#include "MainWindow.h"

#include <map>
#include <random>
#include <set>

#include <QApplication>
#include <QCloseEvent>
#include <QDir>
#include <QFile>
#include <QMessageBox>
#include <QPushButton>
#include <QResizeEvent>
#include <QVBoxLayout>

#include "BlueprintPanel.h"
#include "BuildButtonGrid.h"
#include "BuildingSystem.h"
#include "Command.h"
#include "CommandRequestedEvent.h"
#include "ConfigLoader.h"
#include "EventManager.h"
#include "GameWorldView.h"
#include "RecipeSelectionDialog.h"
#include "SchematicChoiceDialog.h"
#include "HeaderBar.h"
#include "SelectedBuildingPanel.h"
#include "ShipLayoutBlueprintSerializer.h"
#include "ShipLayoutDialog.h"
#include "ItemIconCache.h"
#include "ModalPauseScope.h"
#include "Simulation.h"
#include "Tick.h"
#include "VisualsLoader.h"

MainWindow::MainWindow(Simulation* sim, const std::string& configDir,
                       std::shared_ptr<ParsedReplay> replay, QWidget* parent)
    : QWidget(parent)
    , m_configDir(configDir)
    , m_visuals(VisualsLoader::load(configDir + "/visuals.toml"))
    , m_sim(sim)
    , m_replay(std::move(replay))
{
    setWindowTitle(tr("Dota Factory"));
    resize(1280, 768);

    // Item icons live alongside the config (a sibling of the config dir), read from
    // disk at runtime like the building icons and visuals.toml (REQ-UI-ITEM-ICON).
    const std::string itemsIconDir = QDir::cleanPath(
        QString::fromStdString(m_configDir) + "/../icons/items").toStdString();

    m_itemIcons = std::make_unique<ItemIconCache>(
        QString::fromStdString(itemsIconDir));

    m_headerBar = new HeaderBar(sim, &sim->getConfig(), m_itemIcons.get(), this);

    m_gameWorldView = new GameWorldView(sim, &sim->getConfig(), &m_visuals, m_configDir,
                                        m_itemIcons.get(), m_replay.get(), this);

    m_sidePanel = new QWidget(this);
    QVBoxLayout* sideLayout = new QVBoxLayout(m_sidePanel);
    sideLayout->setContentsMargins(1, 1, 1, 1);
    sideLayout->setSpacing(1);

    // Building icons live alongside the config (a sibling of the config dir), read
    // from disk at runtime the same way visuals.toml is.
    const std::string iconDir = QDir::cleanPath(
        QString::fromStdString(m_configDir) + "/../icons/buildings").toStdString();

    m_selectedBuildingPanel = new SelectedBuildingPanel(sim, &sim->getConfig(), m_sidePanel);
    m_buildButtonGrid       = new BuildButtonGrid(sim, &sim->getConfig(), iconDir, m_itemIcons.get(), m_sidePanel);
    m_blueprintPanel        = new BlueprintPanel(sim, &sim->getConfig(), m_sidePanel);

    sideLayout->addWidget(m_selectedBuildingPanel, 1);
    sideLayout->addWidget(m_buildButtonGrid,       1);
    sideLayout->addWidget(m_blueprintPanel,        1);

    // Draw a thin border around each of the three side-panel sections. The class
    // scoped selectors keep the border on the panels themselves rather than
    // cascading onto their child widgets; WA_StyledBackground lets the plain
    // QWidget subclasses honor the stylesheet box (border/background).
    for (QWidget* panel : { static_cast<QWidget*>(m_selectedBuildingPanel),
                            static_cast<QWidget*>(m_buildButtonGrid),
                            static_cast<QWidget*>(m_blueprintPanel) })
    {
        panel->setAttribute(Qt::WA_StyledBackground, true);
    }
    m_sidePanel->setStyleSheet(QStringLiteral(
        "SelectedBuildingPanel, BuildButtonGrid, BlueprintPanel {"
        " border: 1px solid palette(mid); }"));

    // Created last so it stacks above the other children; covers the whole window and
    // dims the game behind modal dialogs/menus (REQ-UI-MODAL-DIM).
    m_dimOverlay = new ModalDimOverlay(m_visuals.overlays.modalDim, this);

    m_gameWorldView->setFocus();

    connect(qApp, &QApplication::focusChanged, this, [this](QWidget*, QWidget* newWidget) {
        if (newWidget && newWidget != m_gameWorldView && !QApplication::activeModalWidget())
        {
            m_gameWorldView->setFocus();
        }
    });

