using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.PlcFamilies;

namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy;

/// <summary>
///     AB Legacy / PCCC driver — SLC 500, MicroLogix, PLC-5, LogixPccc. Implements
///     <see cref="IDriver"/> only at PR 1 time; read / write / discovery / subscribe / probe /
///     host-resolver capabilities ship in PRs 2 and 3.
/// </summary>
public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, IDisposable, IAsyncDisposable
{
    private readonly AbLegacyDriverOptions _options;
    private readonly string _driverInstanceId;
    private readonly IAbLegacyTagFactory _tagFactory;
    private readonly Dictionary<string, DeviceState> _devices = new(StringComparer.OrdinalIgnoreCase);
    private readonly Dictionary<string, AbLegacyTagDefinition> _tagsByName = new(StringComparer.OrdinalIgnoreCase);
    private DriverHealth _health = new(DriverState.Unknown, null, null);

    public AbLegacyDriver(AbLegacyDriverOptions options, string driverInstanceId,
        IAbLegacyTagFactory? tagFactory = null)
    {
        ArgumentNullException.ThrowIfNull(options);
        _options = options;
        _driverInstanceId = driverInstanceId;
        _tagFactory = tagFactory ?? new LibplctagLegacyTagFactory();
    }

    public string DriverInstanceId => _driverInstanceId;
    public string DriverType => "AbLegacy";

    public Task InitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
    {
        _health = new DriverHealth(DriverState.Initializing, null, null);
        try
        {
            foreach (var device in _options.Devices)
            {
                var addr = AbLegacyHostAddress.TryParse(device.HostAddress)
                    ?? throw new InvalidOperationException(
                        $"AbLegacy device has invalid HostAddress '{device.HostAddress}' — expected 'ab://gateway[:port]/cip-path'.");
                var profile = AbLegacyPlcFamilyProfile.ForFamily(device.PlcFamily);
                _devices[device.HostAddress] = new DeviceState(addr, device, profile);
            }
            foreach (var tag in _options.Tags) _tagsByName[tag.Name] = tag;
            _health = new DriverHealth(DriverState.Healthy, DateTime.UtcNow, null);
        }
        catch (Exception ex)
        {
            _health = new DriverHealth(DriverState.Faulted, null, ex.Message);
            throw;
        }
        return Task.CompletedTask;
    }

    public async Task ReinitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
    {
        await ShutdownAsync(cancellationToken).ConfigureAwait(false);
        await InitializeAsync(driverConfigJson, cancellationToken).ConfigureAwait(false);
    }

    public Task ShutdownAsync(CancellationToken cancellationToken)
    {
        foreach (var state in _devices.Values) state.DisposeRuntimes();
        _devices.Clear();
        _tagsByName.Clear();
        _health = new DriverHealth(DriverState.Unknown, _health.LastSuccessfulRead, null);
        return Task.CompletedTask;
    }

    public DriverHealth GetHealth() => _health;
    public long GetMemoryFootprint() => 0;
    public Task FlushOptionalCachesAsync(CancellationToken cancellationToken) => Task.CompletedTask;

    internal int DeviceCount => _devices.Count;
    internal DeviceState? GetDeviceState(string hostAddress) =>
        _devices.TryGetValue(hostAddress, out var s) ? s : null;

    // ---- IReadable ----

    public async Task<IReadOnlyList<DataValueSnapshot>> ReadAsync(
        IReadOnlyList<string> fullReferences, CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(fullReferences);
        var now = DateTime.UtcNow;
        var results = new DataValueSnapshot[fullReferences.Count];

        for (var i = 0; i < fullReferences.Count; i++)
        {
            var reference = fullReferences[i];
            if (!_tagsByName.TryGetValue(reference, out var def))
            {
                results[i] = new DataValueSnapshot(null, AbLegacyStatusMapper.BadNodeIdUnknown, null, now);
                continue;
            }
            if (!_devices.TryGetValue(def.DeviceHostAddress, out var device))
            {
                results[i] = new DataValueSnapshot(null, AbLegacyStatusMapper.BadNodeIdUnknown, null, now);
                continue;
            }

            try
            {
                var runtime = await EnsureTagRuntimeAsync(device, def, cancellationToken).ConfigureAwait(false);
                await runtime.ReadAsync(cancellationToken).ConfigureAwait(false);

                var status = runtime.GetStatus();
                if (status != 0)
                {
                    results[i] = new DataValueSnapshot(null,
                        AbLegacyStatusMapper.MapLibplctagStatus(status), null, now);
                    _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead,
                        $"libplctag status {status} reading {reference}");
                    continue;
                }

