using System;
using System.Collections.Generic;
using System.Linq;
using Svrnty.CQRS.Abstractions.Discovery;

namespace Svrnty.CQRS.Discovery;

public sealed class QueryDiscovery : IQueryDiscovery
{
    private readonly List<IQueryMeta> _queryMetas;
    private readonly Dictionary<string, IQueryMeta> _queriesByName;
    private readonly Dictionary<Type, IQueryMeta> _queriesByType;

    public QueryDiscovery(IEnumerable<IQueryMeta> queryMetas)
    {
        // Materialize the enumerable to a list once
        _queryMetas = queryMetas.ToList();

        // Build lookup dictionaries for O(1) access
        _queriesByName = new Dictionary<string, IQueryMeta>(_queryMetas.Count);
        _queriesByType = new Dictionary<Type, IQueryMeta>(_queryMetas.Count);

        foreach (var meta in _queryMetas)
        {
            _queriesByName[meta.Name] = meta;
            _queriesByType[meta.QueryType] = meta;
        }
    }

    public IEnumerable<IQueryMeta> GetQueries() => _queryMetas;

    public IQueryMeta FindQuery(string name) =>
        _queriesByName.TryGetValue(name, out var meta) ? meta : null;

    public IQueryMeta FindQuery(Type queryType) =>
        _queriesByType.TryGetValue(queryType, out var meta) ? meta : null;

    public bool QueryExists(string name) =>
        _queriesByName.ContainsKey(name);

    public bool QueryExists(Type queryType) =>
        _queriesByType.ContainsKey(queryType);
}