/*******************************************************************************
 * Copyright (c) 2013, 2016 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal;

import java.util.HashSet;
import java.util.Set;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.dynamichelpers.IExtensionTracker;
import org.eclipse.ui.IPageLayout;
import org.eclipse.ui.IViewLayout;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.internal.e4.compatibility.ModeledPageLayout;
import org.eclipse.ui.internal.registry.IWorkbenchRegistryConstants;
import org.eclipse.ui.internal.registry.RegistryReader;

/**
 * A strategy to read perspective extension from the registry.
 * A pespective extension is one of a view, viewAction, perspAction,
 * newWizardAction, or actionSet.
 */
public class PerspectiveExtensionReader extends RegistryReader {
    private String targetID;

	private ModeledPageLayout pageLayout;

    private Set includeOnlyTags = null;

    private static final String VAL_LEFT = "left";//$NON-NLS-1$

    private static final String VAL_RIGHT = "right";//$NON-NLS-1$

    private static final String VAL_TOP = "top";//$NON-NLS-1$

    private static final String VAL_BOTTOM = "bottom";//$NON-NLS-1$

    private static final String VAL_STACK = "stack";//$NON-NLS-1$

	private static final String VAL_FAST = "fast";//$NON-NLS-1$

	private static final String VAL_TRUE = "true";//$NON-NLS-1$

    // VAL_FALSE added by dan_rubel@instantiations.com
    // TODO: this logic is backwards... we should be checking for true, but
    // technically this is API now...
    private static final String VAL_FALSE = "false";//$NON-NLS-1$

	private IExtensionTracker tracker;

    /**
     * PerspectiveExtensionReader constructor..
     */
    public PerspectiveExtensionReader() {
        // do nothing
    }

    /**
     * Read the view extensions within a registry.
     *
     * @param extensionTracker the tracker
     * @param id the id
     * @param out the layout
     */
	public void extendLayout(IExtensionTracker extensionTracker, String id, ModeledPageLayout out) {
    	tracker = extensionTracker;
    	targetID = id;
        pageLayout = out;
        readRegistry(Platform.getExtensionRegistry(), PlatformUI.PLUGIN_ID,
                IWorkbenchRegistryConstants.PL_PERSPECTIVE_EXTENSIONS);
    }

    /**
     * Returns whether the given tag should be included.
     */
    private boolean includeTag(String tag) {
        return includeOnlyTags == null || includeOnlyTags.contains(tag);
    }

    /**
     * Process an action set.
     */
    private boolean processActionSet(IConfigurationElement element) {
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        if (id != null) {
			pageLayout.addActionSet(id);
		}
        return true;
    }

    /**
     * Process an extension.
     * Assumption: Extension is for current perspective.
     */
    private boolean processExtension(IConfigurationElement element) {
        IConfigurationElement[] children = element.getChildren();
        for (int nX = 0; nX < children.length; nX++) {
            IConfigurationElement child = children[nX];
            String type = child.getName();
            if (includeTag(type)) {
                boolean result = false;
                if (type.equals(IWorkbenchRegistryConstants.TAG_ACTION_SET)) {
					result = processActionSet(child);
				} else if (type.equals(IWorkbenchRegistryConstants.TAG_VIEW)) {
					result = processView(child);
				} else if (type.equals(IWorkbenchRegistryConstants.TAG_VIEW_SHORTCUT)) {
					result = processViewShortcut(child);
				} else if (type.equals(IWorkbenchRegistryConstants.TAG_NEW_WIZARD_SHORTCUT)) {
					result = processWizardShortcut(child);
				} else if (type.equals(IWorkbenchRegistryConstants.TAG_PERSP_SHORTCUT)) {
					result = processPerspectiveShortcut(child);
				} else if (type.equals(IWorkbenchRegistryConstants.TAG_SHOW_IN_PART)) {
					result = processShowInPart(child);
				} else if (type.equals(IWorkbenchRegistryConstants.TAG_HIDDEN_MENU_ITEM)) {
					result = processHiddenMenuItem(child);
				} else if (type.equals(IWorkbenchRegistryConstants.TAG_HIDDEN_TOOLBAR_ITEM)) {
					result = processHiddenToolBarItem(child);
				}
                if (!result) {
                    WorkbenchPlugin.log("Unable to process element: " + //$NON-NLS-1$
                            type
                            + " in perspective extension: " + //$NON-NLS-1$
                            element.getDeclaringExtension()
                                    .getUniqueIdentifier());
                }
            }
        }
        return true;
    }

