#include "HierarchyPanel.h"
#include "Managers/SceneManager.h"
#include "Managers/SelectionManager.h"
#include <imgui.h>
#include <cstring>

namespace UI {

HierarchyPanel::HierarchyPanel() : Panel("Hierarchy") {
    SceneManager::Get().CreateDemoScene();
    
    m_selectionHandlerId = SelectionManager::Get().OnSelectionChanged.Subscribe([this](EntityID) {
    });
}

HierarchyPanel::~HierarchyPanel() {
    SelectionManager::Get().OnSelectionChanged.Unsubscribe(m_selectionHandlerId);
}

void HierarchyPanel::Render() {
    ImGui::Begin(m_name.c_str(), nullptr, ImGuiWindowFlags_None);
    
    RenderSearchBar();
    
    ImGui::Separator();
    
    HandleKeyboardShortcuts();
    
    std::string filter = m_searchBuffer;
    
    ImGui::BeginChild("EntityList");
    
    for (EntityID id : SceneManager::Get().GetRootEntities()) {
        RenderEntity(id, filter);
    }
    
    if (ImGui::IsWindowHovered() && ImGui::IsMouseDown(0) && !ImGui::IsAnyItemHovered()) {
        if (!m_renaming) {
            SelectionManager::Get().ClearSelection();
        }
    }
    
    if (ImGui::BeginPopupContextWindow("HierarchyContextMenu", ImGuiPopupFlags_MouseButtonRight)) {
        RenderCreateMenu(INVALID_ENTITY_ID);
        ImGui::EndPopup();
    }
    
    ImGui::InvisibleButton("##DragTarget", ImVec2(-1, -1));
    if (ImGui::BeginDragDropTarget()) {
        if (const ImGuiPayload* payload = ImGui::AcceptDragDropPayload("ENTITY_ID")) {
            EntityID sourceId = *(const EntityID*)payload->Data;
            if (sourceId != INVALID_ENTITY_ID) {
                const GameObject* sourceEntity = SceneManager::Get().GetEntity(sourceId);
                if (sourceEntity && sourceEntity->parent != INVALID_ENTITY_ID) {
                    SceneManager::Get().MoveEntity(sourceId, INVALID_ENTITY_ID);
                }
            }
        }
        ImGui::EndDragDropTarget();
    }
    
    ImGui::EndChild();
    
    ImGui::End();
}

void HierarchyPanel::RenderSearchBar() {
    ImGui::SetNextItemWidth(-1);
    ImGui::InputTextWithHint("##Search", "Search...", m_searchBuffer, sizeof(m_searchBuffer));
}

void HierarchyPanel::RenderEntity(EntityID id, const std::string& filter) {
    auto& sceneManager = SceneManager::Get();
    GameObject* entity = sceneManager.GetEntity(id);
    if (!entity) return;
    
    if (!filter.empty() && !PassesFilter(id, filter)) {
        return;
    }
    
    ImGui::PushID(static_cast<int>(id));
    
    ImGuiTreeNodeFlags flags = ImGuiTreeNodeFlags_OpenOnArrow | ImGuiTreeNodeFlags_SpanAvailWidth;
    
    if (entity->children.empty()) {
        flags |= ImGuiTreeNodeFlags_Leaf;
    }
    
    if (SelectionManager::Get().IsSelected(id)) {
        flags |= ImGuiTreeNodeFlags_Selected;
    }
    
    if (m_renaming && m_renamingEntity == id) {
        if (m_renameJustStarted) {
            ImGui::SetKeyboardFocusHere();
            m_renameJustStarted = false;
        }
        
        ImGui::SetNextItemWidth(-1);
        if (ImGui::InputText("##Rename", m_renameBuffer, sizeof(m_renameBuffer), ImGuiInputTextFlags_EnterReturnsTrue | ImGuiInputTextFlags_AutoSelectAll)) {
            if (strlen(m_renameBuffer) > 0) {
                sceneManager.RenameEntity(id, m_renameBuffer);
            }
            m_renaming = false;
            m_renamingEntity = INVALID_ENTITY_ID;
        }
        