    // Load layout blueprints from disk. Missing file is silently ignored.
    const QString bpPath = QCoreApplication::applicationDirPath() + "/ship_layouts.toml";
    QFile bpFile(bpPath);
    if (bpFile.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        try
        {
            m_layoutBlueprints = ShipLayoutBlueprintSerializer::deserialize(
                bpFile.readAll().toStdString());
        }
        catch (const std::exception& e)
        {
            QMessageBox::critical(this, tr("Load Error"),
                tr("Failed to load ship_layouts.toml:\n%1").arg(e.what()));
            m_layoutBlueprints.clear();
        }
    }

    registerForEvents();
}

MainWindow::~MainWindow()
{
    unregisterForEvents();
}

void MainWindow::resizeEvent(QResizeEvent* event)
{
    QWidget::resizeEvent(event);
    layoutPanels();
}

void MainWindow::closeEvent(QCloseEvent* event)
{
    const QString path = QCoreApplication::applicationDirPath() + "/ship_layouts.toml";
    QFile file(path);
    if (file.open(QIODevice::WriteOnly | QIODevice::Text))
    {
        try
        {
            const std::string content =
                ShipLayoutBlueprintSerializer::serialize(m_layoutBlueprints);
            file.write(QByteArray::fromStdString(content));
        }
        catch (...) {}
    }
    QWidget::closeEvent(event);
}

void MainWindow::layoutPanels()
{
    const int totalW  = width();
    const int totalH  = height();
    const int headerH = m_headerBar->sizeHint().height();
    if (headerH <= 0) { return; }
    const int mainW = totalW * 75 / 100;
    const int sideW = totalW - mainW;

    m_headerBar->setGeometry(0, 0, mainW, headerH);
    m_gameWorldView->setGeometry(0, headerH, mainW, totalH - headerH);
    m_sidePanel->setGeometry(mainW, 0, sideW, totalH);
    m_dimOverlay->setGeometry(0, 0, totalW, totalH);
}

void MainWindow::handleEvent(std::shared_ptr<const SchematicChoicesAvailableEvent> event)
{
    ModalPauseScope pause(*m_gameWorldView);

    ModalDimScope dim(*m_dimOverlay);
    SchematicChoiceDialog dialog(event->choices, m_sim->getConfig().recipes, this);
    dialog.exec();

    std::shared_ptr<ApplySchematicChoiceCommand> command =
        std::make_shared<ApplySchematicChoiceCommand>();
    command->choiceIndex = dialog.getChosenIndex();
    EventManager::getInstance()->sendEventImmediately(
        std::make_shared<CommandRequestedEvent>(command));
}

void MainWindow::handleEvent(std::shared_ptr<const EscapeMenuRequestedEvent> /*event*/)
{
    ModalPauseScope pause(*m_gameWorldView);

    ModalDimScope dim(*m_dimOverlay);
    QMessageBox box(this);
    box.setWindowTitle(tr("Paused"));
    QPushButton* continueBtn = box.addButton(tr("Continue"), QMessageBox::AcceptRole);
    QPushButton* restartBtn  = box.addButton(tr("Restart"),  QMessageBox::ResetRole);
    QPushButton* quitBtn     = box.addButton(tr("Quit"),     QMessageBox::DestructiveRole);
    box.setEscapeButton(continueBtn);
    box.exec();

    QAbstractButton* clicked = box.clickedButton();
    if (clicked == restartBtn)
    {
        std::optional<GameConfig> newConfig = reloadConfig();
        if (!newConfig.has_value())
        {
            return;
        }
        // Restart is a command boundary; the view resets when the drain applies
        // it (see GameWorldView::onFrame). A fresh random seed starts a new run.
        // resetForNewGame() sets the speed for the new run, so the pre-restart
        // speed is deliberately not restored here.
        pause.release();
        std::shared_ptr<ResetCommand> command = std::make_shared<ResetCommand>();
        command->config = std::make_shared<GameConfig>(std::move(*newConfig));
        command->seed   = std::random_device{}();
        EventManager::getInstance()->sendEventImmediately(
            std::make_shared<CommandRequestedEvent>(command));
    }
    else if (clicked == quitBtn)
    {
        pause.release();
        close();
    }
}

