package ctfc

import (
	"strconv"
	"strings"

	"gitlab.com/Syndamia/ctfc/go-src/csi"
	"gitlab.com/Syndamia/ctfc/go-src/ui"
)

type window func(...string)

func StartupWindow(...string) {
	csi.ClearScreen()

	ui.NormalBox(true, "Login", "Register")
	input := ui.InputField("[L/R]")

	handled := handleInputActions(input, false,
		inputAction{"L", loginWindow, nil},
		inputAction{"R", registerWindow, nil},
	)
	if !handled {
		defer showError(invalidCommand, StartupWindow)
	}
}

func loginWindow(values ...string) {
	// Takes form user input
	inputs := formWindow("Login", StartupWindow,
		[]formInput{
			{"Username", " or [B for Back to start page]", nil},
			{"Password", "", nil},
		},
		values...,
	)
	if len(inputs) == 0 {
		return
	}

	// If login is successful, go to chats window, else show error
	if logInUser(inputs[0], inputs[1]) {
		defer chatsWindow()
	} else {
		defer showError(invalidCredentials, loginWindow, inputs[0])
	}
}

func registerWindow(values ...string) {
	inputs := formWindow("Register", StartupWindow,
		[]formInput{
			{"Username", " [A-z, 0-9, *, ., _, -; at least 1 letter] or [B for Back to start page]", stringValidUsername},
			{"Password", " [5-40 characters; at least 1 number]", stringValidPassword},
			{"Name", " [2-60 characters]", stringValidName},
		},
		values...,
	)
	if len(inputs) == 0 {
		return
	}
	if usernameExists(inputs[0]) {
		defer showError(valueAlreadyTaken("Username"), registerWindow, values...)
		return
	}

	createUser(inputs)
	logInUser(inputs[0], inputs[1])
	defer chatsWindow()
}

func chatsWindow(values ...string) {
	csi.ClearScreen()

	ui.NormalBox(true, "Direct Messages", "Account", "Logout")
	allChats := getAllChats()
	ui.NumberedFields(allChats...)
	ui.PageField(0, 0)
	ui.EmptyLine()

	if len(values) > 0 {
		if values[0] == "ShowHelp" {
			ui.TextField("Chats page options: [(D)irect messages/(A)ccount/(L)ogout/(<) for previous page/(>) for next page/(C) for create chat/(name) for go to chat room by name/(number) for go to chat room by number/(H)elp]")
		}
	}
	input := ui.InputField("[D/A/L/</>/C/E/name/number/H]")

	handled := handleInputActions(input, true,
		inputAction{"C", createChatWindow, nil},
		inputAction{"H", chatsWindow, []string{"ShowHelp"}},
	)
	if !handled {
		// If user input is number, navigate to chat of given number, else show error
		if chatI, err := strconv.Atoi(input); chatI >= 0 && chatI <= len(allChats) && err == nil {
			defer chatWindow(strings.Split(allChats[chatI-1], " : ")[0])
		} else {
			defer showError(invalidCommand, chatsWindow)
		}
	}
}

func createChatWindow(values ...string) {
	inputs := formWindow("Creating a new chat", chatsWindow,
		[]formInput{
			{"Name", " [2-20 characters; A-z, 0-9, spaces, _, -] or [B for Back to chats page]", stringValidChatName},
			{"Description", " [0-30 characters]", stringValidChatDesc},
		},
		values...,
	)
	if len(inputs) == 0 {
		return
	}
	if chatNameExists(inputs[0]) {
		defer showError(valueAlreadyTaken("Chat name"), createChatWindow, values...)
		return
	}

	createChat(inputs[0], inputs[1], loggedInUser.Username)
	defer chatWindow(inputs[0])
}

func chatWindow(values ...string) {
	csi.ClearScreen()

