// Copyright ExByte Studios. Item Interaction Ecosystem.

#include "InteractionResolver.h"
#include "InteractableComponent.h"
#include "InteractionAction.h"
#include "ItemInteractionInterfaces.h"
#include "ItemInteractionLog.h"
#include "ItemNativeTags.h"
#include "ItemDatabaseSubsystem.h"
#include "ItemAuxiliaryRows.h"
#include "InventoryComponent.h"
#include "GameFramework/Pawn.h"
#include "GameFramework/Character.h"
#include "GameFramework/PlayerController.h"

#define LOCTEXT_NAMESPACE "ItemInteraction"

namespace
{
	FInteractionOption MakeOption(const FInteractionContext& Ctx, FGameplayTag ActionTag, EItemInteractionMode Mode,
		const FText& Text, int32 Priority, bool bRequiresHold = false, float HoldDuration = 0.f, float ActionDuration = 0.f)
	{
		FInteractionOption Opt;
		Opt.ActionTag = ActionTag;
		Opt.Mode = Mode;
		Opt.DisplayText = Text;
		Opt.Priority = Priority;
		Opt.bRequiresHold = bRequiresHold;
		Opt.HoldDuration = HoldDuration;
		Opt.ActionDuration = ActionDuration;
		Opt.bIsEnabled = true;

		Opt.Request.Mode = Mode;
		Opt.Request.ActionTag = ActionTag;
		Opt.Request.TargetActor = Ctx.TargetActor;
		if (Ctx.bHasHeldItem) { Opt.Request.ItemInstanceId = Ctx.HeldItem.InstanceId; }
		if (Ctx.bHasTargetItem) { Opt.Request.ItemInstanceId = Ctx.TargetItem.InstanceId; }
		return Opt;
	}

	/**
	 * Evaluates a data-driven requirement string like "FuelAmount>0" or
	 * "BatteryCharge>=0.2" against a subject item's runtime properties (section 18).
	 * The left side maps to the Property.<Name> tag. Empty string = always true.
	 */
	bool EvaluateRequirementString(const FItemInstanceData& Subject, const FString& Req)
	{
		FString Trimmed = Req.TrimStartAndEnd();
		if (Trimmed.IsEmpty())
		{
			return true;
		}

		// Find the comparison operator (order matters: check 2-char first).
		const TCHAR* Ops[] = { TEXT(">="), TEXT("<="), TEXT("=="), TEXT(">"), TEXT("<") };
		FString Op, Left, Right;
		for (const TCHAR* Candidate : Ops)
		{
			int32 Idx;
			if (Trimmed.FindChar(Candidate[0], Idx))
			{
				if (Trimmed.Mid(Idx, FCString::Strlen(Candidate)) == Candidate)
				{
					Op = Candidate;
					Left = Trimmed.Left(Idx).TrimStartAndEnd();
					Right = Trimmed.Mid(Idx + FCString::Strlen(Candidate)).TrimStartAndEnd();
					break;
				}
			}
		}
		if (Op.IsEmpty())
		{
			return true; // unparseable -> don't block
		}

		const FGameplayTag PropTag = FGameplayTag::RequestGameplayTag(FName(*(FString(TEXT("Property.")) + Left)), false);
		const float Value = Subject.RuntimeProperties.GetFloat(PropTag, 0.f);
		const float Threshold = FCString::Atof(*Right);

		if (Op == TEXT(">"))  { return Value > Threshold; }
		if (Op == TEXT("<"))  { return Value < Threshold; }
		if (Op == TEXT(">=")) { return Value >= Threshold; }
		if (Op == TEXT("<=")) { return Value <= Threshold; }
		if (Op == TEXT("==")) { return FMath::IsNearlyEqual(Value, Threshold); }
		return true;
	}

	bool AnyContainerAccepts(UInventoryComponent* Inv, const FItemInstanceData& Item)
	{
		if (!Inv) { return false; }
		TArray<FInventoryContainer> Containers;
		Inv->GetContainers(Containers);
		for (const FInventoryContainer& C : Containers)
		{
			if (Inv->CanAcceptItem(Item, C.ContainerId)) { return true; }
		}
		return false;
	}
}

bool UInteractionResolver::ResolveHeldItem(APawn* Instigator, FItemInstanceData& OutItem)
{
	if (!Instigator) { return false; }

	auto TryObject = [&OutItem](UObject* Obj) -> bool
	{
		if (Obj && Obj->Implements<UHeldItemInterface>())
		{
			IHeldItemInterface* Held = Cast<IHeldItemInterface>(Obj);
			if (Held && Held->HasHeldItem())
			{
				return Held->GetHeldItem(OutItem);
			}
		}
		return false;
	};

	if (TryObject(Instigator)) { return true; }
	for (UActorComponent* Comp : Instigator->GetComponents())
	{
		if (TryObject(Comp)) { return true; }
	}
	return false;
}

