bitforum-backend/Application/Features/Forum/Board/Search/Handler.cs

using Application.Abstractions.Messaging;
using Application.Abstractions.Data;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Forum.Board.Search;

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

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

        if (!string.IsNullOrWhiteSpace(request.Keyword))
        {
            var kw = request.Keyword.Trim();
            query = query.Where(c => c.Name.Contains(kw) || c.Code.Contains(kw));
        }

        var total = await query.CountAsync(ct);

        var list = await query
            .OrderBy(c => c.Order)
            .ThenByDescending(c => c.ID)
            .Skip((request.PageNum - 1) * request.PerPage)
            .Take(request.PerPage)
            .Select(c => new
            {
                c.ID,
                c.BoardGroupID,
                BoardGroupName = c.BoardGroup.Name,
                c.Code,
                c.Name,
                c.Order,
                c.IsSearch,
                c.IsActive,
                c.Posts,
                c.Comments,
                c.UpdatedAt,
                c.CreatedAt
            })
            .ToListAsync(ct);

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

        return new Response(
            total,
            [..list.Select((c, i) => new Response.Row(
                Num: startNum - i,
                c.ID,
                c.BoardGroupID,
                c.BoardGroupName,
                c.Code,
                c.Name,
                c.Order,
                c.IsSearch,
                c.IsActive,
                c.Posts,
                c.Comments,
                c.UpdatedAt,
                c.CreatedAt
            ))]
        );
    }
}