package ui

import (
	"fmt"

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

type shiftDirection int

const (
	shiftLeft shiftDirection = iota
	shiftRight
)

const (
	mainPage string = "main"
	quitPage string = "quit"
	addPage  string = "add"
)

// UI does some magical stuff.
type UI struct {
	*tview.Application

	columns       []column
	flex          *tview.Flex
	pages         *tview.Pages
	focusedColumn int
	board         board.Board
}

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

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

// openBoard opens the kanban project.
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 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.updateBoard(statusList)

	u.setColumnFocus()

	return nil
}

func (u *UI) updateBoard(statusList []board.Status) error {
	u.flex.Clear()

	columns := make([]column, len(statusList))

	for i := range statusList {
		columns[i] = u.newColumn(statusList[i].ID, statusList[i].Name)

		if len(statusList[i].CardIds) > 0 {
			cards, err := u.board.CardList(statusList[i].CardIds)
			if err != nil {
				return fmt.Errorf("unable to get the card list. %w", err)
			}

			for _, c := range cards {
				columns[i].cards.AddItem(fmt.Sprintf("[%d] %s", c.Id(), c.Title), "", 0, nil)
			}
		}

		u.flex.AddItem(columns[i].cards, 0, 1, false)
	}

	u.columns = columns

	return nil
}

func (u *UI) shiftColumnFocus(s shiftDirection) {
	switch s {
	case shiftRight:
		if u.focusedColumn == len(u.columns)-1 {
			u.focusedColumn = 0
		} else {
			u.focusedColumn++
		}
	case shiftLeft:
		if u.focusedColumn == 0 {
			u.focusedColumn = len(u.columns) - 1
		} else {
			u.focusedColumn--
		}
	}

	u.setColumnFocus()
}

func (u *UI) setColumnFocus() {
	u.SetFocus(u.columns[u.focusedColumn].cards)
}

// newCard creates a new card and saves it 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
}

// TODO: Move 'Add' to the centre of the app
// TODO: Customize list primitive or create a new one
// TODO: If customizing existing list primitive, wrap list around a column type. Add statusID to it.
// TODO: Update card status (card ID, oldStatus, newStatus)

//func viewCard() error {
//return nil
//}