#ifndef __SP_OBJECT_H__
#define __SP_OBJECT_H__

/** \file
 * Abstract base class for all nodes
 *
 * Authors:
 *   Lauris Kaplinski <lauris@kaplinski.com>
 *
 * Copyright (C) 1999-2002 authors
 * Copyright (C) 2001-2002 Ximian, Inc.
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

/* SPObject flags */

/* Async modification flags */
#define SP_OBJECT_MODIFIED_FLAG (1 << 0)
#define SP_OBJECT_CHILD_MODIFIED_FLAG (1 << 1)
#define SP_OBJECT_PARENT_MODIFIED_FLAG (1 << 2)
#define SP_OBJECT_STYLE_MODIFIED_FLAG (1 << 3)
#define SP_OBJECT_VIEWPORT_MODIFIED_FLAG (1 << 4)
#define SP_OBJECT_USER_MODIFIED_FLAG_A (1 << 5)
#define SP_OBJECT_USER_MODIFIED_FLAG_B (1 << 6)
#define SP_OBJECT_USER_MODIFIED_FLAG_C (1 << 7)

/* Conveneience */
#define SP_OBJECT_FLAGS_ALL 0xff

/* Flags that mark object as modified */
/* Object, Child, Style, Viewport, User */
#define SP_OBJECT_MODIFIED_STATE (SP_OBJECT_FLAGS_ALL & ~(SP_OBJECT_PARENT_MODIFIED_FLAG))

/* Flags that will propagate downstreams */
/* Parent, Style, Viewport, User */
#define SP_OBJECT_MODIFIED_CASCADE (SP_OBJECT_FLAGS_ALL & ~(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_CHILD_MODIFIED_FLAG))

/* Generic */
#define SP_OBJECT_IS_CLONED(o) (((SPObject *) (o))->cloned)

/* Write flags */
#define SP_OBJECT_WRITE_BUILD (1 << 0)
#define SP_OBJECT_WRITE_EXT (1 << 1)
#define SP_OBJECT_WRITE_ALL (1 << 2)

/* Convenience stuff */
#define SP_OBJECT_ID(o) (((SPObject *) (o))->id)
#define SP_OBJECT_REPR(o) (((SPObject *) (o))->repr)
#define SP_OBJECT_DOCUMENT(o) (((SPObject *) (o))->document)
#define SP_OBJECT_PARENT(o) (((SPObject *) (o))->parent)
#define SP_OBJECT_NEXT(o) (((SPObject *) (o))->next)
#define SP_OBJECT_PREV(o) (sp_object_prev((SPObject *) (o)))
#define SP_OBJECT_HREFCOUNT(o) (((SPObject *) (o))->hrefcount)
#define SP_OBJECT_STYLE(o) (((SPObject *) (o))->style)
#define SP_OBJECT_TITLE(o) sp_object_title_get((SPObject *) (o))
#define SP_OBJECT_DESCRIPTION(o) sp_object_description_get((SPObject *) (o))


#include <glib-object.h>
#include <sigc++/connection.h>
#include <sigc++/functors/slot.h>
#include <sigc++/signal.h>

#include "forward.h"
#include "version.h"
#include "util/forward-pointer-iterator.h"

namespace Inkscape {
namespace XML {
class Node;
}
}


typedef enum {
    SP_NO_EXCEPTION,
    SP_INDEX_SIZE_ERR,
    SP_DOMSTRING_SIZE_ERR,
    SP_HIERARCHY_REQUEST_ERR,
    SP_WRONG_DOCUMENT_ERR,
    SP_INVALID_CHARACTER_ERR,
    SP_NO_DATA_ALLOWED_ERR,
    SP_NO_MODIFICATION_ALLOWED_ERR,
    SP_NOT_FOUND_ERR,
    SP_NOT_SUPPORTED_ERR,
    SP_INUSE_ATTRIBUTE_ERR,
    SP_INVALID_STATE_ERR,
    SP_SYNTAX_ERR,
    SP_INVALID_MODIFICATION_ERR,
    SP_NAMESPACE_ERR,
    SP_INVALID_ACCESS_ERR
} SPExceptionType;

class SPException;