    /**
     * Process a perspective shortcut
     */
    private boolean processPerspectiveShortcut(IConfigurationElement element) {
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        if (id != null) {
			pageLayout.addPerspectiveShortcut(id);
		}
        return true;
    }

    /**
     * Process a show in element.
     */
    private boolean processShowInPart(IConfigurationElement element) {
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        if (id != null) {
			pageLayout.addShowInPart(id);
		}
        return true;
    }

    /**
     * Process a hidden menu item
     */
    private boolean processHiddenMenuItem(IConfigurationElement element) {
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        if (id != null) {
			pageLayout.addHiddenMenuItemId(id);
		}
        return true;
    }

    /**
     * Process a hidden toolbar item
     */
    private boolean processHiddenToolBarItem(IConfigurationElement element) {
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        if (id != null) {
			pageLayout.addHiddenToolBarItemId(id);
		}
        return true;
    }

    // processView(IConfigurationElement) modified by dan_rubel@instantiations.com
    /**
     * Process a view
     */
    private boolean processView(IConfigurationElement element) {
        // Get id, relative, and relationship.
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        String relative = element.getAttribute(IWorkbenchRegistryConstants.ATT_RELATIVE);
        String relationship = element.getAttribute(IWorkbenchRegistryConstants.ATT_RELATIONSHIP);
        String ratioString = element.getAttribute(IWorkbenchRegistryConstants.ATT_RATIO);
        boolean visible = !VAL_FALSE.equals(element.getAttribute(IWorkbenchRegistryConstants.ATT_VISIBLE));
        String closeable = element.getAttribute(IWorkbenchRegistryConstants.ATT_CLOSEABLE);
        String moveable = element.getAttribute(IWorkbenchRegistryConstants.ATT_MOVEABLE);
        String standalone = element.getAttribute(IWorkbenchRegistryConstants.ATT_STANDALONE);
        String showTitle = element.getAttribute(IWorkbenchRegistryConstants.ATT_SHOW_TITLE);

        // Default to 'false'
        String minVal = element.getAttribute(IWorkbenchRegistryConstants.ATT_MINIMIZED);
        boolean minimized = minVal != null && VAL_TRUE.equals(minVal);

        float ratio;

        if (id == null) {
            logMissingAttribute(element, IWorkbenchRegistryConstants.ATT_ID);
            return false;
        }
        if (relationship == null) {
            logMissingAttribute(element, IWorkbenchRegistryConstants.ATT_RELATIONSHIP);
            return false;
        }
		if (!VAL_FAST.equals(relationship) && relative == null) {
			logError(element,
					"Attribute '" + IWorkbenchRegistryConstants.ATT_RELATIVE //$NON-NLS-1$
							+ "' not defined.  This attribute is required when " //$NON-NLS-1$
							+ IWorkbenchRegistryConstants.ATT_RELATIONSHIP + "=\"" + relationship + "\"."); //$NON-NLS-1$ //$NON-NLS-2$
			return false;
		}
        // Get the ratio.
        if (ratioString == null) {
            // The ratio has not been specified.
            ratio = IPageLayout.NULL_RATIO;
        } else {
            try {
                ratio = new Float(ratioString).floatValue();
            } catch (NumberFormatException e) {
                return false;
            }
            // If the ratio is outside the allowable range, mark it as invalid.
            if (ratio < IPageLayout.RATIO_MIN || ratio > IPageLayout.RATIO_MAX) {
				ratio = IPageLayout.INVALID_RATIO;
			}
        }

