/*
    Copyright (c) 2009 Kevin Ottens <ervin@kde.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

#ifndef MESSAGELIST_PANE_H
#define MESSAGELIST_PANE_H

#include <messagelist/enums.h>
#include <messagelist/view.h>
#include <QHash>
#include <QTabWidget>
#include <QVector>

#include <kmime/kmime_message.h>
#include <collection.h>
#include <messagelist_export.h>
#include <AkonadiCore/Item>

class KXMLGUIClient;
class QAbstractItemModel;
class QItemSelectionModel;
class QItemSelection;

namespace KPIM {
class MessageStatus;
}

namespace MessageList {
class Widget;
class StorageModel;

/**
 * This is the main MessageList panel for Akonadi applications.
 * It contains multiple MessageList::Widget tabs
 * so it can actually display multiple folder sets at once.
 *
 * When a KXmlGuiWindow is passed to setXmlGuiClient, the XMLGUI
 * defined context menu @c akonadi_messagelist_contextmenu is
 * used if available.
 *
 */
class MESSAGELIST_EXPORT Pane : public QTabWidget
{
    Q_OBJECT

public:
    /**
    * Create a Pane wrapping the specified model and selection.
    */
    explicit Pane(bool restoreSession, QAbstractItemModel *model, QItemSelectionModel *selectionModel, QWidget *parent = nullptr);
    ~Pane() override;

    virtual MessageList::StorageModel *createStorageModel(QAbstractItemModel *model, QItemSelectionModel *selectionModel, QObject *parent);

    virtual void writeConfig(bool restoreSession);

    /**
    * Sets the XML GUI client which the pane is used in.
    *
    * This is needed if you want to use the built-in context menu.
    * Passing 0 is ok and will disable the builtin context menu.
    *
    * @param xmlGuiClient The KXMLGUIClient the view is used in.
    */
    void setXmlGuiClient(KXMLGUIClient *xmlGuiClient);

    /**
    * Returns the current message for the list as Akonadi::Item.
    * May return an invalid Item if there is no current message or no current folder.
    */
    Q_REQUIRED_RESULT Akonadi::Item currentItem() const;

    /**
    * Returns the current message for the list as KMime::Message::Ptr.
    * May return 0 if there is no current message or no current folder.
    */
    KMime::Message::Ptr currentMessage() const;

    /**
    * Returns the currently selected KMime::Message::Ptr (bound to current StorageModel).
    * The list may be empty if there are no selected messages or no StorageModel.
    *
    * If includeCollapsedChildren is true then the children of the selected but
    * collapsed items are also added to the list.
    *
    * The returned list is guaranteed to be valid only until you return control
    * to the main even loop. Don't store it for any longer. If you need to reference
    * this set of messages at a later stage then take a look at createPersistentSet().
    */
    Q_REQUIRED_RESULT QVector<KMime::Message::Ptr> selectionAsMessageList(bool includeCollapsedChildren = true) const;

    /**
    * Returns the currently selected Items (bound to current StorageModel).
    * The list may be empty if there are no selected messages or no StorageModel.
    *
    * If includeCollapsedChildren is true then the children of the selected but
    * collapsed items are also added to the list.
    *
    * The returned list is guaranteed to be valid only until you return control
    * to the main even loop. Don't store it for any longer. If you need to reference
    * this set of messages at a later stage then take a look at createPersistentSet().
    */
    Q_REQUIRED_RESULT Akonadi::Item::List selectionAsMessageItemList(bool includeCollapsedChildren = true) const;

    /**
    * Returns the currently selected Items id(bound to current StorageModel).
    * The list may be empty if there are no selected messages or no StorageModel.
    *
    * If includeCollapsedChildren is true then the children of the selected but
    * collapsed items are also added to the list.
    *
    * The returned list is guaranteed to be valid only until you return control
    * to the main even loop. Don't store it for any longer. If you need to reference
    * this set of messages at a later stage then take a look at createPersistentSet().
    */
    Q_REQUIRED_RESULT QVector<qlonglong> selectionAsMessageItemListId(bool includeCollapsedChildren = true) const;

