// 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.

/**
 * @fileoverview Defines common conditions for use with
 * {@link webdriver.WebDriver#wait WebDriver wait}.
 *
 * Sample usage:
 *
 *     driver.get('http://www.google.com/ncr');
 *
 *     var query = driver.wait(until.elementLocated(By.name('q')));
 *     query.sendKeys('webdriver\n');
 *
 *     driver.wait(until.titleIs('webdriver - Google Search'));
 *
 * To define a custom condition, simply call WebDriver.wait with a function
 * that will eventually return a truthy-value (neither null, undefined, false,
 * 0, or the empty string):
 *
 *     driver.wait(function() {
 *       return driver.getTitle().then(function(title) {
 *         return title === 'webdriver - Google Search';
 *       });
 *     }, 1000);
 */

'use strict';

const by = require('./by');
const By = require('./by').By;
const error = require('./error');
const webdriver = require('./webdriver'),
    Condition = webdriver.Condition,
    WebElementCondition = webdriver.WebElementCondition;


/**
 * Creates a condition that will wait until the input driver is able to switch
 * to the designated frame. The target frame may be specified as
 *
 * 1. a numeric index into
 *     [window.frames](https://developer.mozilla.org/en-US/docs/Web/API/Window.frames)
 *     for the currently selected frame.
 * 2. a {@link ./webdriver.WebElement}, which must reference a FRAME or IFRAME
 *     element on the current page.
 * 3. a locator which may be used to first locate a FRAME or IFRAME on the
 *     current page before attempting to switch to it.
 *
 * Upon successful resolution of this condition, the driver will be left
 * focused on the new frame.
 *
 * @param {!(number|./webdriver.WebElement|By|
 *           function(!./webdriver.WebDriver): !./webdriver.WebElement)} frame
 *     The frame identifier.
 * @return {!Condition<boolean>} A new condition.
 */
exports.ableToSwitchToFrame = function ableToSwitchToFrame(frame) {
  var condition;
  if (typeof frame === 'number' || frame instanceof webdriver.WebElement) {
    condition = attemptToSwitchFrames;
  } else {
    condition = function(driver) {
      let locator = /** @type {!(By|Function)} */(frame);
      return driver.findElements(locator).then(function(els) {
        if (els.length) {
          return attemptToSwitchFrames(driver, els[0]);
        }
      });
    };
  }

  return new Condition('to be able to switch to frame', condition);

  function attemptToSwitchFrames(driver, frame) {
    return driver.switchTo().frame(frame).then(
        function() { return true; },
        function(e) {
          if (!(e instanceof error.NoSuchFrameError)) {
            throw e;
          }
        });
  }
};


/**
 * Creates a condition that waits for an alert to be opened. Upon success, the
 * returned promise will be fulfilled with the handle for the opened alert.
 *
 * @return {!Condition<!./webdriver.Alert>} The new condition.
 */
exports.alertIsPresent = function alertIsPresent() {
  return new Condition('for alert to be present', function(driver) {
    return driver.switchTo().alert().catch(function(e) {
      if (!(e instanceof error.NoSuchAlertError
        // XXX: Workaround for GeckoDriver error `TypeError: can't convert null
        // to object`. For more details, see
        // https://github.com/SeleniumHQ/selenium/pull/2137
        || (e instanceof error.WebDriverError
          && e.message === `can't convert null to object`)
        )) {
        throw e;
      }
    });
  });
};


/**
 * Creates a condition that will wait for the current page's title to match the
 * given value.
 *
 * @param {string} title The expected page title.
 * @return {!Condition<boolean>} The new condition.
 */
exports.titleIs = function titleIs(title) {
  return new Condition(
      'for title to be ' + JSON.stringify(title),
      function(driver) {
        return driver.getTitle().then(function(t) {
          return t === title;
        });
      });
};


