stream
	return nil
}

func (cs *ClientState) AddMessage(msg *proto.ClientMessage) {
	// TODO i don't like this function
	cs.messages = append(cs.messages, msg)
	if len(cs.messages) > cs.MaxMessages {
		cs.messages = cs.messages[1 : len(cs.messages)-1]
	}

	// TODO look into using the SetChangedFunc thing.
	cs.App.QueueUpdateDraw(func() {
		// TODO trim content of messagesView /or/ see if tview has a buffer size that does it for me. use cs.messages to re-constitute.
		switch msg.Type {
		case proto.ClientMessage_OVERHEARD:
			fmt.Fprintf(cs.messagesView, "%s: %s\n", msg.GetSpeaker(), msg.GetText())
		case proto.ClientMessage_EMOTE:
			fmt.Fprintf(cs.messagesView, "%s %s\n", msg.GetSpeaker(), msg.GetText())
		default:
			fmt.Fprintf(cs.messagesView, "%#v\n", msg)
		}
		cs.messagesView.ScrollToEnd()
	})
}

func _main() error {
	var opts []grpc.DialOption
	if *tls {
		return errors.New("TODO tls unsupported")
		/*
			if *caFile == "" {
				*caFile = data.Path("x509/ca_cert.pem")
			}
			creds, err := credentials.NewClientTLSFromFile(*caFile, *serverHostOverride)
			if err != nil {
				log.Fatalf("Failed to create TLS credentials %v", err)
			}
			opts = append(opts, grpc.WithTransportCredentials(creds))
		*/
	} else {
		opts = append(opts, grpc.WithTransportCredentials(insecure.NewCredentials()))
	}

	conn, err := grpc.Dial(*serverAddr, opts...)
	if err != nil {
		return fmt.Errorf("fail to dial: %w", err)
	}
	defer conn.Close()

	client := proto.NewGameWorldClient(conn)

	app := tview.NewApplication()

	// TODO make a NewClientState
	// TODO rename this, like, UI
	cs := &ClientState{
		App:         app,
		SessionInfo: &proto.SessionInfo{},
		Client:      client,
		MaxMessages: 15, // TODO for testing
		messages:    []*proto.ClientMessage{},
	}

	err = cs.InitCommandStream()
	if err != nil {
		return fmt.Errorf("could not create command stream: %w", err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	if _, err = cs.Client.Ping(ctx, cs.SessionInfo); err != nil {
		log.Fatalf("%v.Ping -> %v", cs.Client, err)
	}

	pages := tview.NewPages()

	pages.AddPage("splash",
		tview.NewModal().
			AddButtons([]string{"hey. let's go"}).
			SetDoneFunc(func(_ int, _ string) {
				pages.SwitchToPage("main")
				app.ResizeToFullScreen(pages)
			}).SetText("h e r m e t i c u m"),
		true,
		true)

	commandInput := tview.NewInputField().SetLabel("> ")
	handleInput := func(_ tcell.Key) {
		input := commandInput.GetText()
		// TODO command history
		commandInput.SetText("")
		// TODO do i need to clear the input's text?
		go cs.HandleInput(input)
	}

	commandInput.SetDoneFunc(handleInput)

	mainPage := tview.NewList().
		AddItem("jack in", "connect using an existing account", '1', func() {
			pages.SwitchToPage("login")
		}).
		AddItem("rez a toon", "create a new account", '2', func() {
			pages.SwitchToPage("register")
		}).
		AddItem("open the hood", "client configuration", '3', nil).
		AddItem("get outta here", "quit the client", '4', func() {
			app.Stop()
		})

	pages.AddPage("main", mainPage, true, false)

	sigC := make(chan os.Signal, 1)
	signal.Notify(sigC, os.Interrupt)

	lunfi := tview.NewInputField().SetLabel("account name")
	lpwfi := tview.NewInputField().SetLabel("password").SetMaskCharacter('~')

	loginPage := tview.NewForm().AddFormItem(lunfi).AddFormItem(lpwfi).
		SetCancelFunc(func() {
			pages.SwitchToPage("main")
		})

	loginSubmitFn := func() {
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		si, err := cs.Client.Login(ctx, &proto.AuthInfo{
			Username: lunfi.GetText(),
			Password: lpwfi.GetText(),
		})
		if err != nil {
			panic(err.Error())
		}

		cs.SessionInfo = si

		pages.SwitchToPage("game")
		app.SetFocus(commandInput)
		go cs.HandleSIGINT(sigC)
		// TODO error handle
		go cs.Messages()
	}

	// TODO login and register pages should refuse blank entries
	// TODO password should have rules
	loginPage.AddButton("gimme that shit", loginSubmitFn)
	loginPage.AddButton("nah get outta here", func() {
		pages.SwitchToPage("main")
	})
	pages.AddPage("login", loginPage, true, false)

	runfi := tview.NewInputField().SetLabel("account name")
	rpwfi := tview.NewInputField().SetLabel("password").SetMaskCharacter('~')

	registerPage := tview.NewForm().AddFormItem(runfi).AddFormItem(rpwfi).
		SetCancelFunc(func() {
			pages.SwitchToPage("main")
		})

	registerSubmitFn := func() {
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		si, err := cs.Client.Register(ctx, &proto.AuthInfo{
			Username: runfi.GetText(),
			Password: rpwfi.GetText(),
		})
		if err != nil {
			panic(err.Error())
		}

		cs.SessionInfo = si

		pages.SwitchToPage("game")
		app.SetFocus(commandInput)
		go cs.HandleSIGINT(sigC)
		// TODO error handle
		go cs.Messages()
	}

	registerPage.AddButton("gimme that shit", registerSubmitFn)
	registerPage.AddButton("nah get outta here", func() {
		pages.SwitchToPage("main")
	})
	pages.AddPage("register", registerPage, true, false)

	msgView := tview.NewTextView().SetScrollable(true).SetWrap(true).SetWordWrap(true)
	cs.messagesView = msgView

	gamePage := tview.NewGrid().
		SetRows(1, 40, 3).
		SetColumns(-1, -1).
		SetBorders(true).
		AddItem(
			tview.NewTextView().SetTextAlign(tview.AlignLeft).SetText("h e r m e t i c u m"),
			0, 0, 1, 1, 1, 1, false).
		AddItem(
			tview.NewTextView().SetTextAlign(tview.AlignRight).SetText("TODO server status"),
			0, 1, 1, 1, 1, 1, false).
		AddItem(
			msgView,
			1, 0, 1, 1, 10, 20, false).
		AddItem(
			tview.NewTextView().SetText("TODO details"),
			1, 1, 1, 1, 10, 10, false).
		AddItem(
			commandInput,
			2, 0, 1, 2, 1, 30, false)

	pages.AddPage("game", gamePage, true, false)

	return app.SetRoot(pages, true).SetFocus(pages).Run()
}

func main() {
	err := _main()
	if err != nil {
		log.Fatal(err.Error())
	}
}