                var parsed = AbLegacyAddress.TryParse(def.Address);
                var value = runtime.DecodeValue(def.DataType, parsed?.BitIndex);
                results[i] = new DataValueSnapshot(value, AbLegacyStatusMapper.Good, now, now);
                _health = new DriverHealth(DriverState.Healthy, now, null);
            }
            catch (OperationCanceledException) { throw; }
            catch (Exception ex)
            {
                results[i] = new DataValueSnapshot(null,
                    AbLegacyStatusMapper.BadCommunicationError, null, now);
                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ex.Message);
            }
        }

        return results;
    }

    // ---- IWritable ----

    public async Task<IReadOnlyList<WriteResult>> WriteAsync(
        IReadOnlyList<WriteRequest> writes, CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(writes);
        var results = new WriteResult[writes.Count];

        for (var i = 0; i < writes.Count; i++)
        {
            var w = writes[i];
            if (!_tagsByName.TryGetValue(w.FullReference, out var def))
            {
                results[i] = new WriteResult(AbLegacyStatusMapper.BadNodeIdUnknown);
                continue;
            }
            if (!def.Writable)
            {
                results[i] = new WriteResult(AbLegacyStatusMapper.BadNotWritable);
                continue;
            }
            if (!_devices.TryGetValue(def.DeviceHostAddress, out var device))
            {
                results[i] = new WriteResult(AbLegacyStatusMapper.BadNodeIdUnknown);
                continue;
            }

            try
            {
                var runtime = await EnsureTagRuntimeAsync(device, def, cancellationToken).ConfigureAwait(false);
                var parsed = AbLegacyAddress.TryParse(def.Address);
                runtime.EncodeValue(def.DataType, parsed?.BitIndex, w.Value);
                await runtime.WriteAsync(cancellationToken).ConfigureAwait(false);

                var status = runtime.GetStatus();
                results[i] = new WriteResult(status == 0
                    ? AbLegacyStatusMapper.Good
                    : AbLegacyStatusMapper.MapLibplctagStatus(status));
            }
            catch (OperationCanceledException) { throw; }
            catch (NotSupportedException nse)
            {
                results[i] = new WriteResult(AbLegacyStatusMapper.BadNotSupported);
                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, nse.Message);
            }
            catch (Exception ex) when (ex is FormatException or InvalidCastException)
            {
                results[i] = new WriteResult(AbLegacyStatusMapper.BadTypeMismatch);
            }
            catch (OverflowException)
            {
                results[i] = new WriteResult(AbLegacyStatusMapper.BadOutOfRange);
            }
            catch (Exception ex)
            {
                results[i] = new WriteResult(AbLegacyStatusMapper.BadCommunicationError);
                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ex.Message);
            }
        }

        return results;
    }

    private async Task<IAbLegacyTagRuntime> EnsureTagRuntimeAsync(
        DeviceState device, AbLegacyTagDefinition def, CancellationToken ct)
    {
        if (device.Runtimes.TryGetValue(def.Name, out var existing)) return existing;

        var parsed = AbLegacyAddress.TryParse(def.Address)
            ?? throw new InvalidOperationException(
                $"AbLegacy tag '{def.Name}' has malformed Address '{def.Address}'.");

        var runtime = _tagFactory.Create(new AbLegacyTagCreateParams(
            Gateway: device.ParsedAddress.Gateway,
            Port: device.ParsedAddress.Port,
            CipPath: device.ParsedAddress.CipPath,
            LibplctagPlcAttribute: device.Profile.LibplctagPlcAttribute,
            TagName: parsed.ToLibplctagName(),
            Timeout: _options.Timeout));
        try
        {
            await runtime.InitializeAsync(ct).ConfigureAwait(false);
        }
        catch
        {
            runtime.Dispose();
            throw;
        }
        device.Runtimes[def.Name] = runtime;
        return runtime;
    }

    public void Dispose() => DisposeAsync().AsTask().GetAwaiter().GetResult();
    public async ValueTask DisposeAsync() => await ShutdownAsync(CancellationToken.None).ConfigureAwait(false);

    internal sealed class DeviceState(
        AbLegacyHostAddress parsedAddress,
        AbLegacyDeviceOptions options,
        AbLegacyPlcFamilyProfile profile)
    {
        public AbLegacyHostAddress ParsedAddress { get; } = parsedAddress;
        public AbLegacyDeviceOptions Options { get; } = options;
        public AbLegacyPlcFamilyProfile Profile { get; } = profile;
        public Dictionary<string, IAbLegacyTagRuntime> Runtimes { get; } =
            new(StringComparer.OrdinalIgnoreCase);

        public void DisposeRuntimes()
        {
            foreach (var r in Runtimes.Values) r.Dispose();
            Runtimes.Clear();
        }
    }
}