package modes

import (
	"strings"

	"github.com/mattn/go-runewidth"

	"github.com/bnema/zut/packages/tui"
)

// frameHeader returns a full-width rule with a small title at the left.
// Matches the thin rule style used for code blocks and tool results so
// every dialog in the TUI looks the same.
//
//	─── title ────────────────────────────────
func frameHeader(th tui.Theme, title string, width int) string {
	label := "── " + title + " "
	if width <= 0 {
		return th.FGColor(th.Muted, label)
	}
	padLen := width - runewidth.StringWidth(label)
	if padLen < 0 {
		padLen = 0
	}
	return th.FGColor(th.Muted, label+strings.Repeat("─", padLen))
}

// frameRule returns a full-width horizontal rule in the muted color.
func frameRule(th tui.Theme, width int) string {
	if width <= 0 {
		width = 1
	}
	return th.FGColor(th.Muted, strings.Repeat("─", width))
}

// padDialogFrame inserts breathing room between the shared dialog frame
// chrome and its body while keeping frameHeader/frameRule as single-row
// primitives for callers that need exact row accounting.
func padDialogFrame(lines []string) []string {
	if len(lines) == 0 {
		return lines
	}

	out := append([]string(nil), lines...)
	if isFrameHeaderLine(out[0]) && (len(out) == 1 || strings.TrimSpace(stripANSIBytes(out[1])) != "") {
		out = append(out[:1], append([]string{""}, out[1:]...)...)
	}

	last := len(out) - 1
	if last > 0 && isFrameRuleLine(out[last]) && strings.TrimSpace(stripANSIBytes(out[last-1])) != "" {
		out = append(out[:last], append([]string{""}, out[last:]...)...)
	}
	return out
}

func isFrameHeaderLine(line string) bool {
	return strings.HasPrefix(stripANSIBytes(line), "── ")
}

func isFrameRuleLine(line string) bool {
	plain := stripANSIBytes(line)
	if plain == "" {
		return false
	}
	for _, r := range plain {
		if r != '─' {
			return false
		}
	}
	return true
}

// frameHeaderColor is like frameHeader but renders in a caller-supplied
// theme color. Used by the update-available banner which wants a yellow
// accent on the rules and title.
func frameHeaderColor(th tui.Theme, title string, width int, color tui.TerminalColor) string {
	label := "── " + title + " "
	if width <= 0 {
		return th.FGColor(color, label)
	}
	padLen := width - runewidth.StringWidth(label)
	if padLen < 0 {
		padLen = 0
	}
	return th.FGColor(color, label+strings.Repeat("─", padLen))
}

// frameRuleColor is like frameRule in an explicit color.
func frameRuleColor(th tui.Theme, width int, color tui.TerminalColor) string {
	if width <= 0 {
		width = 1
	}
	return th.FGColor(color, strings.Repeat("─", width))
}