package ui

import (
	"image"

	"gioui.org/layout"
	"gioui.org/op/clip"
	"gioui.org/op/paint"
	"gioui.org/unit"
	"gioui.org/widget"
	"gioui.org/widget/material"

	"git.wxccs.org/iceking2nd/winauth-go/internal/i18n"
)

// iconPickerDialog shows the full catalog of brand icons in a scrollable
// grid. The user clicks an icon to select it, then OK to confirm. A
// fixed column count keeps row layout cheap (no FlowWrap needed).
type iconPickerDialog struct {
	icons      []string
	selected   string
	clickables []widget.Clickable
	list       widget.List
	okBtn      widget.Clickable
	cancelBtn  widget.Clickable
	cols       int
}

func newIconPickerDialog(currentKey string) *iconPickerDialog {
	keys := allIconKeys()
	d := &iconPickerDialog{
		icons:      keys,
		selected:   currentKey,
		clickables: make([]widget.Clickable, len(keys)),
		cols:       6,
	}
	d.list.Axis = layout.Vertical
	return d
}

// iconExistsInCatalog reports whether key is in the published icon
// catalog (as opposed to the fallback vendor icons).
func iconExistsInCatalog(key string) bool {
	for _, k := range allIconKeys() {
		if k == key {
			return true
		}
	}
	return false
}

func (d *iconPickerDialog) Layout(
	gtx layout.Context, th *material.Theme,
	onDone func(iconKey string, cancel bool),
) layout.Dimensions {
	for i := range d.icons {
		if d.clickables[i].Clicked(gtx) {
			d.selected = d.icons[i]
		}
	}
	if d.cancelBtn.Clicked(gtx) {
		onDone("", true)
		return layout.Dimensions{Size: gtx.Constraints.Max}
	}
	if d.okBtn.Clicked(gtx) {
		onDone(d.selected, false)
		return layout.Dimensions{Size: gtx.Constraints.Max}
	}

	body := func(gtx layout.Context) layout.Dimensions {
		// Cap body height so the picker scrolls instead of overflowing
		// the screen on small windows.
		maxH := gtx.Dp(unit.Dp(320))
		if gtx.Constraints.Max.Y > maxH {
			gtx.Constraints.Max.Y = maxH
		}

		cellDp := unit.Dp(48)
		cellPx := gtx.Dp(cellDp)
		cols := d.cols
		totalRows := (len(d.icons) + cols - 1) / cols

		return material.List(th, &d.list).Layout(gtx, totalRows, func(gtx layout.Context, rowIdx int) layout.Dimensions {
			start := rowIdx * cols
			end := start + cols
			if end > len(d.icons) {
				end = len(d.icons)
			}
			rowIcons := d.icons[start:end]

			children := make([]layout.FlexChild, len(rowIcons))
			for j, key := range rowIcons {
				idx := start + j
				key := key
				sel := key == d.selected
				children[j] = layout.Rigid(func(gtx layout.Context) layout.Dimensions {
					return layout.Inset{
						Right: unit.Dp(4), Bottom: unit.Dp(4),
					}.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
						gtx.Constraints.Min = image.Pt(cellPx, cellPx)
						gtx.Constraints.Max = image.Pt(cellPx, cellPx)
						return d.clickables[idx].Layout(gtx, func(gtx layout.Context) layout.Dimensions {
							return drawIconCell(gtx, key, sel)
						})
					})
				})
			}
			return layout.Flex{Axis: layout.Horizontal}.Layout(gtx, children...)
		})
	}

	return modalCard(gtx, th, i18n.T("dialog_icon_picker_title"),
		i18n.T("btn_ok"), i18n.T("btn_cancel"),
		&d.okBtn, &d.cancelBtn, body)
}

// drawIconCell paints one grid cell: optional selection background +
// the icon scaled to fit. Returns the fixed cell-size dimensions.
func drawIconCell(gtx layout.Context, key string, selected bool) layout.Dimensions {
	size := gtx.Constraints.Min
	if selected {
		rect := clip.Rect{Max: size}.Push(gtx.Ops)
		paint.ColorOp{Color: activePalette.RingBg}.Add(gtx.Ops)
		paint.PaintOp{}.Add(gtx.Ops)
		rect.Pop()
	}
	img := vendorIconFor(key)
	if img != nil {
		w := widget.Image{
			Src:      paint.NewImageOp(img),
			Fit:      widget.Contain,
			Position: layout.Center,
		}
		w.Layout(gtx)
	}
	return layout.Dimensions{Size: size}
}