#pragma once

#include "CoreMinimal.h"
#include "Core/DescentWorldSubsystem.h"
#include "DescentOreSubsystem.generated.h"

/** The mutable state of one ore vein (the vein itself is static data in FDescentWorldDef::Deposits). */
struct FDescentDepositState
{
	int32 Removed = 0;   // removed core samples toward the next chunk
	int32 Mined = 0;     // loose chunks freed so far (<= the deposit's Yield)
};

/**
 * Ore deposit state (DESIGN_UE.md sections 2.12, 9.4 `ore`). Milestone M1 covers the counters: the terrain reports
 * every rock sample it removes inside a vein; every DepositSamplesPerChunk of them free one chunk of ore
 * (`Mined++`, `OnOreFreed`), until the vein's yield is used up and its glow leaves the rock. Loose ore chunks,
 * suction and crystals belong to the mining milestone and subscribe to `OnOreFreed`.
 */
UCLASS()
class THEDESCENT_API UDescentOreSubsystem : public UDescentWorldSubsystem
{
	GENERATED_BODY()

public:
	static UDescentOreSubsystem* Get(const UWorld* World);

	/** Broadcast with the deposit index and the position (metres) of the sample that completed a chunk. */
	DECLARE_MULTICAST_DELEGATE_TwoParams(FOnOreFreed, int32 /*Deposit*/, const FVector& /*PosM*/);
	FOnOreFreed OnOreFreed;

	int32 NumDeposits() const;
	bool IsExhausted(int32 Deposit) const;
	int32 GetMined(int32 Deposit) const;
	int64 GetMinedTotal() const { return MinedTotal; }

	/** Called by the terrain for each core sample that went from rock to water inside vein `Deposit`. */
	void NoteSampleRemoved(int32 Deposit, const FVector& PosM);

	/** `ore.query`: the result of the last Descent.World.NearestDeposit. */
	struct FQuery
	{
		bool bValid = false;
		int32 Index = -1;
		FVector PosM = FVector::ZeroVector;
		FVector NormalM = FVector::ZeroVector;
		int32 Type = 0;
		int32 Yield = 0;
		int32 Mined = 0;
	};
	FQuery LastQuery;
	/** Fills LastQuery for the deposit nearest to PosM (TypeFilter -1 = any). Returns false if none. */
	bool QueryNearest(const FVector& PosM, int32 TypeFilter);

	/** Saving (section 6.12): the per-deposit counters. */
	void GetState(TArray<int32>& OutMined, TArray<int32>& OutRemoved) const;
	void SetState(const TArray<int32>& InMined, const TArray<int32>& InRemoved);

	/** Forgets all counters (tests). */
	void ResetState();

private:
	void EnsureStates() const;
	mutable TArray<FDescentDepositState> States;
	int64 MinedTotal = 0;
};