#include "SkillTreeComponent.h"
#include "Engine/DataTable.h"

USkillTreeComponent::USkillTreeComponent()
{
    PrimaryComponentTick.bCanEverTick = false;

    AvailableSkillPoints = 5; // Start with 5 skill points for testing
    TotalSkillPointsEarned = 5;
    CurrentSelectionCost = 0;
}

void USkillTreeComponent::BeginPlay()
{
    Super::BeginPlay();
    InitializeSkillTree();
}

void USkillTreeComponent::InitializeSkillTree()
{
    AllSkills.Empty();

    if (!SkillDataTable)
    {
        UE_LOG(LogTemp, Warning, TEXT("SkillTreeComponent: No skill data table assigned!"));
        return;
    }

    // Load all skills from the data table using RowNames as IDs
    TArray<FName> RowNames = SkillDataTable->GetRowNames();

    for (const FName& RowName : RowNames)
    {
        FSkillNodeData* Row = SkillDataTable->FindRow<FSkillNodeData>(RowName, TEXT("SkillTreeComponent"));
        if (Row)
        {
            FSkillNodeRuntime RuntimeNode;
            RuntimeNode.NodeData = *Row;
            RuntimeNode.CurrentState = ESkillNodeState::Locked;
            RuntimeNode.bIsSelected = false;

            // Use RowName as the skill ID
            AllSkills.Add(RowName, RuntimeNode);
        }
    }

    UpdateSkillStates();

    UE_LOG(LogTemp, Log, TEXT("SkillTreeComponent: Initialized with %d skills"), AllSkills.Num());
}

void USkillTreeComponent::AddSkillPoints(int32 Amount)
{
    if (Amount > 0)
    {
        AvailableSkillPoints += Amount;
        TotalSkillPointsEarned += Amount;
        OnSkillPointsChanged.Broadcast(AvailableSkillPoints);
        UpdateSkillStates();
    }
}

void USkillTreeComponent::RemoveSkillPoints(int32 Amount)
{
    if (Amount > 0)
    {
        AvailableSkillPoints = FMath::Max(0, AvailableSkillPoints - Amount);
        OnSkillPointsChanged.Broadcast(AvailableSkillPoints);
        UpdateSkillStates();
    }
}

bool USkillTreeComponent::SelectSkill(FName SkillID)
{
    FText ErrorMessage;

    // Check if skill exists
    if (!AllSkills.Contains(SkillID))
    {
        ErrorMessage = FText::FromString(TEXT("Skill does not exist"));
        OnSelectionError.Broadcast(SkillID, ErrorMessage);
        return false;
    }

    FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);

    // Check if already purchased
    if (SkillNode->CurrentState == ESkillNodeState::Purchased)
    {
        ErrorMessage = FText::FromString(TEXT("Skill already purchased"));
        OnSelectionError.Broadcast(SkillID, ErrorMessage);
        return false;
    }

    // Check if already selected
    if (SkillNode->bIsSelected)
    {
        ErrorMessage = FText::FromString(TEXT("Skill already selected"));
        OnSelectionError.Broadcast(SkillID, ErrorMessage);
        return false;
    }

    // For locked skills, we allow selection but will validate on purchase
    // This allows players to "plan" their build
    if (SkillNode->CurrentState == ESkillNodeState::Locked)
    {
        // Check if prerequisites would be met with current selection
        bool bWouldBeAvailable = true;
        for (const FName& PrereqID : SkillNode->NodeData.Prerequisites)
        {
            if (!IsSkillPurchased(PrereqID) && !IsSkillSelected(PrereqID))
            {
                bWouldBeAvailable = false;
                break;
            }
        }

        if (!bWouldBeAvailable)
        {
            ErrorMessage = FText::FromString(TEXT("Prerequisites not selected. Select prerequisite skills first."));
            OnSelectionError.Broadcast(SkillID, ErrorMessage);
            return false;
        }
    }

    // Add to selection
    SkillNode->bIsSelected = true;
    SelectedSkills.Add(SkillID);
    UpdateSelectionCost();

    OnSkillSelectionChanged.Broadcast(CurrentSelectionCost);
    OnSkillStateChanged.Broadcast(SkillID);

    return true;
}

bool USkillTreeComponent::DeselectSkill(FName SkillID)
{
    if (!AllSkills.Contains(SkillID))
    {
        return false;
    }

    FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);

    if (!SkillNode->bIsSelected)
    {
        return false;
    }

    // Check if any selected skills depend on this one
    for (const FName& SelectedID : SelectedSkills)
    {
        if (SelectedID != SkillID)
        {
            FSkillNodeRuntime* SelectedNode = AllSkills.Find(SelectedID);
            if (SelectedNode && SelectedNode->NodeData.Prerequisites.Contains(SkillID))
            {
                // Can't deselect if other selected skills depend on it
                FText ErrorMessage = FText::FromString(TEXT("Other selected skills depend on this one"));
                OnSelectionError.Broadcast(SkillID, ErrorMessage);
                return false;
            }
        }
    }

