using System.ComponentModel.DataAnnotations;
using MAX.Framework.Validation;
using FreeSql;
using MAX.Core.DependencyInjection;
using MAX.Framework.Commons;
using MAX.Framework.Security;
using Store.Users.Contracts.Dtos;
using Store.Users.Entities;
namespace Store.Users.Services;

/// <summary>资金写入集中在事务中完成。账户行锁防止超扣，流水与余额同提交、同回滚。</summary>
public sealed class UserFundsService(IFreeSql orm, ICurrentUser currentUser) : ITransientDependency
{
    public async Task<UserFundsResponse> Change(UserFundsRequest request, bool points, CancellationToken ct)
    {
        RequestValidator.Validate(request);
        // DTO 只检查非空，其余长度、金额和操作组合在服务中手动判断。
        UserInputChecks.Length(request.UserName, 20, "目标账户");
        UserInputChecks.Length(request.RequestId, 64, "请求号");
        UserInputChecks.Length(request.Remark, 255, "备注");
        if (request.Amount is < 0.01m or > 1000000m)
            throw new ValidationException("金额必须为0.01-1000000");
        if (decimal.Round(request.Amount, 2) != request.Amount)
            throw new ValidationException("金额最多保留两位小数");
        if (points ? request.Operation is not ("充值" or "转移") : request.Operation is not ("充值" or "消费"))
            throw new ValidationException("不支持的资金操作类型");
        ct.ThrowIfCancellationRequested();
        if (!currentUser.IsAuthenticated || string.IsNullOrWhiteSpace(currentUser.UserName)) throw new UnauthorizedAccessException();
        using var work = orm.CreateUnitOfWork();
        work.GetOrBeginTransaction();
        var db = work.Orm;
        var actor = await db.Select<UserEntity>().Where(u => u.UserName == currentUser.UserName).FirstAsync(ct)
            ?? throw new UnauthorizedAccessException();
        bool transfer = points && request.Operation == "转移";
        if (!transfer && actor.SaLevel != 1) throw new AppException("充值和余额调整仅允许管理员操作", 403);
        var name = request.UserName.Trim();
        var target = await db.Select<UserEntity>().Where(u => u.UserName == name).FirstAsync(ct)
            ?? throw new AppException("目标账户不存在");
        if (transfer && actor.Id == target.Id) throw new AppException("不能向自己转移积分");
        if (transfer && !UserAccessPolicy.CanManage(actor, target))
            throw new AppException("只能向管理范围内的账户转移积分", 403);
        // 双账户转移按相同主键顺序加锁，避免双方同时转账时产生反向锁顺序。
        var ids = transfer ? new[] { actor.Id, target.Id }.Order().ToArray() : new[] { target.Id };
        foreach (var id in ids)
        {
            var locked = await db.Select<UserEntity>().Where(u => u.Id == id).ForUpdate().FirstAsync(ct)
                ?? throw new AppException("账户已被删除");
            if (id == target.Id) target = locked;
            if (id == actor.Id) actor = locked;
        }
        var key = "user:" + request.RequestId.Trim();
        // 持有目标行锁后检查请求号，相同账户的并发重试只能执行一次。
        bool duplicate = points
            ? await db.Select<UserPointsRecordEntity>().Where(r => r.UserName == target.UserName && r.OutTradeNo == key).AnyAsync(ct)
            : await db.Select<UserPaymentRecordEntity>().Where(r => r.UserName == target.UserName && r.RefundFlowNo == key).AnyAsync(ct);
        if (duplicate) throw new AppException("该请求已处理，请查询流水确认结果，勿重复提交");
        decimal value;
        if (points)
        {
            value = checked(target.Points + request.Amount);
            if (transfer)
            {
                if (actor.Points < request.Amount) throw new AppException("积分不足");
                if (await db.Update<UserEntity>().Set(u => u.Points, actor.Points - request.Amount)
                    .Where(u => u.Id == actor.Id && u.Points == actor.Points).ExecuteAffrowsAsync(ct) != 1)
                    throw new AppException("转出账户状态已改变");
                await AddPointsRecord(db, actor, actor, request.Amount, actor.Points - request.Amount,
                    "转出", target.UserName, key, request.Remark, ct);
            }
            var update = db.Update<UserEntity>().Set(u => u.Points, value)
                .Where(u => u.Id == target.Id && u.Points == target.Points);
            // 延续原系统口径：积分转入也计入接收方累计充值。
            update = update.Set(u => u.RechargePointsTotal, checked((target.RechargePointsTotal ?? 0) + request.Amount));
            if (await update.ExecuteAffrowsAsync(ct) != 1) throw new AppException("账户状态已改变");
            await AddPointsRecord(db, target, actor, request.Amount, value, transfer ? "转入" : "充值",
                transfer ? actor.UserName : null, key, request.Remark, ct);
        }
        else
        {
            bool recharge = request.Operation == "充值";
            value = checked((target.Balance ?? 0) + (recharge ? request.Amount : -request.Amount));
            if (value < 0) throw new AppException("余额不足");
            var update = db.Update<UserEntity>().Set(u => u.Balance, value).Where(u => u.Id == target.Id && u.Balance == target.Balance);
            if (recharge) update = update.Set(u => u.RechargeAmountTotal, checked((target.RechargeAmountTotal ?? 0) + request.Amount));
            if (await update.ExecuteAffrowsAsync(ct) != 1) throw new AppException("账户状态已改变");
            if (await db.Insert(new UserPaymentRecordEntity
            {
                UserName = target.UserName, Type = recharge ? 1 : 0, Amount = request.Amount, Balance = value,
                CreateBy = actor.UserName, CreateTime = DateTime.Now, Remark = request.Remark ?? "",
                PlatformCode = "", OrderId = "", UpdateBy = "", CounterpartyAccountName = "", RefundFlowNo = key
            }).ExecuteAffrowsAsync(ct) != 1) throw new AppException("写入余额流水失败");
        }
        ct.ThrowIfCancellationRequested();
        work.Commit();
        return new(target.UserName, value, request.RequestId);
    }

    private static async Task AddPointsRecord(IFreeSql db, UserEntity user, UserEntity actor, decimal amount,
        decimal value, string operation, string? counterparty, string key, string? remark, CancellationToken ct)
    {
        if (await db.Insert(new UserPointsRecordEntity
        {
            UserName = user.UserName, UserNick = user.NickName, DeltaPoints = amount, NewPoints = value,
            OptionType = operation, OperatorType = actor.SaLevel == 1 ? "管理员" : "用户", OperatorName = actor.UserName,
            CounterpartyAccountName = counterparty, OutTradeNo = key, Remark = remark, AddTime = DateTime.Now
        }).ExecuteAffrowsAsync(ct) != 1) throw new AppException("写入积分流水失败");
    }
}