// Licensed to the Software Freedom Conservancy (SFC) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The SFC licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

'use strict';

const fs = require('fs');

const executors = require('./executors'),
    http = require('./http'),
    io = require('./io'),
    capabilities = require('./lib/capabilities'),
    command = require('./lib/command'),
    logging = require('./lib/logging'),
    promise = require('./lib/promise'),
    webdriver = require('./lib/webdriver'),
    portprober = require('./net/portprober'),
    remote = require('./remote');


/**
 * Name of the PhantomJS executable.
 * @type {string}
 * @const
 */
const PHANTOMJS_EXE =
    process.platform === 'win32' ? 'phantomjs.exe' : 'phantomjs';


/**
 * Capability that designates the location of the PhantomJS executable to use.
 * @type {string}
 * @const
 */
const BINARY_PATH_CAPABILITY = 'phantomjs.binary.path';


/**
 * Capability that designates the CLI arguments to pass to PhantomJS.
 * @type {string}
 * @const
 */
const CLI_ARGS_CAPABILITY = 'phantomjs.cli.args';


/**
 * Custom command names supported by PhantomJS.
 * @enum {string}
 */
const Command = {
  EXECUTE_PHANTOM_SCRIPT: 'executePhantomScript'
};


/**
 * Finds the PhantomJS executable.
 * @param {string=} opt_exe Path to the executable to use.
 * @return {string} The located executable.
 * @throws {Error} If the executable cannot be found on the PATH, or if the
 *     provided executable path does not exist.
 */
function findExecutable(opt_exe) {
  var exe = opt_exe || io.findInPath(PHANTOMJS_EXE, true);
  if (!exe) {
    throw Error(
        'The PhantomJS executable could not be found on the current PATH. ' +
        'Please download the latest version from ' +
        'http://phantomjs.org/download.html and ensure it can be found on ' +
        'your PATH. For more information, see ' +
        'https://github.com/ariya/phantomjs/wiki');
  }
  if (!fs.existsSync(exe)) {
    throw Error('File does not exist: ' + exe);
  }
  return exe;
}


/**
 * Maps WebDriver logging level name to those recognised by PhantomJS.
 * @const {!Map<string, string>}
 */
const WEBDRIVER_TO_PHANTOMJS_LEVEL = new Map([
    [logging.Level.ALL.name, 'DEBUG'],
    [logging.Level.DEBUG.name, 'DEBUG'],
    [logging.Level.INFO.name, 'INFO'],
    [logging.Level.WARNING.name, 'WARN'],
    [logging.Level.SEVERE.name, 'ERROR']]);


/**
 * Creates a command executor with support for PhantomJS' custom commands.
 * @param {!promise.Promise<string>} url The server's URL.
 * @return {!command.Executor} The new command executor.
 */
function createExecutor(url) {
  return new executors.DeferredExecutor(url.then(function(url) {
    var client = new http.HttpClient(url);
    var executor = new http.Executor(client);

    executor.defineCommand(
        Command.EXECUTE_PHANTOM_SCRIPT,
        'POST', '/session/:sessionId/phantom/execute');

    return executor;
  }));
}

/**
 * Creates a new WebDriver client for PhantomJS.
 */
class Driver extends webdriver.WebDriver {
  /**
   * @param {capabilities.Capabilities=} opt_capabilities The desired
   *     capabilities.
   * @param {promise.ControlFlow=} opt_flow The control flow to use,
   *     or {@code null} to use the currently active flow.
   * @param {string=} opt_logFile Path to the log file for the phantomjs
   *     executable's output. For convenience, this may be set at runtime with
   *     the `SELENIUM_PHANTOMJS_LOG` environment variable.
   */
  constructor(opt_capabilities, opt_flow, opt_logFile) {
    // TODO: add an Options class for consistency with the other driver types.