    // Remove from selection
    SkillNode->bIsSelected = false;
    SelectedSkills.Remove(SkillID);
    UpdateSelectionCost();

    OnSkillSelectionChanged.Broadcast(CurrentSelectionCost);
    OnSkillStateChanged.Broadcast(SkillID);

    return true;
}

void USkillTreeComponent::ClearSelection()
{
    for (const FName& SkillID : SelectedSkills)
    {
        if (FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            SkillNode->bIsSelected = false;
            OnSkillStateChanged.Broadcast(SkillID);
        }
    }

    SelectedSkills.Empty();
    UpdateSelectionCost();
    OnSkillSelectionChanged.Broadcast(CurrentSelectionCost);
}

bool USkillTreeComponent::ConfirmPurchase()
{
    // Validate we can afford it
    if (!CanAffordSelection())
    {
        FText ErrorMessage = FText::FromString(TEXT("Not enough skill points"));
        OnSelectionError.Broadcast(NAME_None, ErrorMessage);
        return false;
    }

    // Sort selected skills by purchase order to ensure prerequisites are purchased first
    TArray<FName> SortedSelection = SelectedSkills;
    SortedSelection.Sort([this](const FName& A, const FName& B) {
        FSkillNodeRuntime* NodeA = AllSkills.Find(A);
        FSkillNodeRuntime* NodeB = AllSkills.Find(B);
        if (NodeA && NodeB)
        {
            return NodeA->NodeData.PurchaseOrder < NodeB->NodeData.PurchaseOrder;
        }
        return false;
    });

    // Validate all skills can be purchased in order
    for (const FName& SkillID : SortedSelection)
    {
        FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);
        if (!SkillNode)
        {
            continue;
        }

        // Check prerequisites (considering already processed skills in this batch)
        bool bPrereqsMet = true;
        for (const FName& PrereqID : SkillNode->NodeData.Prerequisites)
        {
            if (!IsSkillPurchased(PrereqID))
            {
                // Check if it's in our current batch and would be purchased before this
                int32 PrereqIndex = SortedSelection.IndexOfByKey(PrereqID);
                int32 CurrentIndex = SortedSelection.IndexOfByKey(SkillID);

                if (PrereqIndex == INDEX_NONE || PrereqIndex >= CurrentIndex)
                {
                    bPrereqsMet = false;
                    break;
                }
            }
        }

        if (!bPrereqsMet)
        {
            FText ErrorMessage = FText::Format(
                FText::FromString(TEXT("Cannot purchase {0}: prerequisites not met")),
                SkillNode->NodeData.DisplayName
            );
            OnSelectionError.Broadcast(SkillID, ErrorMessage);
            return false;
        }
    }

    // Purchase all selected skills
    for (const FName& SkillID : SortedSelection)
    {
        FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);
        if (SkillNode)
        {
            // Mark as purchased
            SkillNode->CurrentState = ESkillNodeState::Purchased;
            SkillNode->bIsSelected = false;
            PurchasedSkills.Add(SkillID);

            // Apply effects
            ApplySkillEffects(SkillNode->NodeData);

            // Broadcast purchase event
            OnSkillPurchased.Broadcast(SkillID);
            OnSkillStateChanged.Broadcast(SkillID);
        }
    }

    // Deduct skill points
    RemoveSkillPoints(CurrentSelectionCost);

    // Clear selection
    SelectedSkills.Empty();
    UpdateSelectionCost();
    UpdateSkillStates();

    OnSkillSelectionChanged.Broadcast(CurrentSelectionCost);

    return true;
}

bool USkillTreeComponent::IsSkillPurchased(FName SkillID) const
{
    return PurchasedSkills.Contains(SkillID);
}

bool USkillTreeComponent::IsSkillSelected(FName SkillID) const
{
    return SelectedSkills.Contains(SkillID);
}

bool USkillTreeComponent::IsSkillAvailable(FName SkillID) const
{
    const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);
    if (!SkillNode)
    {
        return false;
    }

    return SkillNode->CurrentState == ESkillNodeState::Available;
}

bool USkillTreeComponent::CanSelectSkill(FName SkillID, FText& OutErrorMessage) const
{
    const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);
    if (!SkillNode)
    {
        OutErrorMessage = FText::FromString(TEXT("Skill does not exist"));
        return false;
    }

    if (SkillNode->CurrentState == ESkillNodeState::Purchased)
    {
        OutErrorMessage = FText::FromString(TEXT("Skill already purchased"));
        return false;
    }

    if (SkillNode->bIsSelected)
    {
        OutErrorMessage = FText::FromString(TEXT("Skill already selected"));
        return false;
    }

