web/views.py

import hmac
import hashlib
import json
import os
import requests
import threading
from django.shortcuts import render, get_object_or_404, redirect
from django.http import JsonResponse, HttpResponse
from django.views.decorators.csrf import csrf_exempt
from django.conf import settings
from .models import ChatSession, PendingMessage, UserProfile
from urllib.parse import parse_qs
from langchain_huggingface import ChatHuggingFace, HuggingFaceEndpoint
from langchain_core.messages import SystemMessage, HumanMessage, AIMessage
from langchain_core.output_parsers import JsonOutputParser
from pydantic import BaseModel, Field
from typing import List

SUPPORTED_LANGUAGES = [
    {'name': 'Bulgarian', 'code': 'bg', 'small': True, 'regional': False, 'flag': '🇧🇬'},
    {'name': 'Croatian', 'code': 'hr', 'small': True, 'regional': False, 'flag': '🇭🇷'},
    {'name': 'Czech', 'code': 'cs', 'small': True, 'regional': False, 'flag': '🇨🇿'},
    {'name': 'Danish', 'code': 'da', 'small': True, 'regional': False, 'flag': '🇩🇰'},
    {'name': 'Dutch', 'code': 'nl', 'small': False, 'regional': False, 'flag': '🇳🇱'},
    {'name': 'English', 'code': 'en', 'small': False, 'regional': False, 'flag': '🇬🇧'},
    {'name': 'Estonian', 'code': 'et', 'small': True, 'regional': False, 'flag': '🇪🇪'},
    {'name': 'Finnish', 'code': 'fi', 'small': True, 'regional': False, 'flag': '🇫🇮'},
    {'name': 'French', 'code': 'fr', 'small': False, 'regional': False, 'flag': '🇫🇷'},
    {'name': 'German', 'code': 'de', 'small': False, 'regional': False, 'flag': '🇩🇪'},
    {'name': 'Greek', 'code': 'el', 'small': True, 'regional': False, 'flag': '🇬🇷'},
    {'name': 'Hungarian', 'code': 'hu', 'small': True, 'regional': False, 'flag': '🇭🇺'},
    {'name': 'Irish', 'code': 'ga', 'small': True, 'regional': False, 'flag': '🇮🇪'},
    {'name': 'Italian', 'code': 'it', 'small': False, 'regional': False, 'flag': '🇮🇹'},
    {'name': 'Latvian', 'code': 'lv', 'small': True, 'regional': False, 'flag': '🇱🇻'},
    {'name': 'Lithuanian', 'code': 'lt', 'small': True, 'regional': False, 'flag': '🇱🇹'},
    {'name': 'Maltese', 'code': 'mt', 'small': True, 'regional': False, 'flag': '🇲🇹'},
    {'name': 'Polish', 'code': 'pl', 'small': False, 'regional': False, 'flag': '🇵🇱'},
    {'name': 'Portuguese', 'code': 'pt', 'small': False, 'regional': False, 'flag': '🇵🇹'},
    {'name': 'Romanian', 'code': 'ro', 'small': False, 'regional': False, 'flag': '🇷🇴'},
    {'name': 'Slovak', 'code': 'sk', 'small': True, 'regional': False, 'flag': '🇸🇰'},
    {'name': 'Slovenian', 'code': 'sl', 'small': True, 'regional': False, 'flag': '🇸🇮'},
    {'name': 'Spanish', 'code': 'es', 'small': False, 'regional': False, 'flag': '🇪🇸'},
    {'name': 'Swedish', 'code': 'sv', 'small': True, 'regional': False, 'flag': '🇸🇪'},
    {'name': 'Breton', 'code': 'br', 'small': True, 'regional': True, 'flag': '🏴'},
    {'name': 'Catalan', 'code': 'ca', 'small': True, 'regional': True, 'flag': '🇦🇩'},
    {'name': 'Welsh', 'code': 'cy', 'small': True, 'regional': True, 'flag': '🏴󠁧󠁢󠁷󠁬󠁳󠁿'},
    {'name': 'Scottish Gaelic', 'code': 'gd', 'small': True, 'regional': True, 'flag': '🏴󠁧󠁢󠁳󠁣󠁴󠁿'},
    {'name': 'Ukrainian', 'code': 'uk', 'small': False, 'regional': False, 'flag': '🇺🇦'}
]

