// Drawing the picker: the popup that lists the agent's commands or the
// project's files while a "/" or "@" word is being typed. Local coordinates,
// like everything else in view_draw.go.

package acp

import (
	"strings"

	"rickub.com/turbo-editors/turbo-core/theme"
	"rickub.com/turbo-editors/turbo-core/ui"
)

// drawPicker paints the popup just above the rule, over the bottom of the
// conversation, when there is something to list.
func (v *View) drawPicker(p *ui.Painter, th *theme.Theme) {
	choices := v.refresh()
	room := v.transcriptHeight()
	if len(choices) == 0 || room < 3 {
		v.picker.bounds = ui.Rect{}
		return
	}

	height := min(min(len(choices), pickerRows)+2, room)
	width := min(max(widestChoice(choices)+4, pickerMinWidth), p.Size().W)
	bounds := ui.Rect{X: 0, Y: room - height, W: width, H: height}
	v.picker.bounds = bounds

	frame := th.Style(theme.KeyCompletionFrame)
	for row := range height {
		p.HLine(bounds.X, bounds.Y+row, width, ' ', th.Style(theme.KeyCompletionItem))
	}
	ui.DrawFrame(p, bounds, ui.FrameSingle, frame)
	p.TextLimited(bounds.X+2, bounds.Y, max(width-4, 0), v.pickerTitle(), frame)

	for row := range height - 2 {
		index := v.picker.top + row
		if index >= len(choices) {
			break
		}
		v.drawChoice(p, th, row, choices[index], index == v.picker.selected)
	}
}

// pickerTitle names what is being listed, on the frame.
func (v *View) pickerTitle() string {
	if _, word := v.typedWord(); strings.HasPrefix(word, string(mentionRune)) {
		return " files "
	}
	return " commands "
}

// widestChoice is the width of the longest line the popup will show.
func widestChoice(choices []Choice) int {
	widest := 0
	for _, choice := range choices {
		widest = max(widest, len([]rune(choiceText(choice))))
	}
	return widest
}

// choiceText is one line of the popup as plain text: the label, the
// description, and the hint in angle brackets.
func choiceText(choice Choice) string {
	text := choice.Label
	if choice.Detail != "" {
		text += "  " + choice.Detail
	}
	if choice.Hint != "" {
		text += "  <" + choice.Hint + ">"
	}
	return text
}

// drawChoice paints one line of the popup — row rows below the frame's top,
// inside the bounds drawPicker just recorded: the label in the item colour,
// the rest in the detail colour, the whole row highlighted when it is the one.
func (v *View) drawChoice(p *ui.Painter, th *theme.Theme, row int, choice Choice, selected bool) {
	style := th.Style(theme.KeyCompletionItem)
	detail := th.Style(theme.KeyCompletionDetail)
	if selected {
		style = th.Style(theme.KeyCompletionSelected)
		detail = style
	}

	bounds := v.picker.bounds
	x, y := bounds.X+1, bounds.Y+1+row
	width := bounds.W - 2
	p.HLine(x, y, width, ' ', style)

	end := p.TextLimited(x, y, width, choice.Label, style)
	rest := strings.TrimPrefix(choiceText(choice), choice.Label)
	if rest != "" && end < x+width {
		p.TextLimited(end, y, x+width-end, rest, detail)
	}
}