using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Domain.Entities.Common.ValueObject;
using Domain.Entities.Members;
using Domain.Entities.Wallets.Policy;
using Domain.Entities.Wallets.ValueObject;

namespace Domain.Entities.Wallets;

public class Wallet
{
    [ForeignKey(nameof(MemberID))]
    public virtual Member Member { get; private set; } = null!;

    private readonly List<WalletBalance> _balances = [];
    public IReadOnlyCollection<WalletBalance> Balances => _balances;

    private readonly List<WalletTransaction> _transactions = [];
    public IReadOnlyCollection<WalletTransaction> Transactions => _transactions;

    [Key]
    public int ID { get; private set; }

    public Guid WalletKey { get; private set; } = Guid.NewGuid();

    public int MemberID { get; private set; }

    public DateTime? UpdatedAt { get; private set; }

    public DateTime CreatedAt { get; private set; } = DateTime.UtcNow;

    private Wallet() { }

    private Wallet(int memberID)
    {
        if (memberID <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(memberID));
        }

        MemberID = memberID;

        // 지갑 생성 시 구분별 잔액 기본 생성
        EnsureBalance(WalletBalanceType.PgCharged);
        EnsureBalance(WalletBalanceType.Deposit);
        EnsureBalance(WalletBalanceType.Donation);
        EnsureBalance(WalletBalanceType.Reward);
        EnsureBalance(WalletBalanceType.Airdrop);
        EnsureBalance(WalletBalanceType.Locked);
        EnsureBalance(WalletBalanceType.Adjusted);
    }

    public static Wallet Create(int memberID) => new(memberID);

    public Money GetBalance(WalletBalanceType type) => GetBalanceEntity(type).Amount;

    public Money GetTotalAvailable()
    {
        var total = Money.KRW(0);
        foreach (var b in Balances.Where(x => x.Type != WalletBalanceType.Locked))
            total += b.Amount;

        return total;
    }

    /// <summary>
    /// 상점 결제로 사용 가능한 잔액 합계 (SpendPolicy.StoreOrderSpendOrder 기준).
    /// 비활성 잔액 유형(원장 호환용)과 Locked 는 제외.
    /// </summary>
    public Money GetStoreOrderAvailable()
    {
        var total = Money.KRW(0);
        foreach (var type in Policy.SpendPolicy.StoreOrderSpendOrder)
        {
            total += GetBalance(type);
        }
        return total;
    }

    // ---- Credit ----
    public void CreditPgCharge(Money amount, string reason = "PG_CHARGE", string? refID = null)
        => Credit(WalletBalanceType.PgCharged, WalletTransactionType.Charge, amount, reason, refID);

    public void CreditDonationIn(Money amount, string reason, string? refID = null)
        => Credit(WalletBalanceType.Donation, WalletTransactionType.DonationIn, amount, reason, refID);

    public void CreditReward(Money amount, string reason = "REWARD", string? refID = null)
        => Credit(WalletBalanceType.Reward, WalletTransactionType.RewardEarned, amount, reason, refID);

    /// <summary>
    /// 가입 축하 보상 적립: 지정 잔액 유형(코인=Airdrop, 캐시=Adjusted)으로 입금하되
    /// 트랜잭션 타입은 RewardEarned 로 기록해 멱등 판정(RefID "signup:{memberID}")을 일원화한다.
    /// Locked 는 출금 프로세스 전용이라 직접 적립 불가.
    /// </summary>
    public void CreditSignupReward(WalletBalanceType type, Money amount, string reason, string? refID = null)
    {
        if (type == WalletBalanceType.Locked)
        {
            throw new ArgumentException("Locked balance cannot be credited directly.", nameof(type));
        }

        Credit(type, WalletTransactionType.RewardEarned, amount, reason, refID);
    }

    /// <summary>
    /// 상점 환불 환원: 원본 결제(OrderPay)가 차감한 BalanceType 그대로 복원해 출처를 보존한다.
    /// 호출자는 OrderPay 트랜잭션을 BalanceType 별로 집계해 type 마다 한 번씩 호출한다.
    /// </summary>
    public void CreditStoreOrderRefund(WalletBalanceType type, Money amount, string reason = "ORDER_REFUND", string? refID = null)
        => Credit(type, WalletTransactionType.OrderRefund, amount, reason, refID);

    private void Credit(
        WalletBalanceType balanceType,
        WalletTransactionType txType,
        Money amount,
        string reason,
        string? refID
    ) {
        EnsureMoney(amount);

        var balance = EnsureBalance(balanceType);
        balance.Increase(amount);

