using ZB.MOM.WW.OtOpcUa.Driver.FOCAS;

namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests;

internal class FakeFocasClient : IFocasClient
{
    /// <summary>Gets a value indicating whether the client is connected.</summary>
    public bool IsConnected { get; private set; }
    /// <summary>Gets the count of connection attempts.</summary>
    public int ConnectCount { get; private set; }
    /// <summary>Gets the count of dispose operations.</summary>
    public int DisposeCount { get; private set; }
    /// <summary>Gets or sets a value indicating whether to throw on connect.</summary>
    public bool ThrowOnConnect { get; set; }
    /// <summary>Gets or sets a value indicating whether to throw on read.</summary>
    public bool ThrowOnRead { get; set; }
    /// <summary>Gets or sets a value indicating whether to throw on write.</summary>
    public bool ThrowOnWrite { get; set; }
    /// <summary>Gets or sets the result of probe operations.</summary>
    public bool ProbeResult { get; set; } = true;
    /// <summary>Gets or sets the exception to throw.</summary>
    public Exception? Exception { get; set; }

    /// <summary>Gets the dictionary of read values keyed by address.</summary>
    public Dictionary<string, object?> Values { get; } = new(StringComparer.OrdinalIgnoreCase);
    /// <summary>Gets the dictionary of read statuses keyed by address.</summary>
    public Dictionary<string, uint> ReadStatuses { get; } = new(StringComparer.OrdinalIgnoreCase);
    /// <summary>Gets the dictionary of write statuses keyed by address.</summary>
    public Dictionary<string, uint> WriteStatuses { get; } = new(StringComparer.OrdinalIgnoreCase);
    /// <summary>Gets the log of write operations.</summary>
    public List<(FocasAddress addr, FocasDataType type, object? value)> WriteLog { get; } = new();

    /// <summary>Connects to a FOCAS host asynchronously.</summary>
    /// <param name="address">The FOCAS host address.</param>
    /// <param name="timeout">The connection timeout duration.</param>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task ConnectAsync(FocasHostAddress address, TimeSpan timeout, CancellationToken ct)
    {
        ConnectCount++;
        if (ThrowOnConnect) throw Exception ?? new InvalidOperationException();
        IsConnected = true;
        return Task.CompletedTask;
    }

    /// <summary>Reads a value from a FOCAS address asynchronously.</summary>
    /// <param name="address">The FOCAS address to read from.</param>
    /// <param name="type">The data type of the value.</param>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<(object? value, uint status)> ReadAsync(
        FocasAddress address, FocasDataType type, CancellationToken ct)
    {
        if (ThrowOnRead) throw Exception ?? new InvalidOperationException();
        var key = address.Canonical;
        var status = ReadStatuses.TryGetValue(key, out var s) ? s : FocasStatusMapper.Good;
        var value = Values.TryGetValue(key, out var v) ? v : null;
        return Task.FromResult((value, status));
    }

    /// <summary>PMC byte memory the range read serves, keyed by (upper-case letter, byte address); absent = 0.</summary>
    public Dictionary<(string Letter, int Address), byte> PmcMemory { get; } = new();
    /// <summary>Gets the log of range reads issued (letter, slot type, start, end).</summary>
    public List<(string Letter, FocasDataType SlotType, int Start, int End)> PmcRangeReads { get; } = new();
    /// <summary>Ranges (letter, start, end) the fake CNC rejects with <see cref="PmcRangeRejectStatus"/>.</summary>
    public List<Func<string, int, int, bool>> PmcRangeRejectors { get; } = new();
    /// <summary>The status a rejected range returns.</summary>
    public uint PmcRangeRejectStatus { get; set; } = FocasStatusMapper.BadOutOfRange;
    /// <summary>When true every range read throws (transport failure).</summary>
    public bool ThrowOnPmcRange { get; set; }

