/***************************************************************************
 *   Copyright (c) 2025 Kindred Systems                                    *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Library General Public           *
 *   License as published by the Free Software Foundation; either          *
 *   version 2 of the License, or (at your option) any later version.      *
 *                                                                         *
 *   This library  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 Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file COPYING.LIB. If not,    *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/

#ifndef GUI_FILEORIGIN_H
#define GUI_FILEORIGIN_H

#include <string>
#include <QIcon>
#include <FCGlobal.h>
#include <fastsignals/signal.h>

namespace App {
class Document;
}

namespace Gui {

/**
 * @brief Classification of origin types
 */
enum class OriginType {
    Local,   ///< Local filesystem storage
    PLM,     ///< Product Lifecycle Management system (e.g., Silo)
    Cloud,   ///< Generic cloud storage
    Custom   ///< User-defined origin type
};

/**
 * @brief Connection state for origins that require network access
 */
enum class ConnectionState {
    Disconnected,  ///< Not connected
    Connecting,    ///< Connection in progress
    Connected,     ///< Successfully connected
    Error          ///< Connection error occurred
};

/**
 * @brief Abstract base class for document origin handlers
 *
 * FileOrigin provides an interface for different storage backends
 * that can handle FreeCAD documents. Each origin defines workflows
 * for creating, opening, saving, and managing documents.
 *
 * Key insight: Origins don't change where files are stored - all documents
 * are always saved locally. Origins change the workflow and identity model:
 * - Local: Document identity = file path, no external tracking
 * - PLM: Document identity = database UUID, syncs with external system
 */
class GuiExport FileOrigin
{
public:
    virtual ~FileOrigin() = default;

    ///@name Identity Methods
    //@{
    /** Unique identifier for this origin instance */
    virtual std::string id() const = 0;
    /** Display name for UI */
    virtual std::string name() const = 0;
    /** Short nickname for compact UI elements (e.g., toolbar) */
    virtual std::string nickname() const = 0;
    /** Icon for UI representation */
    virtual QIcon icon() const = 0;
    /** Origin type classification */
    virtual OriginType type() const = 0;
    //@}

    ///@name Workflow Characteristics
    //@{
    /** Whether this origin tracks documents externally (e.g., in a database) */
    virtual bool tracksExternally() const = 0;
    /** Whether this origin requires user authentication */
    virtual bool requiresAuthentication() const = 0;
    //@}

    ///@name Capability Queries
    //@{
    /** Whether this origin supports revision history */
    virtual bool supportsRevisions() const { return false; }
    /** Whether this origin supports Bill of Materials */
    virtual bool supportsBOM() const { return false; }
    /** Whether this origin supports part numbers */
    virtual bool supportsPartNumbers() const { return false; }
    /** Whether this origin supports assemblies natively */
    virtual bool supportsAssemblies() const { return false; }
    //@}

    ///@name Connection State
    //@{
    /** Get current connection state */
    virtual ConnectionState connectionState() const { return ConnectionState::Connected; }
    /** Attempt to connect/authenticate */
    virtual bool connect() { return true; }
    /** Disconnect from origin */
    virtual void disconnect() {}
    /** Signal emitted when connection state changes */
    fastsignals::signal<void(ConnectionState)> signalConnectionStateChanged;
    //@}

    ///@name Document Identity
    //@{
    /**
     * Get document identity string (path for local, UUID for PLM)
     * This is the immutable tracking key for the document.
     * @param doc The App document to get identity for
     * @return Identity string or empty if not owned by this origin
     */
    virtual std::string documentIdentity(App::Document* doc) const = 0;

    /**
     * Get human-readable document identity (path for local, part number for PLM)
     * This is for display purposes in the UI.
     * @param doc The App document
     * @return Display identity string or empty if not owned
     */
    virtual std::string documentDisplayId(App::Document* doc) const = 0;

    /**
     * Check if this origin owns the given document.
     * Ownership is determined by document properties, not file path.
     * @param doc The document to check
     * @return true if this origin owns the document
     */
    virtual bool ownsDocument(App::Document* doc) const = 0;
    //@}

