using System;
using System.Threading;
using System.Threading.Tasks;
using HC_APTBS.Models;

namespace HC_APTBS.Services
{
    /// <summary>
    /// Orchestrates the test bench: relay control, temperature PID, RPM control,
    /// and test sequence execution.
    /// </summary>
    public interface IBenchService
    {
        // ── Events ────────────────────────────────────────────────────────────────

        /// <summary>Raised when a test sequence starts.</summary>
        event Action? TestStarted;

        /// <summary>
        /// Raised when a test sequence completes (normally or via stop).
        /// <c>interrupted</c> is true if stopped early; <c>success</c> is the overall pass/fail result.
        /// </summary>
        event Action<bool , bool >? TestFinished; //interrupted,success

        /// <summary>Raised at each phase transition with the phase name.</summary>
        event Action<string >? PhaseChanged; //phaseName

        /// <summary>Raised with verbose status text during test execution (e.g. "Conditioning… 45s").</summary>
        event Action<string >? VerboseMessage; //message

        /// <summary>Raised when a PSG sync-pulse error halts a SVME test.</summary>
        event Action? PsgSyncError;

        /// <summary>
        /// Raised after a phase finishes with its name and pass/fail result.
        /// </summary>
        event Action<string , bool >? PhaseCompleted; // phaseName,passed

        /// <summary>
        /// Raised when a safety check triggers an emergency stop.  The bench motor
        /// and pump parameters are already stopped when this fires.
        /// Fires on a background thread — consumers must marshal to the UI thread.
        /// </summary>
        event Action<string >? EmergencyStopTriggered; //reason

        // ── Active pump ───────────────────────────────────────────────────────────

        /// <summary>
        /// Registers the currently selected pump so that pump-specific CAN parameters
        /// (me, FBKW, mepi, RPM, Temp, Tein, Status, Empf3) can be read and written
        /// through <see cref="ReadParameter"/> and <see cref="SetParameter"/>.
        /// </summary>
        void SetActivePump(PumpDefinition? pump);

        // ── Bench parameter access ────────────────────────────────────────────────

        /// <summary>
        /// Returns the current live value of a bench parameter by name.
        /// </summary>
        /// <param name="parameterName">Bench parameter name (see <see cref="BenchParameterNames"/>).</param>
        double ReadBenchParameter(string parameterName);

        /// <summary>
        /// Returns the current live value of a pump parameter by name.
        /// </summary>
        /// <param name="parameterName">Pump parameter name (see <see cref="PumpParameterNames"/>).</param>
        double ReadPumpParameter(string parameterName);

        /// <summary>
        /// Returns the current live value of a parameter by name.
        /// Looks in the active pump's parameters first, then falls back to bench parameters.
        /// Use <see cref="ReadBenchParameter"/> or <see cref="ReadPumpParameter"/> when the source is known.
        /// </summary>
        /// <param name="parameterName">Parameter name (see <see cref="BenchParameterNames"/> / <see cref="PumpParameterNames"/>).</param>
        double ReadParameter(string parameterName);

        /// <summary>Sets a pump/bench parameter value in the local parameter map.</summary>
        /// <param name="parameterName">Parameter name.</param>
        /// <param name="value">New value in engineering units.</param>
        void SetParameter(string parameterName, double value);

        /// <summary>Flushes all pending parameter changes to the CAN bus.</summary>
        /// <param name="messageId">CAN message ID to transmit.</param>
        void SendParameters(uint messageId);

        // ── Pump control sender ───────────────────────────────────────────────────

        /// <summary>
        /// Sets the target value for a pump control parameter (me, FBKW, mepi).
        /// FBKW is written immediately; ME and PreIn are slew-rate filtered by the periodic sender.
        /// </summary>
        void SetPumpControlValue(string parameterName, double targetValue);

        /// <summary>Starts the periodic CAN sender that transmits pump control parameters.</summary>
        void StartPumpSender();

        /// <summary>Stops the periodic pump control CAN sender.</summary>
        void StopPumpSender();

        /// <summary>Starts the periodic MemoryRequest sender that polls the pump ECU for Tein data.</summary>
        void StartMemoryRequestSender();

        /// <summary>Stops the periodic MemoryRequest sender.</summary>
        void StopMemoryRequestSender();

        /// <summary>Starts the periodic ElectronicMsg keepalive sender (1-second interval).</summary>
        void StartElectronicMsgSender();

        /// <summary>Stops the periodic ElectronicMsg keepalive sender.</summary>
        void StopElectronicMsgSender();

