/*
 * 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 "../gui/SDL_Extensions.h"

#include "../../lib/FunctionList.h"

struct SDL_Surface;
struct Rect;
class CAnimImage;
class CLabel;
class CAnimation;

namespace config
{
	struct ButtonInfo;
}

/// 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<boost::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(boost::optional<SDL_Color> normalBorderColor,
	                    boost::optional<SDL_Color> pressedBorderColor,
	                    boost::optional<SDL_Color> blockedBorderColor,
	                    boost::optional<SDL_Color> highlightedBorderColor);

	// sets the same border color for all button states.
	void setBorderColor(boost::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, int key=0, bool playerColoredButton = false );

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

	/// CIntObject overrides
	void clickRight(tribool down, bool previousState) override;
	void clickLeft(tribool down, bool previousState) override;
	void hover (bool on) override;
	void showAll(SDL_Surface * 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> tooltip(const JsonNode & localizedTexts);
	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);

	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, int key=0, bool playerColoredButton = false );
	void clickLeft(tribool down, bool previousState) 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);
};

/// A typical slider for volume with an animated indicator
class CVolumeSlider : public CIntObject
{
	int value;
	CFunctionList<void(int)> onChange;
	std::shared_ptr<CAnimImage> animImage;
	const std::pair<std::string, std::string> * const helpHandlers;
	void setVolume(const int v);
public:

	/// @param position coordinates of slider
	/// @param defName name of def animation for slider
	/// @param value initial value for volume
	/// @param help pointer to first helptext of slider
	CVolumeSlider(const Point & position, const std::string & defName, const int value,
	              const std::pair<std::string, std::string> * const help);

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


	void clickLeft(tribool down, bool previousState) override;
	void clickRight(tribool down, bool previousState) override;
	void wheelScrolled(bool down, bool in) override;
};

/// A typical slider which can be orientated horizontally/vertically.
class CSlider : public CIntObject
{
	//if vertical then left=up
	std::shared_ptr<CButton> left;
	std::shared_ptr<CButton> right;
	std::shared_ptr<CButton> slider;

	int capacity;//how many elements can be active at same time (e.g. hero list = 5)
	int positions; //number of highest position (0 if there is only one)
	bool horizontal;
	int amount; //total amount of elements (e.g. hero list = 0-8)
	int value; //first active element
	int scrollStep; // how many elements will be scrolled via one click, default = 1
	CFunctionList<void(int)> moved;

	void updateSliderPos();
	void sliderClicked();

public:
	enum EStyle
	{
		BROWN,
		BLUE
	};

	void block(bool on);

	/// Controls how many items wil be scrolled via one click
	void setScrollStep(int to);

	/// Value modifiers
	void moveLeft();
	void moveRight();
	void moveTo(int value);
	void moveBy(int amount);
	void moveToMin();
	void moveToMax();

	/// Amount modifier
	void setAmount(int to);

	/// Accessors
	int getAmount();
	int getValue();

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

	void keyPressed(const SDL_KeyboardEvent & key) override;
	void wheelScrolled(bool down, bool in) override;
	void clickLeft(tribool down, bool previousState) override;
	void mouseMoved (const SDL_MouseMotionEvent & sEvent) override;
	void showAll(SDL_Surface * to) override;

	 /// @param position coordinates of slider
	 /// @param length length of slider ribbon, including left/right buttons
	 /// @param Moved function that will be called whenever slider moves
	 /// @param Capacity maximal number of visible at once elements
	 /// @param Amount total amount of elements, including not visible
	 /// @param Value starting position
	CSlider(Point position, int length, std::function<void(int)> Moved, int Capacity, int Amount,
		int Value=0, bool Horizontal=true, EStyle style = BROWN);
	~CSlider();
};