/**
 * Creates a condition that will wait for the current page's title to contain
 * the given substring.
 *
 * @param {string} substr The substring that should be present in the page
 *     title.
 * @return {!Condition<boolean>} The new condition.
 */
exports.titleContains = function titleContains(substr) {
  return new Condition(
      'for title to contain ' + JSON.stringify(substr),
      function(driver) {
        return driver.getTitle().then(function(title) {
          return title.indexOf(substr) !== -1;
        });
      });
};


/**
 * Creates a condition that will wait for the current page's title to match the
 * given regular expression.
 *
 * @param {!RegExp} regex The regular expression to test against.
 * @return {!Condition<boolean>} The new condition.
 */
exports.titleMatches = function titleMatches(regex) {
  return new Condition('for title to match ' + regex, function(driver) {
    return driver.getTitle().then(function(title) {
      return regex.test(title);
    });
  });
};


/**
 * Creates a condition that will wait for the current page's url to match the
 * given value.
 *
 * @param {string} url The expected page url.
 * @return {!Condition<boolean>} The new condition.
 */
exports.urlIs = function urlIs(url) {
  return new Condition(
      'for URL to be ' + JSON.stringify(url),
      function(driver) {
        return driver.getCurrentUrl().then(function(u) {
          return u === url;
        });
      });
};


/**
 * Creates a condition that will wait for the current page's url to contain
 * the given substring.
 *
 * @param {string} substrUrl The substring that should be present in the current
 *     URL.
 * @return {!Condition<boolean>} The new condition.
 */
exports.urlContains = function urlContains(substrUrl) {
  return new Condition(
      'for URL to contain ' + JSON.stringify(substrUrl),
      function(driver) {
        return driver.getCurrentUrl().then(function(url) {
          return url.indexOf(substrUrl) !== -1;
        });
      });
};


/**
 * Creates a condition that will wait for the current page's url to match the
 * given regular expression.
 *
 * @param {!RegExp} regex The regular expression to test against.
 * @return {!Condition<boolean>} The new condition.
 */
exports.urlMatches = function urlMatches(regex) {
  return new Condition('for URL to match ' + regex, function(driver) {
    return driver.getCurrentUrl().then(function(url) {
      return regex.test(url);
    });
  });
};


/**
 * Creates a condition that will loop until an element is
 * {@link ./webdriver.WebDriver#findElement found} with the given locator.
 *
 * @param {!(By|Function)} locator The locator to use.
 * @return {!WebElementCondition} The new condition.
 */
exports.elementLocated = function elementLocated(locator) {
  locator = by.checkedLocator(locator);
  let locatorStr =
      typeof locator === 'function' ? 'by function()' : locator + '';
  return new WebElementCondition('for element to be located ' + locatorStr,
      function(driver) {
        return driver.findElements(locator).then(function(elements) {
          return elements[0];
        });
      });
};


/**
 * Creates a condition that will loop until at least one element is
 * {@link ./webdriver.WebDriver#findElement found} with the given locator.
 *
 * @param {!(By|Function)} locator The locator to use.
 * @return {!Condition<!Array<!./webdriver.WebElement>>} The new
 *     condition.
 */
exports.elementsLocated = function elementsLocated(locator) {
  locator = by.checkedLocator(locator);
  let locatorStr =
      typeof locator === 'function' ? 'by function()' : locator + '';
  return new Condition(
      'for at least one element to be located ' + locatorStr,
      function(driver) {
        return driver.findElements(locator).then(function(elements) {
          return elements.length > 0 ? elements : null;
        });
      });
};


/**
 * Creates a condition that will wait for the given element to become stale. An
 * element is considered stale once it is removed from the DOM, or a new page
 * has loaded.
 *
 * @param {!./webdriver.WebElement} element The element that should become stale.
 * @return {!Condition<boolean>} The new condition.
 */
exports.stalenessOf = function stalenessOf(element) {
  return new Condition('element to become stale', function() {
    return element.getTagName().then(
        function() { return false; },
        function(e) {
          if (e instanceof error.StaleElementReferenceError) {
            return true;
          }
          throw e;
        });
  });
};