        _transactions.Add(WalletTransaction.Create(
            walletKey: WalletKey,
            balanceType: balanceType,
            txType: txType,
            amount: amount,
            balanceAfter: balance.Amount,
            reason: reason,
            refID: refID
        ));
    }

    /// <summary>
    /// 모의투자 출금 환급: 계좌 → 지갑 토큰(Reward 파티션). 트랜잭션 타입 PaperWithdraw.
    /// </summary>
    public void CreditPaperWithdraw(Money amount, string reason = "PAPER_WITHDRAW", string? refID = null)
        => Credit(WalletBalanceType.Reward, WalletTransactionType.PaperWithdraw, amount, reason, refID);

    /// <summary>
    /// 모의투자 입금: 토큰 파티션(Reward → Airdrop) 순서로 분할 차감하고 사용된 BalanceType 별로
    /// PaperDeposit 트랜잭션을 각각 기록한다. 합계 부족 시 InvalidOperationException —
    /// 호출자가 GetPaperTokenAvailable 로 사전 검증할 것.
    /// </summary>
    public void DebitForPaperDeposit(Money total, string reason = "PAPER_DEPOSIT", string? refID = null)
    {
        EnsureMoney(total);

        var remaining = total;

        foreach (var type in PaperTokenSpendOrder)
        {
            if (remaining.IsZero) break;

            var balance = EnsureBalance(type);
            if (balance.Amount.IsZero) continue;

            var takeValue = Math.Min(balance.Amount.Value, remaining.Value);
            if (takeValue <= 0) continue;

            var take = Money.KRW(takeValue);

            balance.Decrease(take);
            remaining = remaining - take;

            _transactions.Add(WalletTransaction.Create(
                walletKey: WalletKey,
                balanceType: type,
                txType: WalletTransactionType.PaperDeposit,
                amount: take,
                balanceAfter: balance.Amount,
                reason: reason,
                refID: refID
            ));
        }

        if (!remaining.IsZero)
        {
            throw new InvalidOperationException("Insufficient token balance for paper deposit.");
        }
    }

    /// <summary>모의투자 입금 가용 토큰 합계 (Reward + Airdrop).</summary>
    public Money GetPaperTokenAvailable()
    {
        var total = Money.KRW(0);
        foreach (var type in PaperTokenSpendOrder)
        {
            total += GetBalance(type);
        }
        return total;
    }

    // 모의투자 토큰 파티션 (활동 보상 재화 = 코인/토큰). 입금 시 Reward 먼저, 이후 Airdrop.
    private static readonly WalletBalanceType[] PaperTokenSpendOrder =
    {
        WalletBalanceType.Reward,
        WalletBalanceType.Airdrop
    };

    // ---- Debit ----
    public void DebitDonationOut(Money amount, string reason, string? refID = null)
        => DebitSingle(WalletBalanceType.Donation, WalletTransactionType.DonationOut, amount, reason, refID);

    /// <summary>
    /// 상점 결제 전용 다중 잔액 차감: SpendPolicy.StoreOrderSpendOrder 순서로 분할 차감하고
    /// 사용된 BalanceType 별로 OrderPay 트랜잭션을 각각 기록한다 (환불 시 출처 복원용).
    /// 합계 부족 시 InvalidOperationException — 호출자가 GetStoreOrderAvailable 로 사전 검증할 것.
    /// </summary>
    public IReadOnlyList<(WalletBalanceType Type, Money Amount)> DebitForStoreOrder(
        Money total,
        string reason = "ORDER_PAY",
        string? refID = null)
    {
        EnsureMoney(total);

        var remaining = total;
        var splits = new List<(WalletBalanceType, Money)>();

        foreach (var type in Policy.SpendPolicy.StoreOrderSpendOrder)
        {
            if (remaining.IsZero) break;

            var balance = EnsureBalance(type);
            if (balance.Amount.IsZero) continue;

            var takeValue = Math.Min(balance.Amount.Value, remaining.Value);
            if (takeValue <= 0) continue;

            var take = Money.KRW(takeValue);

            balance.Decrease(take);
            remaining = remaining - take;