class WordAnalysis(BaseModel):
    form: str = Field(description="The word as it appears in the text")
    grammar_comments: str = Field(description="Grammatical comments about the word")
    lemma: str = Field(description="The dictionary form of the word")
    translation: str = Field(description="The English translation of the word")

class WordAnalysisList(BaseModel):
    words: List[WordAnalysis]

class StylisticSentence(BaseModel):
    sent_id: int = Field(description="The unique ID of the sentence")
    meaning: str = Field(description="The general meaning of the sentence in English")
    explanation: str = Field(description="An explanation of stylistic choices, colloquialisms, slang, or dialect features.")

class StylisticAnalysis(BaseModel):
    sentences: List[StylisticSentence]

class GrammarSpellingCheck(BaseModel):
    word: str = Field(description="The misspelled word")
    correction: str = Field(description="The corrected form")

class GrammarSentence(BaseModel):
    original: str = Field(description="The original sentence")
    rewritten: str = Field(description="The rewritten sentence with better grammar/style")
    explanation: str = Field(description="Explanation for the changes made. Leave empty if no changes were needed.")

class GrammarAnalysis(BaseModel):
    is_translation: bool = Field(description="True if the input was NOT in the target language and had to be translated")
    translations: List[str] = Field(description="Sentence-by-sentence translations (only if is_translation is True)", default_factory=list)
    spelling_checks: List[GrammarSpellingCheck] = Field(description="List of spelling errors found", default_factory=list)
    sentences: List[GrammarSentence] = Field(description="Sentence-by-sentence rewriting and explanation", default_factory=list)

class NativeSuggestion(BaseModel):
    style: str = Field(description="Description of the style (e.g., Informal, Formal, Idiomatic)")
    text: str = Field(description="The rewritten text in this style")

class NativeRewriteAnalysis(BaseModel):
    suggestions: List[NativeSuggestion]

# Inizializzazione AI Con LangChain
llm_chat = HuggingFaceEndpoint(
    repo_id="meta-llama/Llama-3.1-8B-Instruct",
    huggingfacehub_api_token=settings.HF_TOKEN,
    task="text-generation",
    max_new_tokens=1500,
)
chat_model_main = ChatHuggingFace(llm=llm_chat)

llm_util = HuggingFaceEndpoint(
    repo_id="Qwen/Qwen2.5-7B-Instruct",
    huggingfacehub_api_token=settings.HF_TOKEN,
    task="text-generation",
    max_new_tokens=3000,
)
chat_model_util = ChatHuggingFace(llm=llm_util)

# Modelli per lingue meno diffuse: EuroLLM per EU ufficiali, Aya per regionali
EUROLLM_MODEL = "utter-project/EuroLLM-22B-Instruct-2512"
AYA_MODEL = "CohereLabs/aya-expanse-32b"
HF_ROUTER_URL = "https://router.huggingface.co/v1/chat/completions"

# Dizionario globale per gestire i timer dei messaggi (per chat_id)
active_timers = {}

def fire_delayed_reply(chat_id):
    """Funzione chiamata dal timer per processare la risposta AI"""
    from .models import ChatSession
    try:
        chat = ChatSession.objects.get(id=chat_id)
        process_chat_reply(chat)
    except Exception as e:
        print(f"Errore timer: {e}")
    finally:
        if chat_id in active_timers:
            del active_timers[chat_id]

def validate_init_data(init_data):
    """
    Valida i dati di inizializzazione di Telegram.
    """
    if not init_data:
        return None
    
    parsed_data = parse_qs(init_data)
    data_check_string = "\n".join(f"{k}={v[0]}" for k, v in sorted(parsed_data.items()) if k != "hash")
    
    secret_key = hmac.new(b"WebAppData", settings.TELEGRAM_TOKEN.encode(), hashlib.sha256).digest()
    calculated_hash = hmac.new(secret_key, data_check_string.encode(), hashlib.sha256).hexdigest()
    