    Q_REQUIRED_RESULT QVector<Akonadi::Item::Id> selectionAsListMessageId(bool includeCollapsedChildren = true) const;

    /**
    * Returns the Akonadi::Item bound to the current StorageModel that
    * are part of the current thread. The current thread is the thread
    * that contains currentMessageItem().
    * The list may be empty if there is no currentMessageItem() or no StorageModel.
    *
    * The returned list is guaranteed to be valid only until you return control
    * to the main even loop. Don't store it for any longer. If you need to reference
    * this set of messages at a later stage then take a look at createPersistentSet().
    */
    Q_REQUIRED_RESULT Akonadi::Item::List currentThreadAsMessageList() const;

    /**
    * Selects the next message item in the view.
    *
    * messageTypeFilter can be used to restrict the selection to only certain message types.
    *
    * existingSelectionBehaviour specifies how the existing selection
    * is manipulated. It may be cleared, expanded or grown/shrinked.
    *
    * If centerItem is true then the specified item will be positioned
    * at the center of the view, if possible.
    * If loop is true then the "next" algorithm will restart from the beginning
    * of the list if the end is reached, otherwise it will just stop returning false.
    */
    Q_REQUIRED_RESULT bool selectNextMessageItem(MessageList::Core::MessageTypeFilter messageTypeFilter, MessageList::Core::ExistingSelectionBehaviour existingSelectionBehaviour, bool centerItem, bool loop);

    /**
    * Selects the previous message item in the view.
    * If centerItem is true then the specified item will be positioned
    * at the center of the view, if possible.
    *
    * messageTypeFilter can be used to restrict the selection to only certain message types.
    *
    * existingSelectionBehaviour specifies how the existing selection
    * is manipulated. It may be cleared, expanded or grown/shrinked.
    *
    * If loop is true then the "previous" algorithm will restart from the end
    * of the list if the beginning is reached, otherwise it will just stop returning false.
    */
    Q_REQUIRED_RESULT bool selectPreviousMessageItem(MessageList::Core::MessageTypeFilter messageTypeFilter, MessageList::Core::ExistingSelectionBehaviour existingSelectionBehaviour, bool centerItem, bool loop);

    /**
    * Focuses the next message item in the view without actually selecting it.
    *
    * messageTypeFilter can be used to restrict the selection to only certain message types.
    *
    * If centerItem is true then the specified item will be positioned
    * at the center of the view, if possible.
    * If loop is true then the "next" algorithm will restart from the beginning
    * of the list if the end is reached, otherwise it will just stop returning false.
    */
    Q_REQUIRED_RESULT bool focusNextMessageItem(MessageList::Core::MessageTypeFilter messageTypeFilter, bool centerItem, bool loop);

    /**
    * Focuses the previous message item in the view without actually selecting it.
    *
    * messageTypeFilter can be used to restrict the selection to only certain message types.
    *
    * If centerItem is true then the specified item will be positioned
    * at the center of the view, if possible.
    * If loop is true then the "previous" algorithm will restart from the end
    * of the list if the beginning is reached, otherwise it will just stop returning false.
    */
    Q_REQUIRED_RESULT bool focusPreviousMessageItem(MessageList::Core::MessageTypeFilter messageTypeFilter, bool centerItem, bool loop);

    /**
    * Selects the currently focused message item. May do nothing if the
    * focused message item is already selected (which is very likely).
    * If centerItem is true then the specified item will be positioned
    * at the center of the view, if possible.
    */
    void selectFocusedMessageItem(bool centerItem);

