package org.zwobble.mammoth.internal.xml;

import org.zwobble.mammoth.internal.util.Iterables;

import java.util.List;
import java.util.Map;
import java.util.Optional;

import static org.zwobble.mammoth.internal.util.Iterables.*;
import static org.zwobble.mammoth.internal.util.Lists.toList;
import static org.zwobble.mammoth.internal.util.Maps.lookup;

public class XmlElement implements XmlNode, XmlElementLike {
    private final String name;
    private final Map<String, String> attributes;
    private final List<XmlNode> children;
    
    public XmlElement(String name, Map<String, String> attributes, List<XmlNode> children) {
        this.name = name;
        this.attributes = attributes;
        this.children = children;
    }
    
    public String getName() {
        return name;
    }

    public Map<String, String> getAttributes() {
        return attributes;
    }

    public String getAttribute(String name) {
        return getAttributeOrNone(name)
            .orElseThrow(() -> new RuntimeException("Element has no '" + name + "' attribute"));
    }

    @Override
    public Optional<String> getAttributeOrNone(String name) {
        return lookup(attributes, name);
    }

    @Override
    public String innerText() {
        return String.join("", lazyMap(children, XmlNode::innerText));
    }

    @Override
    public <T> T accept(XmlNodeVisitor<T> visitor) {
        return visitor.visit(this);
    }

    @Override
    public List<XmlNode> getChildren() {
        return children;
    }

    @Override
    public String toString() {
        return "XmlElement(name=" + name + ", attributes=" + attributes
               + ", children=" + children + ")";
    }

    public XmlElementList findChildren(String name) {
        return new XmlElementList(toList(findChildrenIterable(name)));
    }

    public Optional<XmlElement> findChild(String name) {
        return Iterables.getFirst(findChildrenIterable(name));
    }

    @Override
    public boolean hasChild(String name) {
        return findChildrenIterable(name).iterator().hasNext();
    }

    @Override
    public XmlElementLike findChildOrEmpty(String name) {
        return getFirst(findChildrenIterable(name), NullXmlElement.INSTANCE);
    }

    private Iterable<XmlElement> findChildrenIterable(String name) {
        return lazyFilter(
            lazyFilter(children, XmlElement.class),
            child -> child.getName().equals(name));
    }
}