#include "SelectedBuildingPanel.h"

#include <algorithm>
#include <cctype>
#include <map>
#include <set>
#include <string>

#include <QComboBox>
#include <QLabel>
#include <QListWidget>
#include <QPushButton>
#include <QVBoxLayout>

#include "BeltSystem.h"
#include "Building.h"
#include "BuildingSystem.h"
#include "BuildingType.h"
#include "ItemType.h"
#include "ModulesConfig.h"
#include "Rotation.h"
#include "ShipLayoutPreview.h"
#include "Simulation.h"

namespace
{

QString buildingTypeName(BuildingType type)
{
    const std::string id = buildingTypeId(type);
    QString result;
    bool nextUpper = true;
    for (char c : id)
    {
        if (c == '_')
        {
            result += ' ';
            nextUpper = true;
        }
        else if (nextUpper)
        {
            result += static_cast<char>(std::toupper(static_cast<unsigned char>(c)));
            nextUpper = false;
        }
        else
        {
            result += c;
        }
    }
    return result;
}

bool isProductionBuilding(BuildingType type)
{
    return type == BuildingType::Miner
        || type == BuildingType::Smelter
        || type == BuildingType::Assembler
        || type == BuildingType::ReprocessingPlant
        || type == BuildingType::Shipyard;
}

bool isBeltLike(BuildingType type)
{
    return type == BuildingType::Belt || type == BuildingType::Splitter
        || type == BuildingType::TunnelEntry || type == BuildingType::TunnelExit;
}

QString rotationLabel(Rotation r)
{
    switch (r)
    {
        case Rotation::North: return "North (↑)";
        case Rotation::East:  return "East (→)";
        case Rotation::South: return "South (↓)";
        case Rotation::West:  return "West (←)";
    }
    return "";
}

}  // namespace


SelectedBuildingPanel::SelectedBuildingPanel(Simulation* sim,
                                             const GameConfig* config,
                                             QWidget* parent)
    : QWidget(parent)
    , m_sim(sim)
    , m_config(config)
    , m_singleId(kInvalidEntityId)
    , m_splitterTile(0, 0)
{
    m_layout = new QVBoxLayout(this);
    m_layout->setContentsMargins(8, 8, 8, 8);
    m_layout->setSpacing(4);
    m_layout->setAlignment(Qt::AlignTop);

    m_titleLabel   = new QLabel(this);
    m_recipeCombo  = new QComboBox(this);
    m_clearBeltBtn = new QPushButton("Clear Items", this);
    m_filterALabel = new QLabel(this);
    m_filterAList  = new QListWidget(this);
    m_filterBLabel = new QLabel(this);
    m_filterBList  = new QListWidget(this);
    m_layoutPreview      = new ShipLayoutPreview(this);
    m_configureLayoutBtn = new QPushButton("Configure Layout", this);
    m_buffersLabel = new QLabel(this);
    m_buffersLabel->setWordWrap(true);

    m_filterAList->setMaximumHeight(100);
    m_filterBList->setMaximumHeight(100);

    m_layout->addWidget(m_titleLabel);
    m_layout->addWidget(m_recipeCombo);
    m_layout->addWidget(m_layoutPreview);
    m_layout->addWidget(m_configureLayoutBtn);
    m_layout->addWidget(m_clearBeltBtn);
    m_layout->addWidget(m_filterALabel);
    m_layout->addWidget(m_filterAList);
    m_layout->addWidget(m_filterBLabel);
    m_layout->addWidget(m_filterBList);
    m_layout->addWidget(m_buffersLabel);

