// digital.human.audio.js
import * as webllm from "https://esm.run/@mlc-ai/web-llm";

// Ensure the script runs after the DOM is fully loaded
document.addEventListener("DOMContentLoaded", () => {
  // Initialize the Digital Human Voice section
  const voiceMessages = [
    {
      content: "You are Aged Guru, an intelligent assistant skilled in digital human voice interactions. Provide insightful and comprehensive answers using human-like voice responses.",
      role: "system"
    }
  ];

  const voiceAvailableModels = webllm.prebuiltAppConfig.model_list.map(
    (m) => m.model_id
  );
  let voiceSelectedModel = "gemma-2-2b-it-q4f16_1-MLC-1k"; // Default model

  function voiceUpdateEngineInitProgressCallback(report) {
    console.log("Digital Human Voice Initialize", report.progress);
    // Instead of updating a status span, log the progress
    logMessage(`Model Initialization Progress: ${report.text}`, "system");
  }

  const voiceEngine = new webllm.MLCEngine();
  voiceEngine.setInitProgressCallback(voiceUpdateEngineInitProgressCallback);

  let voiceIsGenerating = false; // Flag to prevent multiple generations

  async function voiceInitializeWebLLMEngine() {
    logMessage("Model initialization started.", "system");
    document.getElementById("voice-loading-spinner").classList.remove("hidden"); // Show spinner
    voiceSelectedModel = document.getElementById("voice-model-selection").value;
    const config = {
      temperature: 0.7, // Adjusted for more precise answers
      top_p: 0.9
    };
    try {
      await voiceEngine.reload(voiceSelectedModel, config);
      document.getElementById("voice-selected-model").textContent = voiceSelectedModel;
      document.getElementById("voice-start_button").disabled = false;
      document.getElementById("voice-text-input").disabled = false; // Enable text input after initialization
      document.getElementById("voice-submit-button").disabled = false; // Enable submit button after initialization
      document.getElementById("voice-speech-controls").disabled = false; // Enable speech controls after initialization
      document.getElementById("voice-configuration").classList.remove("hidden");
      logMessage("Model initialized successfully.", "system");
    } catch (error) {
      console.error("Error initializing the model:", error);
      alert("Failed to initialize the model. Please try again.");
      logMessage("Failed to initialize the model.", "error");
    } finally {
      document.getElementById("voice-loading-spinner").classList.add("hidden"); // Hide spinner
    }
  }

  async function voiceStreamingGenerating(messages, onUpdate, onFinish, onError) {
    if (voiceIsGenerating) {
      console.warn("Voice Generation already in progress.");
      return;
    }
    voiceIsGenerating = true;
    try {
      let curMessage = "";
      const completion = await voiceEngine.chat.completions.create({
        stream: true,
        messages
      });
      for await (const chunk of completion) {
        const curDelta = chunk.choices[0].delta.content;
        if (curDelta) {
          curMessage += curDelta;
        }
        onUpdate(curMessage);
      }
      const finalMessage = await voiceEngine.getMessage();
      console.log(`Voice Generated final message: ${finalMessage}`); // Debugging
      onFinish(finalMessage);
      logMessage("Response generated successfully.", "system");
    } catch (err) {
      console.error(err);
      onError(err);
      logMessage("An error occurred during response generation.", "error");
    } finally {
      voiceIsGenerating = false;
    }
  }

  // Flag to track the last input method
  let voiceLastInputWasVoice = false;

  function voiceAppendMessage(message) {
    console.log(`Voice Appending message: ${message.content} (Role: ${message.role})`); // Debugging
    const voiceChatBox = document.getElementById("voice-chat-box");

    // Check if the assistant's message is already appended to avoid duplication
    if (message.role === "assistant") {
      const existingMessages = voiceChatBox.querySelectorAll(".message");
      const lastMessage = existingMessages[existingMessages.length - 1];
      if (lastMessage && lastMessage.textContent === message.content) {
        console.warn("Duplicate assistant message detected in Voice section, skipping append.");

        // Only trigger TTS for assistant messages if the last input was via voice
        if (message.role === "assistant" && message.content !== "typing..." && voiceLastInputWasVoice) {
          voiceSpeak(message.content);
        }

        return; // Exit to avoid appending the same message twice
      }
    }

    const container = document.createElement("div");
    container.classList.add("message-container");
    const newMessage = document.createElement("div");
    newMessage.classList.add("message");
    newMessage.textContent = message.content;

    if (message.role === "user") {
      container.classList.add("user");
    } else {
      container.classList.add("assistant");
    }

    container.appendChild(newMessage);
    voiceChatBox.appendChild(container);
    voiceChatBox.scrollTop = voiceChatBox.scrollHeight;

