package ui

import (
	"fmt"
	"strconv"

	"codeflow.dananglin.me.uk/apollo/canal/internal/board"
	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
)

const (
	shiftLeft int = iota
	shiftRight
)

const (
	mainPageName string = "main"
	quitPageName string = "quit"
	addPageName  string = "add"
	movePageName string = "move"
)

type UI struct {
	*tview.Application

	columns       []column
	flex          *tview.Flex
	pages         *tview.Pages
	focusedColumn int
	board         board.Board
	quit          *tview.Modal
	add           *modalInput
	move          *tview.Flex
}

// NewUI returns a new UI value.
func NewUI() UI {
	ui := UI{
		Application:   tview.NewApplication(),
		pages:         tview.NewPages(),
		flex:          tview.NewFlex(),
		quit:          tview.NewModal(),
		add:           NewModalInput(),
		focusedColumn: 0,
		columns:       nil,
		move:          nil,
		board:         board.Board{},
	}

	ui.init()

	return ui
}

// closeBoard closes the board.
func (u *UI) closeBoard() {
	_ = u.board.Close()
}

// init initialises the UI.
func (u *UI) init() {
	u.pages.AddPage(mainPageName, u.flex, true, true)

	u.initQuitModal()
	u.pages.AddPage(quitPageName, u.quit, false, false)

	u.initAddInputModal()
	u.pages.AddPage(addPageName, u.add, false, false)

	u.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		switch event.Rune() {
		case 'o':
			if u.flex.HasFocus() && len(u.columns) == 0 {
				_ = u.openBoard("")
			}
		}

		return event
	})

	u.SetRoot(u.pages, true)
}

// initAddInputModal initialises the add input modal.
func (u *UI) initAddInputModal() {
	doneFunc := func(text string, success bool) {
		if success {
			_ = u.newCard(text, "")
		}

		u.pages.HidePage(addPageName)
		u.setColumnFocus()
	}

	u.add.SetDoneFunc(doneFunc)
}

// initQuitModal initialises the quit modal.
func (u *UI) initQuitModal() {
	quitDoneFunc := func(_ int, buttonLabel string) {
		switch buttonLabel {
		case "Quit":
			u.shutdown()
		default:
			u.pages.SwitchToPage(mainPageName)
			u.setColumnFocus()
		}
	}

	u.quit.SetText("Do you want to quit the application?").
		AddButtons([]string{"Quit", "Cancel"}).
		SetDoneFunc(quitDoneFunc)
}

// newCard creates and saves a new card to the database.
func (u *UI) newCard(title, content string) error {
	args := board.CardArgs{
		NewTitle:   title,
		NewContent: content,
	}

	if _, err := u.board.CreateCard(args); err != nil {
		return fmt.Errorf("unable to create card, %w", err)
	}

	_ = u.refresh()

	return nil
}

// openBoard opens the kanban board.
func (u *UI) openBoard(path string) error {
	b, err := board.Open(path)
	if err != nil {
		return fmt.Errorf("unable to load board, %w", err)
	}

	u.board = b

	if err = u.refresh(); err != nil {
		return fmt.Errorf("error refreshing the board, %w", err)
	}

	return nil
}

// refresh refreshes the UI.
func (u *UI) refresh() error {
	statusList, err := u.board.StatusList()
	if err != nil {
		return fmt.Errorf("unable to get the status list, %w", err)
	}

	u.updateColumns(statusList)

	u.updateMovePage(statusList)

	u.setColumnFocus()

	return nil
}

// shutdown shuts down the application.
func (u *UI) shutdown() {
	u.closeBoard()
	u.Stop()
}

func (u *UI) updateMovePage(statusList []board.Status) {
	if u.pages.HasPage(movePageName) {
		u.pages.RemovePage(movePageName)
	}

	move := tview.NewFlex()

	statusSelection := tview.NewList()
	statusSelection.SetBorder(true)
	statusSelection.ShowSecondaryText(false)
	statusSelection.SetHighlightFullLine(true)
	statusSelection.SetSelectedFocusOnly(true)
	statusSelection.SetWrapAround(false)

	doneFunc := func() {
		u.pages.HidePage(movePageName)
		u.setColumnFocus()
	}

	statusSelection.SetDoneFunc(doneFunc)

	selectedFunc := func(_ int, _, secondary string, _ rune) {
		currentStatusID := u.columns[u.focusedColumn].statusID

		nextStatusID, err := strconv.Atoi(secondary)
		if err != nil {
			nextStatusID = 0
		}

		currentItem := u.columns[u.focusedColumn].cards.GetCurrentItem()
		_, cardIDText := u.columns[u.focusedColumn].cards.GetItemText(currentItem)
		cardID, _ := strconv.Atoi(cardIDText)

		args := board.MoveToStatusArgs{
			CardID:          cardID,
			CurrentStatusID: currentStatusID,
			NextStatusID:    nextStatusID,
		}
		_ = u.board.MoveToStatus(args)

		u.pages.HidePage(movePageName)
		_ = u.refresh()
	}

	statusSelection.SetSelectedFunc(selectedFunc)

	for _, status := range statusList {
		id := strconv.Itoa(status.ID)
		statusSelection.AddItem(fmt.Sprintf("\u25C9  %s", status.Name), id, 0, nil)
	}

	move.AddItem(statusSelection, 0, 1, true)

	u.move = move

	u.pages.AddPage(movePageName, move, false, false)
}