import * as fsp from 'node:fs/promises'
import { encode } from 'gpt-tokenizer'

/**
 * Generate visual progress bar using ASCII characters
 *
 * @param value - Current value
 * @param max - Maximum value
 * @param width - Width of the bar in characters (default: 25)
 * @param chars - Characters to use for filled and empty sections
 * @param chars.filled - Character for filled portion (default: '█')
 * @param chars.empty - Character for empty portion (default: '░')
 * @returns ASCII progress bar string
 *
 * @example
 * createProgressBar(75, 100, 20) // "███████████████░░░░░"
 * createProgressBar(0.5, 1, 10)  // "█████░░░░░"
 * createProgressBar(0.75, 1, 20, { filled: '▓', empty: '░' }) // "▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░░░░░"
 */
export function createProgressBar(
  value: number,
  max: number,
  width = 25,
  chars: { filled: string, empty: string } = { filled: '█', empty: '░' },
): string {
  const filled = Math.round((value / max) * width)
  const empty = width - filled
  return chars.filled.repeat(filled) + chars.empty.repeat(empty)
}

/**
 * Count tokens in text using gpt-tokenizer (o200k_base encoding)
 *
 * @param text - Text to tokenize
 * @returns Number of tokens
 *
 * @example
 * tokenize("Hello, world!") // 4
 */
export function tokenize(text: string): number {
  return encode(text).length
}

/**
 * Ensure a directory exists, creating it recursively if needed
 *
 * @param dirPath - Directory path to ensure exists
 */
export async function ensureDir(dirPath: string): Promise<void> {
  await fsp.mkdir(dirPath, { recursive: true })
}