    // Only trigger TTS for assistant messages if the last input was via voice
    if (message.role === "assistant" && message.content !== "typing..." && voiceLastInputWasVoice) {
      voiceSpeak(message.content);
    }
  }

  function voiceUpdateLastMessage(content) {
    const messageDoms = document.getElementById("voice-chat-box").querySelectorAll(".message");
    const lastMessageDom = messageDoms[messageDoms.length - 1];
    lastMessageDom.textContent = content;
  }

  function voiceOnSpeechRecognized(transcript) {
    const input = transcript.trim();
    const message = {
      content: input,
      role: "user"
    };
    if (input.length === 0) {
      return;
    }
    voiceLastInputWasVoice = true; // Set flag as voice input
    console.log(`Voice input received: ${input}`); // Debugging
    document.getElementById("voice-start_button").disabled = true;
    document.getElementById("voice-submit-button").disabled = true; // Disable submit button during processing

    voiceMessages.push(message);
    voiceAppendMessage(message);
    logMessage(`User (Voice): ${input}`, "user");

    // Append "typing..." placeholder
    const aiPlaceholder = {
      content: "typing...",
      role: "assistant"
    };
    voiceAppendMessage(aiPlaceholder);
    logMessage("VoiceBot is typing...", "system");

    const onFinishGenerating = (finalMessage) => {
      console.log(`Voice Finishing generation with message: ${finalMessage}`); // Debugging
      // Remove the "typing..." placeholder
      const voiceChatBox = document.getElementById("voice-chat-box");
      const lastMessageContainer = voiceChatBox.lastElementChild;
      if (lastMessageContainer && lastMessageContainer.querySelector(".message").textContent === "typing...") {
        voiceChatBox.removeChild(lastMessageContainer);
      }

      // Append the final message
      const aiMessage = {
        content: finalMessage,
        role: "assistant"
      };
      voiceAppendMessage(aiMessage);
      logMessage(`VoiceBot: ${finalMessage}`, "assistant");

      document.getElementById("voice-start_button").disabled = false;
      document.getElementById("voice-submit-button").disabled = false; // Re-enable submit button after processing
      voiceEngine.runtimeStatsText().then((statsText) => {
        document.getElementById("voice-chat-stats").classList.remove("hidden");
        document.getElementById("voice-chat-stats").textContent = statsText;
        logMessage(`Runtime Stats: ${statsText}`, "system");
      });
    };

    voiceStreamingGenerating(
      voiceMessages,
      voiceUpdateLastMessage,
      onFinishGenerating,
      (err) => {
        console.error(err);
        alert("An error occurred while generating the response. Please try again.");
        logMessage("Error during response generation.", "error");
        document.getElementById("voice-start_button").disabled = false;
        document.getElementById("voice-submit-button").disabled = false;
      }
    );
  }

  // Speech Recognition Code for Voice
  let voiceRecognizing = false;
  let voiceIgnore_onend;
  let voiceFinal_transcript = '';
  let voiceRecognition;

  function voiceStartButton(event) {
    if (voiceRecognizing) {
      voiceRecognition.stop();
      return;
    }
    voiceFinal_transcript = '';
    voiceRecognition.lang = 'en-US';
    voiceRecognition.start();
    voiceIgnore_onend = false;
    document.getElementById("voice-start_button").classList.add("mic-animate");
    logMessage("Voice input started.", "system");
  }

  if (!('webkitSpeechRecognition' in window)) {
    alert("Web Speech API is not supported by this browser.");
    logMessage("Web Speech API not supported by this browser.", "error");
  } else {
    voiceRecognition = new webkitSpeechRecognition();
    voiceRecognition.continuous = false; // Non-continuous recognition
    voiceRecognition.interimResults = false; // Get only final results

    voiceRecognition.onstart = function() {
      voiceRecognizing = true;
      logMessage("Speech recognition started.", "system");
    };

