package de.ugoe.cs.quest.plugin.mfc.guimodel;

import java.util.ArrayList;
import java.util.List;

import de.ugoe.cs.quest.eventcore.guimodel.IGUIElementSpec;
import de.ugoe.cs.util.StringTools;

/**
 * <p>
 * This class implements a node in the {@link WindowTree} that is maintained during parsing a
 * session.
 * </p>
 * <p>
 * The window tree is structure that contains the hierarchy of the windows of a application as well
 * as basic information about each window: the hwnd; its name; its resource id; its class name.
 * </p>
 * 
 * @author Steffen Herbold
 * @version 1.0
 */
public class MFCGUIElementSpec implements IGUIElementSpec {

    /**
     * <p>
     * current name of the window
     * </p>
     */
    private String name;

    /**
     * <p>
     * previous names of the window as it may have changed over time.
     * </p>
     */
    private List<String> formerNames = new ArrayList<String>();

    /**
     * <p>
     * Handle of the window. Used as unique identifier during its existence.
     * </p>
     */
    private long hwnd;

    /**
     * <p>
     * previous handles of the window as the window may have been destroyed and recreated
     * </p>
     */
    private List<Long> formerHwnds = new ArrayList<Long>();

    /**
     * <p>
     * Resource id of the window.
     * </p>
     */
    private final int resourceId;

    /**
     * <p>
     * type (class name) of the window.
     * </p>
     */
    private final String type;

    /**
     * <p>
     * True, if the window is modal.
     * </p>
     */
    private final boolean isModal;

    /**
     * <p>
     * Creates a new WindowTreeNode.
     * </p>
     * <p>
     * The constructor is protected WindowTreeNode may only be created from the WindowTree.
     * </p>
     * 
     * @param hwnd
     *            hwnd of the window
     * @param parent
     *            reference to the parent's WindowTreeNode
     * @param name
     *            name of the window
     * @param resourceId
     *            resource id of the window
     * @param type
     *            type, i.e. class name of the window
     * @param isModal
     *            modality of the window
     */
    protected MFCGUIElementSpec(long    hwnd,
                                String  name,
                                int     resourceId,
                                String  type,
                                boolean isModal)
    {
        this.hwnd = hwnd;
        this.name = name;
        this.resourceId = resourceId;
        this.type = type;
        this.isModal = isModal;
    }

    /**
     * <p>
     * Returns the name of the window.
     * </p>
     * 
     * @return name of the window
     */
    public String getName() {
        StringBuffer names = new StringBuffer();
        
        if (name != null) {
            names.append('"');
            names.append(name);
            names.append('"');
        }
        else {
            names.append("NOT_SET");
        }
        
        if (formerNames.size() > 0) {
            
            names.append(" (aka ");
            
            for (int i = 0; i < formerNames.size(); i++) {
                if (i > 0) {
                    names.append("/");
                }

                names.append('"');
                names.append(formerNames.get(i));
                names.append('"');
            }
            
            names.append(")");
        }
        
        return names.toString();
    }

    /**
     * <p>
     * Returns the hwnd of the window.
     * </p>
     * 
     * @return hwnd of the window
     */
    public long getHwnd() {
        return hwnd;
    }

    /**
     * <p>
     * Returns the resource id of the window.
     * </p>
     * 
     * @return resource id of the window
     */
    public int getResourceId() {
        return resourceId;
    }

    /* (non-Javadoc)
     * @see de.ugoe.cs.quest.eventcore.guimodel.IGUIElementSpec#getType()
     */
    @Override
    public String getType() {
        return type;
    }

    /**
     * <p>
     * TODO: comment
     * </p>
     *
     * @return
     */
    public boolean isModal() {
        return isModal;
    }

    /**
     * <p>
     * Sets the name of the window.
     * </p>
     * 
     * @param text
     *            new name of the window
     */
    public void setName(String newName) {
        if ((this.name != null) &&
            (!this.name.equals(newName)) &&
            (!this.formerNames.contains(this.name)))
        {
            this.formerNames.add(this.name);
        }
        
        this.name = newName;
    }

    /**
     * <p>
     * Sets the hwnd of the window.
     * </p>
     * 
     * @param text
     *            new name of the window
     */
    public void setHwnd(long newHwnd) {
        if (!this.formerHwnds.contains(this.hwnd)) {
            this.formerHwnds.add(this.hwnd);
        }
        
        this.hwnd = newHwnd;
    }

    /* (non-Javadoc)
     * @see de.ugoe.cs.quest.eventcore.guimodel.IGUIElementSpec#getSimilarity(de.ugoe.cs.quest.eventcore.guimodel.IGUIElementSpec)
     */
    @Override
    public boolean getSimilarity(IGUIElementSpec other) {
        
