// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#pragma once

#include <QWidget>
#include <QFileSystemModel>
#include <QSortFilterProxyModel>
#include <QHash>
#include <QDateTime>

class QLineEdit;
class QTreeView;
class QModelIndex;

// Left-side dock alternative to the Processing (reprocessing settings) panel: a directory tree rooted at a
// configurable data root, filtered down to subdirectories and *_master.h5 / *_process.h5 / *.cbf
// files, for browsing to and opening a dataset without caring about reprocessing. Backed by QFileSystemModel,
// which only lists a directory once it is expanded - so a root with hundreds of sibling directories
// (e.g. an SLS beamline's /sls/mx/data/) costs one readdir at each level actually opened, never a
// recursive scan of the whole tree.
//
// New files show up by themselves: F5 (or the refresh button) re-lists the root and every expanded
// directory at once, and a timer does the same every few seconds while the panel is visible. The model's
// own inotify watching covers a local disk, but not files written by another host onto NFS/GPFS/Lustre,
// which is exactly how a detector writer fills a beamline's data directory - hence the polling.
class JFJochViewerFileBrowser : public QWidget {
    Q_OBJECT

    QLineEdit *root_edit_;
    QLineEdit *filter_edit_;
    QTreeView *tree_;
    QFileSystemModel *model_;
    QSortFilterProxyModel *proxy_;
    // Modification time of each directory when it was last listed, so a poll re-lists only those that changed.
    QHash<QString, QDateTime> listed_mtime_;

    void SetRoot(const QString &path);
    void CollectExpanded(const QModelIndex &parent, QStringList &dirs) const;
    [[nodiscard]] static QString DefaultRoot();
    // An SLS account eNNNNN browses its proposal group's raw data, which is pNNNNN with the
    // same five digits; empty for any other user name, on any platform.
    [[nodiscard]] static QString SlsDataRoot(const QString &user);

public slots:
    // "Reset all settings to defaults": back to the root a fresh start would pick.
    void ResetToDefaultRoot();
    // Re-list the root and the expanded directories; unless forced, only those modified since last time.
    void Refresh(bool force = true);

private slots:
    void onBrowseClicked();
    void onRootEditingFinished();
    void onDoubleClicked(const QModelIndex &index);

signals:
    // Mirrors JFJochViewerMenu::fileOpenSelected, so the window wires it to LoadFile the same way.
    void openDataset(const QString &filename, qint64 image_number, qint64 summation, bool retry);

public:
    explicit JFJochViewerFileBrowser(QWidget *parent = nullptr);

    // A dataset opened elsewhere (menu, D-Bus) and lying inside the current root moves the tree's
    // selection to it; one outside the root leaves the browser exactly as it was.
    void FollowPath(const QString &path);
};