        /// <summary>
        /// Raised when a pump control value is set (e.g. during test execution),
        /// so the ViewModel can update slider positions. Arguments: parameterName, value.
        /// </summary>
        event Action<string, double>? PumpControlValueSet;

        // ── RPM control ───────────────────────────────────────────────────────────

        /// <summary>
        /// Commands the bench motor to the specified RPM by computing and applying
        /// the corresponding voltage from the RPM-to-voltage lookup table.
        /// Used by automated test execution for direct voltage jumps.
        /// </summary>
        void SetRpm(double rpm);

        /// <summary>
        /// Starts the PID-based RPM ramp controller to smoothly reach the target RPM.
        /// Sends an initial voltage jump from the RPM-voltage lookup table, then hands
        /// control to the PID loop after an approach delay.
        /// Used for interactive (manual) bench control.
        /// </summary>
        /// <param name="targetRpm">Desired RPM setpoint.</param>
        void StartRpmPid(double targetRpm);

        /// <summary>
        /// Stops the PID RPM controller, sends 0 V to the motor.
        /// </summary>
        void StopRpmPid();

        /// <summary>The last RPM target that was commanded via <see cref="SetRpm"/> or <see cref="StartRpmPid"/>.</summary>
        double LastTargetRpm { get; }

        /// <summary>The last voltage value sent to the motor CAN parameter.</summary>
        double LastCommandVoltage { get; }

        /// <summary>Raised after a voltage command is sent to the motor (from <see cref="SetRpm"/> or the PID loop).</summary>
        event Action? RpmCommandSent;

        // ── Temperature control ───────────────────────────────────────────────────

        /// <summary>
        /// Sets the temperature PID setpoint.
        /// </summary>
        /// <param name="setpointCelsius">Target temperature in °C.</param>
        /// <param name="toleranceCelsius">Acceptable deviation in °C.</param>
        /// <returns>
        /// True if the temperature check should be ignored (e.g. sensor fault or
        /// the DefaultIgnoreTin setting is active).
        /// </returns>
        bool SetTemperatureSetpoint(double setpointCelsius, double toleranceCelsius);

        // ── Relay control ─────────────────────────────────────────────────────────

        /// <summary>Energises or de-energises the named relay.</summary>
        /// <param name="relayName">Relay name (see <see cref="RelayNames"/>).</param>
        /// <param name="state">True = ON, false = OFF.</param>
        void SetRelay(string relayName, bool state);

        /// <summary>
        /// Transmits the current relay bitmask once. Called on CAN connect so the
        /// bench controller receives the initial relay state immediately.
        /// </summary>
        void SendInitialRelayState();

        /// <summary>Starts the periodic relay bitmask sender (~21 ms cycle).</summary>
        void StartRelaySender();

        /// <summary>Stops the periodic relay bitmask sender.</summary>
        void StopRelaySender();

        // ── Test execution ────────────────────────────────────────────────────────

        /// <summary>
        /// Starts the full test sequence for the given pump in a background task.
        /// </summary>
        /// <param name="pump">Pump definition containing tests and CAN parameters.</param>
        /// <param name="ct">Cancellation token — cancel to trigger a controlled stop.</param>
        Task RunTestsAsync(PumpDefinition pump, CancellationToken ct);

        /// <summary>Requests a controlled stop of the currently running test sequence.</summary>
        void StopTests();

        // ── Lock angle ────────────────────────────────────────────────────────────

        /// <summary>
        /// Raised during test execution to signal that the Lock Angle measurement phase
        /// is ready.  The ViewModel should display the lock angle acquisition UI.
        /// </summary>
        event Action? LockAngleFaseReady;

        /// <summary>
        /// Raised when the PSG encoder synchronisation phase begins.
        /// </summary>
        event Action? PsgModeFaseReady;

        // ── DFI auto-adjust ───────────────────────────────────────────────────────

        /// <summary>Returns true if auto-DFI adjustment is currently enabled by the operator.</summary>
        bool IsAutoDfiEnabled { get; }

        /// <summary>
        /// Writes a new DFI value to the pump ECU as part of the auto-adjust loop.
        /// </summary>
        void SetDfi(double dfi);

        // ── Tolerance display ─────────────────────────────────────────────────────

        /// <summary>
        /// Raised so the chart view can draw tolerance bands for the specified parameter.
        /// </summary>
        event Action<string , double , double >? ToleranceUpdated; //parameterName, value, tolerance

        /// <summary>
        /// Raised for each individual measurement sample collected during a test phase.
        /// Fires on a background thread — consumers must marshal to the UI thread.
        /// </summary>
        event Action<string , double >? MeasurementSampled; //parameterName, value
    }
}