    /**
    * Selects the first message item in the view that matches the specified Core::MessageTypeFilter.
    * If centerItem is true then the specified item will be positioned
    * at the center of the view, if possible.
    *
    * If the current view is already loaded then the request will
    * be satisfied immediately (well... if an unread message exists at all).
    * If the current view is still loading then the selection of the first
    * message will be scheduled to be executed when loading terminates.
    *
    * So this function doesn't actually guarantee that an unread or new message
    * was selected when the call returns. Take care :)
    *
    * The function returns true if a message was selected and false otherwise.
    */
    Q_REQUIRED_RESULT bool selectFirstMessageItem(MessageList::Core::MessageTypeFilter messageTypeFilter, bool centerItem);

    /**
    * Selects the last message item in the view that matches the specified Core::MessageTypeFilter.
    * If centerItem is true then the specified item will be positioned
    * at the center of the view, if possible.
    *
    * The function returns true if a message was selected and false otherwise.
    */
    Q_REQUIRED_RESULT bool selectLastMessageItem(MessageList::Core::MessageTypeFilter messageTypeFilter, bool centerItem);

    /**
    * If expand is true then it expands the current thread, otherwise
    * collapses it.
    */
    void setCurrentThreadExpanded(bool expand);

    /**
    * If expand is true then it expands all the threads, otherwise
    * collapses them.
    */
    void setAllThreadsExpanded(bool expand);

    /**
    * If expand is true then it expands all the groups (only the toplevel
    * group item: inner threads are NOT expanded). If expand is false
    * then it collapses all the groups. If no grouping is in effect
    * then this function does nothing.
    */
    void setAllGroupsExpanded(bool expand);

    /**
    * Sets the focus on the quick search line of the currently active tab.
    */
    void focusQuickSearch(const QString &selectedText = QString());

    /**
    * Returns the Akonadi::MessageStatus in the current quicksearch field.
    */
    Q_REQUIRED_RESULT QVector<Akonadi::MessageStatus> currentFilterStatus() const;

    /**
    * Returns the search term in the current quicksearch field.
    */
    Q_REQUIRED_RESULT QString currentFilterSearchString() const;

    /**
    * Returns true if the current Aggregation is threaded, false otherwise
    * (or if there is no current Aggregation).
    */
    Q_REQUIRED_RESULT bool isThreaded() const;

    /**
    * Fast function that determines if the selection is empty
    */
    Q_REQUIRED_RESULT bool selectionEmpty() const;
    /**
    * Fills the lists of the selected message serial numbers and of the selected+visible ones.
    * Returns true if the returned stats are valid (there is a current folder after all)
    * and false otherwise. This is called by KMMainWidget in a single place so we optimize by
    * making it a single sweep on the selection.
    *
    * If includeCollapsedChildren is true then the children of the selected but
    * collapsed items are also included in the stats
    */
    Q_REQUIRED_RESULT bool getSelectionStats(Akonadi::Item::List &selectedItems, Akonadi::Item::List &selectedVisibleItems, bool *allSelectedBelongToSameThread, bool includeCollapsedChildren = true) const;
    /**
    * Deletes the persistent set pointed by the specified reference.
    * If the set does not exist anymore, nothing happens.
    */
    void deletePersistentSet(MessageList::Core::MessageItemSetReference ref);

    /**
    * If bMark is true this function marks the messages as "about to be removed"
    * so they appear dimmer and aren't selectable in the view.
    * If bMark is false then this function clears the "about to be removed" state
    * for the specified MessageItems.
    */
    void markMessageItemsAsAboutToBeRemoved(MessageList::Core::MessageItemSetReference ref, bool bMark);

    /**
    * Return Akonadi::Item from messageItemReference
    */
    Q_REQUIRED_RESULT Akonadi::Item::List itemListFromPersistentSet(MessageList::Core::MessageItemSetReference ref);

    /**
    * Return a persistent set from current selection
    */
    Q_REQUIRED_RESULT MessageList::Core::MessageItemSetReference selectionAsPersistentSet(bool includeCollapsedChildren = true) const;

    /**
    * Return a persistent set from current thread
    */
    Q_REQUIRED_RESULT MessageList::Core::MessageItemSetReference currentThreadAsPersistentSet() const;
    /**
    * Sets the focus on the view of the currently active tab.
    */
    void focusView();

