export const logging = assign({}, console);
export const NS_HTML = 'http://www.w3.org/1999/xhtml';
/** When looking for documentElement, use '*' to also support XML pages */
export const elemByTag = (tag, i) => document::getElementsByTagName(tag)[i || 0];

// Firefox defines `isFinite` on `global` not on `window`
const { isFinite } = global; // eslint-disable-line no-restricted-properties
const { toString: numberToString } = 0;
const isArray = obj => (
  // ES3 way, not reliable if prototype is modified
  // Object.prototype.toString.call(obj) === '[object Array]'
  // #565 steamcommunity.com has overridden `Array.prototype`
  // support duck typing
  obj && typeof obj.length === 'number' && typeof obj.splice === 'function'
);

// Reference: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/JSON#Polyfill
const escMap = {
  '"': '\\"',
  '\\': '\\\\',
  '\b': '\\b',
  '\f': '\\f',
  '\n': '\\n',
  '\r': '\\r',
  '\t': '\\t',
};
const escRE = /[\\"\u0000-\u001F\u2028\u2029]/g; // eslint-disable-line no-control-regex
const escFunc = m => escMap[m] || `\\u${(m::charCodeAt(0) + 0x10000)::numberToString(16)::slice(1)}`;
// When running in the page context we must beware of sites that override Array#toJSON
// leading to an invalid result, which is why our jsonDump() ignores toJSON.
// Thus, we use the native JSON.stringify() only in the content script context and only until
// a userscript is injected into this context (due to `@inject-into` and/or a CSP problem).
export function jsonDump(value) {
  if (value == null) return 'null';
  const type = typeof value;
  if (type === 'number') return isFinite(value) ? `${value}` : 'null';
  if (type === 'boolean') return `${value}`;
  if (type === 'object') {
    if (isArray(value)) {
      return `[${value::map(jsonDump)::join(',')}]`;
    }
    if (value::objectToString() === '[object Object]') {
      const res = objectKeys(value)::map((key) => {
        const v = value[key];
        return v !== undefined && `${jsonDump(key)}:${jsonDump(v)}`;
      });
      // JSON.stringify skips undefined in objects i.e. {foo: undefined} produces {}
      return `{${res::filter(Boolean)::join(',')}}`;
    }
  }
  return `"${value::replace(escRE, escFunc)}"`;
}

/** args is [tags?, ...rest] */
export function log(level, ...args) {
  args[0] = `[Violentmonkey]${args[0] ? `[${args[0]::join('][')}]` : ''}`;
  logging[level]::apply(logging, args);
}