'use strict';

const assert = require('assert');

/**
 * RegExp to match field-content in RFC 7230 sec 3.2
 *
 * field-content = field-vchar [ 1*( SP / HTAB ) field-vchar ]
 * field-vchar   = VCHAR / obs-text
 * obs-text      = %x80-FF
 */

const fieldContentRegExp = /^[\u0009\u0020-\u007e\u0080-\u00ff]+$/; // eslint-disable-line no-control-regex

/**
* RegExp to match Same-Site cookie attribute value.
* https://en.wikipedia.org/wiki/HTTP_cookie#SameSite_cookie
*/

const sameSiteRegExp = /^(?:none|lax|strict)$/i;

class Cookie {
  constructor(name, value, attrs) {
    assert(fieldContentRegExp.test(name), 'argument name is invalid');
    assert(!value || fieldContentRegExp.test(value), 'argument value is invalid');

    this.name = name;
    this.value = value || '';
    this.attrs = mergeDefaultAttrs(attrs);
    assert(!this.attrs.path || fieldContentRegExp.test(this.attrs.path), 'argument option path is invalid');
    assert(!this.attrs.domain || fieldContentRegExp.test(this.attrs.domain), 'argument option domain is invalid');
    assert(!this.attrs.sameSite || this.attrs.sameSite === true || sameSiteRegExp.test(this.attrs.sameSite), 'argument option sameSite is invalid');
    if (!value) {
      this.attrs.expires = new Date(0);
      // make sure maxAge is empty
      this.attrs.maxAge = null;
    }
  }

  toString() {
    return this.name + '=' + this.value;
  }

  toHeader() {
    let header = this.toString();
    const attrs = this.attrs;
    if (attrs.path) header += '; path=' + attrs.path;
    const maxAge = parseInt(attrs.maxAge, 10);
    // ignore 0, `session` and other invalid maxAge
    if (maxAge) {
      header += '; max-age=' + Math.round(maxAge / 1000);
      attrs.expires = new Date(Date.now() + maxAge);
    }
    if (attrs.expires) header += '; expires=' + attrs.expires.toUTCString();
    if (attrs.domain) header += '; domain=' + attrs.domain;
    if (attrs.sameSite) header += '; samesite=' + (attrs.sameSite === true ? 'strict' : attrs.sameSite.toLowerCase());
    if (attrs.secure) header += '; secure';
    if (attrs.httpOnly) header += '; httponly';

    return header;
  }
}

const ATTRS = [ 'path', 'expires', 'domain', 'httpOnly', 'secure', 'maxAge', 'overwrite', 'sameSite' ];
function mergeDefaultAttrs(attrs) {
  const merged = {
    path: '/',
    httpOnly: true,
    secure: false,
    overwrite: false,
    sameSite: false,
  };
  if (!attrs) return merged;

  for (let i = 0; i < ATTRS.length; i++) {
    const key = ATTRS[i];
    if (key in attrs) merged[key] = attrs[key];
  }
  return merged;
}

module.exports = Cookie;