	// We determine page number by length of a string
	// This method should be faster than having to cast to int all the time
	if len(values) == 1 {
		values = append(values, ".")
	}

	currChat := getChat(values[0])
	ui.NormalBox(true, "Chats", "Direct Messages", "Account", "Logout")
	ui.TextField(currChat.Name + " : " + currChat.Description)
	ui.TextField("Brought to you by " + currChat.Owner.Name + " (" + currChat.Owner.Username + ")")

	// One empty line to separate the "Brought to you by" line
	// with the chat messages, and then empty line for each chat message
	for i := 0; i <= pageSize+1; i++ {
		ui.EmptyLine()
	}

	lastLine := 0
	go routinePaginatedSubwindow(&currChat.Messages,
		func(s *[]string) { *s = getChat(values[0]).Messages },
		&lastLine,
		len(values[1]),
	)

	input := ui.InputField("Message or [C/D/A/L/</>/H]")

	handled := handleInputActions(input, true)
	if !handled {
		switch input {
		case ">":
			// If possible, increment to the next page (adds a dot to the end of the string)
			if len(values[1]) < totalPages(len(currChat.Messages)) {
				values[1] += "."
			}
		case "<":
			// If possible, decrement to the previous page (removes a dot from the string)
			if len(values[1]) > 1 {
				values[1] = values[1][:len(values[1])-1]
			}
		default: // Send a message
			values[1] = "." // Make sure to be at the first page, when sending a message
			// Since "C" is a command, to just enter the letter C you'll need to input "\C"
			currChat.addMessage(strings.TrimPrefix(input, "\\"), loggedInUser.Username)
		}

		defer chatWindow(values...)
	}
	lastLine = -1 // Practically stops execution of the paginated subwindow routine
}

func logoutWindow(...string) {
	csi.ClearScreen()

	ui.NormalBox(true, "Are you sure you want to Log out of "+loggedInUser.Username+"?")
	ui.EmptyLine()

	input := ui.InputField("[Y/N]")

	if strings.ToLower(input) == "y" {
		logoutUser()
		defer StartupWindow()
	} else {
		defer chatsWindow()
	}
}

func showError(message string, callback window, callbackData ...string) {
	csi.ClearScreen()

	ui.ErrorBox(message)
	csi.BlockClearScreenNextTime()

	defer callback(callbackData...)
}

/* Form */

type formInput struct {
	name           string
	specification  string
	validationFunc func(string) bool
}

func formWindow(boxTitle string, backWindow window, formInputs []formInput, currentValues ...string) (userInputs []string) {
	userInputs = currentValues
	// Go through all inputs
	for i, v := range formInputs[len(currentValues):] {
		csi.ClearScreen()

		ui.NormalBox(true, boxTitle)

		// Show filled input fields
		for j, va := range userInputs {
			ui.InputFieldFilled(formInputs[j].name, va)
		}

		// Wait for input on current input field
		input := ui.InputField(v.name + v.specification)

		// Go to the "backWindow", if we're on the first input, we are given a back window, and the letter B is given
		if i == 0 && backWindow != nil && strings.ToLower(input) == "b" {
			defer backWindow()
			return
		}

		// If we're validating input data, try to validate
		if v.validationFunc != nil {
			// If input data isn't valid, show an error and the same screen
			if !v.validationFunc(input) {
				formCallback := func(...string) {
					defer formWindow(boxTitle, backWindow, formInputs, userInputs...)
				}
				defer showError(invalidValueFor(v.name), formCallback)
				return
			}
		}

		// Add current input as a filled input
		userInputs = append(userInputs, input)
	}
	return
}

/* Input actions */

type inputAction struct {
	value   string
	execute window
	args    []string
}

func handleInputActions(input string, handleNav bool, ia ...inputAction) bool {
	if handleNav {
		ia = append(ia,
			inputAction{"C", chatsWindow, nil},
			inputAction{"D", chatsWindow, nil},
			inputAction{"A", chatsWindow, nil},
			inputAction{"L", logoutWindow, nil},
		)
	}
	for _, v := range ia {
		if strings.ToLower(input) == strings.ToLower(v.value) {
			defer v.execute(v.args...)
			return true
		}
	}
	return false
}