    if calculated_hash == parsed_data.get("hash", [""])[0]:
        user_data = json.loads(parsed_data.get("user", ["{}"])[0])
        return user_data
    return None

from django.contrib.auth import login, authenticate
from django.contrib.auth.models import User
from django.contrib.auth.decorators import login_required

from django.utils import timezone

def get_or_create_tg_user(user_data):
    """
    Sincronizza l'utente Telegram con il DB Django.
    """
    username = f"tg_{user_data['id']}"
    user = User.objects.filter(username=username).first()
    if not user:
        user = User.objects.create(
            username=username,
            first_name=user_data.get('first_name', ''),
            last_name=user_data.get('last_name', ''),
            last_login=timezone.now(),
            date_joined=timezone.now()
        )
    
    # Ensure profile exists
    UserProfile.objects.get_or_create(user=user)
    return user

def ensure_user_session(request):
    if request.user.is_authenticated:
        return request.user
    
    # Try to get data from URL or Headers
    init_data = request.GET.get('initData') or request.headers.get('X-Telegram-Init-Data')
    
    if init_data:
        user_data = validate_init_data(init_data)
        if user_data:
            user = get_or_create_tg_user(user_data)
            login(request, user)
            return user
        else:
            # DEBUG: If validation fails, it's usually a wrong TELEGRAM_TOKEN
            print("TELEGRAM VALIDATION FAILED") 
            
    return None

@csrf_exempt
def login_page(request):

    if request.method == 'POST':
        username = request.POST.get('username')
        if username:
            user = User.objects.filter(username=username).first()
            if not user:
                user = User.objects.create(
                    username=username,
                    last_login=timezone.now(),
                    date_joined=timezone.now()
                )
            UserProfile.objects.get_or_create(user=user)
            login(request, user)
            return redirect('index')
    return render(request, 'web/login.html')

def index(request):
    user = ensure_user_session(request)
    
    if not user:
        # If we are NOT logged in, we still show the index page, 
        # but with an empty chat list. The JS will then try to log in.
        return render(request, 'web/index.html', {
            'chats': [], 
            'user_name': 'Guest'
        })
        
    chats = user.chats.all().order_by('-created_at')
    return render(request, 'web/index.html', {
        'chats': chats, 
        'user_name': user.first_name
    })
def chat_detail(request, chat_id):
    user = ensure_user_session(request)
    if not user:
        return redirect('login_page')
    
    chat = get_object_or_404(ChatSession, id=chat_id, user=user)
    messages = chat.messages.all().order_by('created_at')

    
    return render(request, 'web/chat.html', {
        'chat': chat,
        'messages': messages,
        'user_name': user.first_name
    })

@csrf_exempt
def check_messages(request, chat_id):
    user = ensure_user_session(request)
    if not user:
        return JsonResponse({'error': 'Unauthorized'}, status=401)
    
    chat = get_object_or_404(ChatSession, id=chat_id, user=user)
    messages = chat.messages.all().order_by('created_at')
    
    msgr_list = []
    for m in messages:
        msgr_list.append({
            'id': m.id,
            'content': m.content,
            'is_user': m.is_user,
            'created_at': m.created_at.isoformat()
        })
    
    return JsonResponse({'messages': msgr_list})

@csrf_exempt
def send_message(request, chat_id):
    if request.method != 'POST':
        return JsonResponse({'error': 'POST only'}, status=405)
    
    user = ensure_user_session(request)
    if not user:
        return JsonResponse({'error': 'Unauthorized'}, status=401)
    
    chat = get_object_or_404(ChatSession, id=chat_id, user=user)
    data = json.loads(request.body)

    content = data.get('content')
    
    if content:
        msg = PendingMessage.objects.create(chat=chat, content=content, is_user=True)
        
        # Gestione Timer per risposte differite
        if chat.id not in active_timers:
            timer_duration = chat.reply_timer if chat.reply_timer > 0 else 0.5
            timer = threading.Timer(timer_duration, fire_delayed_reply, args=[chat.id])
            active_timers[chat.id] = timer
            timer.start()
            
        return JsonResponse({'status': 'ok', 'delayed': True})
    return JsonResponse({'error': 'missing content'}, status=400)

