function codePointWidth(codePoint: number): number {
  if (codePoint === 0) return 0;
  if (codePoint < 32 || (codePoint >= 0x7f && codePoint < 0xa0)) return 0;
  if (
    (codePoint >= 0x1100 && codePoint <= 0x115f) ||
    (codePoint >= 0x2329 && codePoint <= 0x232a) ||
    (codePoint >= 0x2e80 && codePoint <= 0xa4cf) ||
    (codePoint >= 0xac00 && codePoint <= 0xd7a3) ||
    (codePoint >= 0xf900 && codePoint <= 0xfaff) ||
    (codePoint >= 0xfe10 && codePoint <= 0xfe19) ||
    (codePoint >= 0xfe30 && codePoint <= 0xfe6f) ||
    (codePoint >= 0xff00 && codePoint <= 0xff60) ||
    (codePoint >= 0xffe0 && codePoint <= 0xffe6) ||
    (codePoint >= 0x1f300 && codePoint <= 0x1faff) ||
    (codePoint >= 0x20000 && codePoint <= 0x3fffd)
  ) {
    return 2;
  }
  return 1;
}

export function visibleColumns(value: string): number {
  let width = 0;
  for (const character of value) width += codePointWidth(character.codePointAt(0) ?? 0);
  return width;
}

export function sliceColumns(value: string, start: number, width: number): string {
  if (width <= 0) return "";
  let column = 0;
  let output = "";
  for (const character of value) {
    const characterWidth = codePointWidth(character.codePointAt(0) ?? 0);
    const next = column + characterWidth;
    if (next <= start) {
      column = next;
      continue;
    }
    if (column >= start + width || next > start + width) break;
    output += character;
    column = next;
  }
  const outputWidth = visibleColumns(output);
  return output + " ".repeat(Math.max(0, width - outputWidth));
}

export function markerColumn(lines: string[], marker: string): { row: number; column: number } | undefined {
  for (const [row, line] of lines.entries()) {
    const index = line.indexOf(marker);
    if (index >= 0) return { row, column: visibleColumns(line.slice(0, index)) };
  }
  return undefined;
}

export function cropViewport(
  lines: string[],
  width: number,
  height: number,
  offsetX: number,
  offsetY: number,
): string[] {
  const selected = lines.slice(Math.max(0, offsetY), Math.max(0, offsetY) + Math.max(0, height));
  return selected.map((line) => sliceColumns(line, Math.max(0, offsetX), Math.max(0, width)));
}