package org.tessell.model.dsl;

import org.tessell.gwt.user.client.ui.HasCss;
import org.tessell.model.commands.HasActive;
import org.tessell.model.commands.UiCommand;
import org.tessell.model.properties.Property;
import org.tessell.util.OnEnterKeyHandler;
import org.tessell.widgets.IsTextList;

import com.google.gwt.event.dom.client.HasAllKeyHandlers;
import com.google.gwt.event.dom.client.HasClickHandlers;
import com.google.gwt.user.client.ui.HasEnabled;

/** Binds various things to a command. */
public class UiCommandBinder {

  private final Binder b;
  private final UiCommand command;

  public UiCommandBinder(final Binder b, final UiCommand command) {
    this.b = b;
    this.command = command;
  }

  /** Binds clicks from {@code clickable} to our command, and our errors to {@code errors}. */
  public UiCommandBinder to(final HasClickHandlers clickable, final IsTextList errors) {
    return to(clickable).errorsTo(errors);
  }

  /** Binds "enter" from key down handlers to our command. */
  public UiCommandBinder toEnterKey(final HasAllKeyHandlers... allKeys) {
    OnEnterKeyHandler h = new OnEnterKeyHandler(() -> command.execute());
    for (HasAllKeyHandlers allKey : allKeys) {
      b.add(allKey.addKeyDownHandler(h));
    }
    return this;
  }

  /** Has our command execute only if {@code onlyIf} is true. */
  public UiCommandBinder onlyIf(final Property<Boolean> onlyIf) {
    command.addOnlyIf(onlyIf);
    return this;
  }

  /** Binds clicks from {@code clickable} to our command. */
  public UiCommandBinder to(final HasClickHandlers clickable) {
    b.add(clickable.addClickHandler(e -> {
      command.execute();
      e.preventDefault();
    }));
    // Assume that if command.active() is available, and HasEnabled is available,
    // it just makes sense to disable clickable while the command is active
    if (command instanceof HasActive && clickable instanceof HasEnabled) {
      Property<Boolean> active = ((HasActive) command).active();
      b.when(active).is(true).disable((HasEnabled) clickable);
    }
    return this;
  }

  /** Shows {@code hasCss} only when the command is active. */
  public UiCommandBinder spin(final HasCss hasCss) {
    if (command instanceof HasActive) {
      Property<Boolean> active = ((HasActive) command).active();
      b.when(active).is(true).visible(hasCss);
    } else {
      throw new IllegalStateException("Not a command that has .active() available");
    }
    return this;
  }

  /** Binds errors for our command to {@code errors}. */
  public UiCommandBinder errorsTo(IsTextList errors) {
    final TextListOnError i = new TextListOnError(errors);
    b.add(command.addRuleTriggeredHandler(i));
    b.add(command.addRuleUntriggeredHandler(i));
    return this;
  }
}