        if (this == other) {
            return true;
        }
        
        if (!(other instanceof MFCGUIElementSpec)) {
            return false;
        }
        
        MFCGUIElementSpec otherSpec = (MFCGUIElementSpec) other;

        if ((type != otherSpec.type) && ((type != null) && (!type.equals(otherSpec.type)))) {
            return false;
        }

        if (isModal != otherSpec.isModal) {
            return false;
        }

        if (resourceId != otherSpec.resourceId) {
            return false;
        }

        // up to now, we compared, if the basics match. Now lets compare the id and the
        // name. Both may change. The name may be reset (e.g. the title of a frame using the
        // asterisk in the case data was changed). The id may change if e.g. a dialog is closed
        // and reopend, i.e. a new instance is created. If one of them stays the same, then
        // similarity is given. Therefore these are the first two comparisons
        
        if (hwnd == otherSpec.hwnd) {
            return true;
        }
        
        if ((name != null) && (name.equals(otherSpec.name))) {
            return true;
        }
        
        if ((((name == null) && (otherSpec.name == null)) ||
             (("".equals(name)) && ("".equals(otherSpec.name)))) &&
            (formerNames.size() == 0) && (otherSpec.formerNames.size() == 0))
        {
            return true;
        }
        
        // if the hwnd and the name did not stay the same, then the name should be checked first.
        // The current name of one of the specs must be contained in the former names of the
        // respective other spec for similarity. Either of the specs should contain the name of the
        // respective other spec in its former names. We can rely on this, as in the MFC context
        // we get to know each name change. I.e. although currently the names of the specs differ,
        // once they were identical. But it is sufficient to do it for the current names of the
        // elements, as only one of them may have experienced more name changes then the other.

        if ((otherSpec.name != null) && formerNames.contains(otherSpec.name)) {
            return true;
        }

        if ((name != null) && otherSpec.formerNames.contains(name)) {
            return true;
        }
        
        // ok. Even the names do not match. This is usually a clear indication, that the elements
        // are distinct. However, we check, if the former handles matched. This is very unlikely
        // to happen. But it may occur, if a GUI element does not have a name or its name stays
        // the empty string and if this GUI element is created, destroyed, and created again.

        if (formerHwnds.contains(otherSpec.hwnd) || otherSpec.formerHwnds.contains(hwnd)) {
            return true;
        }

        // now we can be really sure, that the GUI elements differ
        
        return false;
    }

    /* (non-Javadoc)
     * @see de.ugoe.cs.quest.eventcore.guimodel.IGUIElementSpec#equals(IGUIElementSpec)
     */
    @Override
    public boolean equals(IGUIElementSpec other) {
        
        if (this == other) {
            return true;
        }
        
        if (!(other instanceof MFCGUIElementSpec)) {
            return false;
        }
        
        MFCGUIElementSpec otherSpec = (MFCGUIElementSpec) other;
        
        return
            (hwnd == otherSpec.hwnd) && (isModal == otherSpec.isModal) &&
            (resourceId == otherSpec.resourceId) &&
            ((type == otherSpec.type) || ((type != null) && (type.equals(otherSpec.type)))) &&
            ((name == otherSpec.name) || ((name != null) && (name.equals(otherSpec.name))));
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        // reuse only invariable elements
        return (type + isModal + resourceId).hashCode();
    }

    /**
     * <p>
     * Returns a string identfier of the window:<br>
     * {@code [resourceId;"windowName";"className";modality]}
     * </p>
     * 
     * @return identifier string of the window
     */
    @Override
    public String toString() {
        return "[" + resourceId + ";" + getName() + ";\"" + type + "\";" + isModal + ";" +
            hwnd + "]";
    }

    /**
     * <p>
     * TODO: comment
     * </p>
     */
    String toXML() {
        return
            "<window name=\"" + (name != null ? StringTools.xmlEntityReplacement(name) : "") +
            "\" class=\"" + StringTools.xmlEntityReplacement(type) +
            "\" resourceId=\"" + resourceId + "\" isModal=\"" +
            isModal + "\"/>";
    }

    /**
     * <p>
     * TODO: comment
     * </p>
     *
     * @param furtherSpec
     */
    void update(IGUIElementSpec furtherSpec) {
        MFCGUIElementSpec other = (MFCGUIElementSpec) furtherSpec;
        
        if (other != this) {
            for (long formerHwnd : other.formerHwnds) {
                setHwnd(formerHwnd);
            }

            if (hwnd != other.hwnd) {
                hwnd = other.hwnd;
            }

            for (String formerName : other.formerNames) {
                setName(formerName);
            }

            if ((name != other.name) && (name != null) && (!name.equals(other.name)))
            {
                setName(other.name);
            }
        }
    }

}