export type TextOverflowMode = "ellipsis" | "clip";

export function displayWidth(value: string): number {
  return Bun.stringWidth(value);
}

function sliceByDisplayWidth(value: string, maxWidth: number): string {
  if (maxWidth <= 0) return "";

  let output = "";
  for (const char of value) {
    const next = `${output}${char}`;
    if (displayWidth(next) > maxWidth) break;
    output = next;
  }
  return output;
}

export function truncateEnd(
  value: string,
  maxWidth: number,
  options: {
    overflow?: TextOverflowMode;
    ellipsis?: string;
  } = {},
): string {
  if (maxWidth <= 0) return "";

  const overflow = options.overflow ?? "ellipsis";
  const ellipsis = options.ellipsis ?? "...";
  const currentWidth = displayWidth(value);
  if (currentWidth <= maxWidth) return value;

  if (overflow === "clip") {
    return sliceByDisplayWidth(value, maxWidth);
  }

  const ellipsisWidth = displayWidth(ellipsis);
  if (maxWidth <= ellipsisWidth) {
    return sliceByDisplayWidth(value, maxWidth);
  }

  return `${sliceByDisplayWidth(value, maxWidth - ellipsisWidth)}${ellipsis}`;
}

export function padEndTo(value: string, width: number): string {
  if (width <= 0) return "";
  const currentWidth = displayWidth(value);
  if (currentWidth >= width) return value;
  return `${value}${" ".repeat(width - currentWidth)}`;
}

export function formatFixedWidth(
  value: string,
  width: number,
  options: {
    overflow?: TextOverflowMode;
    ellipsis?: string;
  } = {},
): string {
  return padEndTo(truncateEnd(value, width, options), width);
}