    /**
    * Reloads global configuration and eventually reloads all the views.
    */
    void reloadGlobalConfiguration();

    /**
    * Returns the QItemSelectionModel for the currently displayed tab.
    */
    QItemSelectionModel *currentItemSelectionModel();

    /**
    * Sets the current folder to be displayed by this Pane.
    * If the specified folder is already open in one of the tabs
    * then that tab is made current (and no reloading happens).
    * If the specified folder is not open yet then behaviour
    * depends on the preferEmptyTab value as follows.
    *
    * @param etmIndex the index for the collection in the EntityTreeModel (source model)
    *
    * If preferEmptyTab is set to false then the (new) folder is loaded
    * in the current tab. If preferEmptyTab is set to true then the (new) folder is
    * loaded in the first empty tab (or a new one if there are no empty ones).
    *
    * Pre-selection is the action of automatically selecting a message just after the folder
    * has finished loading. See Model::setStorageModel() for more information.
    *
    * If overrideLabel is not empty then it's used as the tab text for the
    * specified folder. This is useful to signal a particular folder state
    * like "loading..."
    */
    void setCurrentFolder(
        const Akonadi::Collection &fld, const QModelIndex &etmIndex, bool preferEmptyTab = false, MessageList::Core::PreSelectionMode preSelectionMode = MessageList::Core::PreSelectLastSelected, const QString &overrideLabel = QString());

    void resetModelStorage();

    void setPreferEmptyTab(bool emptyTab);

    void updateTabIconText(const Akonadi::Collection &collection, const QString &label, const QIcon &icon);

    void saveCurrentSelection();

    void updateTagComboBox();

    bool searchEditHasFocus() const;

    void setQuickSearchClickMessage(const QString &msg);

    void populateStatusFilterCombo();

    Core::QuickSearchLine::SearchOptions currentOptions() const;

    Q_REQUIRED_RESULT Akonadi::Collection currentFolder() const;

public Q_SLOTS:
    /**
    * Selects all the items in the current folder.
    */
    void selectAll();

    /**
    * Add a new tab to the Pane and select it.
    */
    QItemSelectionModel *createNewTab();

    void sortOrderMenuAboutToShow();

    void aggregationMenuAboutToShow();

    void themeMenuAboutToShow();

Q_SIGNALS:
    /**
    * Emitted when a message is selected (that is, single clicked and thus made current in the view)
    * Note that this message CAN be 0 (when the current item is cleared, for example).
    *
    * This signal is emitted when a SINGLE message is selected in the view, probably
    * by clicking on it or by simple keyboard navigation. When multiple items
    * are selected at once (by shift+clicking, for example) then you will get
    * this signal only for the last clicked message (or at all, if the last shift+clicked
    * thing is a group header...). You should handle selection changed in this case.
    */
    void messageSelected(const Akonadi::Item &item);

    /**
    * Emitted when a message is doubleclicked or activated by other input means
    */
    void messageActivated(const Akonadi::Item &item);

    /**
    * Emitted when the selection in the view changes.
    */
    void selectionChanged();

    /**
    * Emitted when a message wants its status to be changed
    */
    void messageStatusChangeRequest(const Akonadi::Item &item, const Akonadi::MessageStatus &set, const Akonadi::MessageStatus &clear);

    /**
    * Notify the outside when updating the status bar with a message
    * could be useful
    */
    void statusMessage(const QString &message);

    /**
    * Emitted when the current tab has changed. Clients using the
    *  selection model from currentItemSelectionModel() should
    *  ask for it again, as it may be different now.
    */
    void currentTabChanged();

    void forceLostFocus();

private:
    void restoreHeaderSettings(int index);
    void readConfig(bool restoreSession);

    bool eventFilter(QObject *obj, QEvent *event) override;

    class Private;
    Private *const d;
};
} // namespace MessageList

#endif //!__MESSAGELIST_PANE_H
