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

namespace Application.Features.Api.Channel.SearchForOrder;

public sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var query = db.Channel.AsNoTracking()
            .Where(c => c.IsActive && c.MemberID != request.MemberID)
            .AsQueryable();

        if (!string.IsNullOrWhiteSpace(request.Keyword))
        {
            var kw = request.Keyword.Trim();
            var codeKw = kw.ToUpperInvariant();
            query = query.Where(c =>
                c.Name.Contains(kw)
                || (c.Handle != null && c.Handle.Contains(kw))
                || (c.DonationCode != null && c.DonationCode == codeKw));
        }

        var total = await query.CountAsync(ct);

        // Random=true 면 SQL NEWID() 로 셔플 — 공평한 노출.
        // 그 외는 인증/구독자 수 정렬 (관리자 노출 기준).
        var ordered = request.Random
            ? query.OrderBy(c => Guid.NewGuid())
            : query
                .OrderByDescending(c => c.IsVerified)
                .ThenByDescending(c => c.SubscriberCount);

        var list = await ordered
            .Skip((request.Page - 1) * request.PerPage)
            .Take(request.PerPage)
            .Select(c => new Response.Row(
                c.ID,
                c.SID,
                c.Name,
                c.Handle,
                c.ThumbnailUrl,
                c.SubscriberCount,
                c.IsVerified,
                c.DonationCode
            ))
            .ToListAsync(ct);

        return new Response(total, list);
    }
}