// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "SlateFwd.h"
#include "Misc/Attribute.h"
#include "InputCoreTypes.h"
#include "Types/SlateStructs.h"
#include "Fonts/SlateFontInfo.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SWidget.h"
#include "Widgets/SCompoundWidget.h"
#include "Widgets/Input/SButton.h"
#include "Widgets/Views/STableViewBase.h"
#include "Widgets/Views/STableRow.h"
#include "Widgets/Views/STreeView.h"
#include "EditorStyleSet.h"

class FKeyTreeInfo;
class SComboButton;

DECLARE_DELEGATE_OneParam(FOnKeyChanged, TSharedPtr<FKey>)

    //////////////////////////////////////////////////////////////////////////
    // SKeySelector

    typedef TSharedPtr<FKeyTreeInfo> FKeyTreeItem;
typedef STreeView<FKeyTreeItem> SKeyTreeView;

/** Widget for selecting an input key */
class UNREALED_API SKeySelector: public SCompoundWidget
{
public:
    SLATE_BEGIN_ARGS(SKeySelector)
        : _CurrentKey(FKey()), _TreeViewWidth(300.f), _TreeViewHeight(400.f), _Font(FEditorStyle::GetFontStyle(TEXT("NormalFont"))), _FilterBlueprintBindable(true), _AllowClear(true)
    {}
    SLATE_ATTRIBUTE(TOptional<FKey>, CurrentKey)
    SLATE_ATTRIBUTE(FOptionalSize, TreeViewWidth)
    SLATE_ATTRIBUTE(FOptionalSize, TreeViewHeight)
    SLATE_EVENT(FOnKeyChanged, OnKeyChanged)
    SLATE_ATTRIBUTE(FSlateFontInfo, Font)
    SLATE_ARGUMENT(bool, FilterBlueprintBindable)
    SLATE_ARGUMENT(bool, AllowClear)
    SLATE_END_ARGS()
public:
    void Construct(const FArguments& InArgs);

protected:
    /** Gets the icon for the key being manipulated */
    const FSlateBrush* GetKeyIconImage() const;
    /** Toggles the icon's color when in listen mode */
    FSlateColor GetKeyIconColor() const;

    /** Gets a succinct description for the key being manipulated */
    FText GetKeyDescription() const;
    /** Gets a tooltip for the selected key */
    FText GetKeyTooltip() const;

    /** Treeview support functions */
    virtual TSharedRef<ITableRow> GenerateKeyTreeRow(FKeyTreeItem InItem, const TSharedRef<STableViewBase>& OwnerTree);
    void OnKeySelectionChanged(FKeyTreeItem Selection, ESelectInfo::Type SelectInfo);
    void GetKeyChildren(FKeyTreeItem InItem, TArray<FKeyTreeItem>& OutChildren);

    /** Gets the Menu Content, setting it up if necessary */
    virtual TSharedRef<SWidget> GetMenuContent();

    /** Key searching support */
    void OnFilterTextChanged(const FText& NewText);
    void OnFilterTextCommitted(const FText& NewText, ETextCommit::Type CommitInfo);
    void GetSearchTokens(const FString& SearchString, TArray<FString>& OutTokens) const;

    /** Helper to generate the filtered list of keys, based on the search string matching */
    bool GetChildrenMatchingSearch(const TArray<FString>& SearchTokens, const TArray<FKeyTreeItem>& UnfilteredList, TArray<FKeyTreeItem>& OutFilteredList);

    /** Start listening for the next key press */
    FReply ListenForInput();
    /** Assigns the heard input as the current key */
    FReply ProcessHeardInput(FKey KeyHeard);

    virtual bool SupportsKeyboardFocus() const override { return bListenForNextInput; }

    /** Input listeners */
    virtual FReply OnKeyDown(const FGeometry& MyGeometry, const FKeyEvent& InKeyEvent) override;
    virtual FReply OnMouseButtonDown(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent) override;
    virtual FReply OnMouseWheel(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent) override;
    virtual FReply OnMouseMove(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent) override;
    virtual FReply OnAnalogValueChanged(const FGeometry& MyGeometry, const FAnalogInputEvent& InAnalogInputEvent) override;

    /**
     * Determine the best icon to represent the given key.
     *
     * @param Key		The key to get the icon for.
     * @param returns a brush that best represents the icon
     */
    const FSlateBrush* GetIconFromKey(FKey Key) const;

protected:
    /** Combo Button that shows current key and icon */
    TSharedPtr<SComboButton> KeyComboButton;

    /** Reference to the menu content that's displayed when the key button is clicked on */
    TSharedPtr<SWidget> MenuContent;
    TSharedPtr<SSearchBox> FilterTextBox;
    TSharedPtr<SKeyTreeView> KeyTreeView;
    FText SearchText;

    /** The key attribute that we're modifying with this widget, or an empty optional if the key contains multiple values */
    TAttribute<TOptional<FKey>> CurrentKey;

    /** Delegate that is called every time the key changes. */
    FOnKeyChanged OnKeyChanged;

    /** Desired width of the tree view widget */
    TAttribute<FOptionalSize> TreeViewWidth;
    /** Desired height of the tree view widget */
    TAttribute<FOptionalSize> TreeViewHeight;

    /** Font used for category tree entries */
    FSlateFontInfo CategoryFont;
    /** Font used for key tree entries */
    FSlateFontInfo KeyFont;

    /** Array containing the unfiltered list of all values this key could possibly have */
    TArray<FKeyTreeItem> KeyTreeRoot;
    /** Array containing a filtered list, according to the text in the searchbox */
    TArray<FKeyTreeItem> FilteredKeyTreeRoot;

    bool bListenForNextInput = false;
};