    /// <summary>Reads a PMC range as raw big-endian slots from <see cref="PmcMemory"/>.</summary>
    /// <param name="letter">PMC letter.</param>
    /// <param name="slotType">Slot type.</param>
    /// <param name="start">First byte.</param>
    /// <param name="end">Last byte, inclusive.</param>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<(IReadOnlyList<long>? slots, uint status)> ReadPmcSlotsAsync(
        string letter, FocasDataType slotType, int start, int end, CancellationToken ct)
    {
        PmcRangeReads.Add((letter, slotType, start, end));
        if (ThrowOnPmcRange) throw new InvalidOperationException("transport down");
        if (PmcRangeRejectors.Any(r => r(letter, start, end)))
            return Task.FromResult<(IReadOnlyList<long>?, uint)>((null, PmcRangeRejectStatus));

        var width = slotType switch
        {
            FocasDataType.Int16 => 2,
            FocasDataType.Int32 or FocasDataType.Float32 => 4,
            FocasDataType.Float64 => 8,
            _ => 1,
        };
        var slots = new List<long>();
        for (var o = start; o + width - 1 <= end; o += width)
        {
            long v = 0;
            for (var k = 0; k < width; k++)
                v = (v << 8) | (PmcMemory.TryGetValue((letter, o + k), out var b) ? b : (byte)0);
            // Sign-extend like the wire parser (Int16/Int32/Int64 big-endian); width 1 stays 0..255.
            v = width switch { 2 => (short)v, 4 => (int)v, _ => v };
            slots.Add(v);
        }
        return Task.FromResult<(IReadOnlyList<long>?, uint)>((slots, FocasStatusMapper.Good));
    }

    /// <summary>Writes a value to a FOCAS address asynchronously.</summary>
    /// <param name="address">The FOCAS address to write to.</param>
    /// <param name="type">The data type of the value.</param>
    /// <param name="value">The value to write.</param>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<uint> WriteAsync(
        FocasAddress address, FocasDataType type, object? value, CancellationToken ct)
    {
        if (ThrowOnWrite) throw Exception ?? new InvalidOperationException();
        WriteLog.Add((address, type, value));
        Values[address.Canonical] = value;
        var status = WriteStatuses.TryGetValue(address.Canonical, out var s) ? s : FocasStatusMapper.Good;
        return Task.FromResult(status);
    }

    /// <summary>Probes the FOCAS connection asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<bool> ProbeAsync(CancellationToken ct) => Task.FromResult(ProbeResult);

    /// <summary>Gets the list of active alarms.</summary>
    public List<FocasActiveAlarm> Alarms { get; } = [];

    /// <summary>Gets or sets a value indicating whether the alarm read throws (Gitea #647: a failed read).</summary>
    public bool ThrowOnReadAlarms { get; set; }

    /// <summary>Gets or sets an exception the alarm read throws (e.g. a CNC refusal carrying an rc).</summary>
    public Exception? AlarmReadException { get; set; }

    /// <summary>Gets the number of alarm reads served (successful or not).</summary>
    public int AlarmReadCount => Volatile.Read(ref _alarmReadCount);

    private int _alarmReadCount;

    /// <summary>Replaces the active alarm list atomically with respect to the poll thread.</summary>
    /// <param name="alarms">The new active alarms.</param>
    public void SetAlarms(params FocasActiveAlarm[] alarms)
    {
        lock (Alarms) { Alarms.Clear(); Alarms.AddRange(alarms); }
    }

    /// <summary>Reads active alarms asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<IReadOnlyList<FocasActiveAlarm>> ReadAlarmsAsync(CancellationToken ct)
    {
        Interlocked.Increment(ref _alarmReadCount);
        if (AlarmReadException is { } refusal) throw refusal;
        if (ThrowOnReadAlarms) throw new InvalidOperationException("cnc_rdalmmsg2 failed (fake)");
        lock (Alarms) return Task.FromResult<IReadOnlyList<FocasActiveAlarm>>([.. Alarms]);
    }

    // ---- Fixed-tree T1 ----
    /// <summary>Gets or sets the system information.</summary>
    public FocasSysInfo SysInfo { get; set; } = new(0, 3, "M", "M", "30i", "A1.0", 3);
    /// <summary>Gets the list of axis names.</summary>
    public List<FocasAxisName> AxisNames { get; } = [new("X", ""), new("Y", ""), new("Z", "")];
    /// <summary>Gets the list of spindle names.</summary>
    public List<FocasSpindleName> SpindleNames { get; } = [new("S", "1", "", "")];
    /// <summary>Gets the dictionary of dynamic snapshots keyed by axis index.</summary>
    public Dictionary<int, FocasDynamicSnapshot> DynamicByAxis { get; } = [];

