// Package textutil wraps and clips plain text for a fixed terminal width.
package textutil

import "strings"

// Clip shortens s to at most n runes, replacing tabs and newlines with spaces.
func Clip(s string, n int) string {
	if n <= 0 {
		return ""
	}
	s = strings.ReplaceAll(strings.ReplaceAll(s, "\t", " "), "\n", " ")
	r := []rune(s)
	if len(r) <= n {
		return string(r)
	}
	if n == 1 {
		return "…"
	}
	return string(r[:n-1]) + "…"
}

// Wrap breaks s into lines no wider than width runes, preserving blank lines.
func Wrap(s string, width int) []string {
	if width <= 1 {
		if s == "" {
			return []string{""}
		}
		return []string{s}
	}
	var out []string
	for _, para := range strings.Split(s, "\n") {
		if para == "" {
			out = append(out, "")
			continue
		}
		line := ""
		for _, word := range strings.Split(para, " ") {
			for len([]rune(word)) > width {
				if line != "" {
					out = append(out, line)
					line = ""
				}
				r := []rune(word)
				out = append(out, string(r[:width]))
				word = string(r[width:])
			}
			switch {
			case line == "":
				line = word
			case len([]rune(line))+1+len([]rune(word)) <= width:
				line += " " + word
			default:
				out = append(out, line)
				line = word
			}
		}
		out = append(out, line)
	}
	if len(out) == 0 {
		return []string{""}
	}
	return out
}

// Pad pads s with spaces on the right until it is n runes wide.
func Pad(s string, n int) string {
	r := []rune(s)
	if len(r) >= n {
		return string(r)
	}
	return string(r) + strings.Repeat(" ", n-len(r))
}