    connect(m_recipeCombo, qOverload<int>(&QComboBox::currentIndexChanged),
            this, &SelectedBuildingPanel::onRecipeChanged);
    connect(m_clearBeltBtn, &QPushButton::clicked,
            this, &SelectedBuildingPanel::onClearBelt);
    connect(m_configureLayoutBtn, &QPushButton::clicked, this, [this]() {
        if (m_singleId != kInvalidEntityId)
        {
            emit layoutDialogRequested(m_singleId);
        }
    });
    connect(m_filterAList, &QListWidget::itemChanged,
            this, &SelectedBuildingPanel::onSplitterFilterChanged);
    connect(m_filterBList, &QListWidget::itemChanged,
            this, &SelectedBuildingPanel::onSplitterFilterChanged);

    buildEmpty();
}

void SelectedBuildingPanel::onSelectionChanged(const std::vector<EntityId>& ids)
{
    m_selection = ids;
    rebuild();
}

void SelectedBuildingPanel::rebuild()
{
    if (m_selection.empty())
    {
        buildEmpty();
    }
    else if (m_selection.size() == 1)
    {
        buildSingle(m_selection[0]);
    }
    else
    {
        buildMulti(m_selection);
    }
}

void SelectedBuildingPanel::buildEmpty()
{
    m_singleId = kInvalidEntityId;
    m_titleLabel->hide();
    m_recipeCombo->hide();
    m_layoutPreview->hide();
    m_configureLayoutBtn->hide();
    m_clearBeltBtn->hide();
    m_filterALabel->hide();
    m_filterAList->hide();
    m_filterBLabel->hide();
    m_filterBList->hide();
    m_buffersLabel->hide();
}

void SelectedBuildingPanel::buildSingle(EntityId id)
{
    m_singleId = id;

    const Building* b = m_sim->buildings().findBuilding(id);
    if (!b)
    {
        const ConstructionSite* s = m_sim->buildings().findSite(id);
        if (!s)
        {
            buildEmpty();
            return;
        }

        QString progress;
        if (s->completesAt == 0)
        {
            progress = "Queued";
        }
        else
        {
            const BuildingDef* def = nullptr;
            for (const BuildingDef& d : m_config->buildings.buildings)
            {
                if (d.type == s->type) { def = &d; break; }
            }
            if (def && def->constructionTimeSeconds > 0)
            {
                const Tick duration = secondsToTicks(def->constructionTimeSeconds);
                const Tick elapsed  = m_sim->currentTick() - (s->completesAt - duration);
                const int pct = static_cast<int>(
                    std::max(Tick(0), std::min(duration, elapsed)) * 100 / duration);
                progress = QString::number(pct) + "% complete";
            }
            else
            {
                progress = "Building...";
            }
        }

        m_titleLabel->setText("(Building) " + buildingTypeName(s->type));
        m_titleLabel->show();
        m_buffersLabel->setText(progress);
        m_buffersLabel->show();
        return;
    }

    m_titleLabel->setText(buildingTypeName(b->type));
    m_titleLabel->show();
    m_buffersLabel->show();

    if (isProductionBuilding(b->type))
    {
        m_recipeCombo->blockSignals(true);
        m_recipeCombo->clear();

        m_recipeCombo->addItem("(none)", QString());

        if (b->type == BuildingType::Shipyard)
        {
            for (const ShipDef& def : m_config->ships.ships)
            {
                if (m_sim->isSchematicUnlocked(def.id))
                {
                    m_recipeCombo->addItem(
                        QString::fromStdString(def.id),
                        QString::fromStdString(def.id));
                }
            }
        }
        else
        {
            for (const RecipeDef& recipe : m_config->recipes.recipes)
            {
                if (recipe.building == b->type)
                {
                    m_recipeCombo->addItem(
                        QString::fromStdString(recipe.id),
                        QString::fromStdString(recipe.id));
                }
            }
        }

        const int currentIdx = m_recipeCombo->findData(QString::fromStdString(b->recipeId));
        m_recipeCombo->setCurrentIndex(currentIdx >= 0 ? currentIdx : 0);
        m_recipeCombo->blockSignals(false);
        m_recipeCombo->show();