FInteractionContext UInteractionResolver::BuildContext(APawn* Instigator, AActor* TargetActor)
{
	FInteractionContext Ctx;
	Ctx.TargetActor = TargetActor;
	Ctx.Character = Cast<ACharacter>(Instigator);
	if (Instigator)
	{
		Ctx.PlayerController = Cast<APlayerController>(Instigator->GetController());
		Ctx.PlayerInventory = Instigator->FindComponentByClass<UInventoryComponent>();
		Ctx.bHasHeldItem = ResolveHeldItem(Instigator, Ctx.HeldItem);
	}

	if (TargetActor)
	{
		Ctx.TargetInteractable = TargetActor->FindComponentByClass<UInteractableComponent>();
		if (Ctx.TargetInteractable)
		{
			Ctx.WorldTags = Ctx.TargetInteractable->InteractionTags;
		}
		if (TargetActor->Implements<UWorldItemProvider>())
		{
			if (IWorldItemProvider* Provider = Cast<IWorldItemProvider>(TargetActor))
			{
				Ctx.bHasTargetItem = Provider->GetProvidedItem(Ctx.TargetItem);
			}
		}
	}
	return Ctx;
}

void UInteractionResolver::GatherCapabilityOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out)
{
	if (!Ctx.bHasTargetItem)
	{
		return;
	}
	const UItemDatabaseSubsystem* DB = UItemDatabaseSubsystem::Get(Ctx.TargetActor);
	const FItemDefinitionRow* Def = DB ? DB->GetItemDefinition(Ctx.TargetItem.ItemId) : nullptr;
	if (!Def)
	{
		return;
	}

	const FText Name = Def->DisplayName.IsEmpty() ? FText::FromName(Ctx.TargetItem.ItemId) : Def->DisplayName;

	if (Def->bCanInstantPickup || Def->bCanStoreInInventory)
	{
		const EItemInteractionMode Mode = Def->bCanInstantPickup ? EItemInteractionMode::InstantPickup : EItemInteractionMode::PickupToInventory;
		const FGameplayTag Tag = Def->bCanInstantPickup ? ItemEcosystemTags::Action_Pickup_Instant : ItemEcosystemTags::Action_Pickup;
		FText Text = Ctx.TargetItem.Quantity > 1
			? FText::Format(LOCTEXT("PickUpQty", "Pick up {0} x{1}"), Name, FText::AsNumber(Ctx.TargetItem.Quantity))
			: FText::Format(LOCTEXT("PickUp", "Pick up {0}"), Name);
		FInteractionOption Opt = MakeOption(Ctx, Tag, Mode, Text, 600);
		if (!AnyContainerAccepts(Ctx.PlayerInventory, Ctx.TargetItem))
		{
			Opt.bIsEnabled = false;
			Opt.DisabledReason = LOCTEXT("InventoryFull", "Inventory Full");
		}
		Out.Add(Opt);
	}

	if (Def->bCanWorldCarry)
	{
		FInteractionOption Opt = MakeOption(Ctx, ItemEcosystemTags::Action_Carry, EItemInteractionMode::CarryAttached,
			FText::Format(LOCTEXT("Carry", "Carry {0}"), Name), 500);
		if (Ctx.bHasHeldItem)
		{
			Opt.bIsEnabled = false;
			Opt.DisabledReason = LOCTEXT("HandsFull", "Hands Full");
		}
		Out.Add(Opt);
	}
}

void UInteractionResolver::GatherContainerOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out)
{
	if (!Ctx.TargetActor)
	{
		return;
	}
	// A target that owns an inventory (and isn't the player themselves) can be opened.
	UInventoryComponent* TargetInv = Ctx.TargetActor->FindComponentByClass<UInventoryComponent>();
	if (!TargetInv || TargetInv == Ctx.PlayerInventory)
	{
		return;
	}

