integration/Source/Integration/AnimQueue.h

#pragma once

#include "CoreMinimal.h"
#include "StringDecoder.h"
#include "Containers/Deque.h"
#include "AnimQueue.generated.h"

////////////////////////////////////////////////
//
// This is copied over from Luprex source.  Not ideal.
//
////////////////////////////////////////////////

enum class ElxAnimValueType {
	STRING,
	NUMBER,
	BOOLEAN,
	XYZ,
	INVALID
};

////////////////////////////////////////////////
//
// An single animation step.
// 
// The body consists of a sequence of FlxAnimationField
// records.  The body is encoded, to read the
// FlxAnimationField records you need an
// FlxAnimationStepDecoder.
//
////////////////////////////////////////////////

USTRUCT(Blueprintable)
struct INTEGRATION_API FlxAnimationStep {
	GENERATED_BODY()

public:
	UPROPERTY()
	bool Finished;

	UPROPERTY()
	uint64 Hash;

	UPROPERTY()
	TArray<uint8> Body;

	UPROPERTY()
	FString Blueprint;

	FlxAnimationStep() : Finished(false), Hash(0), Body(), Blueprint() {}
	FlxAnimationStep(uint64 h, std::string_view b);

	// Unpack an AnimStep into a UObject
	//
	// Stores the key-value pairs of the animation step into
	// properties of a UObject.  For example, if the key-value
	// pair "color=blue" is present in the AnimStep, then this
	// routine tries to find a string property "color" in the
	// UObject, and then it sets that property to "blue."
	//
	// Returns true if all of the key-value pairs in the
	// animation step could be unpacked into fields of the UObject.
	// This could fail, for instance, if the UObject just doesn't
	// contain one of the necessary properties.  It can also
	// fail if there's a type mismatch.  For example, "color=blue"
	// cannot be stored in a property "color" of type int.
	//
	// The prefix is prepended to the key names.  For example,
	// if one of the key-value pairs is "color=blue", and the
	// prefix is "aq", then the property "aqColor=blue" will be
	// stored in the UObject.
	//
	// If pre-clear is true, then all properties of the UObject
	// starting with the specified prefix are cleared before
	// unpacking the animation step.
	//
	bool Unpack(const FString& prefix, UObject* into, bool preclear = true) const;
};

////////////////////////////////////////////////
//
// This UClass is never instantiated.  It exists to
// expose certain static functions to the blueprint
// library.
//
////////////////////////////////////////////////

UCLASS()
class INTEGRATION_API UlxAnimationStepLibrary : public UObject
{
	GENERATED_BODY()

public:
	UFUNCTION(BlueprintCallable, BlueprintPure, Category = Luprex)
	static FString AnimationStepDebugString(const FlxAnimationStep& step);

	UFUNCTION(BlueprintCallable, Meta = (DefaultToSelf = "into"), Category = Luprex)
	static void UnpackAnimationStep(UObject* into, const FlxAnimationStep& step, const FString& VariableNamePrefix);

	UFUNCTION(BlueprintCallable, BlueprintPure, Category = Luprex)
	static bool AnimationStepIsIdle(const FlxAnimationStep &step);
	
	UFUNCTION(BlueprintCallable, BlueprintPure, Category = Luprex)
	static FVector AnimationStepGetVector(const FlxAnimationStep& step, const FString& name);

	UFUNCTION(BlueprintCallable, BlueprintPure, Category = Luprex)
	static double AnimationStepGetFloat(const FlxAnimationStep& step, const FString& name);

	UFUNCTION(BlueprintCallable, BlueprintPure, Category = Luprex)
	static FString AnimationStepGetString(const FlxAnimationStep& step, const FString& name);

	UFUNCTION(BlueprintCallable, BlueprintPure, Category = Luprex)
	static bool AnimationStepGetBool(const FlxAnimationStep& step, const FString& name);
};

////////////////////////////////////////////////
//
// 
////////////////////////////////////////////////

struct FlxAnimationStepView {
	uint64 Hash;
	std::string_view Body;

	FlxAnimationStepView() : Hash(0), Body("") {}
	FlxAnimationStepView(uint64 h, std::string_view b) : Hash(h), Body(b) {}
};