    /// <summary>Gets system information asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<FocasSysInfo> GetSysInfoAsync(CancellationToken ct) => Task.FromResult(SysInfo);
    /// <summary>Gets axis names asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<IReadOnlyList<FocasAxisName>> GetAxisNamesAsync(CancellationToken ct) =>
        Task.FromResult<IReadOnlyList<FocasAxisName>>([.. AxisNames]);
    /// <summary>Gets spindle names asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<IReadOnlyList<FocasSpindleName>> GetSpindleNamesAsync(CancellationToken ct) =>
        Task.FromResult<IReadOnlyList<FocasSpindleName>>([.. SpindleNames]);
    /// <summary>Reads dynamic data for an axis asynchronously.</summary>
    /// <param name="axisIndex">The zero-based axis index.</param>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<FocasDynamicSnapshot> ReadDynamicAsync(int axisIndex, CancellationToken ct)
    {
        if (!DynamicByAxis.TryGetValue(axisIndex, out var snap))
            snap = new FocasDynamicSnapshot(axisIndex, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
        return Task.FromResult(snap);
    }

    /// <summary>Gets or sets the program information.</summary>
    public FocasProgramInfo ProgramInfo { get; set; } = new("O0001", 1, 0, 1);
    /// <summary>Gets program information asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<FocasProgramInfo> GetProgramInfoAsync(CancellationToken ct) =>
        Task.FromResult(ProgramInfo);

    /// <summary>Gets or sets the cnc_statinfo status snapshot.</summary>
    public FocasStatus Status { get; set; } = new(1, 3, 1, 0, 0, 0, 0, 0);
    /// <summary>Gets or sets a value indicating whether <see cref="GetStatusAsync"/> throws (older series / refused call).</summary>
    public bool ThrowOnStatus { get; set; }
    /// <summary>Gets the number of status reads served.</summary>
    public int StatusReads { get; private set; }
    /// <summary>Gets the CNC status flags asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<FocasStatus> GetStatusAsync(CancellationToken ct)
    {
        StatusReads++;
        if (ThrowOnStatus) throw new InvalidOperationException("cnc_statinfo refused");
        return Task.FromResult(Status);
    }

    /// <summary>Gets the dictionary of timers keyed by timer kind.</summary>
    public Dictionary<FocasTimerKind, FocasTimer> Timers { get; } = [];
    /// <summary>Gets timer data asynchronously.</summary>
    /// <param name="kind">The timer kind to retrieve.</param>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<FocasTimer> GetTimerAsync(FocasTimerKind kind, CancellationToken ct)
    {
        if (!Timers.TryGetValue(kind, out var t))
            t = new FocasTimer(kind, 0, 0);
        return Task.FromResult(t);
    }

    /// <summary>Gets the list of servo loads.</summary>
    public List<FocasServoLoad> ServoLoads { get; } = [];
    /// <summary>Gets servo loads asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<IReadOnlyList<FocasServoLoad>> GetServoLoadsAsync(CancellationToken ct) =>
        Task.FromResult<IReadOnlyList<FocasServoLoad>>([.. ServoLoads]);

    /// <summary>Gets the list of spindle load percentages (null = undescribable slot).</summary>
    public List<double?> SpindleLoads { get; } = [];
    /// <summary>Gets the list of spindle motor-speed percentages (null = undescribable slot).</summary>
    public List<double?> SpindleMotorSpeeds { get; } = [];
    /// <summary>Gets spindle loads asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<IReadOnlyList<double?>> GetSpindleLoadsAsync(CancellationToken ct) =>
        Task.FromResult<IReadOnlyList<double?>>([.. SpindleLoads]);
    /// <summary>Gets spindle motor-speed percentages asynchronously.</summary>
    /// <param name="ct">The cancellation token.</param>
    public virtual Task<IReadOnlyList<double?>> GetSpindleMotorSpeedsAsync(CancellationToken ct) =>
        Task.FromResult<IReadOnlyList<double?>>([.. SpindleMotorSpeeds]);

    /// <summary>Disposes the client.</summary>
    public virtual void Dispose()
    {
        DisposeCount++;
        IsConnected = false;
    }
}

/// <summary>A factory for creating fake FOCAS clients.</summary>
internal sealed class FakeFocasClientFactory : IFocasClientFactory
{
    /// <summary>Gets the list of created clients.</summary>
    public List<FakeFocasClient> Clients { get; } = new();
    /// <summary>Gets or sets a customization function for creating clients.</summary>
    public Func<FakeFocasClient>? Customise { get; set; }

    /// <summary>No-op usability probe — the fake factory is always usable.</summary>
    public void EnsureUsable() { }

    /// <summary>Creates a fake FOCAS client.</summary>
    public IFocasClient Create()
    {
        var c = Customise?.Invoke() ?? new FakeFocasClient();
        Clients.Add(c);
        return c;
    }
}