    voiceRecognition.onerror = function(event) {
      if (event.error == 'no-speech') {
        document.getElementById("voice-start_button").classList.remove("mic-animate");
        alert('No speech was detected in Voice section.');
        logMessage("No speech detected.", "error");
        voiceIgnore_onend = true;
      }
      if (event.error == 'audio-capture') {
        document.getElementById("voice-start_button").classList.remove("mic-animate");
        alert('No microphone was found in Voice section.');
        logMessage("No microphone found.", "error");
        voiceIgnore_onend = true;
      }
      if (event.error == 'not-allowed') {
        alert('Permission to use microphone was denied in Voice section.');
        logMessage("Microphone permission denied.", "error");
        voiceIgnore_onend = true;
      }
    };

    voiceRecognition.onend = function() {
      voiceRecognizing = false;
      document.getElementById("voice-start_button").classList.remove("mic-animate");
      logMessage("Speech recognition ended.", "system");
      if (voiceIgnore_onend) {
        return;
      }
      if (!voiceFinal_transcript) {
        logMessage("No transcript captured.", "error");
        return;
      }
      // Process the final transcript
      voiceOnSpeechRecognized(voiceFinal_transcript);
    };

    voiceRecognition.onresult = function(event) {
      for (let i = event.resultIndex; i < event.results.length; ++i) {
        if (event.results[i].isFinal) {
          voiceFinal_transcript += event.results[i][0].transcript;
        }
      }
      voiceFinal_transcript = voiceFinal_transcript.trim();
      logMessage(`Recognized Speech: ${voiceFinal_transcript}`, "user");
    };
  }

  document.getElementById("voice-start_button").addEventListener("click", function(event) {
    voiceStartButton(event);
  });

  // Initialize Model Selection
  voiceAvailableModels.forEach((modelId) => {
    const option = document.createElement("option");
    option.value = modelId;
    option.textContent = modelId;
    document.getElementById("voice-model-selection").appendChild(option);
  });
  document.getElementById("voice-model-selection").value = voiceSelectedModel;

  // **Enable the Download Model button after models are loaded**
  document.getElementById("voice-download").disabled = false;

  document.getElementById("voice-download").addEventListener("click", function () {
    voiceInitializeWebLLMEngine().then(() => {
      document.getElementById("voice-start_button").disabled = false;
      // Enable speech controls after model initialization
      document.getElementById("voice-speech-rate").disabled = false;
      document.getElementById("voice-speech-pitch").disabled = false;
      logMessage("Model download initiated.", "system");
    });
  });

  document.getElementById("voice-clear-logs").addEventListener("click", function () {
    document.getElementById("voice-logs").innerHTML = '';
    logMessage("Logs cleared.", "system");
  });

  // ===== TTS Integration =====

  // Initialize Speech Synthesis
  let voiceSpeech = new SpeechSynthesisUtterance();
  voiceSpeech.lang = "en";

  let voiceVoices = [];

  // Use addEventListener instead of directly assigning to onvoiceschanged
  window.speechSynthesis.addEventListener("voiceschanged", () => {
    voiceVoices = window.speechSynthesis.getVoices();
    voicePopulateVoices();
  });

  function voicePopulateVoices() {
    const voiceSelect = document.getElementById("voice-tools");
    voiceSelect.innerHTML = ''; // Clear existing options
    voiceVoices.forEach((voice, i) => {
      const option = new Option(voice.name, i);
      voiceSelect.appendChild(option);
    });
    if (voiceVoices.length > 0) {
      const savedVoice = localStorage.getItem("voiceSelectedVoice");
      if (savedVoice !== null && voiceVoices[savedVoice]) {
        voiceSpeech.voice = voiceVoices[savedVoice];
        voiceSelect.value = savedVoice;
      } else {
        voiceSpeech.voice = voiceVoices[0];
      }
    }
  }

  // Voice Selection Event Listener
  document.getElementById("voice-tools").addEventListener("change", () => {
    const selectedVoiceIndex = document.getElementById("voice-tools").value;
    voiceSpeech.voice = voiceVoices[selectedVoiceIndex];
    // Save to localStorage
    localStorage.setItem("voiceSelectedVoice", selectedVoiceIndex);
    logMessage(`Voice changed to: ${voiceVoices[selectedVoiceIndex].name}`, "system");
  });

  // Function to Speak Text with Voice Selection and Handling Large Texts
  function voiceSpeak(text) {
    if (!window.speechSynthesis) {
      console.warn("Speech Synthesis not supported in this browser for Voice section.");
      logMessage("Speech Synthesis not supported in this browser.", "error");
      return;
    }

