ANTOOZA-BACKEND/Application/Features/Admin/Store/Product/Search/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Domain.Entities.Store.ValueObject;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Admin.Store.Product.Search;

public sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var query = db.Product.AsNoTracking().Include(c => c.Game).AsQueryable();

        if (request.GameID.HasValue)
        {
            query = query.Where(c => c.GameID == request.GameID.Value);
        }

        if (request.Type.HasValue)
        {
            query = query.Where(c => c.Type == request.Type.Value);
        }

        if (request.IsActive.HasValue)
        {
            query = query.Where(c => c.IsActive == request.IsActive.Value);
        }

        if (!string.IsNullOrWhiteSpace(request.Keyword))
        {
            var kw = request.Keyword.Trim();

            query = request.Search switch
            {
                1 => int.TryParse(kw, out var id) ? query.Where(c => c.ID == id) : query.Where(c => false),
                _ => query.Where(c => c.Name.Contains(kw))
            };
        }

        if (DateTime.TryParse(request.StartAt, out var startAt))
        {
            query = query.Where(c => c.CreatedAt >= startAt);
        }

        if (DateTime.TryParse(request.EndAt, out var endAt))
        {
            query = query.Where(c => c.CreatedAt <= endAt);
        }

        var total = await query.CountAsync(ct);

        var list = await query
            .OrderBy(c => c.Order)
            .ThenByDescending(c => c.ID)
            .Skip((request.Page - 1) * request.PerPage)
            .Take(request.PerPage)
            .Select(c => new
            {
                c.ID,
                c.GameID,
                GameName = c.Game!.KorName,
                c.Name,
                c.Thumbnail,
                c.Type,
                c.Price,
                c.DiscountType,
                c.DiscountValue,
                c.Stock,
                c.IsActive,
                c.Order,
                c.SaleStartAt,
                c.SaleEndAt,
                c.UpdatedAt,
                c.CreatedAt
            })
            .ToListAsync(ct);

        var startNum = total - ((request.Page - 1) * request.PerPage);

        return new Response(
            total,
            [.. list.Select((c, i) => {
                var salePrice = c.DiscountType switch
                {
                    DiscountType.Percent => Math.Max(0, c.Price - (c.Price * c.DiscountValue / 100)),
                    DiscountType.Amount  => Math.Max(0, c.Price - c.DiscountValue),
                    _                    => c.Price
                };

                return new Response.Row(
                    Num: startNum - i,
                    c.ID,
                    c.GameID ?? 0,
                    c.GameName,
                    c.Name,
                    c.Thumbnail,
                    c.Type,
                    c.Price,
                    c.DiscountType,
                    c.DiscountValue,
                    salePrice,
                    c.Stock,
                    c.IsActive,
                    c.Order,
                    c.SaleStartAt,
                    c.SaleEndAt,
                    c.UpdatedAt,
                    c.CreatedAt
                );
            })]
        );
    }
}