@csrf_exempt
def create_new_chat(request):

    user = ensure_user_session(request)
    if not user:
        return redirect('login_page')
    
    profile, _ = UserProfile.objects.get_or_create(user=user)
    
    if request.method == 'POST':
        name = request.POST.get('name')
        bio = request.POST.get('bio')
        lang = request.POST.get('lang')
        
        chat = ChatSession.objects.create(
            user=user,
            chat_name=name,
            character_bio=bio if bio else profile.global_bio,
            language=lang if lang else profile.global_language,
            mcp_tools=profile.global_mcp_tools,
            reply_timer=int(request.POST.get('reply_timer', profile.global_timer))
        )
        return redirect('chat_detail', chat_id=chat.id)
    
    return render(request, 'web/new_chat.html', {
        'profile': profile,
        'supported_languages': SUPPORTED_LANGUAGES
    })


@csrf_exempt
def chat_settings(request, chat_id):

    user = ensure_user_session(request)
    if not user:
        return redirect('login_page')
    
    chat = get_object_or_404(ChatSession, id=chat_id, user=user)
    
    if request.method == 'POST':

        chat.chat_name = request.POST.get('name')
        chat.character_bio = request.POST.get('bio')
        chat.language = request.POST.get('lang')
        mcp_list = request.POST.getlist('mcp_tools')
        
        # Filter empty strings & save
        chat.mcp_tools = [url.strip() for url in mcp_list if url.strip()]
        chat.reply_timer = int(request.POST.get('reply_timer', chat.reply_timer))
        chat.save()
        
        return redirect('chat_detail', chat_id=chat.id)

    
    return render(request, 'web/chat_settings.html', {
        'chat': chat,
        'supported_languages': SUPPORTED_LANGUAGES
    })


@csrf_exempt
def delete_chat(request, chat_id):

    user = ensure_user_session(request)
    if not user:
        return redirect('login_page')
    
    chat = get_object_or_404(ChatSession, id=chat_id, user=user)
    chat.delete()

    return redirect('index')

@csrf_exempt
def global_settings(request):

    user = ensure_user_session(request)
    if not user:
        return redirect('login_page')
    
    profile, _ = UserProfile.objects.get_or_create(user=user)
    
    if request.method == 'POST':
        mcp_list = request.POST.getlist('mcp_tools')
        profile.global_mcp_tools = [url.strip() for url in mcp_list if url.strip()]
        profile.global_timer = int(request.POST.get('global_timer', profile.global_timer))
        profile.global_language = request.POST.get('global_language', profile.global_language)
        profile.save()
        return redirect('index')
    
    return render(request, 'web/settings.html', {
        'profile': profile,
        'supported_languages': SUPPORTED_LANGUAGES
    })





@csrf_exempt
def telegram_webhook(request):
    # Logica per gestire i messaggi da Telegram bot
    # Se il bot è ancora attivo, può inviare i dati qui
    return HttpResponse("OK")

@csrf_exempt
def ai_action(request, chat_id):
    if request.method != 'POST':
        return JsonResponse({'error': 'POST only'}, status=405)
    
    user = ensure_user_session(request)
    if not user:
        return JsonResponse({'error': 'Unauthorized'}, status=401)
    
    data = json.loads(request.body)
    action = data.get('action')
    text_to_analyze = data.get('text')
    user_question = data.get('question', '')
    
    if not action or not text_to_analyze:
        return JsonResponse({'error': 'Missing parameters'}, status=400)
    
    chat = get_object_or_404(ChatSession, id=chat_id, user=user)

    target_lang = chat.language
    lang_info = next((l for l in SUPPORTED_LANGUAGES if l['name'] == target_lang), None)
    # Per le lingue "piccole" usiamo MADLAD in cascata o per traduzioni dirette
    is_small_lang = lang_info['small'] if lang_info else False
    