        if (b->type == BuildingType::Shipyard && !b->recipeId.empty())
        {
            const ShipDef* sDef = findShipDef(b->recipeId);
            if (sDef && !sDef->layout.empty())
            {
                ShipLayoutConfig layout;
                if (b->shipLayout.has_value())
                {
                    layout = *b->shipLayout;
                }
                m_layoutPreview->setShipAndLayout(
                    sDef->layout, layout, &m_config->modules.modules);
                m_layoutPreview->show();
                m_configureLayoutBtn->show();
            }
            else
            {
                m_layoutPreview->hide();
                m_configureLayoutBtn->hide();
            }
        }
        else
        {
            m_layoutPreview->hide();
            m_configureLayoutBtn->hide();
        }
    }
    else
    {
        m_recipeCombo->hide();
        m_layoutPreview->hide();
        m_configureLayoutBtn->hide();
    }

    if (isBeltLike(b->type))
    {
        m_clearBeltBtn->show();
    }
    else
    {
        m_clearBeltBtn->hide();
    }

    if (b->type == BuildingType::Splitter)
    {
        m_splitterTile = b->anchor;
        buildSplitterFilters(m_splitterTile);
    }
    else
    {
        m_filterALabel->hide();
        m_filterAList->hide();
        m_filterBLabel->hide();
        m_filterBList->hide();
    }

    refreshBuffers(b);
}

void SelectedBuildingPanel::refreshBuffers(const Building* b)
{
    const RecipeDef* recipe  = findRecipe(b);
    const ShipDef*   shipDef = (b->type == BuildingType::Shipyard)
                                ? findShipDef(b->recipeId)
                                : nullptr;

    QString bufText;

    if (!b->inputBuffer.counts.empty())
    {
        bufText += "Input: ";
        for (const std::pair<const ItemType, int>& entry : b->inputBuffer.counts)
        {
            int perCycle = 0;
            if (recipe)
            {
                for (const RecipeIngredient& ing : recipe->inputs)
                {
                    if (ing.item == entry.first.id) { perCycle = ing.amount; break; }
                }
            }
            else if (shipDef)
            {
                for (const RecipeIngredient& mat : shipDef->schematic.materials)
                {
                    if (mat.item == entry.first.id) { perCycle = mat.amount; break; }
                }
                if (b->shipLayout.has_value())
                {
                    for (const PlacedModule& pm : b->shipLayout->placedModules)
                    {
                        for (const ModuleDef& modDef : m_config->modules.modules)
                        {
                            if (modDef.id == pm.moduleId)
                            {
                                for (const RecipeIngredient& ing : modDef.materials)
                                {
                                    if (ing.item == entry.first.id)
                                    {
                                        perCycle += ing.amount;
                                    }
                                }
                                break;
                            }
                        }
                    }
                }
            }
            bufText += QString::fromStdString(entry.first.id)
                + ": " + QString::number(entry.second);
            if (perCycle > 0)
            {
                bufText += "/" + QString::number(perCycle);
            }
            bufText += "  ";
        }
        bufText += "\n";
    }

    if (recipe && !recipe->outputs.empty())
    {
        std::map<std::string, int> outCounts;
        for (const Item& item : b->outputBuffer.items)
        {
            outCounts[item.type.id]++;
        }
        bufText += "Output: ";
        for (const RecipeOutput& out : recipe->outputs)
        {
            const std::map<std::string, int>::const_iterator it =
                outCounts.find(out.item);
            const int count = (it != outCounts.end()) ? it->second : 0;
            bufText += QString::fromStdString(out.item)
                + ": " + QString::number(count)
                + "/" + QString::number(out.amount) + "  ";
        }
    }
    else if (!b->outputBuffer.items.empty())
    {
        std::map<std::string, int> outCounts;
        for (const Item& item : b->outputBuffer.items)
        {
            outCounts[item.type.id]++;
        }
        bufText += "Output: ";
        for (const std::pair<const std::string, int>& entry : outCounts)
        {
            bufText += QString::fromStdString(entry.first)
                + ": " + QString::number(entry.second) + "  ";
        }
    }

