'use strict';

var configPageHtml = require('./tmp/config-page.html');
var toSource = require('tosource');
var standardComponents = require('./src/scripts/components');

/**
 * @param {string} input
 * @returns {string}
 */
function encodeDataUri(input) {
  if (window.btoa) {
    return 'data:text/html;base64,' + encodeURIComponent(window.btoa(input));
  }

  // iOS doesn't have a window so we need to polyfil window.btoa
  // extracted from https://github.com/inexorabletash/polyfill
  var B64_ALPHABET =
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
  input = String(input);
  var position = 0;
  var out = [];
  var o1;
  var o2;
  var o3;
  var e1;
  var e2;
  var e3;
  var e4;

  if (/[^\x00-\xFF]/.test(input)) { throw Error('InvalidCharacterError'); }

  while (position < input.length) {
    o1 = input.charCodeAt(position++);
    o2 = input.charCodeAt(position++);
    o3 = input.charCodeAt(position++);

    // 111111 112222 222233 333333
    e1 = o1 >> 2;
    e2 = ((o1 & 0x3) << 4) | (o2 >> 4);
    e3 = ((o2 & 0xf) << 2) | (o3 >> 6);
    e4 = o3 & 0x3f;

    if (position === input.length + 2) {
      e3 = 64;
      e4 = 64;
    } else if (position === input.length + 1) {
      e4 = 64;
    }

    out.push(B64_ALPHABET.charAt(e1),
             B64_ALPHABET.charAt(e2),
             B64_ALPHABET.charAt(e3),
             B64_ALPHABET.charAt(e4));
  }

  return 'data:text/html;base64,' + encodeURIComponent(out.join(''));
}

/**
 * @param {Array} config - the Clay config
 * @param {function} [customFn] - custom code to run from the config page.
 * Will run with api as context
 * @constructor
 */
function Clay(config, customFn) {
  var self = this;

  self.config = config;
  self.customFn = customFn || function() {};
  self.components = [];

  /**
   * @private
   * @param {Clay~ConfigItem|Array} item
   * @return {void}
   */
  function _registerStandardComponents(item) {
    if (Array.isArray(item)) {
      item.forEach(function(item) {
        _registerStandardComponents(item);
      });
    } else if (item.type === 'section') {
      _registerStandardComponents(item.items);
    } else if (standardComponents[item.type]) {
      self.registerComponent(standardComponents[item.type]);
    }
  }

  _registerStandardComponents(self.config);
}

Clay.prototype.registerComponent = function(component) {
  this.components.push(component);
};

/**
 * Generate the Data URI used by the config Page with settings injected
 * @param {string} returnTo - used while developing on desktop.
 * @return {string}
 */
Clay.prototype.generateUrl = function(returnTo) {
  var settings;
  try {
    settings = JSON.parse(localStorage.getItem('clay-settings')) || {};
  } catch (e) {
    console.error(e);
    settings = {};
  }

  // Show config page
  return encodeDataUri(configPageHtml
    .replace('$$CUSTOM_FN$$', toSource(this.customFn))
    .replace('$$RETURN_TO$$', returnTo || 'pebblejs://close#')
    .replace('$$CONFIG$$', toSource(this.config))
    .replace('$$SETTINGS$$', toSource(settings))
    .replace('$$COMPONENTS$$', toSource(this.components))
  );
};

/**
 * Parse the response from the webviewclosed event data
 * @param {string} response
 * @returns {{}}
 */
Clay.prototype.getSettings = function(response) {
  // Decode and parse config data as JSON
  var settings = JSON.parse(decodeURIComponent(response));
  // @todo get defaults in here
  if (!settings) return {};

  localStorage.setItem('clay-settings', JSON.stringify(settings));
  return settings;
};

module.exports = Clay;