std::optional<GameConfig> MainWindow::reloadConfig()
{
    // Config is reloaded from disk on every restart (REQ-CFG-RELOAD); a malformed
    // file must not leave the window half-updated, so the visuals are only applied
    // once both files have parsed.
    try
    {
        GameConfig    newConfig  = ConfigLoader::loadFromDirectory(m_configDir);
        VisualsConfig newVisuals = VisualsLoader::load(m_configDir + "/visuals.toml");
        m_visuals = std::move(newVisuals);
        m_dimOverlay->setDimColor(m_visuals.overlays.modalDim);
        return newConfig;
    }
    catch (const std::exception& e)
    {
        QMessageBox::critical(this, tr("Config Error"),
            tr("Failed to reload config:\n%1").arg(e.what()));
        return std::nullopt;
    }
}

void MainWindow::openShipLayoutDialog(BuildingId shipyardId,
                                      const std::string& schematicId,
                                      const ShipLayoutConfig& currentLayout)
{
    ModalPauseScope pause(*m_gameWorldView);

    std::set<std::string> unlockedModuleIds;
    for (const ModuleDef& def : m_sim->getConfig().modules.modules)
    {
        if (m_sim->isModuleSchematicUnlocked(def.id))
        {
            unlockedModuleIds.insert(def.id);
        }
    }

    ModalDimScope dim(*m_dimOverlay);
    ShipLayoutDialog dialog(&m_sim->getConfig(), schematicId, currentLayout,
                            m_layoutBlueprints,
                            std::move(unlockedModuleIds),
                            m_gameWorldView->isDebugDrawEnabled(),
                            this);
    if (dialog.exec() == QDialog::Accepted && dialog.getResult().has_value())
    {
        std::shared_ptr<SetShipLayoutCommand> command =
            std::make_shared<SetShipLayoutCommand>();
        command->id     = shipyardId;
        command->layout = *dialog.getResult();
        EventManager::getInstance()->sendEventImmediately(
            std::make_shared<CommandRequestedEvent>(command));
    }
}

void MainWindow::handleEvent(std::shared_ptr<const LayoutDialogRequestedEvent> event)
{
    // A construction site has no Building yet; fall back to its site record so
    // the shipyard layout can be configured before it is built (REQ-BLD-SITE-CONFIG).
    const Building* b = m_sim->getBuildings().findBuilding(event->shipyardId);
    const ConstructionSite* s =
        b ? nullptr : m_sim->getBuildings().findSite(event->shipyardId);
    if (!b && !s)
    {
        return;
    }

    const std::string& schematicId = b ? b->recipeId : s->recipeId;
    const std::optional<ShipLayoutConfig>& layoutOpt =
        b ? b->shipLayout : s->shipLayout;

    ShipLayoutConfig currentLayout;
    if (layoutOpt.has_value())
    {
        currentLayout = *layoutOpt;
    }

    openShipLayoutDialog(event->shipyardId, schematicId, currentLayout);
}

void MainWindow::handleEvent(std::shared_ptr<const RecipeSelectionRequestedEvent> event)
{
    ModalPauseScope pause(*m_gameWorldView);

    // A construction site has no Building yet; fall back to its site record so
    // the recipe/schematic can be chosen before it is built (REQ-BLD-SITE-CONFIG).
    const Building* b = m_sim->getBuildings().findBuilding(event->buildingId);
    const ConstructionSite* s =
        b ? nullptr : m_sim->getBuildings().findSite(event->buildingId);
    if (!b && !s)
    {
        return;
    }

    // Held across both the selection dialog and any auto-opened layout dialog so the
    // dim stays continuously visible through that sequence (REQ-UI-MODAL-DIM).
    ModalDimScope dim(*m_dimOverlay);

    const BuildingType type = b ? b->type : s->type;
    // Captured as a copy: a queued command may drain during the modal dialog's
    // event loop and reallocate the building vectors, so b/s must not be
    // dereferenced after dialog.exec() returns.
    const std::string oldSchematic = b ? b->recipeId : s->recipeId;
    const std::vector<RecipeSelectionOption> options =
        buildRecipeSelectionOptions(type, *m_sim, m_sim->getConfig());
    const QString title = (type == BuildingType::Shipyard)
        ? tr("Select Schematic")
        : tr("Select Recipe");

    bool autoOpenLayout = false;
    std::string chosenSchematic;
    RecipeSelectionDialog dialog(options, title, m_itemIcons.get(), this);
    if (dialog.exec() == QDialog::Accepted && dialog.getChosenId().has_value())
    {
        std::shared_ptr<SetRecipeCommand> command = std::make_shared<SetRecipeCommand>();
        command->id       = event->buildingId;
        command->recipeId = *dialog.getChosenId();
        EventManager::getInstance()->sendEventImmediately(
            std::make_shared<CommandRequestedEvent>(command));