/// An attempt to implement exceptions, unused?
struct SPException {
    SPExceptionType code;
};

#define SP_EXCEPTION_INIT(ex) {(ex)->code = SP_NO_EXCEPTION;}
#define SP_EXCEPTION_IS_OK(ex) (!(ex) || ((ex)->code == SP_NO_EXCEPTION))

class SPCtx;

/// Unused
struct SPCtx {
    unsigned int flags;
};

enum {
    SP_XML_SPACE_DEFAULT,
    SP_XML_SPACE_PRESERVE
};

class SPIXmlSpace;

/// Internal class consisting of two bits.
struct SPIXmlSpace {
    guint set : 1;
    guint value : 1;
};

class SPObject;

/*
 * Refcounting
 *
 * Owner is here for debug reasons, you can set it to NULL safely
 * Ref should return object, NULL is error, unref return always NULL
 */

SPObject *sp_object_ref(SPObject *object, SPObject *owner=NULL);
SPObject *sp_object_unref(SPObject *object, SPObject *owner=NULL);

SPObject *sp_object_href(SPObject *object, gpointer owner);
SPObject *sp_object_hunref(SPObject *object, gpointer owner);

/// A refcounting tree node object.
struct SPObject : public GObject {
    enum CollectionPolicy {
        COLLECT_WITH_PARENT,
        ALWAYS_COLLECT
    };

    unsigned int cloned : 1;
    unsigned int uflags : 8;
    unsigned int mflags : 8;
    SPIXmlSpace xml_space;
    unsigned int hrefcount; /* number of xlink:href references */
    unsigned int _total_hrefcount; /* our hrefcount + total descendants */
    SPDocument *document; /* Document we are part of */
    SPObject *parent; /* Our parent (only one allowed) */
    SPObject *children; /* Our children */
    SPObject *_last_child; /* Remembered last child */
    SPObject *next; /* Next object in linked list */
    Inkscape::XML::Node *repr; /* Our xml representation */
    gchar *id; /* Our very own unique id */

    /** @brief cleans up an SPObject, releasing its references and
     *         requesting that references to it be released
     */
    void releaseReferences();

    /** @brief connects to the release request signal
     *
     *  @param slot the slot to connect
     *
     *  @returns the sigc::connection formed
     */
    sigc::connection connectRelease(sigc::slot<void, SPObject *> slot) {
        return _release_signal.connect(slot);
    }

    /**
     * Represents the style properties, whether from presentation attributes, the <tt>style</tt>
     * attribute, or inherited.
     *
     * sp_object_private_set doesn't handle SP_ATTR_STYLE or any presentation attributes at the
     * time of writing, so this is probably NULL for all SPObject's that aren't an SPItem.
     *
     * However, this gives rise to the bugs mentioned in sp_object_get_style_property.
     * Note that some non-SPItem SPObject's, such as SPStop, do need styling information,
     * and need to inherit properties even through other non-SPItem parents like \<defs\>.
     */
    SPStyle *style;

    /// Switch containing next() method.
    struct ParentIteratorStrategy {
        static SPObject const *next(SPObject const *object) {
            return object->parent;
        }
    };
    /// Switch containing next() method.
    struct SiblingIteratorStrategy {
        static SPObject const *next(SPObject const *object) {
            return object->next;
        }
    };

    typedef Inkscape::Util::ForwardPointerIterator<SPObject, ParentIteratorStrategy> ParentIterator;
    typedef Inkscape::Util::ForwardPointerIterator<SPObject const, ParentIteratorStrategy> ConstParentIterator;
    typedef Inkscape::Util::ForwardPointerIterator<SPObject, SiblingIteratorStrategy> SiblingIterator;
    typedef Inkscape::Util::ForwardPointerIterator<SPObject const, SiblingIteratorStrategy> ConstSiblingIterator;

    bool isSiblingOf(SPObject const *object) const {
        g_return_val_if_fail(object != NULL, false);
        return this->parent && this->parent == object->parent;
    }
    bool isAncestorOf(SPObject const *object) const;