    OutErrorMessage = FText::GetEmpty();
    return true;
}

ESkillNodeState USkillTreeComponent::GetSkillState(FName SkillID) const
{
    const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);
    if (SkillNode)
    {
        return SkillNode->CurrentState;
    }

    return ESkillNodeState::Locked;
}

bool USkillTreeComponent::GetSkillNodeData(FName SkillID, FSkillNodeRuntime& OutNodeData) const
{
    const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID);
    if (SkillNode)
    {
        OutNodeData = *SkillNode;
        return true;
    }

    return false;
}

TArray<FSkillNodeRuntime> USkillTreeComponent::GetAllSkillNodes() const
{
    TArray<FSkillNodeRuntime> Result;
    for (const auto& Pair : AllSkills)
    {
        Result.Add(Pair.Value);
    }
    return Result;
}

float USkillTreeComponent::GetTotalHealthBonus() const
{
    float Total = 0.0f;
    for (const FName& SkillID : PurchasedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            Total += SkillNode->NodeData.HealthBonus;
        }
    }
    return Total;
}

float USkillTreeComponent::GetTotalDamageBonus() const
{
    float Total = 0.0f;
    for (const FName& SkillID : PurchasedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            Total += SkillNode->NodeData.DamageBonus;
        }
    }
    return Total;
}

float USkillTreeComponent::GetTotalSpeedBonus() const
{
    float Total = 0.0f;
    for (const FName& SkillID : PurchasedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            Total += SkillNode->NodeData.SpeedBonus;
        }
    }
    return Total;
}

float USkillTreeComponent::GetTotalHealthBonusPercent() const
{
    float Total = 0.0f;
    for (const FName& SkillID : PurchasedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            Total += SkillNode->NodeData.HealthBonusPercent;
        }
    }
    return Total;
}

float USkillTreeComponent::GetTotalDamageBonusPercent() const
{
    float Total = 0.0f;
    for (const FName& SkillID : PurchasedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            Total += SkillNode->NodeData.DamageBonusPercent;
        }
    }
    return Total;
}

float USkillTreeComponent::GetTotalSpeedBonusPercent() const
{
    float Total = 0.0f;
    for (const FName& SkillID : PurchasedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            Total += SkillNode->NodeData.SpeedBonusPercent;
        }
    }
    return Total;
}

void USkillTreeComponent::ResetAllSkills()
{
    // Refund all skill points
    int32 RefundAmount = 0;
    for (const FName& SkillID : PurchasedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            RefundAmount += SkillNode->NodeData.Cost;
            RemoveSkillEffects(SkillNode->NodeData);
        }
    }

    // Clear purchases
    PurchasedSkills.Empty();

    // Reset all skill states
    for (auto& Pair : AllSkills)
    {
        Pair.Value.CurrentState = ESkillNodeState::Locked;
        Pair.Value.bIsSelected = false;
    }

    // Clear selection
    SelectedSkills.Empty();
    CurrentSelectionCost = 0;

    // Add refunded points
    AddSkillPoints(RefundAmount);

    // Update states
    UpdateSkillStates();

    // Broadcast events
    OnSkillSelectionChanged.Broadcast(CurrentSelectionCost);
}

void USkillTreeComponent::UpdateSkillStates()
{
    for (auto& Pair : AllSkills)
    {
        FSkillNodeRuntime& SkillNode = Pair.Value;

        // Skip if already purchased
        if (SkillNode.CurrentState == ESkillNodeState::Purchased)
        {
            continue;
        }

        // Check if prerequisites are met
        if (ArePrerequisitesMet(SkillNode.NodeData))
        {
            SkillNode.CurrentState = SkillNode.bIsSelected ?
                ESkillNodeState::Selected : ESkillNodeState::Available;
        }
        else
        {
            SkillNode.CurrentState = SkillNode.bIsSelected ?
                ESkillNodeState::Selected : ESkillNodeState::Locked;
        }
    }
}

void USkillTreeComponent::UpdateSelectionCost()
{
    CurrentSelectionCost = 0;
    for (const FName& SkillID : SelectedSkills)
    {
        if (const FSkillNodeRuntime* SkillNode = AllSkills.Find(SkillID))
        {
            CurrentSelectionCost += SkillNode->NodeData.Cost;
        }
    }
}

bool USkillTreeComponent::ArePrerequisitesMet(const FSkillNodeData& SkillData) const
{
    for (const FName& PrereqID : SkillData.Prerequisites)
    {
        if (!IsSkillPurchased(PrereqID))
        {
            return false;
        }
    }
    return true;
}

bool USkillTreeComponent::HasChildrenPurchased(FName SkillID) const
{
    for (const auto& Pair : AllSkills)
    {
        // Pair.Key is the RowName (SkillID)
        if (Pair.Value.NodeData.Prerequisites.Contains(SkillID) &&
            IsSkillPurchased(Pair.Key))
        {
            return true;
        }
    }
    return false;
}

void USkillTreeComponent::ApplySkillEffects(const FSkillNodeData& SkillData)
{
    // This is where you would apply the actual skill effects to the character
    // For now, we just log it
    UE_LOG(LogTemp, Log, TEXT("Applied skill effects for: %s"), *SkillData.DisplayName.ToString());
}

void USkillTreeComponent::RemoveSkillEffects(const FSkillNodeData& SkillData)
{
    // This is where you would remove skill effects from the character
    // For now, we just log it
    UE_LOG(LogTemp, Log, TEXT("Removed skill effects for: %s"), *SkillData.DisplayName.ToString());
}