            _transactions.Add(WalletTransaction.Create(
                walletKey: WalletKey,
                balanceType: type,
                txType: WalletTransactionType.OrderPay,
                amount: take,
                balanceAfter: balance.Amount,
                reason: reason,
                refID: refID
            ));

            splits.Add((type, take));
        }

        if (!remaining.IsZero)
        {
            throw new InvalidOperationException("Insufficient balance for store order.");
        }

        return splits;
    }

    /// <summary>
    /// PG 결제 취소 회수: 충전분(PgCharged)을 되돌린다.
    /// 잔액 부족 시 WalletBalance.Decrease 예외 — 호출자가 PgCharged 잔액을 사전 검증할 것.
    /// </summary>
    public void DebitChargeCancel(Money amount, string reason = "CHARGE_CANCEL", string? refID = null)
        => DebitSingle(WalletBalanceType.PgCharged, WalletTransactionType.ChargeCancelled, amount, reason, refID);

    // ---- Spend (정책 순서대로 분할 차감) ----
    public void Spend(Money amount, string reason = "SPEND", string? refID = null)
    {
        EnsureMoney(amount);

        var remaining = amount;

        foreach (var type in SpendPolicy.DefaultSpendOrder)
        {
            if (remaining.IsZero) break;

            var balance = EnsureBalance(type);
            if (balance.Amount.IsZero) continue;

            var takeValue = Math.Min(balance.Amount.Value, remaining.Value);
            if (takeValue <= 0) continue;

            var take = Money.KRW(takeValue);

            balance.Decrease(take);
            remaining = remaining - take;

            _transactions.Add(WalletTransaction.Create(
                walletKey: WalletKey,
                balanceType: type,
                txType: WalletTransactionType.Spend,
                amount: take,
                balanceAfter: balance.Amount,
                reason: reason,
                refID: refID
            ));
        }

        if (!remaining.IsZero)
        {
            throw new InvalidOperationException("Insufficient balance for spending.");
        }
    }

    // ---- Lock/Unlock ----
    public void LockForWithdrawal(Money amount, string reason = "WITHDRAW_REQUEST", string? refID = null)
    {
        EnsureMoney(amount);

        var from = EnsureBalance(WalletBalanceType.Donation);
        var locked = EnsureBalance(WalletBalanceType.Locked);

        from.Decrease(amount);
        _transactions.Add(WalletTransaction.Create(WalletKey, WalletBalanceType.Donation, WalletTransactionType.Lock, amount, from.Amount, reason, refID));

        locked.Increase(amount);
        _transactions.Add(WalletTransaction.Create(WalletKey, WalletBalanceType.Locked, WalletTransactionType.Lock, amount, locked.Amount, reason, refID));
    }

    public void UnlockWithdrawal(Money amount, string reason = "WITHDRAW_CANCEL", string? refID = null)
    {
        EnsureMoney(amount);

        var locked = EnsureBalance(WalletBalanceType.Locked);
        var donation = EnsureBalance(WalletBalanceType.Donation);

        locked.Decrease(amount);
        _transactions.Add(WalletTransaction.Create(WalletKey, WalletBalanceType.Locked, WalletTransactionType.Unlock, amount, locked.Amount, reason, refID));

        donation.Increase(amount);
        _transactions.Add(WalletTransaction.Create(WalletKey, WalletBalanceType.Donation, WalletTransactionType.Unlock, amount, donation.Amount, reason, refID));
    }

    // ---- Adjust ----
    public void AdjustIncrease(Money amount, string reason, string? refID = null, string? memo = null)
        => AdjustIncrease(WalletBalanceType.Adjusted, amount, reason, refID, memo);

    /// <summary>
    /// 관리자 조정 충전: 지정한 잔액 유형으로 입금. 트랜잭션 타입은 Adjusted 로 기록해 수동 조작 추적을 보존한다.
    /// Locked 는 출금 프로세스 전용이라 직접 조정 불가.
    /// </summary>
    public void AdjustIncrease(WalletBalanceType type, Money amount, string reason, string? refID = null, string? memo = null)
    {
        EnsureMoney(amount);
        EnsureAdjustableType(type);

        if (string.IsNullOrWhiteSpace(reason))
        {
            throw new ArgumentException("Adjustment reason is required.", nameof(reason));
        }

        var balance = EnsureBalance(type);
        balance.Increase(amount);

