using System.Text.Json;
using Microsoft.Extensions.Logging;
using StellaOps.Messaging.Abstractions;
using StackExchange.Redis;

namespace StellaOps.Messaging.Transport.Valkey;

/// <summary>
/// Valkey/Redis implementation of <see cref="ISetStore{TKey, TElement}"/>.
/// Uses set commands (SADD, SMEMBERS, SISMEMBER, SREM, etc.).
/// </summary>
public sealed class ValkeySetStore<TKey, TElement> : ISetStore<TKey, TElement>
    where TKey : notnull
{
    private readonly ValkeyConnectionFactory _connectionFactory;
    private readonly string _name;
    private readonly ILogger<ValkeySetStore<TKey, TElement>>? _logger;
    private readonly JsonSerializerOptions _jsonOptions;
    private readonly Func<TKey, string> _keySerializer;

    public ValkeySetStore(
        ValkeyConnectionFactory connectionFactory,
        string name,
        ILogger<ValkeySetStore<TKey, TElement>>? logger = null,
        JsonSerializerOptions? jsonOptions = null,
        Func<TKey, string>? keySerializer = null)
    {
        _connectionFactory = connectionFactory ?? throw new ArgumentNullException(nameof(connectionFactory));
        _name = name ?? throw new ArgumentNullException(nameof(name));
        _logger = logger;
        _jsonOptions = jsonOptions ?? new JsonSerializerOptions
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
            WriteIndented = false
        };
        _keySerializer = keySerializer ?? (key => key?.ToString() ?? throw new ArgumentNullException(nameof(key)));
    }

    /// <inheritdoc />
    public string ProviderName => "valkey";

    /// <inheritdoc />
    public async ValueTask<bool> AddAsync(
        TKey setKey,
        TElement element,
        CancellationToken cancellationToken = default)
    {
        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        var serialized = Serialize(element);
        return await db.SetAddAsync(redisKey, serialized).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public async ValueTask<long> AddRangeAsync(
        TKey setKey,
        IEnumerable<TElement> elements,
        CancellationToken cancellationToken = default)
    {
        ArgumentNullException.ThrowIfNull(elements);

        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        var values = elements.Select(e => (RedisValue)Serialize(e)).ToArray();
        if (values.Length == 0)
        {
            return 0;
        }

        return await db.SetAddAsync(redisKey, values).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public async ValueTask<IReadOnlySet<TElement>> GetMembersAsync(
        TKey setKey,
        CancellationToken cancellationToken = default)
    {
        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        var members = await db.SetMembersAsync(redisKey).ConfigureAwait(false);
        var result = new HashSet<TElement>();

        foreach (var member in members)
        {
            if (!member.IsNullOrEmpty)
            {
                var element = Deserialize((string)member!);
                if (element is not null)
                {
                    result.Add(element);
                }
            }
        }

        return result;
    }

    /// <inheritdoc />
    public async ValueTask<bool> ContainsAsync(
        TKey setKey,
        TElement element,
        CancellationToken cancellationToken = default)
    {
        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        var serialized = Serialize(element);
        return await db.SetContainsAsync(redisKey, serialized).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public async ValueTask<bool> RemoveAsync(
        TKey setKey,
        TElement element,
        CancellationToken cancellationToken = default)
    {
        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        var serialized = Serialize(element);
        return await db.SetRemoveAsync(redisKey, serialized).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public async ValueTask<long> RemoveRangeAsync(
        TKey setKey,
        IEnumerable<TElement> elements,
        CancellationToken cancellationToken = default)
    {
        ArgumentNullException.ThrowIfNull(elements);

        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        var values = elements.Select(e => (RedisValue)Serialize(e)).ToArray();
        if (values.Length == 0)
        {
            return 0;
        }

        return await db.SetRemoveAsync(redisKey, values).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public async ValueTask<bool> DeleteAsync(
        TKey setKey,
        CancellationToken cancellationToken = default)
    {
        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        return await db.KeyDeleteAsync(redisKey).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public async ValueTask<long> CountAsync(
        TKey setKey,
        CancellationToken cancellationToken = default)
    {
        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        return await db.SetLengthAsync(redisKey).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public async ValueTask SetExpirationAsync(
        TKey setKey,
        TimeSpan ttl,
        CancellationToken cancellationToken = default)
    {
        var redisKey = BuildKey(setKey);
        var db = await _connectionFactory.GetDatabaseAsync(cancellationToken).ConfigureAwait(false);

        await db.KeyExpireAsync(redisKey, ttl).ConfigureAwait(false);
    }

    private string BuildKey(TKey setKey)
    {
        var keyString = _keySerializer(setKey);
        return $"set:{_name}:{keyString}";
    }

    private string Serialize(TElement element)
    {
        // For primitive types, use ToString directly
        if (element is string s)
        {
            return s;
        }

        return JsonSerializer.Serialize(element, _jsonOptions);
    }

    private TElement? Deserialize(string value)
    {
        // For string types, return directly
        if (typeof(TElement) == typeof(string))
        {
            return (TElement)(object)value;
        }

        return JsonSerializer.Deserialize<TElement>(value, _jsonOptions);
    }
}

/// <summary>
/// Factory for creating Valkey set store instances.
/// </summary>
public sealed class ValkeySetStoreFactory : ISetStoreFactory
{
    private readonly ValkeyConnectionFactory _connectionFactory;
    private readonly ILoggerFactory? _loggerFactory;
    private readonly JsonSerializerOptions? _jsonOptions;

    public ValkeySetStoreFactory(
        ValkeyConnectionFactory connectionFactory,
        ILoggerFactory? loggerFactory = null,
        JsonSerializerOptions? jsonOptions = null)
    {
        _connectionFactory = connectionFactory ?? throw new ArgumentNullException(nameof(connectionFactory));
        _loggerFactory = loggerFactory;
        _jsonOptions = jsonOptions;
    }

    /// <inheritdoc />
    public string ProviderName => "valkey";

    /// <inheritdoc />
    public ISetStore<TKey, TElement> Create<TKey, TElement>(string name)
        where TKey : notnull
    {
        ArgumentNullException.ThrowIfNull(name);
        return new ValkeySetStore<TKey, TElement>(
            _connectionFactory,
            name,
            _loggerFactory?.CreateLogger<ValkeySetStore<TKey, TElement>>(),
            _jsonOptions);
    }
}