/***************************************************************************
 *   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                                *
 *                                                                         *
 ***************************************************************************/

#include "PreCompiled.h"

#include <App/Application.h>
#include <Base/Console.h>

#include "OriginManager.h"
#include "FileOrigin.h"


namespace Gui {

// Preferences path for origin settings
static const char* PREF_PATH = "User parameter:BaseApp/Preferences/General/Origin";
static const char* PREF_CURRENT_ORIGIN = "CurrentOriginId";

// Built-in origin ID that cannot be unregistered
static const char* LOCAL_ORIGIN_ID = "local";


OriginManager* OriginManager::_instance = nullptr;

OriginManager* OriginManager::instance()
{
    if (!_instance) {
        _instance = new OriginManager();
    }
    return _instance;
}

void OriginManager::destruct()
{
    delete _instance;
    _instance = nullptr;
}

OriginManager::OriginManager()
{
    ensureLocalOrigin();
    loadPreferences();
}

OriginManager::~OriginManager()
{
    savePreferences();
    _origins.clear();
}

void OriginManager::ensureLocalOrigin()
{
    // Create the built-in local filesystem origin
    auto localOrigin = std::make_unique<LocalFileOrigin>();
    _origins[LOCAL_ORIGIN_ID] = std::move(localOrigin);
    _currentOriginId = LOCAL_ORIGIN_ID;
}

void OriginManager::loadPreferences()
{
    try {
        auto hGrp = App::GetApplication().GetParameterGroupByPath(PREF_PATH);
        std::string savedOriginId = hGrp->GetASCII(PREF_CURRENT_ORIGIN, LOCAL_ORIGIN_ID);

        // Only use saved origin if it's registered
        if (_origins.find(savedOriginId) != _origins.end()) {
            _currentOriginId = savedOriginId;
        }
    }
    catch (...) {
        // Ignore preference loading errors
        _currentOriginId = LOCAL_ORIGIN_ID;
    }
}

void OriginManager::savePreferences()
{
    try {
        auto hGrp = App::GetApplication().GetParameterGroupByPath(PREF_PATH);
        hGrp->SetASCII(PREF_CURRENT_ORIGIN, _currentOriginId.c_str());
    }
    catch (...) {
        // Ignore preference saving errors
    }
}

bool OriginManager::registerOrigin(FileOrigin* origin)
{
    if (!origin) {
        return false;
    }

    std::string originId = origin->id();
    if (originId.empty()) {
        Base::Console().warning("OriginManager: Cannot register origin with empty ID\n");
        delete origin;
        return false;
    }

    // Check if ID already in use
    if (_origins.find(originId) != _origins.end()) {
        Base::Console().warning("OriginManager: Origin '%s' already registered\n", originId.c_str());
        delete origin;
        return false;
    }

    _origins[originId] = std::unique_ptr<FileOrigin>(origin);
    Base::Console().log("OriginManager: Registered origin '%s'\n", originId.c_str());

    signalOriginRegistered(originId);
    return true;
}

bool OriginManager::unregisterOrigin(const std::string& id)
{
    // Cannot unregister the built-in local origin
    if (id == LOCAL_ORIGIN_ID) {
        Base::Console().warning("OriginManager: Cannot unregister built-in local origin\n");
        return false;
    }

    auto it = _origins.find(id);
    if (it == _origins.end()) {
        return false;
    }

    // If unregistering the current origin, switch to local
    if (_currentOriginId == id) {
        _currentOriginId = LOCAL_ORIGIN_ID;
        signalCurrentOriginChanged(_currentOriginId);
    }

    _origins.erase(it);
    Base::Console().log("OriginManager: Unregistered origin '%s'\n", id.c_str());

    signalOriginUnregistered(id);
    return true;
}

std::vector<std::string> OriginManager::originIds() const
{
    std::vector<std::string> ids;
    ids.reserve(_origins.size());
    for (const auto& pair : _origins) {
        ids.push_back(pair.first);
    }
    return ids;
}

FileOrigin* OriginManager::getOrigin(const std::string& id) const
{
    auto it = _origins.find(id);
    if (it != _origins.end()) {
        return it->second.get();
    }
    return nullptr;
}

FileOrigin* OriginManager::currentOrigin() const
{
    auto it = _origins.find(_currentOriginId);
    if (it != _origins.end()) {
        return it->second.get();
    }
    // Fallback to local (should never happen)
    return _origins.at(LOCAL_ORIGIN_ID).get();
}

std::string OriginManager::currentOriginId() const
{
    return _currentOriginId;
}

bool OriginManager::setCurrentOrigin(const std::string& id)
{
    if (_origins.find(id) == _origins.end()) {
        return false;
    }

    if (_currentOriginId != id) {
        _currentOriginId = id;
        savePreferences();
        signalCurrentOriginChanged(_currentOriginId);
    }

    return true;
}

FileOrigin* OriginManager::findOwningOrigin(App::Document* doc) const
{
    if (!doc) {
        return nullptr;
    }

    // Check each origin to see if it owns this document
    // Start with non-local origins since they have specific ownership criteria
    for (const auto& pair : _origins) {
        if (pair.first == LOCAL_ORIGIN_ID) {
            continue;  // Check local last as fallback
        }
        if (pair.second->ownsDocument(doc)) {
            return pair.second.get();
        }
    }

    // If no PLM origin claims it, check local
    auto localIt = _origins.find(LOCAL_ORIGIN_ID);
    if (localIt != _origins.end() && localIt->second->ownsDocument(doc)) {
        return localIt->second.get();
    }

    return nullptr;
}

FileOrigin* OriginManager::originForDocument(App::Document* doc) const
{
    if (!doc) {
        return nullptr;
    }

    // Check explicit association first
    auto it = _documentOrigins.find(doc);
    if (it != _documentOrigins.end()) {
        FileOrigin* origin = getOrigin(it->second);
        if (origin) {
            return origin;
        }
        // Origin was unregistered, clear stale association
        _documentOrigins.erase(it);
    }

    // Fall back to ownership detection
    FileOrigin* owner = findOwningOrigin(doc);
    if (owner) {
        // Cache the result
        _documentOrigins[doc] = owner->id();
        return owner;
    }

    return nullptr;
}

void OriginManager::setDocumentOrigin(App::Document* doc, FileOrigin* origin)
{
    if (!doc) {
        return;
    }

    std::string originId = origin ? origin->id() : "";

    if (origin) {
        _documentOrigins[doc] = originId;
    } else {
        _documentOrigins.erase(doc);
    }

    signalDocumentOriginChanged(doc, originId);
}

void OriginManager::clearDocumentOrigin(App::Document* doc)
{
    if (!doc) {
        return;
    }

    auto it = _documentOrigins.find(doc);
    if (it != _documentOrigins.end()) {
        _documentOrigins.erase(it);
    }
}

FileOrigin* OriginManager::originForNewDocument() const
{
    return currentOrigin();
}

}  // namespace Gui