using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MongoDB.Bson;
using MongoDB.Driver;
using StellaOps.Signals.Models;

namespace StellaOps.Signals.Persistence;

public sealed class MongoUnknownsRepository : IUnknownsRepository
{
    private readonly IMongoCollection<UnknownSymbolDocument> collection;

    public MongoUnknownsRepository(IMongoCollection<UnknownSymbolDocument> collection)
    {
        this.collection = collection ?? throw new ArgumentNullException(nameof(collection));
    }

    public async Task UpsertAsync(string subjectKey, IEnumerable<UnknownSymbolDocument> items, CancellationToken cancellationToken)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(subjectKey);
        ArgumentNullException.ThrowIfNull(items);

        // deterministic replace per subject to keep the registry stable
        await collection.DeleteManyAsync(doc => doc.SubjectKey == subjectKey, cancellationToken).ConfigureAwait(false);

        var batch = items.ToList();
        if (batch.Count == 0)
        {
            return;
        }

        await collection.InsertManyAsync(batch, cancellationToken: cancellationToken).ConfigureAwait(false);
    }

    public async Task<IReadOnlyList<UnknownSymbolDocument>> GetBySubjectAsync(string subjectKey, CancellationToken cancellationToken)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(subjectKey);

        var cursor = await collection.FindAsync(doc => doc.SubjectKey == subjectKey, cancellationToken: cancellationToken).ConfigureAwait(false);
        return await cursor.ToListAsync(cancellationToken).ConfigureAwait(false);
    }

    public async Task<int> CountBySubjectAsync(string subjectKey, CancellationToken cancellationToken)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(subjectKey);

        var count = await collection.CountDocumentsAsync(doc => doc.SubjectKey == subjectKey, cancellationToken: cancellationToken).ConfigureAwait(false);
        return (int)count;
    }
}