package org.springframework.webflow.engine.builder;

import java.util.LinkedHashSet;
import java.util.Set;

import org.springframework.core.style.ToStringCreator;
import org.springframework.util.Assert;

/**
 * Contains the information needed to bind model to a view. This information consists of one or more {@link Binding
 * bindings} that connect properties of the model to UI elements of the view.
 * 
 * @see ViewFactoryCreator
 * 
 * @author Keith Donald
 */
public class BinderConfiguration {

	private Set<Binding> bindings = new LinkedHashSet<Binding>();

	/**
	 * Adds a new binding to this binding configuration.
	 * @param binding the binding
	 */
	public void addBinding(Binding binding) {
		bindings.add(binding);
	}

	/**
	 * Returns the set of bindings associated with this binding configuration.
	 */
	public Set<Binding> getBindings() {
		return bindings;
	}

	/**
	 * Gets the binding with the specified name, or returns null if no such binding is found.
	 * @param name the name of the binding.
	 * @return the binding
	 */
	public Binding getBinding(String name) {
		for (Binding binding : bindings) {
			if (name.equals(binding.getProperty())) {
				return binding;
			}
		}
		return null;
	}

	/**
	 * Gets the converterId for the binding with the specified name. Returns null if either a binding or a converterId
	 * for the given name is not found.
	 * 
	 * @param name the name of the binding.
	 * @return the binding
	 */
	public String getConverterId(String name) {
		Binding binding = getBinding(name);
		if (binding != null) {
			return binding.getConverter();
		} else {
			return null;
		}
	}

	/**
	 * A binding that provides the information needed to connect an element of the view to a property of the model.
	 * 
	 * @author Keith Donald
	 */
	public static final class Binding {

		private String property;

		private String converter;

		private boolean required;

		/**
		 * Creates a new view binding
		 * @param property the model property to bind to
		 * @param converter the id of a custom converter to apply type conversion during binding
		 * @param required whether this binding is required
		 */
		public Binding(String property, String converter, boolean required) {
			Assert.hasText(property, "The property is required");
			this.property = property;
			this.converter = converter;
			this.required = required;
		}

		public boolean equals(Object object) {
			if (!(object instanceof Binding)) {
				return false;
			}
			Binding binding = (Binding) object;
			return property.equals(binding.property);
		}

		public int hashCode() {
			return property.hashCode();
		}

		/**
		 * The name of the bound property.
		 * @return the property
		 */
		public String getProperty() {
			return property;
		}

		/**
		 * The id of the custom converter to use to convert bound property values.
		 * @return the converter id, or null
		 */
		public String getConverter() {
			return converter;
		}

		/**
		 * Whether a non-empty value is required for each binding attempt.
		 * @return the required status
		 */
		public boolean getRequired() {
			return required;
		}

		public String toString() {
			return new ToStringCreator(this).append("property", property).append("converter", converter)
					.append("required", required).toString();
		}
	}

}