/*
 * Buttons.h, part of VCMI engine
 *
 * Authors: listed in file AUTHORS in main folder
 *
 * License: GNU General Public License v2.0 or later
 * Full text of license available in license.txt file, in main folder
 *
 */
#pragma once

#include "../gui/CIntObject.h"
#include "../render/Colors.h"
#include "../../lib/FunctionList.h"

#include <SDL_pixels.h>

VCMI_LIB_NAMESPACE_BEGIN
class Rect;
VCMI_LIB_NAMESPACE_END

class CAnimImage;
class CLabel;
class CAnimation;

/// Typical Heroes 3 button which can be inactive or active and can
/// hold further information if you right-click it
class CButton : public CKeyShortcut
{
	CFunctionList<void()> callback;

public:
	enum ButtonState
	{
		NORMAL=0,
		PRESSED=1,
		BLOCKED=2,
		HIGHLIGHTED=3
	};
private:
	std::vector<std::string> imageNames;//store list of images that can be used by this button
	size_t currentImage;

	ButtonState state;//current state of button from enum

	std::array<int, 4> stateToIndex; // mapping of button state to index of frame in animation
	std::array<std::string, 4> hoverTexts; //texts for statusbar, if empty - first entry will be used
	std::array<std::optional<SDL_Color>, 4> stateToBorderColor; // mapping of button state to border color
	std::string helpBox; //for right-click help

	std::shared_ptr<CAnimImage> image; //image for this button
	std::shared_ptr<CIntObject> overlay;//object-overlay, can be null
	bool animateLonelyFrame = false;
protected:
	void onButtonClicked(); // calls callback
	void update();//to refresh button after image or text change

	// internal method to change state. Public change can be done only via block()
	void setState(ButtonState newState);
	ButtonState getState();

public:
	bool actOnDown,//runs when mouse is pressed down over it, not when up
		hoverable,//if true, button will be highlighted when hovered (e.g. main menu)
		soundDisabled;

	// sets border color for each button state;
	// if it's set, the button will have 1-px border around it with this color
	void setBorderColor(std::optional<SDL_Color> normalBorderColor,
						std::optional<SDL_Color> pressedBorderColor,
						std::optional<SDL_Color> blockedBorderColor,
						std::optional<SDL_Color> highlightedBorderColor);

	// sets the same border color for all button states.
	void setBorderColor(std::optional<SDL_Color> borderColor);

	/// adds one more callback to on-click actions
	void addCallback(std::function<void()> callback);

	/// adds overlay on top of button image. Only one overlay can be active at once
	void addOverlay(std::shared_ptr<CIntObject> newOverlay);
	void addTextOverlay(const std::string & Text, EFonts font, SDL_Color color = Colors::WHITE);

	void addImage(std::string filename);
	void addHoverText(ButtonState state, std::string text);

	void setImageOrder(int state1, int state2, int state3, int state4);
	void setAnimateLonelyFrame(bool agreement);
	void block(bool on);

	/// State modifiers
	bool isBlocked();
	bool isHighlighted();

	/// Constructor
	CButton(Point position, const std::string & defName, const std::pair<std::string, std::string> & help,
			CFunctionList<void()> Callback = 0, EShortcut key = {}, bool playerColoredButton = false );

	/// Appearance modifiers
	void setIndex(size_t index);
	void setImage(std::shared_ptr<CAnimation> anim, int animFlags=0);
	void setPlayerColor(PlayerColor player);

	/// CIntObject overrides
	void showPopupWindow(const Point & cursorPosition) override;
	void clickPressed(const Point & cursorPosition) override;
	void clickReleased(const Point & cursorPosition) override;
	void clickCancel(const Point & cursorPosition) override;
	void hover (bool on) override;
	void showAll(Canvas & to) override;

	/// generates tooltip that can be passed into constructor
	static std::pair<std::string, std::string> tooltip();
	static std::pair<std::string, std::string> tooltipLocalized(const std::string & key);
	static std::pair<std::string, std::string> tooltip(const std::string & hover, const std::string & help = "");
};

class CToggleBase
{
	CFunctionList<void(bool)> callback;
protected:

	bool selected;

	// internal method for overrides
	virtual void doSelect(bool on);

	// returns true if toggle can change its state
	bool canActivate();

public:
	/// if set to false - button can not be deselected normally
	bool allowDeselection;

	CToggleBase(CFunctionList<void(bool)> callback);
	virtual ~CToggleBase();

	/// Changes selection to "on", and calls callback
	void setSelected(bool on);

	/// Changes selection to "on" without calling callback
	void setSelectedSilent(bool on);

	void addCallback(std::function<void(bool)> callback);

	/// Set whether the toggle is currently enabled for user to use, this is only inplemented in ToggleButton, not for other toggles yet.
	virtual void setEnabled(bool enabled);
};

/// A button which can be selected/deselected, checkbox
class CToggleButton : public CButton, public CToggleBase
{
	void doSelect(bool on) override;
	void setEnabled(bool enabled) override;

public:
	CToggleButton(Point position, const std::string &defName, const std::pair<std::string, std::string> &help,
				  CFunctionList<void(bool)> Callback = 0, EShortcut key = {}, bool playerColoredButton = false );

	void clickPressed(const Point & cursorPosition) override;
	void clickReleased(const Point & cursorPosition) override;
	void clickCancel(const Point & cursorPosition) override;

	// bring overrides into scope
	//using CButton::addCallback;
	using CToggleBase::addCallback;
};

class CToggleGroup : public CIntObject
{
	CFunctionList<void(int)> onChange; //called when changing selected button with new button's id

	int selectedID;
	void selectionChanged(int to);
public:
	std::map<int, std::shared_ptr<CToggleBase>> buttons;

	CToggleGroup(const CFunctionList<void(int)> & OnChange);

	void addCallback(std::function<void(int)> callback);
	void resetCallback();

	/// add one toggle/button into group
	void addToggle(int index, std::shared_ptr<CToggleBase> button);
	/// Changes selection to specific value. Will select toggle with this ID, if present
	void setSelected(int id);
	/// in some cases, e.g. LoadGame difficulty selection, after refreshing the UI, the ToggleGroup should 
	/// reset all of it's child buttons to BLOCK state, then make selection again
	void setSelectedOnly(int id);
	int getSelected() const;
};