        // Get relationship details.
        boolean stack = false;
        int intRelation = 0;
		boolean fast = false;
        if (relationship.equals(VAL_LEFT)) {
			intRelation = IPageLayout.LEFT;
		} else if (relationship.equals(VAL_RIGHT)) {
			intRelation = IPageLayout.RIGHT;
		} else if (relationship.equals(VAL_TOP)) {
			intRelation = IPageLayout.TOP;
		} else if (relationship.equals(VAL_BOTTOM)) {
			intRelation = IPageLayout.BOTTOM;
		} else if (relationship.equals(VAL_STACK)) {
			stack = true;
		} else if (relationship.equals(VAL_FAST)) {
			fast = true;
		} else {
			return false;
		}

        if (visible) {
        	// If adding a view (not just a placeholder), remove any existing placeholder.
        	// See bug 85948 [Perspectives] Adding register & expressions view by default to debug perspective fails
        	pageLayout.removePlaceholder(id);
        }

        // If stack ..
        if (stack) {
            if (visible) {
				pageLayout.stackView(id, relative, true);
			} else {
				pageLayout.stackView(id, relative, false);
			}
		}
		// If the view is a fast view...
		else if (fast) {
			if (ratio == IPageLayout.NULL_RATIO) {
				// The ratio has not been specified.
				pageLayout.addFastView(id);
			} else {
				pageLayout.addFastView(id, ratio);
			}
		} else {

            // The view is a regular view.
            // If the ratio is not specified or is invalid, use the default ratio.
            if (ratio == IPageLayout.NULL_RATIO
                    || ratio == IPageLayout.INVALID_RATIO) {
				ratio = IPageLayout.DEFAULT_VIEW_RATIO;
			}

            if (visible) {
                if (VAL_TRUE.equals(standalone)) {
                    pageLayout.addStandaloneView(id, !VAL_FALSE
                            .equals(showTitle), intRelation, ratio, relative);
                } else {
                    pageLayout.addView(id, intRelation, ratio, relative, minimized);
                }
            } else {
				// Fix for 99155, CGross (schtoo@schtoo.com)
				// Adding standalone placeholder for standalone views
				if (VAL_TRUE.equals(standalone)) {
					pageLayout.addStandaloneViewPlaceholder(id, intRelation,
							ratio, relative, !VAL_FALSE.equals(showTitle));
				} else {
					pageLayout.addPlaceholder(id, intRelation, ratio, relative);
				}
			}
        }
        IViewLayout viewLayout = pageLayout.getViewLayout(id);
        // may be null if it's been filtered by activity
        if (viewLayout != null) {
			if (closeable != null) {
				viewLayout.setCloseable(!VAL_FALSE.equals(closeable));
			}
			if (moveable != null) {
				viewLayout.setMoveable(!VAL_FALSE.equals(moveable));
			}
		}

        return true;
    }

    /**
	 * Process a view shortcut
	 */
    private boolean processViewShortcut(IConfigurationElement element) {
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        if (id != null) {
			pageLayout.addShowViewShortcut(id);
		}
        return true;
    }

    /**
     * Process a wizard shortcut
     */
    private boolean processWizardShortcut(IConfigurationElement element) {
        String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
        if (id != null) {
			pageLayout.addNewWizardShortcut(id);
		}
        return true;
    }

    @Override
	protected boolean readElement(IConfigurationElement element) {
        String type = element.getName();
        if (type.equals(IWorkbenchRegistryConstants.TAG_PERSPECTIVE_EXTENSION)) {
            String id = element.getAttribute(IWorkbenchRegistryConstants.ATT_TARGET_ID);
            if (targetID.equals(id) || "*".equals(id)) { //$NON-NLS-1$
            	if (tracker != null) {
					tracker.registerObject(element.getDeclaringExtension(), new DirtyPerspectiveMarker(id), IExtensionTracker.REF_STRONG);
				}
                return processExtension(element);
            }
            return true;
        }
        return false;
    }

    /**
     * Sets the tags to include.  All others are ignored.
     *
     * @param tags the tags to include
     */
    public void setIncludeOnlyTags(String[] tags) {
        includeOnlyTags = new HashSet();
        for (int i = 0; i < tags.length; i++) {
            includeOnlyTags.add(tags[i]);
        }
    }
}