    # Inizialmente usiamo sempre il modello base per la struttura
    current_util_model = chat_model_util

    # Prompt logic based on bot copy.py
    if action == "grammar_check":
        prompt = (
            f"Analyze the following text for grammatical errors in {target_lang}. "
            f"First, check if the text is predominantly in {target_lang}. If NOT, set is_translation to true and provide sentence-by-sentence translations. "
            f"If it IS in {target_lang}, set is_translation to false, identify spelling errors, and provide a sentence-by-sentence rewrite with explanations for any changes. "
            f"\n\nText: {text_to_analyze}"
        )
    elif action == "native_rewrite":
        prompt = (
            f"Rewrite the following text to sound more native and natural in {target_lang}. "
            f"Provide multiple suggestions, each with a brief description of the native style (e.g., Informal, Formal, Idiomatic). "
            f"\n\nText: {text_to_analyze}"
        )
    elif action == "open_question":
        prompt = f"The user has a specific question about this text in {target_lang}:\n'{user_question}'\n\nPlease answer the question based on this context:\nText: {text_to_analyze}"

    elif action == "translate":
        prompt = f"Translate the following text into English. Provide ONLY the translation without any introduction.\n\nText: {text_to_analyze}."
    elif action == "translate_to_target":
        prompt = f"Translate the following English text into {target_lang}. Provide ONLY the translation without any introduction.\n\nText: {text_to_analyze}."
    elif action == "word_to_word":
        if target_lang:
            lang_code = lang_info['code'] if lang_info else "en"
            api_url = f"https://randusertry-stanzalazymodels.hf.space/{lang_code}/analyze"
            try:
                # Chiamata API esterna (Stanza as a Service) per analisi morfo-sintattica
                resp = requests.post(api_url, json={"text": text_to_analyze}, timeout=60)
                if resp.status_code == 200:
                    data = resp.json()
                    word_objects = []
                    lemmas_to_translate = []
                    
                    # Gestione flessibile della risposta (flat list vs nested sentences)
                    if isinstance(data, list):
                        # Caso 1: Lista piatta di parole (come visto nell'output PowerShell dell'utente)
                        if len(data) > 0 and isinstance(data[0], dict) and ('text' in data[0] or 'lemma' in data[0]):
                            words_to_process = data
                        else:
                            # Caso 2: Lista di frasi (che a loro volta sono liste di parole)
                            words_to_process = []
                            for sent in data:
                                if isinstance(sent, list):
                                    words_to_process.extend(sent)
                                elif isinstance(sent, dict) and "words" in sent:
                                    words_to_process.extend(sent["words"])
                    else:
                        # Caso 3: Dizionario con chiave "sentences"
                        words_to_process = []
                        for sent in data.get("sentences", []):
                            words_to_process.extend(sent if isinstance(sent, list) else sent.get("words", []))
                    
                    for word in words_to_process:
                        if not isinstance(word, dict): continue
                        # L'API usa 'pos' e 'morph' invece di 'upos' e 'feats'
                        upos = word.get("pos") or word.get("upos", "")
                        morph = word.get("morph") or word.get("feats", "")
                        
                        if upos == 'PUNCT': continue
                        
                        word_objects.append({
                            "form": word.get("text"),
                            "grammar_comments": f"{upos} {morph}".strip(),
                            "lemma": word.get("lemma"),
                            "translation": ""
                        })
                        if word.get("lemma"):
                            lemmas_to_translate.append(word.get("lemma"))
                    
                    # Route to EuroLLM (official EU) or Aya (regional) for translation
                    if lemmas_to_translate:
                        lemmas_to_translate = [l for l in lemmas_to_translate if any(c.isalpha() for c in l)]
                        lang_meta = next((l for l in SUPPORTED_LANGUAGES if l['name'] == chat.language), None)
                        is_regional = lang_meta.get('regional', False) if lang_meta else False
                        model_id = AYA_MODEL if is_regional else EUROLLM_MODEL
                        active_source = f"Stanza + {'Aya 32B' if is_regional else 'EuroLLM 22B'}"
                        
