export function ensureTrailingSlash(path: string): string {
  if (path != null && !path.endsWith("/")) {
    return `${path}/`;
  }
  return path;
}

export function ensureLeadingHash(hash: string): string {
  if (hash != null && !hash.startsWith("#")) {
    return `#${hash}`;
  }
  return hash;
}

export function absolutePath(path: string, basename = "/"): string {
  if (!path) {
    return path;
  }

  let pathname = path;

  // Make relative path absolute to basename
  if (!pathname.startsWith("/")) {
    pathname = ensureTrailingSlash(basename) + pathname;
  }

  // Expand path
  if (pathname.indexOf(".") >= 0) {
    const stack = [];
    for (const part of pathname.split("/")) {
      if (part === ".") {
        continue;
      } else if (part === ".." && stack.length > 0) {
        stack.pop();
      } else {
        stack.push(part);
      }
    }
    pathname = stack.join("/");
  }

  return ensureTrailingSlash(pathname);
}

export function nthIndexOf(str: string, pattern: string, n: number, start?: number): number {
  const index = str.indexOf(pattern, start ?? 0);
  if (index >= 0 && n > 1) {
    return nthIndexOf(str, pattern, n - 1, index + 1);
  }
  return index;
}

/**
 * Like Python’s `.capitalize()`.
 */
export function capitalize(string: string): string {
  return string.slice(0, 1).toUpperCase() + string.slice(1).toLowerCase();
}

/**
 * Like Python’s `.title()`.
 */
export function title(string: string): string {
  return string.split(" ").map(capitalize).join(" ");
}