using System;
using System.Threading;
using OnDeviceAgent.AgentCore;
namespace OnDeviceAgent.VoiceManager
{

    public sealed class VoiceEventRelay
    {
        readonly IAgentRuntime m_Runtime;
        readonly AgentInterruptController m_Interrupt;
        readonly AgentEventBus m_EventBus;
        readonly AgentTraceStore m_TraceStore;
        readonly Action<string> m_Log;
        readonly Func<bool> m_StreamingPreferred;

        public bool EnableVoiceEvents { get; set; } = true;
        public bool EnableInterrupts { get; set; } = true;
        public bool EnableBargeIn { get; set; } = true;
        public bool EnableEventBus { get; set; } = true;

        public VoiceEventRelay(
            IAgentRuntime runtime,
            AgentInterruptController interrupt,
            AgentEventBus eventBus,
            AgentTraceStore traceStore,
            Action<string> log,
            Func<bool> streamingPreferred)
        {
            if (runtime == null) throw new ArgumentNullException(nameof(runtime));
            if (interrupt == null) throw new ArgumentNullException(nameof(interrupt));
            if (eventBus == null) throw new ArgumentNullException(nameof(eventBus));
            if (traceStore == null) throw new ArgumentNullException(nameof(traceStore));

            m_Runtime = runtime;
            m_Interrupt = interrupt;
            m_EventBus = eventBus;
            m_TraceStore = traceStore;
            m_Log = log ?? (_ => { });
            m_StreamingPreferred = streamingPreferred ?? (() => true);
        }

        public void OnFinalTranscript(string text)
        {
            if (!EnableVoiceEvents || string.IsNullOrWhiteSpace(text))
                return;

            if (m_Runtime.IsRunning && TryHandleInterruptPrompt(text, "Voice"))
                return;

            if (EnableBargeIn && m_Runtime.IsRunning)
            {
                m_Log("Voice barge-in: cancelling current run.");
                m_Runtime.TryInterrupt("voice barge-in");
            }

            PublishAgentEvent("Voice", text, AgentEventPriority.High);
        }

        public void ProcessQueuedEvents()
        {
            if (m_Runtime.IsRunning)
                return;

            AgentEvent agentEvent;
            if (!m_EventBus.TryDequeue(out agentEvent))
                return;

            StartRunWithPrompt(agentEvent.Prompt, agentEvent.Source);
        }

        void PublishAgentEvent(string source, string prompt, AgentEventPriority priority)
        {
            if (EnableEventBus)
            {
                m_EventBus.Publish(source, prompt, priority);
                m_TraceStore.RecordEvent("event", source + " queued.");
                return;
            }

            if (m_Runtime.IsRunning)
            {
                m_EventBus.Publish(source, prompt, priority);
                return;
            }

            StartRunWithPrompt(prompt, source);
        }

        bool TryHandleInterruptPrompt(string prompt, string origin)
        {
            if (!EnableInterrupts || !m_Runtime.IsRunning)
                return false;

            AgentInterruptRequest request;
            if (!m_Interrupt.TryCreateInterrupt(prompt, out request))
                return false;

            var originText = string.IsNullOrWhiteSpace(origin) ? "User" : origin.Trim();
            m_Log(originText + " interrupt: " + request.Reason);
            m_Runtime.TryInterrupt(request.Reason);
            if (!string.IsNullOrWhiteSpace(request.FollowUpPrompt))
                PublishAgentEvent(origin, request.FollowUpPrompt, AgentEventPriority.High);

            return true;
        }

        void StartRunWithPrompt(string prompt, string origin)
        {
            var label = string.IsNullOrWhiteSpace(origin) ? "Voice" : origin.Trim();
            m_Log(label + ": " + (prompt ?? string.Empty));

            var request = new AgentRunRequest(prompt, origin, m_StreamingPreferred(), null);
            m_Runtime.RunAsync(request, CancellationToken.None).ContinueWith(
                t => m_Log("RunAsync fault: " + t.Exception),
                System.Threading.Tasks.TaskContinuationOptions.OnlyOnFaulted);
        }
    }
}