const SemVer = require('../classes/semver');
const parse = require('./parse');
const { safeRe: re, t } = require('../internal/re');

const coerce = (version, options) => {
  if (version instanceof SemVer) {
    return version;
  }

  if (typeof version === 'number') {
    version = String(version);
  }

  if (typeof version !== 'string') {
    return null;
  }

  options = options || {};

  let match = null;
  if (!options.rtl) {
    match = version.match(
      options.includePrerelease ? re[t.COERCEFULL] : re[t.COERCE]
    );
  } else {
    // Find the right-most coercible string that does not share
    // a terminus with a more left-ward coercible string.
    // Eg, '1.2.3.4' wants to coerce '2.3.4', not '3.4' or '4'
    // With includePrerelease option set, '1.2.3.4-rc' wants to coerce '2.3.4-rc', not '2.3.4'
    //
    // Walk through the string checking with a /g regexp
    // Manually set the index so as to pick up overlapping matches.
    // Stop when we get a match that ends at the string end, since no
    // coercible string can be more right-ward without the same terminus.
    const coerceRtlRegex =
      options.includePrerelease ? re[t.COERCERTLFULL] : re[t.COERCERTL];
    let next;
    while (
      (next = coerceRtlRegex.exec(version)) &&
      (!match || match.index + match[0].length !== version.length)
    ) {
      if (
        !match ||
        next.index + next[0].length !== match.index + match[0].length
      ) {
        match = next;
      }
      coerceRtlRegex.lastIndex = next.index + next[1].length + next[2].length;
    }
    // leave it in a clean state
    coerceRtlRegex.lastIndex = -1;
  }

  if (match === null) {
    return null;
  }

  const major = match[2];
  const minor = match[3] || '0';
  const patch = match[4] || '0';
  const prerelease =
    options.includePrerelease && match[5] ? `-${match[5]}` : '';
  const build = options.includePrerelease && match[6] ? `+${match[6]}` : '';

  return parse(`${major}.${minor}.${patch}${prerelease}${build}`, options);
};
module.exports = coerce;