package tg

type PanelPager interface {
	GetPanelPage(
		panel *PanelPagerCompo,
		c Context, page, size int,
	) PanelPage
}

type PanelPage struct {
	Next, Prev bool
	Rows []ButtonRow
}

type PanelPagerFunc func(
	panel *PanelPagerCompo,
	c Context, page, size int,
) PanelPage
func (fn PanelPagerFunc) GetPanelPage(
	panel *PanelPagerCompo, c Context, page, size int,
) PanelPage {
	return fn(panel, c, page, size)
}

type PanelPagerCompo struct {
	PanelCompo
	page int
	size int
	nextFormat, prevFormat, delFormat string
	pager PanelPager
}

func (compo *MessageCompo) PanelPager(
	c Context,
	startPage, size int,
	pager PanelPager,
) (*PanelPagerCompo) {
	ret := &PanelPagerCompo{}
	ret.page = startPage
	ret.size = size
	ret.pager = pager
	ret.prevFormat = "<<<"
	ret.nextFormat = ">>>"
	ret.delFormat = "..."

	ret.PanelCompo = (*compo.Panel(
		c, ret,
	))

	return ret
}

func (panel *PanelPagerCompo) GetPanelRows(
	pcompo *PanelCompo, c Context,
) []ButtonRow {
	page := panel.pager.GetPanelPage(
		panel, c, panel.page, panel.size,
	)

	controlRow := ButtonRow{}

	rows := page.Rows
	next := func(c Context){
		panel.page++
		panel.Update(c)
	}
	prev := func(c Context){
		panel.page--
		panel.Update(c)
	}

	if page.Prev {
		if panel.delFormat != "" {
			rows = append(
				[]ButtonRow{
					ButtonRow{
						Buttonf(panel.delFormat).Rand().
							WithAction(Func(prev)),
					},
				},
				rows...,
			)
		}
		controlRow = append(
			controlRow,
			Buttonf(panel.prevFormat).Rand().
				WithAction(Func(prev)),
		)
	}

	if page.Next {
		if panel.delFormat != "" {
			rows = append(
				rows,
				ButtonRow{
					Buttonf(panel.delFormat).Rand().
						WithAction(Func(next)),
				},
			)
		}
		controlRow = append(
			controlRow,
			Buttonf(panel.nextFormat).Rand().
				WithAction(Func(next)),
		)
	}

	return append(
		rows,
		controlRow,
	)
}