package tools

import "strings"

// RemoveFirstLines removes the first n lines. Returns "" if n >= total lines.
func RemoveFirstLines(input string, n int) string {
	lines := strings.Split(input, "\n")
	if n >= len(lines) {
		return ""
	}
	return strings.Join(lines[n:], "\n")
}

// RemoveLastLines removes the last n lines. Returns "" if n >= total lines.
func RemoveLastLines(input string, n int) string {
	lines := strings.Split(input, "\n")
	if n >= len(lines) {
		return ""
	}
	return strings.Join(lines[:len(lines)-n], "\n")
}

// CropBefore removes everything before the first occurrence of y (inclusive of y).
// Returns input unchanged if y is not found.
func CropBefore(input string, y string) string {
	idx := strings.Index(input, y)
	if idx == -1 {
		return input
	}
	return input[idx:]
}

// CropAfter removes everything after the last occurrence of y (inclusive of y).
// Returns input unchanged if y is not found.
func CropAfter(input string, y string) string {
	idx := strings.LastIndex(input, y)
	if idx == -1 {
		return input
	}
	return input[:idx+len(y)]
}

// CropBeforeExclude removes everything before and including the first occurrence of y.
// Returns input unchanged if y is not found.
func CropBeforeExclude(input string, y string) string {
	idx := strings.Index(input, y)
	if idx == -1 {
		return input
	}
	return input[idx+len(y):]
}

// CropAfterExclude removes everything from the last occurrence of y onwards.
// Returns input unchanged if y is not found.
func CropAfterExclude(input string, y string) string {
	idx := strings.LastIndex(input, y)
	if idx == -1 {
		return input
	}
	return input[:idx]
}