    if (isProductionBuilding(b->type) && (recipe || shipDef))
    {
        double durationSeconds = recipe
            ? recipe->durationSeconds
            : shipDef->schematic.productionTimeSeconds;

        if (shipDef && b->shipLayout.has_value())
        {
            for (const PlacedModule& pm : b->shipLayout->placedModules)
            {
                for (const ModuleDef& modDef : m_config->modules.modules)
                {
                    if (modDef.id == pm.moduleId)
                    {
                        durationSeconds += modDef.productionTimeSeconds;
                        break;
                    }
                }
            }
        }

        bufText += QString("Cycle: %1 s\n").arg(durationSeconds, 0, 'f', 1);

        if (b->production.has_value())
        {
            const Tick cycleTicks  = secondsToTicks(durationSeconds);
            const Tick completesAt = b->production->completesAt;
            const Tick currentTick = m_sim->currentTick();
            const Tick elapsed     = currentTick - (completesAt - cycleTicks);
            const int  pct         = static_cast<int>(
                std::max(Tick(0), std::min(cycleTicks, elapsed)) * 100 / cycleTicks);
            bufText += QString("Progress: %1%\n").arg(pct);
        }
        else
        {
            bufText += "Progress: idle\n";
        }
    }

    m_buffersLabel->setText(bufText);

    if (b->type == BuildingType::Shipyard && shipDef && !shipDef->layout.empty())
    {
        ShipLayoutConfig layout;
        if (b->shipLayout.has_value())
        {
            layout = *b->shipLayout;
        }
        m_layoutPreview->setShipAndLayout(
            shipDef->layout, layout, &m_config->modules.modules);
    }
}

const RecipeDef* SelectedBuildingPanel::findRecipe(const Building* b) const
{
    if (b->recipeId.empty()) { return nullptr; }
    for (const RecipeDef& r : m_config->recipes.recipes)
    {
        if (r.id == b->recipeId && r.building == b->type) { return &r; }
    }
    return nullptr;
}

const ShipDef* SelectedBuildingPanel::findShipDef(const std::string& id) const
{
    if (id.empty()) { return nullptr; }
    for (const ShipDef& s : m_config->ships.ships)
    {
        if (s.id == id) { return &s; }
    }
    return nullptr;
}

void SelectedBuildingPanel::onStateUpdated(Tick /*tick*/, int /*blocks*/, double /*speed*/)
{
    if (m_singleId == kInvalidEntityId) { return; }
    const Building* b = m_sim->buildings().findBuilding(m_singleId);
    if (b)
    {
        // If the panel was last showing this id as a construction site, the
        // full building UI (recipe combo, ports, etc.) hasn't been built yet.
        if (m_titleLabel->text().startsWith("(Building) "))
        {
            rebuild();
        }
        else
        {
            refreshBuffers(b);
        }
        return;
    }
    const ConstructionSite* s = m_sim->buildings().findSite(m_singleId);
    if (s)
    {
        rebuild();
        return;
    }
    buildEmpty();
}

void SelectedBuildingPanel::buildMulti(const std::vector<EntityId>& ids)
{
    m_singleId = kInvalidEntityId;
    m_recipeCombo->hide();
    m_clearBeltBtn->hide();
    m_filterALabel->hide();
    m_filterAList->hide();
    m_filterBLabel->hide();
    m_filterBList->hide();
    m_buffersLabel->hide();

    std::map<BuildingType, int> counts;
    for (EntityId id : ids)
    {
        const Building* b = m_sim->buildings().findBuilding(id);
        if (b)
        {
            counts[b->type]++;
            continue;
        }
        const ConstructionSite* s = m_sim->buildings().findSite(id);
        if (s)
        {
            counts[s->type]++;
        }
    }

