"use strict";

/**
 * This is the common logic for both the Node.js and web browser
 * implementations of `debug()`.
 */
function setup(env) {
  createDebug.debug = createDebug;
  createDebug.default = createDebug;
  createDebug.coerce = coerce;
  createDebug.disable = disable;
  createDebug.enable = enable;
  createDebug.enabled = enabled;
  createDebug.humanize = require('ms');
  Object.keys(env).forEach(function (key) {
    createDebug[key] = env[key];
  });
  /**
  * Active `debug` instances.
  */

  createDebug.instances = [];
  /**
  * The currently active debug mode names, and names to skip.
  */

  createDebug.names = [];
  createDebug.skips = [];
  /**
  * Map of special "%n" handling functions, for the debug "format" argument.
  *
  * Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
  */

  createDebug.formatters = {};
  /**
  * Selects a color for a debug namespace
  * @param {String} namespace The namespace string for the for the debug instance to be colored
  * @return {Number|String} An ANSI color code for the given namespace
  * @api private
  */

  function selectColor(namespace) {
    var hash = 0;

    for (var i = 0; i < namespace.length; i++) {
      hash = (hash << 5) - hash + namespace.charCodeAt(i);
      hash |= 0; // Convert to 32bit integer
    }

    return createDebug.colors[Math.abs(hash) % createDebug.colors.length];
  }

  createDebug.selectColor = selectColor;
  /**
  * Create a debugger with the given `namespace`.
  *
  * @param {String} namespace
  * @return {Function}
  * @api public
  */

  function createDebug(namespace) {
    var prevTime;

    function debug() {
      // Disabled?
      if (!debug.enabled) {
        return;
      }

      for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
        args[_key] = arguments[_key];
      }

      var self = debug; // Set `diff` timestamp

      var curr = Number(new Date());
      var ms = curr - (prevTime || curr);
      self.diff = ms;
      self.prev = prevTime;
      self.curr = curr;
      prevTime = curr;
      args[0] = createDebug.coerce(args[0]);

      if (typeof args[0] !== 'string') {
        // Anything else let's inspect with %O
        args.unshift('%O');
      } // Apply any `formatters` transformations


      var index = 0;
      args[0] = args[0].replace(/%([a-zA-Z%])/g, function (match, format) {
        // If we encounter an escaped % then don't increase the array index
        if (match === '%%') {
          return match;
        }

        index++;
        var formatter = createDebug.formatters[format];

        if (typeof formatter === 'function') {
          var val = args[index];
          match = formatter.call(self, val); // Now we need to remove `args[index]` since it's inlined in the `format`

          args.splice(index, 1);
          index--;
        }

        return match;
      }); // Apply env-specific formatting (colors, etc.)

      createDebug.formatArgs.call(self, args);
      var logFn = self.log || createDebug.log;
      logFn.apply(self, args);
    }

    debug.namespace = namespace;
    debug.enabled = createDebug.enabled(namespace);
    debug.useColors = createDebug.useColors();
    debug.color = selectColor(namespace);
    debug.destroy = destroy;
    debug.extend = extend; // Debug.formatArgs = formatArgs;
    // debug.rawLog = rawLog;
    // env-specific initialization logic for debug instances

    if (typeof createDebug.init === 'function') {
      createDebug.init(debug);
    }

    createDebug.instances.push(debug);
    return debug;
  }

  function destroy() {
    var index = createDebug.instances.indexOf(this);

    if (index !== -1) {
      createDebug.instances.splice(index, 1);
      return true;
    }

    return false;
  }

  function extend(namespace, delimiter) {
    return createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
  }
  /**
  * Enables a debug mode by namespaces. This can include modes
  * separated by a colon and wildcards.
  *
  * @param {String} namespaces
  * @api public
  */


  function enable(namespaces) {
    createDebug.save(namespaces);
    createDebug.names = [];
    createDebug.skips = [];
    var i;
    var split = (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/);
    var len = split.length;

    for (i = 0; i < len; i++) {
      if (!split[i]) {
        // ignore empty strings
        continue;
      }

      namespaces = split[i].replace(/\*/g, '.*?');

      if (namespaces[0] === '-') {
        createDebug.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
      } else {
        createDebug.names.push(new RegExp('^' + namespaces + '$'));
      }
    }

    for (i = 0; i < createDebug.instances.length; i++) {
      var instance = createDebug.instances[i];
      instance.enabled = createDebug.enabled(instance.namespace);
    }
  }
  /**
  * Disable debug output.
  *
  * @api public
  */


  function disable() {
    createDebug.enable('');
  }
  /**
  * Returns true if the given mode name is enabled, false otherwise.
  *
  * @param {String} name
  * @return {Boolean}
  * @api public
  */


  function enabled(name) {
    if (name[name.length - 1] === '*') {
      return true;
    }

    var i;
    var len;

    for (i = 0, len = createDebug.skips.length; i < len; i++) {
      if (createDebug.skips[i].test(name)) {
        return false;
      }
    }

    for (i = 0, len = createDebug.names.length; i < len; i++) {
      if (createDebug.names[i].test(name)) {
        return true;
      }
    }

    return false;
  }
  /**
  * Coerce `val`.
  *
  * @param {Mixed} val
  * @return {Mixed}
  * @api private
  */


  function coerce(val) {
    if (val instanceof Error) {
      return val.stack || val.message;
    }

    return val;
  }

  createDebug.enable(createDebug.load());
  return createDebug;
}

module.exports = setup;