    SPObject const *nearestCommonAncestor(SPObject const *object) const;
    /* A non-const version can be similarly constructed if you want one.
     * (Don't just cast away the constness, which would be ill-formed.) */

    bool hasChildren() const { return ( children != NULL ); }

    SPObject *firstChild() { return children; }
    SPObject const *firstChild() const { return children; }
    SPObject *lastChild() { return _last_child; }
    SPObject const *lastChild() const { return _last_child; }

    enum Action { ActionGeneral, ActionBBox, ActionUpdate, ActionShow };    
    /** @brief Retrieves children as a GSList */
    GSList *childList(bool add_ref, Action action = ActionGeneral);

    SPObject *appendChildRepr(Inkscape::XML::Node *repr);

    /** @brief Gets the author-visible label for this object. */ 
    gchar const *label() const;
    /** @brief Returns a default label for this object. */ 
    gchar const *defaultLabel() const;
    /** @brief Sets the author-visible label for this object.
     *
     * Sets the author-visible label for the object.
     *
     * @param label the new label
     */
    void setLabel(gchar const *label);

    /** Retrieves the title of this object */
    gchar const *title() const { return NULL; /* TODO */ }
    /** Sets the title of this object */
    void setTitle(gchar const *title) { (void)title; /* TODO */ }

    /** Retrieves the description of this object */
    gchar const *desc() const { return NULL; /* TODO */ }
    /** Sets the description of this object */
    void setDesc(gchar const *desc) { (void)desc; /* TODO */ }

    /** @brief Set the policy under which this object will be
     *         orphan-collected.
     *
     * Orphan-collection is the process of deleting all objects which no longer have
     * hyper-references pointing to them.  The policy determines when this happens.  Many objects
     * should not be deleted simply because they are no longer referred to; other objects (like
     * "intermediate" gradients) are more or less throw-away and should always be collected when no
     * longer in use.
     *
     * Along these lines, there are currently two orphan-collection policies:
     *
     *  COLLECT_WITH_PARENT - don't worry about the object's hrefcount;
     *                        if its parent is collected, this object
     *                        will be too
     *
     *  COLLECT_ALWAYS - always collect the object as soon as its
     *                   hrefcount reaches zero
     *
     * @returns the current collection policy in effect for this object
     */
    CollectionPolicy collectionPolicy() const { return _collection_policy; }

    /** @brief Sets the orphan-collection policy in effect for this object.
     *
     * @see SPObject::collectionPolicy
     *
     * @param policy the new policy to adopt
     */
    void setCollectionPolicy(CollectionPolicy policy) {
        _collection_policy = policy;
    }

    /** @brief Requests a later automatic call to collectOrphan().
     *
     * This method requests that collectOrphan() be called during the document update cycle,
     * deleting the object if it is no longer used.
     *
     * If the current collection policy is COLLECT_WITH_PARENT, this function has no effect.
     *
     * @see SPObject::collectOrphan
     */
    void requestOrphanCollection();

    /** @brief Unconditionally delete the object if it is not referenced.
     *
     * Unconditionally delete the object if there are no outstanding hyper-references to it.
     * Observers are not notified of the object's deletion (at the SPObject level; XML tree
     * notifications still fire).
     *
     * @see SPObject::deleteObject
     */
    void collectOrphan() {
        if ( _total_hrefcount == 0 ) {
            deleteObject(false);
        }
    }

    /** @brief Check if object is referenced by any other object.
     */
    bool isReferenced() { return ( _total_hrefcount > 0 ); }

    /** @brief Deletes an object.
     *
     * Detaches the object's repr, and optionally sends notification that the object has been
     * deleted.
     *
     * @param propagate notify observers that the object has been deleted?
     *
     * @param propagate_descendants notify observers of children that they have been deleted?
     */
    void deleteObject(bool propagate, bool propagate_descendants);

    /** @brief Deletes on object.
     *
     * @param propagate Notify observers of this object and its children that they have been
     *                  deleted?
     */
    void deleteObject(bool propagate=true) {
        deleteObject(propagate, propagate);
    }