        if (!ImGui::IsItemActive() && ImGui::IsMouseClicked(0)) {
            if (strlen(m_renameBuffer) > 0) {
                sceneManager.RenameEntity(id, m_renameBuffer);
            }
            m_renaming = false;
            m_renamingEntity = INVALID_ENTITY_ID;
        }
    } else {
        bool isOpen = ImGui::TreeNodeEx(entity->name.c_str(), flags);
        
        if (ImGui::IsItemClicked() && !ImGui::IsItemToggledOpen()) {
            SelectionManager::Get().SetSelectedEntity(id);
        }
        
        if (ImGui::IsItemHovered() && ImGui::IsMouseDoubleClicked(0)) {
            m_renaming = true;
            m_renamingEntity = id;
            strcpy_s(m_renameBuffer, entity->name.c_str());
            m_renameJustStarted = true;
        }
        
        HandleDragDrop(id);
        
        if (ImGui::BeginPopupContextItem("EntityContextMenu")) {
            RenderContextMenu(id);
            ImGui::EndPopup();
        }
        
        if (isOpen) {
            for (EntityID childId : entity->children) {
                RenderEntity(childId, filter);
            }
            ImGui::TreePop();
        }
    }
    
    ImGui::PopID();
}

void HierarchyPanel::RenderContextMenu(EntityID id) {
    auto& sceneManager = SceneManager::Get();
    auto& selectionManager = SelectionManager::Get();
    
    if (ImGui::BeginMenu("Create")) {
        RenderCreateMenu(id);
        ImGui::EndMenu();
    }
    
    ImGui::Separator();
    
    if (ImGui::MenuItem("Rename", "F2")) {
        const GameObject* entity = sceneManager.GetEntity(id);
        if (entity) {
            m_renaming = true;
            m_renamingEntity = id;
            strcpy_s(m_renameBuffer, entity->name.c_str());
            m_renameJustStarted = true;
        }
    }
    
    if (ImGui::MenuItem("Delete", "Delete")) {
        sceneManager.DeleteEntity(id);
    }
    
    ImGui::Separator();
    
    if (ImGui::MenuItem("Copy", "Ctrl+C")) {
        sceneManager.CopyEntity(id);
    }
    
    if (ImGui::MenuItem("Paste", "Ctrl+V", false, sceneManager.HasClipboardData())) {
        sceneManager.PasteEntity(id);
    }
    
    if (ImGui::MenuItem("Duplicate", "Ctrl+D")) {
        EntityID newId = sceneManager.DuplicateEntity(id);
        if (newId != INVALID_ENTITY_ID) {
            selectionManager.SetSelectedEntity(newId);
        }
    }
}

void HierarchyPanel::RenderCreateMenu(EntityID parent) {
    auto& sceneManager = SceneManager::Get();
    auto& selectionManager = SelectionManager::Get();
    
    if (ImGui::MenuItem("Empty Object")) {
        EntityID newId = sceneManager.CreateEntity("GameObject", parent);
        selectionManager.SetSelectedEntity(newId);
    }
    
    ImGui::Separator();
    
    if (ImGui::MenuItem("Camera")) {
        EntityID newId = sceneManager.CreateEntity("Camera", parent);
        sceneManager.GetEntity(newId)->AddComponent<TransformComponent>();
        selectionManager.SetSelectedEntity(newId);
    }
    
    if (ImGui::MenuItem("Light")) {
        EntityID newId = sceneManager.CreateEntity("Light", parent);
        selectionManager.SetSelectedEntity(newId);
    }
    
    ImGui::Separator();
    
    if (ImGui::MenuItem("Cube")) {
        EntityID newId = sceneManager.CreateEntity("Cube", parent);
        sceneManager.GetEntity(newId)->AddComponent<TransformComponent>();
        sceneManager.GetEntity(newId)->AddComponent<MeshRendererComponent>()->meshName = "Cube";
        selectionManager.SetSelectedEntity(newId);
    }
    
    if (ImGui::MenuItem("Sphere")) {
        EntityID newId = sceneManager.CreateEntity("Sphere", parent);
        sceneManager.GetEntity(newId)->AddComponent<TransformComponent>();
        sceneManager.GetEntity(newId)->AddComponent<MeshRendererComponent>()->meshName = "Sphere";
        selectionManager.SetSelectedEntity(newId);
    }
    