                        word_count = len(lemmas_to_translate)
                        # Number each lemma so the model knows exactly how many to return
                        numbered_input = "\n".join(f"{i+1}. {l}" for i, l in enumerate(lemmas_to_translate))
                        hf_headers = {"Authorization": f"Bearer {settings.HF_TOKEN}"}
                        sys_msg = (
                            f"You are a linguistic expert in {chat.language}. "
                            f"You will receive exactly {word_count} numbered {chat.language} words/lemmas. "
                            f"Translate each one into English. "
                            f"Reply with exactly {word_count} numbered lines in the format: '1. translation'. "
                            f"If you do not know the translation for a word, write '?' as the placeholder — do NOT skip that line. "
                            f"Do NOT add any extra text, commentary, or blank lines."
                        )
                        try:
                            print(f"DEBUG - Routing to {model_id} ({word_count} words)")
                            r = requests.post(HF_ROUTER_URL, headers=hf_headers, json={
                                "model": model_id,
                                "messages": [{"role": "system", "content": sys_msg},
                                             {"role": "user", "content": numbered_input}],
                                "max_tokens": 800, "temperature": 0.1
                            }, timeout=120)
                            if r.status_code == 200:
                                translated_bulk = r.json()['choices'][0]['message']['content'].strip()
                                print(f"DEBUG - Translated: {translated_bulk[:120]}...")
                                # Strip numbering: "1. be" → "be"
                                import re
                                translations = [re.sub(r'^\d+\.\s*', '', t).strip() for t in translated_bulk.split("\n") if t.strip()]
                                if len(translations) == len(lemmas_to_translate):
                                    for i, trans in enumerate(translations):
                                        if i < len(word_objects):
                                            word_objects[i]["translation"] = trans
                                else:
                                    print(f"DEBUG - Mismatch ({len(translations)} vs {len(lemmas_to_translate)}), sequential fallback.")
                                    for i, lemma in enumerate(lemmas_to_translate):
                                        if i >= len(word_objects): break
                                        r2 = requests.post(HF_ROUTER_URL, headers=hf_headers, json={
                                            "model": model_id,
                                            "messages": [{"role": "system", "content": f"Translate this {chat.language} word to English. Reply with ONLY the English word."},
                                                         {"role": "user", "content": lemma}],
                                            "max_tokens": 50, "temperature": 0.1
                                        }, timeout=45)
                                        if r2.status_code == 200:
                                            word_objects[i]["translation"] = r2.json()['choices'][0]['message']['content'].strip()
                            else:
                                print(f"DEBUG - {model_id} error {r.status_code}: {r.text}")
                                raise Exception(f"API Error {r.status_code}")
                        except Exception as e:
                            print(f"Translation failure ({model_id}): {repr(e)}")
                            for obj in word_objects:
                                if not obj["translation"]:
                                    obj["translation"] = "[error]"
                    else:
                        active_source = 'Stanza API'
                    
                    return JsonResponse({
                        'result': {"words": word_objects},
                        'is_structured': True,
                        'source': active_source
                    })
            except Exception as e:
                print(f"Stanza API error: {e}")

        # Fallback per Breton o se l'API Stanza fallisce
        prompt = (
            f"Provide a word-for-word literal translation of the following text into English (or {target_lang} if it is already in English). "
            f"Format the output as a JSON with 'words' as key containing a list of objects, each with 'form', 'lemma', 'grammar_comments', and 'translation'. "
            f"\n\nText: {text_to_analyze}"
        )
    elif action == "grammatical_explanation":
        prompt = (
            f"Provide a stylistic analysis of the following text in {target_lang}. "
            f"For each sentence, explain the stylistic choices, why it was said in that way, and identify if it uses colloquialisms, slang, or dialect. Also make sure to mention noteworthy grammatical structures and idiomatic expressions."
            f"\n\nText: {text_to_analyze}"
        )
    else:
        return JsonResponse({'error': 'Invalid action'}, status=400)