    /** @brief Connects a slot to be called when an object is deleted.
     *
     * This connects a slot to an object's internal delete signal, which is invoked when the object
     * is deleted
     *
     * The signal is mainly useful for e.g. knowing when to break hrefs or dissociate clones.
     *
     * @param slot the slot to connect
     *
     * @see SPObject::deleteObject
     */
    sigc::connection connectDelete(sigc::slot<void, SPObject *> slot) {
        return _delete_signal.connect(slot);
    }

    sigc::connection connectPositionChanged(sigc::slot<void, SPObject *> slot) {
        return _position_changed_signal.connect(slot);
    }

    /** @brief Returns the object which supercedes this one (if any).
     *
     * This is mainly useful for ensuring we can correctly perform a series of moves or deletes,
     * even if the objects in question have been replaced in the middle of the sequence.
     */
    SPObject *successor() { return _successor; }

    /** @brief Indicates that another object supercedes this one. */
    void setSuccessor(SPObject *successor) {
        g_assert(successor != NULL);
        g_assert(_successor == NULL);
        g_assert(successor->_successor == NULL);
        sp_object_ref(successor, NULL);
        _successor = successor;
    }

    /* modifications; all three sets of methods should probably ultimately be protected, as they
     * are not really part of its public interface.  However, other parts of the code to
     * occasionally use them at present. */

    /* the no-argument version of updateRepr() is intended to be a bit more public, however -- it
     * essentially just flushes any changes back to the backing store (the repr layer); maybe it
     * should be called something else and made public at that point. */

    /** @brief Updates the object's repr based on the object's state.
     *
     *  This method updates the the repr attached to the object to reflect the object's current
     *  state; see the two-argument version for details.
     *
     *  @param flags object write flags that apply to this update
     *
     *  @return the updated repr
     */
    Inkscape::XML::Node *updateRepr(unsigned int flags=SP_OBJECT_WRITE_EXT);

    /** @brief Updates the given repr based on the object's state.
     *
     *  This method updates the given repr to reflect the object's current state.  There are
     *  several flags that affect this:
     *
     *   SP_OBJECT_WRITE_BUILD - create new reprs
     *
     *   SP_OBJECT_WRITE_EXT   - write elements and attributes
     *                           which are not part of pure SVG
     *                           (i.e. the Inkscape and Sodipodi
     *                           namespaces)
     *
     *   SP_OBJECT_WRITE_ALL   - create all nodes and attributes,
     *                           even those which might be redundant
     *
     *  @param repr the repr to update
     *  @param flags object write flags that apply to this update
     *
     *  @return the updated repr
     */
    Inkscape::XML::Node *updateRepr(Inkscape::XML::Node *repr, unsigned int flags);

    /** @brief Queues an deferred update of this object's display.
     *
     *  This method sets flags to indicate updates to be performed later, during the idle loop.
     *
     *  There are several flags permitted here:
     *
     *   SP_OBJECT_MODIFIED_FLAG - the object has been modified
     *
     *   SP_OBJECT_CHILD_MODIFIED_FLAG - a child of the object has been
     *                                   modified
     *
     *   SP_OBJECT_STYLE_MODIFIED_FLAG - the object's style has been
     *                                   modified
     *
     *  There are also some subclass-specific modified flags which are hardly ever used.
     *
     *  One of either MODIFIED or CHILD_MODIFIED is required.
     *
     *  @param flags flags indicating what to update
     */
    void requestDisplayUpdate(unsigned int flags);

    /** @brief Updates the object's display immediately
     *
     *  This method is called during the idle loop by SPDocument in order to update the object's
     *  display.
     *
     *  One additional flag is legal here:
     *
     *   SP_OBJECT_PARENT_MODIFIED_FLAG - the parent has been
     *                                    modified
     *
     *  @param ctx an SPCtx which accumulates various state
     *             during the recursive update -- beware! some
     *             subclasses try to cast this to an SPItemCtx *
     *
     *  @param flags flags indicating what to update (in addition
     *               to any already set flags)
     */
    void updateDisplay(SPCtx *ctx, unsigned int flags);

    /** @brief Requests that a modification notification signal
     *         be emitted later (e.g. during the idle loop)
     *
     *  @param flags flags indicating what has been modified
     */
    void requestModified(unsigned int flags);

