package main

import (
	"crypto/rsa"
	"fmt"
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/data/binding"
	"fyne.io/fyne/v2/dialog"
	"fyne.io/fyne/v2/layout"
	"fyne.io/fyne/v2/theme"
	"fyne.io/fyne/v2/widget"
	"image/color"
	"regexp"
	"strings"
)

type UserData struct {
	ServerUrl     string
	Username      string
	ServerKey     []byte
	UserKey       []byte
	ParsedUserKey *rsa.PublicKey
}

const DefaultPort = "12345"

func parseServerUrl(url string) (string, error) {
	url = strings.TrimRight(url, "/")
	urlFormat, err := regexp.Compile("(.*://)?((.*):(\\d+)|(.*))")
	if err != nil {
		return "", err
	}

	matches := urlFormat.FindStringSubmatch(url)

	host := ""
	port := ""

	if matches[5] != "" {
		host = matches[5]
		port = DefaultPort
	} else {
		host = matches[3]
		port = matches[4]
	}

	addr := fmt.Sprintf("http://%s:%s", host, port)

	return addr, nil
}

func chatLayout(window fyne.Window, user UserData) {
	window.SetTitle("Сообщения")
	storage.binding = binding.BindStringList(&storage.data)
	go runClient(user)

	list := widget.NewListWithData(storage.binding,
		func() fyne.CanvasObject {
			return widget.NewLabel("template")
		},
		func(i binding.DataItem, o fyne.CanvasObject) {
			o.(*widget.Label).Bind(i.(binding.String))
		})

	entry := widget.NewEntry()
	submit := widget.NewButton("Отправить", func() {
		go sendMessage(user, entry.Text)
		entry.SetText("")

		storage.RLock()
		lastIdx := storage.binding.Length() - 1
		list.Select(lastIdx)
		list.Unselect(lastIdx)
		storage.RUnlock()
	})

	window.SetContent(container.NewBorder(
		nil,
		container.NewBorder(nil, nil, nil, submit, entry),
		nil, nil,
		list,
	))
}

func loginLayout(window fyne.Window, user UserData) {
	window.SetTitle("Войти в чат")

	keyIsSetup := false

	label := canvas.NewText("Chat", color.White)
	label.TextSize = 40

	urlLabel := widget.NewLabel("URL: ")
	urlEntry := widget.NewEntry()
	urlEntry.Text = "localhost"

	loginLabel := widget.NewLabel("Логин: ")
	loginEntry := widget.NewEntry()

	chooseKey := widget.NewButton("Выбрать ключ для подписи", func() {
		dialog.ShowFileOpen(func(closer fyne.URIReadCloser, err error) {
			if closer == nil {
				return
			}

			bufSize := 4096
			data := make([]byte, 0)
			buf := make([]byte, bufSize)
			n := bufSize

			for n >= bufSize {
				n, _ = closer.Read(buf)
				data = append(data, buf...)
			}

			user.ParsedUserKey, err = parseKey(data)
			if err != nil {
				dialog.ShowInformation("Ошибка", "Выбранный файл не является ключом", window)
				return
			}
			user.UserKey = data
			user.ServerKey = nil

			keyIsSetup = true

			_ = closer.Close()
		}, window)
	})

	loginButton := widget.NewButton("Войти", func() {
		if !keyIsSetup {
			dialog.ShowInformation("Ошибка", "Не выбран ключ", window)
			return
		}

		if len(loginEntry.Text) == 0 {
			dialog.ShowInformation("Ошибка", "Логин не может быть пустым", window)
			return
		}
		user.Username = loginEntry.Text

		if len(urlEntry.Text) == 0 {
			dialog.ShowInformation("Ошибка", "URL не может быть пустым", window)
			return
		}
		url, err := parseServerUrl(urlEntry.Text)
		if err != nil {
			dialog.ShowInformation("Ошибка", err.Error(), window)
		}
		user.ServerUrl = url

		err = pingServer(user)
		if err != nil {
			dialog.ShowInformation("Ошибка", "Нет связи с указанным сервером", window)
			return
		}

		_, err = tryAuth(user)
		if err != nil {
			dialog.ShowInformation("Ошибка", fmt.Sprint(err), window)
			return
		}

		chatLayout(window, user)
	})

	back := widget.NewButton("Назад", func() {
		startLayout(window, user)
	})

	mainContainer := container.NewCenter(container.NewVBox(
		container.NewCenter(label), layout.NewSpacer(),
		container.NewBorder(nil, nil, urlLabel, nil, urlEntry),
		container.NewBorder(nil, nil, loginLabel, nil, loginEntry),
		chooseKey,
		loginButton,
		back,
	))
	window.SetContent(mainContainer)
}

func registerLayout(window fyne.Window, user UserData) {
	window.SetTitle("Регистрация")

	keyIsSetup := false

	label := canvas.NewText("Chat", color.White)
	label.TextSize = 40

	urlLabel := widget.NewLabel("URL: ")
	urlEntry := widget.NewEntry()
	urlEntry.Text = "localhost"

	loginLabel := widget.NewLabel("Логин: ")
	loginEntry := widget.NewEntry()

	generateKeysBtn := widget.NewButton("Сгенерировать ключи подписи", func() {
		dialog.ShowFileSave(func(closer fyne.URIWriteCloser, err error) {
			if closer == nil {
				return
			}
			private, public, err := generateKeys()
			if err != nil {
				dialog.ShowInformation("Ошибка", fmt.Sprint(err), window)
				return
			}

			user.ServerKey = private
			user.UserKey = public
			user.ParsedUserKey, _ = parseKey(user.UserKey)
			keyIsSetup = true

			_, _ = closer.Write(user.UserKey)
			_ = closer.Close()
		}, window)
	})

	registerButton := widget.NewButton("Зарегистрироваться", func() {
		if !keyIsSetup {
			dialog.ShowInformation("Ошибка", "Не выбран ключ", window)
			return
		}

		if len(loginEntry.Text) == 0 {
			dialog.ShowInformation("Ошибка", "Логин не может быть пустым", window)
			return
		}
		user.Username = loginEntry.Text

		if len(urlEntry.Text) == 0 {
			dialog.ShowInformation("Ошибка", "URL не может быть пустым", window)
			return
		}
		url, err := parseServerUrl(urlEntry.Text)
		if err != nil {
			dialog.ShowInformation("Ошибка", err.Error(), window)
		}
		user.ServerUrl = url

		err = pingServer(user)
		if err != nil {
			dialog.ShowInformation("Ошибка", "Нет связи с указанным сервером", window)
			return
		}

		_, err = register(user, string(user.ServerKey))
		if err != nil {
			dialog.ShowInformation("Ошибка", fmt.Sprint(err), window)
			return
		}

		chatLayout(window, user)
	})

	back := widget.NewButton("Назад", func() {
		startLayout(window, user)
	})

	window.SetContent(container.NewCenter(container.NewVBox(
		container.NewCenter(label), layout.NewSpacer(),
		container.NewBorder(nil, nil, urlLabel, nil, urlEntry),
		container.NewBorder(nil, nil, loginLabel, nil, loginEntry),
		generateKeysBtn,
		registerButton,
		back,
	)))
}

func startLayout(window fyne.Window, user UserData) {
	window.SetTitle("Chat")

	label := canvas.NewText("Chat", color.White)
	label.TextSize = 40
	login := widget.NewButton("Войти", func() {
		loginLayout(window, user)
	})
	signup := widget.NewButton("Зарегистрироваться", func() {
		registerLayout(window, user)
	})

	mainContainer := container.NewCenter(container.NewVBox(
		container.NewCenter(label), layout.NewSpacer(), login, signup))
	window.SetContent(mainContainer)
}

func main() {
	myApp := app.New()
	myApp.Settings().SetTheme(theme.DarkTheme())
	window := myApp.NewWindow("")
	window.Resize(fyne.Size{Width: 640, Height: 480})
	var user UserData

	startLayout(window, user)
	window.ShowAndRun()
}