	FText Label = (Ctx.TargetInteractable && !Ctx.TargetInteractable->DisplayName.IsEmpty())
		? FText::Format(LOCTEXT("OpenNamed", "Open {0}"), Ctx.TargetInteractable->DisplayName)
		: LOCTEXT("Open", "Open");
	Out.Add(MakeOption(Ctx, ItemEcosystemTags::Action_Open, EItemInteractionMode::OpenLootUI, Label, 700));
}

void UInteractionResolver::GatherDataDrivenOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out)
{
	const UObject* WorldCtx = Ctx.TargetActor ? static_cast<const UObject*>(Ctx.TargetActor) : static_cast<const UObject*>(Ctx.Character);
	const UItemDatabaseSubsystem* DB = UItemDatabaseSubsystem::Get(WorldCtx);
	if (!DB)
	{
		return;
	}

	// For a "Held+Vehicle" style context, the suffix after '+' must match one of the
	// target's world tags or its interactable type (loose, case-insensitive).
	auto TargetMatchesSuffix = [&Ctx](const FString& Suffix) -> bool
	{
		if (Suffix.IsEmpty()) { return true; }
		if (Ctx.TargetInteractable && Ctx.TargetInteractable->InteractableType.IsValid()
			&& Ctx.TargetInteractable->InteractableType.ToString().Contains(Suffix))
		{
			return true;
		}
		for (const FGameplayTag& Tag : Ctx.WorldTags)
		{
			if (Tag.ToString().Contains(Suffix)) { return true; }
		}
		return false;
	};

	auto AppendRows = [&](const FItemInstanceData& Item, bool bHeldContext)
	{
		TArray<FItemInteractionRow> Rows;
		DB->GetInteractionRows(Item.ItemId, Rows);
		for (const FItemInteractionRow& Row : Rows)
		{
			const FString Context = Row.Context.ToString();
			const bool bIsHeldRow = Context.StartsWith(TEXT("Held"));
			if (bHeldContext != bIsHeldRow)
			{
				continue;
			}
			if (bIsHeldRow)
			{
				FString Suffix;
				Context.Split(TEXT("+"), nullptr, &Suffix);
				if (!TargetMatchesSuffix(Suffix)) { continue; }
			}
			FInteractionOption Opt = MakeOption(Ctx, Row.ActionTag, Row.InteractionMode,
				FText::FromName(Row.ActionTag.GetTagName()), Row.Priority,
				Row.bRequiresHold, Row.HoldDuration, Row.ActionDuration);
			Opt.Request.ItemInstanceId = Item.InstanceId;
			Opt.Request.Quantity = Item.Quantity;

			// Data-driven requirement gate (section 18).
			if (!Row.Requirement.IsEmpty() && !EvaluateRequirementString(Item, Row.Requirement))
			{
				Opt.bIsEnabled = false;
				Opt.DisabledReason = FText::FromString(Row.Requirement);
			}
			Out.Add(Opt);
		}
	};

	if (Ctx.bHasTargetItem) { AppendRows(Ctx.TargetItem, /*bHeldContext*/ false); }
	if (Ctx.bHasHeldItem)   { AppendRows(Ctx.HeldItem,   /*bHeldContext*/ true); }
}

void UInteractionResolver::GatherActionClassOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out)
{
	if (!Ctx.TargetInteractable)
	{
		return;
	}
	for (const UInteractionAction* Action : Ctx.TargetInteractable->AvailableActions)
	{
		if (Action)
		{
			Out.Add(Action->BuildOption(Ctx));
		}
	}
}

void UInteractionResolver::GetAvailableInteractions(APawn* Instigator, AActor* TargetActor, TArray<FInteractionOption>& OutOptions)
{
	if (!TargetActor)
	{
		return;
	}
	const FInteractionContext Ctx = BuildContext(Instigator, TargetActor);

	GatherActionClassOptions(Ctx, OutOptions);
	GatherCapabilityOptions(Ctx, OutOptions);
	GatherContainerOptions(Ctx, OutOptions);
	GatherDataDrivenOptions(Ctx, OutOptions);

	OutOptions.StableSort([](const FInteractionOption& A, const FInteractionOption& B)
	{
		return A.Priority > B.Priority;
	});
}

bool UInteractionResolver::GetPrimaryInteraction(APawn* Instigator, AActor* TargetActor, FInteractionOption& OutOption)
{
	TArray<FInteractionOption> Options;
	GetAvailableInteractions(Instigator, TargetActor, Options);
	for (const FInteractionOption& Opt : Options)
	{
		if (Opt.bIsEnabled)
		{
			OutOption = Opt;
			return true;
		}
	}
	if (Options.Num() > 0)
	{
		OutOption = Options[0]; // disabled, but lets UI show the reason
		return true;
	}
	return false;
}

#undef LOCTEXT_NAMESPACE