    /** @brief Emits a modification notification signal
     *
     *  @param flags indicating what has been modified
     */
    void emitModified(unsigned int flags);

    /** @brief Connects to the modification notification signal
     *
     *  @param slot the slot to connect
     *
     *  @returns the connection formed thereby
     */
    sigc::connection connectModified(
      sigc::slot<void, SPObject *, unsigned int> slot
    ) {
        return _modified_signal.connect(slot);
    }

    void _sendDeleteSignalRecursive();
    void _updateTotalHRefCount(int increment);

    void _requireSVGVersion(unsigned major, unsigned minor) {
        _requireSVGVersion(Inkscape::Version(major, minor));
    }
    void _requireSVGVersion(Inkscape::Version version);

    sigc::signal<void, SPObject *> _release_signal;
    sigc::signal<void, SPObject *> _delete_signal;
    sigc::signal<void, SPObject *> _position_changed_signal;
    sigc::signal<void, SPObject *, unsigned int> _modified_signal;
    SPObject *_successor;
    CollectionPolicy _collection_policy;
    gchar *_label;
    mutable gchar *_default_label;
};

/// The SPObject vtable.
struct SPObjectClass {
    GObjectClass parent_class;

    void (* build) (SPObject *object, SPDocument *doc, Inkscape::XML::Node *repr);
    void (* release) (SPObject *object);

    /* Virtual handlers of repr signals */
    void (* child_added) (SPObject *object, Inkscape::XML::Node *child, Inkscape::XML::Node *ref);
    void (* remove_child) (SPObject *object, Inkscape::XML::Node *child);

    void (* order_changed) (SPObject *object, Inkscape::XML::Node *child, Inkscape::XML::Node *old, Inkscape::XML::Node *new_repr);

    void (* set) (SPObject *object, unsigned int key, gchar const *value);

    void (* read_content) (SPObject *object);

    /* Update handler */
    void (* update) (SPObject *object, SPCtx *ctx, unsigned int flags);
    /* Modification handler */
    void (* modified) (SPObject *object, unsigned int flags);

    Inkscape::XML::Node * (* write) (SPObject *object, Inkscape::XML::Node *repr, unsigned int flags);
};


/*
 * Attaching/detaching
 */

void sp_object_attach(SPObject *parent, SPObject *object, SPObject *prev);
void sp_object_reorder(SPObject *object, SPObject *prev);
void sp_object_detach(SPObject *parent, SPObject *object);

inline SPObject *sp_object_first_child(SPObject *parent) {
    return parent->firstChild();
}
SPObject *sp_object_get_child_by_repr(SPObject *object, Inkscape::XML::Node *repr);

void sp_object_invoke_build(SPObject *object, SPDocument *document, Inkscape::XML::Node *repr, unsigned int cloned);

void sp_object_set(SPObject *object, unsigned int key, gchar const *value);

void sp_object_read_attr(SPObject *object, gchar const *key);

/*
 * Get and set descriptive parameters.
 *
 * These are inefficent, so they are not intended to be used interactively.
 */

gchar const *sp_object_title_get(SPObject *object);
gchar const *sp_object_description_get(SPObject *object);
unsigned int sp_object_title_set(SPObject *object, gchar const *title);
unsigned int sp_object_description_set(SPObject *object, gchar const *desc);

/* Public */

gchar const *sp_object_tagName_get(SPObject const *object, SPException *ex);
gchar const *sp_object_getAttribute(SPObject const *object, gchar const *key, SPException *ex);
void sp_object_setAttribute(SPObject *object, gchar const *key, gchar const *value, SPException *ex);
void sp_object_removeAttribute(SPObject *object, gchar const *key, SPException *ex);

/* Style */

gchar const *sp_object_get_style_property(SPObject const *object,
					  gchar const *key, gchar const *def);

Inkscape::Version sp_object_get_sodipodi_version(SPObject *object);

int sp_object_compare_position(SPObject const *first, SPObject const *second);

SPObject *sp_object_prev(SPObject *child);


#endif


/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :