using LCU.API.Internal.DocumentLib.Containers;
using LCU.API.Internal.DocumentLib.Utilities;
using Microsoft.Extensions.Logging;
using MongoDB.Driver;

namespace OwnerNumberMigration.Logging;

public delegate IAttributeMigration AttributeMigrationLoggingDecoratorFactory
(
    IAttributeMigration migration,
    string attributeName,
    string destinationAttributeName
);

public class AttributeMigrationLoggingDecorator : IAttributeMigration
{
    private readonly IAttributeMigration _migration;
    private readonly ILogger _logger;
    private readonly IMongoCollection<DocumentInformation> _documents;
    private readonly string _attributeName;
    private readonly string _destinationAttributeName;
    private readonly IDocumentFilterFactory _filterFactory;

    public AttributeMigrationLoggingDecorator
    (
        IAttributeMigration migration,
        ILogger logger,
        IMongoCollectionFactory collectionFactory,
        string attributeName,
        string destinationAttributeName,
        IDocumentFilterFactory filterFactory
    )
    {
        _migration = migration;
        _logger = logger;
        _documents = collectionFactory.GetCollection<DocumentInformation>();
        _attributeName = attributeName;
        _destinationAttributeName = destinationAttributeName;
        _filterFactory = filterFactory;
    }

    public async Task Migrate(CancellationToken cancellationToken)
    {
        var countToMigration = await _documents.CountDocumentsAsync
        (
            _filterFactory.AppliesForMigrationFilterFactory(_attributeName, _destinationAttributeName),
            cancellationToken: cancellationToken
        );
        _logger.LogInformation
        (
            "starting to migration {attribute} with {count} documents",
            _attributeName,
            countToMigration
        );
        var start = DateTime.Now;

        await _migration.Migrate(cancellationToken);

        var duration = DateTime.Now - start;
        _logger.LogInformation("finished migration for {attribute} in {elapsed}", _attributeName, duration);
    }
}