Rewrite search integration

This huge commit is a nearly complete rewrite of the Dolphin search
code. It implements most of the improved Dolphin search UI/UX as
designed and discussed in a collaborative effort by Kristen McWilliam,
Jin Liu, Andy Betts, Tagwerk, a few others and me.
See https://invent.kde.org/system/dolphin/-/issues/46.

# Notable changes

- A toggle to change the search tool is provided as most contributors
deemed that useful in
https://invent.kde.org/system/dolphin/-/merge_requests/642#note_985112.
- The default search is changed to filenamesearch for maximum
reliability.
- Removing all search parameters will take users back to the view state
prior to starting a search instead of keeping the search results open.
- The UI for choosing file types or modification dates has been made
more powerful with more granularity and more options.
- Most search parameters can be configured from a popup menu which
gives us extra space for extra clarity.
- Labels and help buttons as well as hyperlinks to settings makes sure
the user always knows why some search parameters are unavailable in
some contexts.
- Chips show important search parameters while the popup is closed.
They allow quickly removing filters.
- The titles of the search and the input field placeholder message
change to make clear whether file names or file contents are searched.
- When the user actively switches the search tool, whether content
should be searched, or whether to search everywhere, this is preserved
for the initial state of the search bar when the user opens it the next
time after restarting Dolphin.

# Architecture

- The new DolphinQuery class is independent of the UI and contains all
search parameters modifiable in Dolphin as easy setters and getters.
- DolphinQuery objects are also used to update the states of every
component in the search UI. There is now a clear separation of UI and
search configuration/DolphinQuery.
- DolphinQuery is responsible for exporting to and importing from
search URLs.
- The search UI always reflects the currently configured DolphinQuery
no matter if the user changed the UI to change the DolphinQuery or
loaded a DolphinQuery/older search URL which then is reflected in the
UI.
- I tried to simplify all classes and their interaction between each
other as much as possible.
- I added some tests

BUG: 386754
CCBUG: 435119
CCBUG: 458761
BUG: 446387
BUG: 470136
CCBUG: 471556
CCBUG: 475439
CCBUG: 477969
BUG: 480001
BUG: 483578
BUG: 488047
BUG: 488845
BUG: 500103
FIXED-IN: 25.08