    try:
        is_structured = False
        if action == "word_to_word":
            parser = JsonOutputParser(pydantic_object=WordAnalysisList)
            full_prompt = prompt + "\n\n" + parser.get_format_instructions()
            messages = [
                SystemMessage(content="You are a highly capable linguistic assistant that always responds in valid JSON format as requested."),
                HumanMessage(content=full_prompt)
            ]
            response_ai = current_util_model.invoke(messages)
            try:
                ai_text = parser.parse(response_ai.content)
                is_structured = True
            except Exception:
                ai_text = response_ai.content
        elif action == "grammatical_explanation":
            parser = JsonOutputParser(pydantic_object=StylisticAnalysis)
            full_prompt = prompt + "\n\n" + parser.get_format_instructions()
            messages = [
                SystemMessage(content="You are a highly capable linguistic assistant that always responds in valid JSON format as requested."),
                HumanMessage(content=full_prompt)
            ]
            response_ai = current_util_model.invoke(messages)
            try:
                ai_text = parser.parse(response_ai.content)
                is_structured = True
            except Exception:
                ai_text = response_ai.content
        elif action == "grammar_check":
            parser = JsonOutputParser(pydantic_object=GrammarAnalysis)
            full_prompt = prompt + "\n\n" + parser.get_format_instructions()
            messages = [
                SystemMessage(content="You are a linguistic expert assistant. Always respond in JSON format."),
                HumanMessage(content=full_prompt)
            ]
            response_ai = current_util_model.invoke(messages)
            try:
                ai_text = parser.parse(response_ai.content)
                is_structured = True
            except Exception:
                ai_text = response_ai.content
        elif action == "native_rewrite":
            parser = JsonOutputParser(pydantic_object=NativeRewriteAnalysis)
            full_prompt = prompt + "\n\n" + parser.get_format_instructions()
            messages = [
                SystemMessage(content="You are a native speaker linguistic assistant. Always respond in JSON format."),
                HumanMessage(content=full_prompt)
            ]
            response_ai = current_util_model.invoke(messages)
            try:
                ai_text = parser.parse(response_ai.content)
                is_structured = True
            except Exception:
                ai_text = response_ai.content
        elif action in ["translate", "translate_to_target"]:
            # Per le traduzioni in lingue piccole, usiamo direttamente MADLAD (Base LLM)
            if is_small_lang:
                target_code = "en" if action == "translate" else lang_info['code']
                madlad_prompt = f"<2{target_code}> {text_to_analyze}"
                try:
                    ai_text = llm_small_lang.invoke(madlad_prompt).strip()
                except Exception as e:
                    print(f"MADLAD Translate error: {e}")
                    # Fallback a modello base
                    messages = [
                        SystemMessage(content="You are a high-quality translator. Provide only the translation without any introduction."),
                        HumanMessage(content=prompt)
                    ]
                    response_ai = chat_model_util.invoke(messages)
                    ai_text = response_ai.content
            else:
                messages = [
                    SystemMessage(content="You are a high-quality translator. Provide only the translation without any introduction."),
                    HumanMessage(content=prompt)
                ]
                response_ai = chat_model_util.invoke(messages)
                ai_text = response_ai.content
        else:
            messages = [
                SystemMessage(content="You are a highly capable linguistic assistant."),
                HumanMessage(content=prompt)
            ]
            response_ai = current_util_model.invoke(messages)
            ai_text = response_ai.content

        # --- POST-PROCESSING per Lingue Piccole (MADLAD Overlay) ---
        if is_small_lang and is_structured:
            lang_code = lang_info['code'] if lang_info else "en"
            if action == "grammar_check" and isinstance(ai_text, dict) and "sentences" in ai_text:
                for s in ai_text["sentences"]:
                    if s.get("rewritten"):
                        try:
                            # Prompt con tag MADLAD: <2xx> per output nella lingua target
                            refine_prompt = f"<2{lang_code}> {s['rewritten']}"
                            refined_text = llm_small_lang.invoke(refine_prompt)
                            s["rewritten"] = refined_text.strip()
                        except Exception as e:
                            print(f"Refinement error: {e}")
            
            elif action == "native_rewrite" and isinstance(ai_text, dict) and "suggestions" in ai_text:
                for s in ai_text["suggestions"]:
                    if s.get("text"):
                        try:
                            refine_prompt = f"<2{lang_code}> {s['text']}"
                            refined_text = llm_small_lang.invoke(refine_prompt)
                            s["text"] = refined_text.strip()
                        except Exception as e:
                            print(f"Refinement error: {e}")

        return JsonResponse({
            'result': ai_text, 
            'is_structured': is_structured,
            'source': 'AI Model (Llama/Qwen)' if action == 'word_to_word' else None
        })
    except Exception as e:
        return JsonResponse({'error': str(e)}, status=500)