    var caps = opt_capabilities || capabilities.Capabilities.phantomjs();
    var exe = findExecutable(caps.get(BINARY_PATH_CAPABILITY));
    var args = [];

    var logPrefs = caps.get(capabilities.Capability.LOGGING_PREFS);
    if (logPrefs instanceof logging.Preferences) {
      logPrefs = logPrefs.toJSON();
    }

    if (logPrefs && logPrefs[logging.Type.DRIVER]) {
      let level = WEBDRIVER_TO_PHANTOMJS_LEVEL.get(
          logPrefs[logging.Type.DRIVER]);
      if (level) {
        args.push('--webdriver-loglevel=' + level);
      }
    }

    opt_logFile = process.env['SELENIUM_PHANTOMJS_LOG'] || opt_logFile;
    if (typeof opt_logFile === 'string') {
      args.push('--webdriver-logfile=' + opt_logFile);
    }

    var proxy = caps.get(capabilities.Capability.PROXY);
    if (proxy) {
      switch (proxy.proxyType) {
        case 'manual':
          if (proxy.httpProxy) {
            args.push(
                '--proxy-type=http',
                '--proxy=http://' + proxy.httpProxy);
          }
          break;
        case 'pac':
          throw Error('PhantomJS does not support Proxy PAC files');
        case 'system':
          args.push('--proxy-type=system');
          break;
        case 'direct':
          args.push('--proxy-type=none');
          break;
      }
    }
    args = args.concat(caps.get(CLI_ARGS_CAPABILITY) || []);

    var port = portprober.findFreePort();
    var service = new remote.DriverService(exe, {
      port: port,
      args: promise.when(port, function(port) {
        args.push('--webdriver=' + port);
        return args;
      })
    });

    var executor = createExecutor(service.start());
    var driver = webdriver.WebDriver.createSession(executor, caps, opt_flow);

    super(driver.getSession(), executor, driver.controlFlow());

    var boundQuit = this.quit.bind(this);

    /** @override */
    this.quit = function() {
      return boundQuit().thenFinally(service.kill.bind(service));
    };
  }

  /**
   * This function is a no-op as file detectors are not supported by this
   * implementation.
   * @override
   */
  setFileDetector() {}

  /**
   * Executes a PhantomJS fragment. This method is similar to
   * {@link #executeScript}, except it exposes the
   * <a href="http://phantomjs.org/api/">PhantomJS API</a> to the injected
   * script.
   *
   * <p>The injected script will execute in the context of PhantomJS's
   * {@code page} variable. If a page has not been loaded before calling this
   * method, one will be created.</p>
   *
   * <p>Be sure to wrap callback definitions in a try/catch block, as failures
   * may cause future WebDriver calls to fail.</p>
   *
   * <p>Certain callbacks are used by GhostDriver (the PhantomJS WebDriver
   * implementation) and overriding these may cause the script to fail. It is
   * recommended that you check for existing callbacks before defining your own.
   * </p>
   *
   * As with {@link #executeScript}, the injected script may be defined as
   * a string for an anonymous function body (e.g. "return 123;"), or as a
   * function. If a function is provided, it will be decompiled to its original
   * source. Note that injecting functions is provided as a convenience to
   * simplify defining complex scripts. Care must be taken that the function
   * only references variables that will be defined in the page's scope and
   * that the function does not override {@code Function.prototype.toString}
   * (overriding toString() will interfere with how the function is
   * decompiled.
   *
   * @param {(string|!Function)} script The script to execute.
   * @param {...*} var_args The arguments to pass to the script.
   * @return {!promise.Promise<T>} A promise that resolve to the
   *     script's return value.
   * @template T
   */
  executePhantomJS(script, var_args) {
    if (typeof script === 'function') {
      script = 'return (' + script + ').apply(this, arguments);';
    }
    var args = arguments.length > 1
        ? Array.prototype.slice.call(arguments, 1) : [];
    return this.schedule(
        new command.Command(Command.EXECUTE_PHANTOM_SCRIPT)
            .setParameter('script', script)
            .setParameter('args', args),
        'Driver.executePhantomJS()');
  }
}


// PUBLIC API

exports.Driver = Driver;