////////////////////////////////////////////////
//
// A single animation field.
// 
// A field consists of a variable name,
// a persistent flag, a type, and some fields
// to hold the values.
//
// If the value is boolean, it is stored in
// X, as either 1 or 0.   If the value is double,
// it is stored in X.
// 
////////////////////////////////////////////////

struct FlxAnimationField {
	std::string_view Name;
	bool Persistent;
	ElxAnimValueType Type;
	double X, Y, Z;
	std::string_view S;
};

////////////////////////////////////////////////
//
// An Animation Queue Decoder.
//
// This acts a lot like a stream reader,
// it reads one AnimEntry at a time from
// the animation queue until you reach
// 'end-of-file'.
//
////////////////////////////////////////////////

class FlxAnimQueueDecoder {
private:
	FlxStringDecoder Decoder;
	
	// These values are immediately read from the header.
	//
	int SizeLimit;
	int ActualSize;

public:
	// Initialize the FlxAnimQueueDecoder with the encoded animation queue.
	//
	FlxAnimQueueDecoder(std::string_view s);
	
	// Get the size limit of the animation queue.
	// 
	int GetSizeLimit() const { return SizeLimit; }

	// Get the Actual Size of the animation queue.
	//
	int GetActualSize() const { return ActualSize; }

	// Return true if the parser has reached the end of the string.
	//
	bool AtEOF() { return Decoder.at_eof(); }

	// Read one animation step.
	// 
	FlxAnimationStepView ReadStep();

	// Peek at the hash of the next animation step.
	//
	uint64 PeekHash();

	// Convert an AnimQueue to an FString.
	//
	static FString DebugString(std::string_view s);
};

////////////////////////////////////////////////
//
// An Animation Step Decoder.
//
// This acts a lot like a stream reader,
// it reads one FlxAnimationField at a time from
// the animation queue until you reach
// 'end-of-file'.
//
////////////////////////////////////////////////

class FlxAnimationStepDecoder {
private:
	FlxStringDecoder Decoder;

public:
	// Initialize the FlxAnimationStepDecoder from the FlxAnimationStepView.
	// 
	FlxAnimationStepDecoder(std::string_view body) : Decoder(body) {}

	// Return true if the parser has reached the end of the string.
	//
	bool AtEOF() { return Decoder.at_eof(); }

	// Read one field.
	// 
	FlxAnimationField ReadField();

	// Convert an AnimStep to an FString.
	//
	static FString DebugString(uint64 hash, std::string_view body);
};

////////////////////////////////////////////////
//
// FlxAnimTracker
//
// This class monitors the animation queue for a single
// tangible.  It can identify when a new animation has
// appeared on the animation queue, and when animations have
// been removed from the animation queue.  It also
// keeps track of which animations have been started.
// 
////////////////////////////////////////////////

class FlxAnimTracker {
public:
	// Our own copy of the animation queue.  We only
	// store the hashes, not the steps.  The First element
	// of the queue is the oldest item.
	//
	TDeque<FlxAnimationStep> AQ;

	// True if something has recently changed.
	//
	bool Changed;

private:
public:
	// Construct a tracker.
	//
	// Initially, the tracker is in the empty (Clear) state.
	//
	FlxAnimTracker();

	// Clear everything, reset to the initial state.
	//
	void Clear();

	// Update from the specified animation queue.
	//
	// After the update is done, AQ will be a copy
	// of the animation queue that is passed in.
	//
	void Update(std::string_view encqueue);

	// Get the current animation step.
	//
	// Get the current animation step.  This is the step that the
	// blueprint should currently be playing.
	// 
	FlxAnimationStep GetCurrentAnimation();

	// Declare that an animation is finished.
	//
	// The blueprint uses this function call to indicate that it
	// is done playing the specified animation.   This will cause the
	// animation to be marked as finished, which in turn causes
	// 'GetCurrentStep' to advance to the next animation.
	// 
	void FinishedAnimation(uint64 Hash);

	// Skip to the end of the animation queue.
	// 
	// This is equivalent to calling 'FinishedHash' on every
	// animation in the entire queue.
	//
	void SkipToEnd();

	// Clear the 'Changed' flag.
	//
	void ClearChanged() { Changed = false; }

	// Get the 'Changed' flag.
	//
	// The changed flag is set to true whenever the Luprex animation
	// queue changes from its previous state.  The changed flag is also
	// set to true whenever 'SetFinished' marks an animation as finished.
	// The changed flag can only be set to false by 'ClearChanged,' above.
	//
	bool IsChanged() const { return Changed; }
};