# --- AI Logic ---

def send_to_telegram(chat, text):
    """Invia un messaggio tramite Telegram Bot API"""
    username = chat.user.username
    if not username.startswith("tg_"):
        return
    
    tg_id = username.replace("tg_", "")
    url = f"https://api.telegram.org/bot{settings.TELEGRAM_TOKEN}/sendMessage"
    
    payload = {
        "chat_id": tg_id,
        "text": f"*{chat.chat_name}*: \n\n{text[:15]}...",
        "parse_mode": "Markdown"
    }
    
    if chat.telegram_thread_id:
        payload["message_thread_id"] = chat.telegram_thread_id
        
    try:
        requests.post(url, json=payload, timeout=10)
    except Exception as e:
        print(f"Errore invio Telegram: {e}")

def process_chat_reply(chat):
    """
    Chiama l'AI e salva la risposta.
    """
    
    messages = chat.messages.all().order_by('-created_at')[:10][::-1]
    
    history = []
    for msg in messages:
        role = "user" if msg.is_user else "assistant"
        history.append({"role": role, "content": msg.content})
    
    try:
        # Construct LangChain message list
        langchain_messages = []
        if chat.summary:
            langchain_messages.append(SystemMessage(content=f"You are {chat.chat_name}, {chat.character_bio}, you speak {chat.language}. Remember, you are NOT a psychologist, not a lover, you only stick to your role where appropriate. Your main goal is to help the user learn {chat.language}. Remember to only speak in said language: {chat.language}.\nPrevious context: {chat.summary}"))
        else:
            langchain_messages.append(SystemMessage(content=f"You are {chat.chat_name}, {chat.character_bio}, you speak {chat.language}. Remember, you are NOT a psychologist, not a lover, you only stick to your role where appropriate. Your main goal is to help the user learn {chat.language}. Remember to only speak in said language: {chat.language}."))

        for msg in messages:
            if msg.is_user:
                langchain_messages.append(HumanMessage(content=msg.content))
            else:
                langchain_messages.append(AIMessage(content=msg.content))

        response = chat_model_main.invoke(langchain_messages)
        ai_content = response.content
        PendingMessage.objects.create(chat=chat, content=ai_content, is_user=False)
        
        # Notifica Telegram se il timer è >= 120 e l'utente è da Telegram
        if chat.reply_timer >= 120:
            send_to_telegram(chat, ai_content)
        
    except Exception as e:
        print(f"Error AI: {e}")
        PendingMessage.objects.create(chat=chat, content="Sorry, I'm having trouble thinking right now.", is_user=False)
@csrf_exempt
def tts_proxy(request):
    if request.method == "POST":
        try:
            data = json.loads(request.body)
            text = data.get("text", "")
            lang_name = data.get("lang", "English")
            
            # Look up lang code from SUPPORTED_LANGUAGES
            lang_code = "en"
            for l in SUPPORTED_LANGUAGES:
                if l['name'] == lang_name:
                    lang_code = l['code']
                    break
            
            url = "https://feliksius-ai-translation.hf.space/v1/tts"
            payload = {
                "input_text": text,
                "from_language": lang_code
            }
            
            response = requests.post(url, json=payload, timeout=20)
            if response.status_code == 200:
                # Return the audio as a wav response
                django_response = HttpResponse(response.content, content_type="audio/wav")
                django_response['Content-Disposition'] = 'inline; filename="speech.wav"'
                return django_response
            else:
                return JsonResponse({"error": f"TTS microservice error: {response.status_code}"}, status=response.status_code)
        except Exception as e:
            return JsonResponse({"error": str(e)}, status=500)
    return HttpResponse(status=405)