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

namespace Application.Features.Api.DonationAlert.GetSignatureImages;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var page = request.Page < 1 ? 1 : request.Page;
        var perPage = request.PerPage < 1 ? 6 : request.PerPage > 30 ? 30 : request.PerPage;

        var resolved = await ChannelIdentifierResolver.ResolveAsync(db, request.Identifier, ct);

        if (resolved.ChannelSID is null)
        {
            return new Response([], 0, false);
        }

        var channelID = await db.Channel.AsNoTracking()
            .Where(c => c.SID == resolved.ChannelSID && c.IsActive)
            .Select(c => (int?)c.ID)
            .FirstOrDefaultAsync(ct);

        if (channelID is null)
        {
            return new Response([], 0, false);
        }

        var baseQuery = db.DonationAlertConfig.AsNoTracking()
            .Where(c => c.ChannelID == channelID.Value
                     && c.IsActive
                     && c.EnableImage
                     && c.ImageUrl != null);

        var total = await baseQuery.CountAsync(ct);

        var list = await baseQuery
            .OrderBy(c => c.Amount)
            .Skip((page - 1) * perPage)
            .Take(perPage)
            .Select(c => new SignatureItem(
                c.ID,
                c.Title,
                c.Amount,
                c.MatchType,
                c.ImageUrl!
            ))
            .ToListAsync(ct);

        var hasMore = page * perPage < total;

        return new Response(list, total, hasMore);
    }
}