        _transactions.Add(WalletTransaction.Create(
            walletKey: WalletKey,
            balanceType: type,
            txType: WalletTransactionType.Adjusted,
            amount: amount,
            balanceAfter: balance.Amount,
            reason: $"ADJUST_IN:{reason}",
            refID: refID,
            memo: memo
        ));
    }

    public void AdjustDecrease(Money amount, string reason, string? refID = null, string? memo = null)
        => AdjustDecrease(WalletBalanceType.Adjusted, amount, reason, refID, memo);

    /// <summary>
    /// 관리자 조정 차감: 지정한 잔액 유형에서만 차감. 잔액 부족 시 WalletBalance.Decrease 가 예외 —
    /// 호출자가 해당 잔액을 사전 검증할 것.
    /// </summary>
    public void AdjustDecrease(WalletBalanceType type, Money amount, string reason, string? refID = null, string? memo = null)
    {
        EnsureMoney(amount);
        EnsureAdjustableType(type);

        if (string.IsNullOrWhiteSpace(reason))
        {
            throw new ArgumentException("Adjustment reason is required.", nameof(reason));
        }

        var balance = EnsureBalance(type);
        balance.Decrease(amount);

        _transactions.Add(WalletTransaction.Create(
            walletKey: WalletKey,
            balanceType: type,
            txType: WalletTransactionType.Adjusted,
            amount: amount,
            balanceAfter: balance.Amount,
            reason: $"ADJUST_OUT:{reason}",
            refID: refID,
            memo: memo
        ));
    }

    private static void EnsureAdjustableType(WalletBalanceType type)
    {
        if (type == WalletBalanceType.Locked)
        {
            throw new ArgumentException("Locked balance cannot be adjusted directly.", nameof(type));
        }
    }

    /// <summary>
    /// 관리자 차감 전용 다중 잔액 분할 차감: SpendPolicy.DefaultSpendOrder 순서로 분할 차감하고
    /// 사용된 BalanceType 별로 Adjusted 트랜잭션을 각각 기록한다.
    /// 합계 부족 시 InvalidOperationException — 호출자가 GetTotalAvailable 로 사전 검증할 것.
    /// </summary>
    public void AdjustDecreaseAcrossBalances(Money amount, string reason, string? refID = null, string? memo = null)
    {
        EnsureMoney(amount);

        if (string.IsNullOrWhiteSpace(reason))
        {
            throw new ArgumentException("Adjustment reason is required.", nameof(reason));
        }

        var remaining = amount;

        foreach (var type in SpendPolicy.DefaultSpendOrder)
        {
            if (remaining.IsZero) break;

            var balance = EnsureBalance(type);
            if (balance.Amount.IsZero) continue;

            var takeValue = Math.Min(balance.Amount.Value, remaining.Value);
            if (takeValue <= 0) continue;

            var take = Money.KRW(takeValue);

            balance.Decrease(take);
            remaining = remaining - take;

            _transactions.Add(WalletTransaction.Create(
                walletKey: WalletKey,
                balanceType: type,
                txType: WalletTransactionType.Adjusted,
                amount: take,
                balanceAfter: balance.Amount,
                reason: $"ADJUST_OUT:{reason}",
                refID: refID,
                memo: memo
            ));
        }

        if (!remaining.IsZero)
        {
            throw new InvalidOperationException("Insufficient balance for adjustment.");
        }
    }

    // ---- Internal ----
    private void DebitSingle(WalletBalanceType balanceType, WalletTransactionType txType, Money amount, string reason, string? refID)
    {
        EnsureMoney(amount);

        var balance = EnsureBalance(balanceType);
        balance.Decrease(amount);

        _transactions.Add(WalletTransaction.Create(
            walletKey: WalletKey,
            balanceType: balanceType,
            txType: txType,
            amount: amount,
            balanceAfter: balance.Amount,
            reason: reason,
            refID: refID
        ));
    }

    private WalletBalance GetBalanceEntity(WalletBalanceType type)
    {
        var found = _balances.SingleOrDefault(x => x.Type == type);
        if (found is null)
        {
            throw new InvalidOperationException($"Balance type '{type}' not initialized.");
        }

        return found;
    }

    private WalletBalance EnsureBalance(WalletBalanceType type)
    {
        var found = _balances.SingleOrDefault(x => x.Type == type);
        if (found != null)
        {
            return found;
        }

        var created = WalletBalance.Create(WalletKey, type);
        _balances.Add(created);

        return created;
    }

    private static void EnsureMoney(Money amount)
    {
        if (amount.IsZero || amount.Value <= 0)
        {
            throw new ArgumentException("Amount must be positive.", nameof(amount));
        }
    }
}