/**
 * Creates a condition that will wait for the given element to become visible.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @return {!WebElementCondition} The new condition.
 * @see ./webdriver.WebDriver#isDisplayed
 */
exports.elementIsVisible = function elementIsVisible(element) {
  return new WebElementCondition('until element is visible', function() {
    return element.isDisplayed().then(v => v ? element : null);
  });
};


/**
 * Creates a condition that will wait for the given element to be in the DOM,
 * yet not visible to the user.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @return {!WebElementCondition} The new condition.
 * @see ./webdriver.WebDriver#isDisplayed
 */
exports.elementIsNotVisible = function elementIsNotVisible(element) {
  return new WebElementCondition('until element is not visible', function() {
    return element.isDisplayed().then(v => v ? null : element);
  });
};


/**
 * Creates a condition that will wait for the given element to be enabled.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @return {!WebElementCondition} The new condition.
 * @see webdriver.WebDriver#isEnabled
 */
exports.elementIsEnabled = function elementIsEnabled(element) {
  return new WebElementCondition('until element is enabled', function() {
    return element.isEnabled().then(v => v ? element : null);
  });
};


/**
 * Creates a condition that will wait for the given element to be disabled.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @return {!WebElementCondition} The new condition.
 * @see webdriver.WebDriver#isEnabled
 */
exports.elementIsDisabled = function elementIsDisabled(element) {
  return new WebElementCondition('until element is disabled', function() {
    return element.isEnabled().then(v => v ? null : element);
  });
};


/**
 * Creates a condition that will wait for the given element to be selected.
 * @param {!./webdriver.WebElement} element The element to test.
 * @return {!WebElementCondition} The new condition.
 * @see webdriver.WebDriver#isSelected
 */
exports.elementIsSelected = function elementIsSelected(element) {
  return new WebElementCondition('until element is selected', function() {
    return element.isSelected().then(v => v ? element : null);
  });
};


/**
 * Creates a condition that will wait for the given element to be deselected.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @return {!WebElementCondition} The new condition.
 * @see webdriver.WebDriver#isSelected
 */
exports.elementIsNotSelected = function elementIsNotSelected(element) {
  return new WebElementCondition('until element is not selected', function() {
    return element.isSelected().then(v => v ? null : element);
  });
};


/**
 * Creates a condition that will wait for the given element's
 * {@link webdriver.WebDriver#getText visible text} to match the given
 * {@code text} exactly.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @param {string} text The expected text.
 * @return {!WebElementCondition} The new condition.
 * @see webdriver.WebDriver#getText
 */
exports.elementTextIs = function elementTextIs(element, text) {
  return new WebElementCondition('until element text is', function() {
    return element.getText().then(t => t === text ? element : null);
  });
};


/**
 * Creates a condition that will wait for the given element's
 * {@link webdriver.WebDriver#getText visible text} to contain the given
 * substring.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @param {string} substr The substring to search for.
 * @return {!WebElementCondition} The new condition.
 * @see webdriver.WebDriver#getText
 */
exports.elementTextContains = function elementTextContains(element, substr) {
  return new WebElementCondition('until element text contains', function() {
    return element.getText()
        .then(t => t.indexOf(substr) != -1 ? element : null);
  });
};


/**
 * Creates a condition that will wait for the given element's
 * {@link webdriver.WebDriver#getText visible text} to match a regular
 * expression.
 *
 * @param {!./webdriver.WebElement} element The element to test.
 * @param {!RegExp} regex The regular expression to test against.
 * @return {!WebElementCondition} The new condition.
 * @see webdriver.WebDriver#getText
 */
exports.elementTextMatches = function elementTextMatches(element, regex) {
  return new WebElementCondition('until element text matches', function() {
    return element.getText().then(t => regex.test(t) ? element : null);
  });
};