import { join } from "path";
import {mkdirSync, writeFileSync} from 'fs';

export const RUST_OUT_DIR = join(__dirname, '..', 'src', 'gen');

try {
  mkdirSync(RUST_OUT_DIR);
} catch (err) {
  if (err.code !== 'EEXIST') {
    throw err;
  }
}
writeFileSync(join(RUST_OUT_DIR, 'mod.rs'), `
pub mod attrs;
pub mod codepoints;
pub mod entities;
`);

export const DATA_DIR = join(__dirname, 'data');

export const leftPad = (str: string, n: number) => '0'.repeat(n - str.length) + str;

export const prettyJson = (v: any) => JSON.stringify(v, null, 2);

export const byteStringLiteral = (bytes: number[]): string => 'b"' + bytes.map(c => {
  if (c > 255) throw new Error('Not a byte');
  // 0x20 == ' '.
  // 0x7E == '~'.
  // 0x5C == '\\'.
  // 0x22 == '"'.
  if (c >= 0x20 && c <= 0x7E && c != 0x5C && c != 0x22) {
    return String.fromCharCode(c);
  } else {
    return `\\x${leftPad(c.toString(16), 2)}`;
  }
}).join('') + '"';