#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "Core/DescentHandle.h"
#include "Core/Tuning/DescentTune_Player.h"
#include "DescentVitals.generated.h"

/** What the vitals rules need to know about this step. */
namespace Descent::Vitals
{
	/** U2: 100 points in 2,400 s (40 minutes). */
	constexpr double NutritionDrainPerSec = 100.0 / 2400.0;
	constexpr double StarveHPPerSec = 1.0;
}

struct FDescentVitalsInput
{
	bool bSwimming = false;
	bool bSprint = false;              // sprinting or gliding: O2 x 1.4
	bool bHeadAtPoolSurface = false;   // in the shaft, head within 0.6 m of the pool surface: O2 refills
	bool bHonestVoid = false;          // swimming inside an honest void
};

/**
 * The player's vitals as plain data and arithmetic (DESIGN_UE.md sections 5.3 and 5.8), so the rules are tested without a world.
 * M3 owns O2, health, death and respawn; nutrition is a number that does not move until M8; the debt is kept here until M5 owns money.
 */
struct THEDESCENT_API FDescentVitalsState
{
	double Nutrition = Descent::Tune::Player::NutritionStartPct;
	double O2 = Descent::Tune::Player::O2BaseSec;
	double O2Max = Descent::Tune::Player::O2BaseSec;
	double Health = 100.0;
	double Debt = 0.0;
	bool bDrowning = false;
	bool bDead = false;
	FString DeadReason;
	int32 Deaths = 0;

	void Advance(const FDescentVitalsInput& In, double Dt);
	/** "drown" (also an honest void while swimming) adds 900 cr of debt, "implode" 4,800 cr. */
	void Die(const TCHAR* Reason);
	/** Health 60, O2 full, alive (section 5.8). */
	void Respawn();
};

/** The vitals of the character, stepped in sim step 6 (Vitals). */
UCLASS(ClassGroup = (Descent))
class THEDESCENT_API UDescentVitalsComponent : public UActorComponent
{
	GENERATED_BODY()

public:
	UDescentVitalsComponent();

	virtual void BeginPlay() override;
	virtual void EndPlay(const EEndPlayReason::Type Reason) override;

	FDescentVitalsState State;

private:
	void Step(double Dt);
	FDescentHandle StepHandle;
};