    ///@name Property Synchronization
    //@{
    /**
     * Sync document properties to the origin backend.
     * For local origin this is a no-op. For PLM origins this pushes
     * property changes to the database.
     * @param doc The document to sync
     * @return true if sync succeeded
     */
    virtual bool syncProperties(App::Document* doc) { (void)doc; return true; }
    //@}

    ///@name Core Document Operations
    //@{
    /**
     * Create a new document managed by this origin.
     * Local: Creates empty document
     * PLM: Shows part creation form
     * @param name Optional document name
     * @return The created document or nullptr on failure
     */
    virtual App::Document* newDocument(const std::string& name = "") = 0;

    /**
     * Open a document by identity (non-interactive).
     * Local: Opens file at path
     * PLM: Opens document by UUID (downloads if needed)
     * @param identity Document identity (path or UUID)
     * @return The opened document or nullptr on failure
     */
    virtual App::Document* openDocument(const std::string& identity) = 0;

    /**
     * Open a document interactively (shows dialog).
     * Local: Shows file picker dialog
     * PLM: Shows search/browse dialog
     * @return The opened document or nullptr if cancelled/failed
     */
    virtual App::Document* openDocumentInteractive() = 0;

    /**
     * Save the document.
     * Local: Saves to disk (if path known)
     * PLM: Saves to disk and syncs with external system
     * @param doc The document to save
     * @return true if save succeeded
     */
    virtual bool saveDocument(App::Document* doc) = 0;

    /**
     * Save document with new identity (non-interactive).
     * @param doc The document to save
     * @param newIdentity New identity (path or part number)
     * @return true if save succeeded
     */
    virtual bool saveDocumentAs(App::Document* doc, const std::string& newIdentity) = 0;

    /**
     * Save document interactively (shows dialog).
     * Local: Shows file picker for new path
     * PLM: Shows migration or copy workflow dialog
     * @param doc The document to save
     * @return true if save succeeded
     */
    virtual bool saveDocumentAsInteractive(App::Document* doc) = 0;
    //@}

    ///@name Extended Operations (PLM-specific, default to no-op)
    //@{
    /** Commit document changes to external system */
    virtual bool commitDocument(App::Document* doc) { (void)doc; return false; }
    /** Pull latest changes from external system */
    virtual bool pullDocument(App::Document* doc) { (void)doc; return false; }
    /** Push local changes to external system */
    virtual bool pushDocument(App::Document* doc) { (void)doc; return false; }
    /** Show document info dialog */
    virtual void showInfo(App::Document* doc) { (void)doc; }
    /** Show Bill of Materials dialog */
    virtual void showBOM(App::Document* doc) { (void)doc; }
    //@}

protected:
    FileOrigin() = default;

    // Non-copyable
    FileOrigin(const FileOrigin&) = delete;
    FileOrigin& operator=(const FileOrigin&) = delete;
};


/**
 * @brief Local filesystem origin - default origin for local files
 *
 * This is the default origin that handles documents stored on the
 * local filesystem without any external tracking or synchronization.
 */
class GuiExport LocalFileOrigin : public FileOrigin
{
public:
    LocalFileOrigin();
    ~LocalFileOrigin() override = default;

    // Identity
    std::string id() const override { return "local"; }
    std::string name() const override { return "Local Files"; }
    std::string nickname() const override { return "Local"; }
    QIcon icon() const override;
    OriginType type() const override { return OriginType::Local; }

    // Characteristics
    bool tracksExternally() const override { return false; }
    bool requiresAuthentication() const override { return false; }

    // Document identity
    std::string documentIdentity(App::Document* doc) const override;
    std::string documentDisplayId(App::Document* doc) const override;
    bool ownsDocument(App::Document* doc) const override;

    // Document operations
    App::Document* newDocument(const std::string& name = "") override;
    App::Document* openDocument(const std::string& identity) override;
    App::Document* openDocumentInteractive() override;
    bool saveDocument(App::Document* doc) override;
    bool saveDocumentAs(App::Document* doc, const std::string& newIdentity) override;
    bool saveDocumentAsInteractive(App::Document* doc) override;
};

}  // namespace Gui

#endif  // GUI_FILEORIGIN_H