package ui

import (
	"fmt"

	"forge.dananglin.me.uk/code/dananglin/canal/internal/board"
	"github.com/rivo/tview"
	bolt "go.etcd.io/bbolt"
)

type shiftDirection int

const (
	shiftLeft shiftDirection = iota
	shiftRight
)

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

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

	columns       []column
	flex          *tview.Flex
	pages         *tview.Pages
	focusedColumn int
	db            *bolt.DB
}

// shutdown shuts down the application.
func (a *App) shutdown() {
	a.closeDB()
	a.Stop()
}

// closeDB closes the BoltDB database.
func (a *App) closeDB() {
	if a.db != nil {
		_ = a.db.Close()
	}
}

// openProject opens the kanban project.
func (a *App) openProject(path string) error {
	if a.db != nil && len(a.db.Path()) > 0 {
		a.db.Close()
	}

	db, err := board.OpenProject(path)
	if err != nil {
		return fmt.Errorf("unable to load board, %w", err)
	}

	a.db = db

	if err = a.refresh(); err != nil {
		return err
	}

	return nil
}

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

	a.updateBoard(statusList)

	a.setColumnFocus()

	return nil
}

func (a *App) updateBoard(statusList []board.Status) error {
	a.flex.Clear()
	columns := make([]column, len(statusList))

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

		if len(statusList[i].CardIds) > 0 {
			cards, err := board.ReadCardList(a.db, 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)
			}
		}

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

	a.columns = columns

	return nil
}

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

	a.setColumnFocus()
}

func (a *App) setColumnFocus() {
	a.SetFocus(a.columns[a.focusedColumn].cards)
}

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

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

	a.refresh()

	return nil
}

// TODO: Move 'Add' to the centre of the app
// TODO: Customize list primitive or create a new one
// TODO: If customizing exisiing 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
//}