1 files changed, 206 insertions, 0 deletions

diff --git a/src/search/bar.h b/src/search/bar.h
new file mode 100644
index 000000000..e681b8a6e
--- /dev/null
+++ b/src/search/bar.h
@@ -0,0 +1,206 @@
+/*
+    SPDX-FileCopyrightText: 2010 Peter Penz <[email protected]>
+    SPDX-FileCopyrightText: 2025 Felix Ernst <[email protected]>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#ifndef SEARCHBAR_H
+#define SEARCHBAR_H
+
+#include "animatedheightwidget.h"
+#include "dolphinquery.h"
+#include "updatablestateinterface.h"
+
+#include <KMessageWidget>
+
+#include <QUrl>
+
+class DolphinSearchBarTest;
+class QHBoxLayout;
+class QLineEdit;
+class QToolButton;
+class QVBoxLayout;
+
+namespace Search
+{
+class BarSecondRowFlowLayout;
+template<class Selector>
+class Chip;
+class DateSelector;
+class FileTypeSelector;
+class MinimumRatingSelector;
+class Popup;
+class TagsSelector;
+
+/**
+ * @brief User interface for searching files and folders.
+ *
+ * This Bar is both for configuring a new search as well as showing the search parameter of any search URL opened in Dolphin.
+ * There are many search parameters whose availability can depend on various conditions. Those include:
+ * - Where to search: Everywhere or below the current directory
+ * - What to search: Filenames or content
+ * - How to search: Which search tool to use
+ * - etc.
+ *
+ * The class which defines the state of this Bar and its children is DolphinQuery.
+ * @see DolphinQuery.
+ */
+class Bar : public AnimatedHeightWidget, public UpdatableStateInterface
+{
+    Q_OBJECT
+
+public:
+    /**
+     * @brief Constructs a Search::Bar with an initial state matching @p dolphinQuery and with parent @p parent.
+     */
+    explicit Bar(std::shared_ptr<const DolphinQuery> dolphinQuery, QWidget *parent = nullptr);
+
+    /**
+     * Returns the text that should be used as input
+     * for searching.
+     */
+    QString text() const;
+
+    /**
+     * Sets the current path that is used as root for searching files.
+     * If @url is the Home dir, "From Here" is selected instead.
+     */
+    void setSearchPath(const QUrl &url);
+
+    /**
+     * Selects the whole text of the search box.
+     */
+    void selectAll();
+
+    /**
+     * All showing and hiding of this bar is supposed to go through this method. When hiding this bar, it emits all the necessary signals to restore the view
+     * container to a non-search URL.
+     * This method also aims to make sure that visibilityChanged() will be emitted no matter from where setVisible() is called. This way the "Find" action can
+     * be properly un/checked.
+     * @see AnimatedHeightWidget::setVisible().
+     */
+    void setVisible(bool visible, Animated animated);
+
+    /**
+     * @returns false, when the search UI has not yet been changed to search for anything specific. For example when no search term has been entered yet.
+     *          Otherwise returns true, for example when a search term has been entered or there is a search request for all files of a specific file type or
+     *          with a specific modification date.
+     */
+    bool isSearchConfigured() const;
+
+    /**
+     * @returns the title for the search that is currently configured in this bar.
+     * @see DolphinQuery::title().
+     */
+    QString queryTitle() const;
+
+Q_SIGNALS:
+    /**
+     * This signals a request for the attached view container to switch to @p url.
+     * A URL for searching is requested when the user actively engages with this UI to trigger a search.
+     * A non-search URL is requested when this search UI is closed and no search results should be displayed anymore.
+     */
+    void urlChangeRequested(const QUrl &url);
+
+    /**
+     * Is emitted when the bar should receive focus. This is usually triggered by a user action that implies that this bar should no longer have focus.
+     */
+    void focusViewRequest();
+
+    /**
+     * Requests for @p message with the given @p messageType to be shown to the user in a non-modal way.
+     */
+    void showMessage(const QString &message, KMessageWidget::MessageType messageType);
+
+    /**
+     * Requests for a progress update to be shown to the user in a non-modal way.
+     * @param currentlyRunningTaskTitle     The task that is currently progressing.
+     * @param installationProgressPercent   The current percentage of completion.
+     */
+    void showInstallationProgress(const QString &currentlyRunningTaskTitle, int installationProgressPercent);
+
+    /**
+     * Is emitted when a change of the visibility of this bar is invoked in any way. This can happen from code calling from outside this class, for example
+     * when the user triggered a keyboard shortcut to show this bar, or from inside, for example because the close button on this bar was pressed or an Escape
+     * key press was received.
+     */
+    void visibilityChanged(bool visible);
+
+protected:
+    /** Handles Escape key presses to clear the search field or close this bar. */
+    void keyPressEvent(QKeyEvent *event) override;
+    /** Allows moving the focus to the view with the Down arrow key. */
+    void keyReleaseEvent(QKeyEvent *event) override;
+
+private Q_SLOTS:
+    /**
+     * Is called when any component within this Bar emits a configurationChanged() signal.
+     * This method is then responsible to communicate the changed search configuration to every other interested party by calling
+     * UpdatableStateInterface::updateStateToMatch() methods and commiting the new search configuration.
+     * @see UpdatableStateInterface::updateStateToMatch().
+     * @see commitCurrentConfiguration().
+     */
+    void slotConfigurationChanged(const DolphinQuery &searchConfiguration);
+
+    /**
+     * Changes the m_searchConfiguration in response to the user editing the search term. If no further changes to the search term happen within a time limit,
+     * the new search configuration will eventually be commited.
+     * @see commitCurrentConfiguration.
+     */
+    void slotSearchTermEdited(const QString &text);
+
+    /**
+     * Commits the current search configuration and then requests moving focus away from this bar and to the view.
+     * @see commitCurrentConfiguration.
+     */
+    void slotReturnPressed();
+
+    /**
+     * Translates the current m_searchConfiguration into URLs which are then emitted through the urlChangeRequested() signal.
+     * If the current m_searchConfiguration is a valid search, a searchUrl is emitted. If it is not a valid search, i.e. when isSearchConfigured() is false,
+     * the search path is instead emitted so the view returns to showing a normal folder instead of search results.
+     * @see urlChangeRequested().
+     */
+    void commitCurrentConfiguration();
+
+    /** Adds the current search as a link/favorite to the Places panel. */
+    void slotSaveSearch();
+
+private:
+    /**
+     * This Search::Bar always represents a search configuration. This method takes a new @p dolphinQuery i.e. search configuration and updates itself and all
+     * child widgets to match it. This way the user always knows which search parameters lead to the query results that appear in the view.
+     * @see UpdatableStateInterface::updateStateToMatch().
+     */
+    void updateState(const std::shared_ptr<const DolphinQuery> &dolphinQuery) override;
+
+    /** @see AnimatedHeightWidget::preferredHeight() */
+    int preferredHeight() const override;
+
+private:
+    QVBoxLayout *m_topLayout = nullptr;
+
+    // The widgets below are sorted by their tab order.
+
+    QLineEdit *m_searchTermEditor = nullptr;
+    QAction *m_saveSearchAction = nullptr;
+    /// The main popup of this bar that allows configuring most search parameters.
+    Popup *m_popup = nullptr;
+    BarSecondRowFlowLayout *m_secondRowLayout = nullptr;
+    QToolButton *m_fromHereButton = nullptr;
+    QToolButton *m_everywhereButton = nullptr;
+    Chip<FileTypeSelector> *m_fileTypeSelectorChip = nullptr;
+    Chip<DateSelector> *m_modifiedSinceDateSelectorChip = nullptr;
+    Chip<MinimumRatingSelector> *m_minimumRatingSelectorChip = nullptr;
+    Chip<TagsSelector> *m_requiredTagsSelectorChip = nullptr;
+
+    /// Starts a new search when the user has finished typing the search term.
+    QTimer *m_startSearchTimer = nullptr;
+
+    friend DolphinSearchBarTest;
+};
+
+}
+
+#endif