    bool hasBelt = false;
    QString text;
    for (const std::pair<const BuildingType, int>& entry : counts)
    {
        text += buildingTypeName(entry.first) + ": "
            + QString::number(entry.second) + "\n";
        if (isBeltLike(entry.first))
        {
            hasBelt = true;
        }
    }
    m_titleLabel->setText(text.trimmed());
    m_titleLabel->show();

    if (hasBelt)
    {
        m_clearBeltBtn->show();
    }
}

void SelectedBuildingPanel::onRecipeChanged(int comboIndex)
{
    if (m_singleId == kInvalidEntityId)
    {
        return;
    }
    const QString recipeId = m_recipeCombo->itemData(comboIndex).toString();
    m_sim->buildings().setRecipe(m_singleId, recipeId.toStdString());
    rebuild();
}

void SelectedBuildingPanel::buildSplitterFilters(QPoint splitterTile)
{
    const std::optional<BeltSystem::SplitterInfo> info =
        m_sim->belts().getSplitterInfo(splitterTile);
    if (!info.has_value())
    {
        m_filterALabel->hide();
        m_filterAList->hide();
        m_filterBLabel->hide();
        m_filterBList->hide();
        return;
    }

    const std::vector<std::string> items = allItemIds();

    auto populateList = [&](QListWidget* list, QLabel* label,
                            const QString& dirLabel,
                            const std::vector<ItemType>& filter)
    {
        label->setText(dirLabel + " filter (empty = all):");
        list->blockSignals(true);
        list->clear();
        for (const std::string& itemId : items)
        {
            QListWidgetItem* row = new QListWidgetItem(
                QString::fromStdString(itemId), list);
            const bool checked = filter.empty()
                ? false
                : std::find(filter.begin(), filter.end(),
                            ItemType{itemId}) != filter.end();
            row->setCheckState(checked ? Qt::Checked : Qt::Unchecked);
            row->setFlags(row->flags() | Qt::ItemIsUserCheckable);
        }
        list->blockSignals(false);
        label->show();
        list->show();
    };

    populateList(m_filterAList, m_filterALabel,
                 rotationLabel(info->outputA), info->filterA);
    populateList(m_filterBList, m_filterBLabel,
                 rotationLabel(info->outputB), info->filterB);
}

void SelectedBuildingPanel::onSplitterFilterChanged()
{
    if (m_singleId == kInvalidEntityId)
    {
        return;
    }

    auto collectFilter = [](QListWidget* list) -> std::vector<ItemType>
    {
        std::vector<ItemType> filter;
        for (int i = 0; i < list->count(); ++i)
        {
            const QListWidgetItem* row = list->item(i);
            if (row->checkState() == Qt::Checked)
            {
                filter.push_back(ItemType{row->text().toStdString()});
            }
        }
        return filter;
    };

    m_sim->belts().setSplitterFilters(
        m_splitterTile,
        collectFilter(m_filterAList),
        collectFilter(m_filterBList));
}

std::vector<std::string> SelectedBuildingPanel::allItemIds() const
{
    std::set<std::string> seen;
    for (const RecipeDef& recipe : m_config->recipes.recipes)
    {
        for (const RecipeIngredient& ing : recipe.inputs)
        {
            seen.insert(ing.item);
        }
        for (const RecipeOutput& out : recipe.outputs)
        {
            seen.insert(out.item);
        }
    }
    return std::vector<std::string>(seen.begin(), seen.end());
}

void SelectedBuildingPanel::onClearBelt()
{
    std::vector<QPoint> tiles;
    for (EntityId id : m_selection)
    {
        const Building* b = m_sim->buildings().findBuilding(id);
        if (b && isBeltLike(b->type))
        {
            for (const QPoint& cell : b->bodyCells)
            {
                tiles.push_back(cell);
            }
        }
    }
    if (!tiles.empty())
    {
        m_sim->belts().clearTiles(tiles);
    }
}