    // Show spinner and enable Stop button
    document.getElementById("voice-loading-spinner").classList.remove("hidden");
    document.getElementById("voice-stop_button").disabled = false;
    logMessage("TTS started.", "system");

    // Retrieve the currently selected voice
    const selectedVoice = voiceSpeech.voice;

    // Split the text into sentences to manage large texts
    const sentences = text.match(/[^\.!\?]+[\.!\?]+/g) || [text];

    let utterancesCount = sentences.length;

    sentences.forEach(sentence => {
      const utterance = new SpeechSynthesisUtterance(sentence.trim());

      // Assign the selected voice to the utterance
      if (selectedVoice) {
        utterance.voice = selectedVoice;
      }

      // Assign rate and pitch from sliders
      const rate = parseFloat(document.getElementById("voice-speech-rate").value);
      const pitch = parseFloat(document.getElementById("voice-speech-pitch").value);
      utterance.rate = rate; // Adjust the speaking rate (0.1 to 10)
      utterance.pitch = pitch; // Adjust the pitch (0 to 2)

      // Add event listeners for debugging or additional functionality
      utterance.onstart = () => {
        console.log("Speech started:", sentence);
        logMessage(`TTS started: ${sentence.trim()}`, "system");
      };

      utterance.onend = () => {
        console.log("Speech ended:", sentence);
        logMessage(`TTS ended: ${sentence.trim()}`, "system");
        utterancesCount--;
        if (utterancesCount === 0) {
          // Hide spinner and disable Stop button when all utterances have been spoken
          document.getElementById("voice-loading-spinner").classList.add("hidden");
          document.getElementById("voice-stop_button").disabled = true;
          logMessage("All TTS messages have been spoken.", "system");
        }
      };

      utterance.onerror = (e) => {
        console.error("Speech Synthesis Error:", e);
        alert("An error occurred during speech synthesis. Please try again.");
        logMessage("Speech synthesis encountered an error.", "error");
        utterancesCount = 0;
        document.getElementById("voice-loading-spinner").classList.add("hidden");
        document.getElementById("voice-stop_button").disabled = true;
      };

      window.speechSynthesis.speak(utterance);
    });
  }

  // ===== New: Stop Speech Functionality =====

  /**
   * Stops any ongoing speech synthesis.
   */
  function voiceStopSpeech() {
    if (window.speechSynthesis.speaking) {
      window.speechSynthesis.cancel();
      document.getElementById("voice-loading-spinner").classList.add("hidden");
      document.getElementById("voice-stop_button").disabled = true;
      logMessage("Speech synthesis stopped by user.", "system");
    }
  }

  // Event Listener for Stop Button
  document.getElementById("voice-stop_button").addEventListener("click", function () {
    voiceStopSpeech();
  });

  // ===== New: Text Input Handling =====

  // Function to Handle Text Submission
  function voiceHandleTextSubmit() {
    const textInput = document.getElementById("voice-text-input");
    const input = textInput.value.trim();
    if (input.length === 0) {
      return;
    }
    textInput.value = ''; // Clear the input field
    const message = {
      content: input,
      role: "user" // Ensure this is correctly set
    };
    console.log(`Voice Text input received: ${input}`); // Debugging
    logMessage(`User: ${input}`, "user");

    voiceLastInputWasVoice = false; // Set flag as text input
    document.getElementById("voice-submit-button").disabled = true; // Disable to prevent multiple submissions

    voiceMessages.push(message);
    voiceAppendMessage(message);

    // Append "typing..." placeholder
    const aiPlaceholder = {
      content: "typing...",
      role: "assistant"
    };
    voiceAppendMessage(aiPlaceholder);
    logMessage("VoiceBot is typing...", "system");

    const onFinishGenerating = (finalMessage) => {
      console.log(`Voice Finishing generation with message: ${finalMessage}`); // Debugging
      // Remove the "typing..." placeholder
      const voiceChatBox = document.getElementById("voice-chat-box");
      const lastMessageContainer = voiceChatBox.lastElementChild;
      if (lastMessageContainer && lastMessageContainer.querySelector(".message").textContent === "typing...") {
        voiceChatBox.removeChild(lastMessageContainer);
      }

      // Append the final message
      const aiMessage = {
        content: finalMessage,
        role: "assistant"
      };
      voiceAppendMessage(aiMessage);
      logMessage(`VoiceBot: ${finalMessage}`, "assistant");

