package com.atlassian.pageobjects.elements.query.webdriver;
   
   import com.google.common.base.Function;
   import com.google.common.base.Supplier;
   import org.openqa.selenium.*;
   
   import static com.atlassian.pageobjects.elements.util.StringConcat.asString;
   import static com.google.common.base.Preconditions.checkNotNull;
   
  /**
   * <p>
   * WebDriver based timed query that retrieves {@link org.openqa.selenium.WebElement} using provided
   * {@link org.openqa.selenium.By} and applies provided function from that element to the target value.
   *
   * <p>
   * If given element is not found, the 'invalid value' semantics of the timed query are applied. 
   *
   */
  public class WebElementBasedTimedQuery<T> extends GenericWebDriverTimedQuery<T>
  {
      private final By by;
  
      public WebElementBasedTimedQuery(WebDriver driver, By by, final Function<WebElement, T> valueProvider, long timeout)
      {
          super(new WebElementSupplier<T>(driver, by, valueProvider), timeout);
          this.by = by;
      }
  
      public WebElementBasedTimedQuery(SearchContext searchContext, By by, final Function<WebElement, T> valueProvider, long timeout,
              long interval)
      {
          super(new WebElementSupplier<T>(searchContext, by, valueProvider), timeout, interval);
          this.by = by;
      }
  
      public WebElementBasedTimedQuery(SearchContext searchContext, By by, final Function<WebElement, T> valueProvider, long timeout,
              long interval, T invalidValue)
      {
          super(new WebElementSupplier<T>(searchContext, by, valueProvider, invalidValue), timeout, interval);
          this.by = by;
      }
  
      public WebElementBasedTimedQuery(WebElementBasedTimedQuery<T> origin, long timeout)
      {
          super(origin.webElementSupplier(), timeout, origin.interval);
          this.by = null;
      }
  
      WebElementSupplier<T> webElementSupplier()
      {
          return (WebElementSupplier<T>) valueSupplier; 
      }
  
      @Override
      public String toString()
      {
          return asString(super.toString(), "[locator=", by, "]");
      }
  
      private static class WebElementSupplier<S> implements Supplier<S>
      {
          private final SearchContext searchContext;
          private final By by;
          private final Function<WebElement, S> valueProvider;
          private final S invalidValue;
  
           public WebElementSupplier(final SearchContext searchContext, final By by, final Function<WebElement, S> valueProvider,
                   S invalid)
          {
              this.valueProvider = valueProvider;
              this.searchContext = checkNotNull(searchContext);
              this.by = checkNotNull(by);
              this.invalidValue = invalid;
          }
  
          public WebElementSupplier(final SearchContext searchContext, final By by, final Function<WebElement, S> valueProvider)
          {
              this(searchContext, by, valueProvider, null);
          }
  
          public S get()
          {
              try
              {
                  return valueProvider.apply(searchContext.findElement(by));
              }
              catch (NoSuchElementException e)
              {
                  throw new InvalidValue(invalidValue);
              }
          }
      }
  }