// Package tui holds small, reusable terminal-UI primitives shared across the
// tools in benvin-utils: direction markers, a common style palette, and
// width-aware padding/truncation helpers that respect ANSI styling.
package tui

import (
	"strings"

	"github.com/charmbracelet/lipgloss"
)

// Shared style palette. Tools should prefer these so every benvin-utils TUI
// looks consistent.
var (
	Header = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("15")).Background(lipgloss.Color("240"))
	Title  = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("87"))
	Dim    = lipgloss.NewStyle().Foreground(lipgloss.Color("244"))
	Up     = lipgloss.NewStyle().Foreground(lipgloss.Color("203")) // a rising value = red-ish
	Down   = lipgloss.NewStyle().Foreground(lipgloss.Color("84"))  // a falling value = green
	Hot    = lipgloss.NewStyle().Foreground(lipgloss.Color("203")) // over threshold
	Warn   = lipgloss.NewStyle().Foreground(lipgloss.Color("214")) // approaching threshold
	Err    = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("203"))
)

// Marker glyphs for direction-of-change indicators.
const (
	GlyphUp   = "▲"
	GlyphDown = "▼"
	GlyphFlat = "·"
)

// Arrow renders a direction marker: 1 = up (▲), -1 = down (▼), 0 = flat (·).
func Arrow(dir int) string {
	switch {
	case dir > 0:
		return Up.Render(GlyphUp)
	case dir < 0:
		return Down.Render(GlyphDown)
	default:
		return Dim.Render(GlyphFlat)
	}
}

// Sign reports whether d is positive (1), negative (-1), or zero (0). It is the
// usual companion to Arrow when comparing a new sample against a previous one.
func Sign[T int | int64 | float64](d T) int {
	switch {
	case d > 0:
		return 1
	case d < 0:
		return -1
	default:
		return 0
	}
}

// Pad right-pads plain (unstyled) text to width w, truncating if longer.
func Pad(s string, w int) string {
	if len(s) > w {
		s = s[:w]
	}
	return s + strings.Repeat(" ", w-len(s))
}

// PadVisible right-pads a possibly ANSI-styled cell to width w using its visible
// (rendered) width, so styled cells still align in a table.
func PadVisible(s string, w int) string {
	if vis := lipgloss.Width(s); vis < w {
		return s + strings.Repeat(" ", w-vis)
	}
	return s
}

// Truncate shortens s to at most n runes, adding an ellipsis when it cuts.
func Truncate(s string, n int) string {
	if n <= 0 {
		return ""
	}
	if len(s) <= n {
		return s
	}
	if n == 1 {
		return "…"
	}
	return s[:n-1] + "…"
}