        // REQ-MOD-UI-AUTO-DIALOG: picking a new schematic for a shipyard opens the
        // layout configuration dialog immediately. Only on an actual change.
        if (type == BuildingType::Shipyard && *dialog.getChosenId() != oldSchematic)
        {
            autoOpenLayout = true;
            chosenSchematic = *dialog.getChosenId();
        }
    }

    // The SetRecipeCommand above is queued (drains on a later frame) and clears
    // the shipyard's layout, so open the dialog with the chosen schematic and an
    // empty layout rather than reading the not-yet-updated building state. Speed
    // is restored first so the helper snapshots the real speed to restore.
    pause.restore();
    if (autoOpenLayout)
    {
        openShipLayoutDialog(event->buildingId, chosenSchematic, ShipLayoutConfig{});
    }
}

void MainWindow::handleEvent(std::shared_ptr<const GameOverEvent> /*event*/)
{
    const Tick tick = m_sim->getCurrentTick();
    const int totalSeconds = static_cast<int>(ticksToSeconds(tick));
    const int minutes = totalSeconds / 60;
    const int seconds = totalSeconds % 60;

    ModalDimScope dim(*m_dimOverlay);
    QMessageBox box(this);
    box.setWindowTitle(tr("Game Over"));
    box.setText(tr("HQ destroyed!\nSurvival time: %1:%2")
        .arg(minutes, 2, 10, QChar('0'))
        .arg(seconds, 2, 10, QChar('0')));
    QPushButton* restartBtn = box.addButton(tr("Restart"), QMessageBox::AcceptRole);
    box.addButton(tr("Quit"), QMessageBox::RejectRole);
    box.exec();

    if (box.clickedButton() == restartBtn)
    {
        std::optional<GameConfig> newConfig = reloadConfig();
        if (!newConfig.has_value())
        {
            return;
        }
        // Restart is a command boundary; the view resets when the drain applies it.
        std::shared_ptr<ResetCommand> command = std::make_shared<ResetCommand>();
        command->config = std::make_shared<GameConfig>(std::move(*newConfig));
        command->seed   = std::random_device{}();
        EventManager::getInstance()->sendEventImmediately(
            std::make_shared<CommandRequestedEvent>(command));
    }
    else
    {
        close();
    }
}

void MainWindow::handleEvent(std::shared_ptr<const WinEvent> /*event*/)
{
    const Tick tick = m_sim->getCurrentTick();
    const int totalSeconds = static_cast<int>(ticksToSeconds(tick));
    const int minutes = totalSeconds / 60;
    const int seconds = totalSeconds % 60;

    ModalDimScope dim(*m_dimOverlay);
    QMessageBox box(this);
    box.setWindowTitle(tr("Won!"));
    box.setText(tr("You collected all artifacts!\nSurvival time: %1:%2")
        .arg(minutes, 2, 10, QChar('0'))
        .arg(seconds, 2, 10, QChar('0')));
    QPushButton* restartBtn = box.addButton(tr("Restart"), QMessageBox::AcceptRole);
    box.addButton(tr("Quit"), QMessageBox::RejectRole);
    box.exec();

    if (box.clickedButton() == restartBtn)
    {
        std::optional<GameConfig> newConfig = reloadConfig();
        if (!newConfig.has_value())
        {
            return;
        }
        // Restart is a command boundary; the view resets when the drain applies it.
        std::shared_ptr<ResetCommand> command = std::make_shared<ResetCommand>();
        command->config = std::make_shared<GameConfig>(std::move(*newConfig));
        command->seed   = std::random_device{}();
        EventManager::getInstance()->sendEventImmediately(
            std::make_shared<CommandRequestedEvent>(command));
    }
    else
    {
        close();
    }
}