      // Trigger TTS for assistant messages if required
      if (voiceLastInputWasVoice) {
        voiceSpeak(finalMessage);
      }

      document.getElementById("voice-submit-button").disabled = false; // Re-enable submit button after processing
      voiceEngine.runtimeStatsText().then((statsText) => {
        document.getElementById("voice-chat-stats").classList.remove("hidden");
        document.getElementById("voice-chat-stats").textContent = statsText;
        logMessage(`Runtime Stats: ${statsText}`, "system");
      });
    };

    voiceStreamingGenerating(
      voiceMessages,
      voiceUpdateLastMessage,
      onFinishGenerating,
      (err) => {
        console.error(err);
        alert("An error occurred while generating the response. Please try again.");
        logMessage("Error during response generation.", "error");
        document.getElementById("voice-submit-button").disabled = false;
      }
    );
  }

  // Event Listener for Submit Button
  document.getElementById("voice-submit-button").addEventListener("click", function () {
    voiceHandleTextSubmit();
  });

  // Event Listener for Enter Key in Text Input
  document.getElementById("voice-text-input").addEventListener("keypress", function (e) {
    if (e.key === 'Enter') {
      voiceHandleTextSubmit();
    }
  });

  // ===== Persisting User Preferences =====

  // Load Preferences on Initialization
  window.addEventListener("load", () => {
    const savedVoice = localStorage.getItem("voiceSelectedVoice");
    if (savedVoice !== null && voiceVoices[savedVoice]) {
      document.getElementById("voice-tools").value = savedVoice;
      voiceSpeech.voice = voiceVoices[savedVoice];
      logMessage(`Loaded saved voice: ${voiceVoices[savedVoice].name}`, "system");
    }

    const savedRate = localStorage.getItem("voiceSpeechRate");
    if (savedRate !== null) {
      document.getElementById("voice-speech-rate").value = savedRate;
      voiceSpeech.rate = parseFloat(savedRate);
      logMessage(`Loaded saved speech rate: ${savedRate}`, "system");
    }

    const savedPitch = localStorage.getItem("voiceSpeechPitch");
    if (savedPitch !== null) {
      document.getElementById("voice-speech-pitch").value = savedPitch;
      voiceSpeech.pitch = parseFloat(savedPitch);
      logMessage(`Loaded saved speech pitch: ${savedPitch}`, "system");
    }
  });

  // Save Speech Rate
  document.getElementById("voice-speech-rate").addEventListener("input", (e) => {
    const rate = e.target.value;
    voiceSpeech.rate = parseFloat(rate);
    localStorage.setItem("voiceSpeechRate", rate);
    logMessage(`Speech rate changed to: ${rate}`, "system");
  });

  // Save Speech Pitch
  document.getElementById("voice-speech-pitch").addEventListener("input", (e) => {
    const pitch = e.target.value;
    voiceSpeech.pitch = parseFloat(pitch);
    localStorage.setItem("voiceSpeechPitch", pitch);
    logMessage(`Speech pitch changed to: ${pitch}`, "system");
  });

  // ===== Logging Function =====

  /**
   * Logs messages to the #voice-logs container.
   * @param {string} message - The message to log.
   * @param {string} type - The type of message: 'user', 'assistant', 'system', 'error'.
   */
  function logMessage(message, type) {
    const voiceLogs = document.getElementById("voice-logs");
    const logEntry = document.createElement("div");
    logEntry.classList.add("log-entry");
    logEntry.textContent = `[${type.toUpperCase()}] ${message}`;

    // Style log entries based on type
    switch(type) {
      case 'user':
        logEntry.style.color = "#00796B";
        break;
      case 'assistant':
        logEntry.style.color = "#004D40";
        break;
      case 'system':
        logEntry.style.color = "#555555";
        break;
      case 'error':
        logEntry.style.color = "#E53935";
        break;
      default:
        logEntry.style.color = "#000000";
    }

    voiceLogs.appendChild(logEntry);
    voiceLogs.scrollTop = voiceLogs.scrollHeight;
  }

  // ===== TTS Integration Continued =====

  // Optional: Global Listener to Detect When All Speech Has Finished
  window.speechSynthesis.addEventListener('end', () => {
    console.log("All voice speech has been spoken.");
    logMessage("All TTS messages have been spoken.", "system");
    // Ensure Stop button is disabled after speech ends
    document.getElementById("voice-stop_button").disabled = true;
  });
});