    if (ImGui::MenuItem("Plane")) {
        EntityID newId = sceneManager.CreateEntity("Plane", parent);
        sceneManager.GetEntity(newId)->AddComponent<TransformComponent>();
        sceneManager.GetEntity(newId)->AddComponent<MeshRendererComponent>()->meshName = "Plane";
        selectionManager.SetSelectedEntity(newId);
    }
}

void HierarchyPanel::HandleDragDrop(EntityID id) {
    auto& sceneManager = SceneManager::Get();
    
    if (ImGui::BeginDragDropSource(ImGuiDragDropFlags_None)) {
        m_dragSource = id;
        ImGui::SetDragDropPayload("ENTITY_ID", &id, sizeof(EntityID));
        const GameObject* entity = sceneManager.GetEntity(id);
        if (entity) {
            ImGui::Text("%s", entity->name.c_str());
        }
        ImGui::EndDragDropSource();
    }
    
    if (ImGui::BeginDragDropTarget()) {
        if (const ImGuiPayload* payload = ImGui::AcceptDragDropPayload("ENTITY_ID")) {
            EntityID sourceId = *(const EntityID*)payload->Data;
            if (sourceId != id && sourceId != INVALID_ENTITY_ID) {
                const GameObject* targetEntity = sceneManager.GetEntity(id);
                const GameObject* sourceEntity = sceneManager.GetEntity(sourceId);
                
                bool isValidMove = true;
                EntityID checkParent = targetEntity ? targetEntity->parent : INVALID_ENTITY_ID;
                while (checkParent != INVALID_ENTITY_ID) {
                    if (checkParent == sourceId) {
                        isValidMove = false;
                        break;
                    }
                    const GameObject* parentEntity = sceneManager.GetEntity(checkParent);
                    checkParent = parentEntity ? parentEntity->parent : INVALID_ENTITY_ID;
                }
                
                if (isValidMove && sourceEntity && sourceEntity->parent != id) {
                    sceneManager.MoveEntity(sourceId, id);
                }
            }
        }
        ImGui::EndDragDropTarget();
    }
}

void HierarchyPanel::HandleKeyboardShortcuts() {
    auto& sceneManager = SceneManager::Get();
    auto& selectionManager = SelectionManager::Get();
    
    EntityID selectedId = selectionManager.GetSelectedEntity();
    
    if (ImGui::IsWindowFocused()) {
        if (ImGui::IsKeyPressed(ImGuiKey_Delete)) {
            if (selectedId != INVALID_ENTITY_ID) {
                sceneManager.DeleteEntity(selectedId);
            }
        }
        
        if (ImGui::IsKeyPressed(ImGuiKey_F2)) {
            if (selectedId != INVALID_ENTITY_ID) {
                const GameObject* entity = sceneManager.GetEntity(selectedId);
                if (entity) {
                    m_renaming = true;
                    m_renamingEntity = selectedId;
                    strcpy_s(m_renameBuffer, entity->name.c_str());
                    m_renameJustStarted = true;
                }
            }
        }
        
        ImGuiIO& io = ImGui::GetIO();
        if (io.KeyCtrl) {
            if (ImGui::IsKeyPressed(ImGuiKey_C)) {
                if (selectedId != INVALID_ENTITY_ID) {
                    sceneManager.CopyEntity(selectedId);
                }
            }
            
            if (ImGui::IsKeyPressed(ImGuiKey_V)) {
                if (sceneManager.HasClipboardData()) {
                    sceneManager.PasteEntity(selectedId);
                }
            }
            
            if (ImGui::IsKeyPressed(ImGuiKey_D)) {
                if (selectedId != INVALID_ENTITY_ID) {
                    EntityID newId = sceneManager.DuplicateEntity(selectedId);
                    if (newId != INVALID_ENTITY_ID) {
                        selectionManager.SetSelectedEntity(newId);
                    }
                }
            }
        }
    }
}

bool HierarchyPanel::PassesFilter(EntityID id, const std::string& filter) {
    auto& sceneManager = SceneManager::Get();
    const GameObject* entity = sceneManager.GetEntity(id);
    if (!entity) return false;
    
    if (entity->name.find(filter) != std::string::npos) {
        return true;
    }
    
    for (EntityID childId : entity->children) {
        if (PassesFilter(childId, filter)) {
            return true;
        }
    }
    
    return false;
}

}