import os
import re
import json
import html
import logging
import requests
from openai import OpenAI, AuthenticationError
from pydantic import BaseModel, Field
from celery import shared_task
from django.utils import timezone
from ads.models import Ad, AdEvaluation, NotificationLog

logger = logging.getLogger(__name__)

# Pydantic model for strict OpenAI structured output format
class AdEvaluationResult(BaseModel):
    is_flagged: bool = Field(description="True if the ad matches the criteria in the prompt, otherwise False")
    reason: str = Field(description="A concise explanation in Persian describing why the ad matches or doesn't match the criteria")
    confidence: float = Field(description="Confidence score between 0.0 and 1.0")

class SingleBatchAdResult(BaseModel):
    evaluation_id: str = Field(description="The exact UUID evaluation_id provided for the ad")
    is_flagged: bool = Field(description="True if the ad matches the target criteria, otherwise False")
    reason: str = Field(description="A concise explanation in Persian describing why the ad matches or doesn't match")
    confidence: float = Field(description="Confidence score between 0.0 and 1.0")

class BatchAdEvaluationResult(BaseModel):
    results: list[SingleBatchAdResult] = Field(description="List of evaluation results corresponding to each ad in the batch")


def extract_and_parse_json(text: str):
    """
    Cleans raw LLM text (removing markdown code fences, preambles, thinking process)
    and extracts a valid JSON object or list.
    """
    if not text:
        raise ValueError("Empty response from LLM")

    text = text.strip()

    # 1. Check for markdown code fences
    fence_match = re.search(r'```(?:json)?\s*([\s\S]*?)\s*```', text, re.IGNORECASE)
    if fence_match:
        text = fence_match.group(1).strip()

    # 2. Try direct json.loads
    try:
        return json.loads(text)
    except json.JSONDecodeError:
        pass

    # 3. Find outermost '{' ... '}' or '[' ... ']'
    start_dict = text.find('{')
    end_dict = text.rfind('}')
    start_list = text.find('[')
    end_list = text.rfind(']')

    if start_dict != -1 and end_dict != -1 and end_dict > start_dict:
        try:
            return json.loads(text[start_dict:end_dict + 1])
        except json.JSONDecodeError:
            pass

    if start_list != -1 and end_list != -1 and end_list > start_list:
        try:
            return json.loads(text[start_list:end_list + 1])
        except json.JSONDecodeError:
            pass

    raise ValueError(f"Could not extract valid JSON from LLM response: {text[:200]}")


def call_llm_with_structured_fallback(client, model_name, system_instruction, user_content, pydantic_cls, max_tokens, timeout):
    """
    Attempts to call LLM using OpenAI beta parse first, then falls back to standard completions
    with json_object response format and robust markdown-stripping JSON parsing.
    """
    # 1. First attempt: beta structured parse (ideal for official OpenAI models / compatible endpoints)
    try:
        completion = client.beta.chat.completions.parse(
            model=model_name,
            messages=[
                {"role": "system", "content": system_instruction},
                {"role": "user", "content": user_content}
            ],
            response_format=pydantic_cls,
            max_tokens=max_tokens,
            timeout=timeout
        )
        if completion.choices and completion.choices[0].message.parsed:
            return completion.choices[0].message.parsed
    except Exception:
        # Fallback to chat completions if beta parse fails (e.g. OpenRouter returning markdown wrappers or non-strict JSON)
        pass

    # 2. Second attempt: standard chat completions with json_object response format
    system_instruction_json = (
        f"{system_instruction}\n"
        "CRITICAL REQUIREMENT: You MUST reply strictly with a valid JSON object. "
        "Do NOT wrap the JSON in markdown code blocks like ```json ... ```. "
        "Do NOT include any introduction, thinking process, or explanatory text before or after the JSON."
    )

    try:
        completion = client.chat.completions.create(
            model=model_name,
            messages=[
                {"role": "system", "content": system_instruction_json},
                {"role": "user", "content": user_content}
            ],
            response_format={"type": "json_object"},
            max_tokens=max_tokens,
            timeout=timeout
        )
        raw_text = completion.choices[0].message.content or ""
        json_data = extract_and_parse_json(raw_text)
        return pydantic_cls.model_validate(json_data)
    except Exception:
        pass

    # 3. Third attempt: standard chat completions without response_format constraint
    completion = client.chat.completions.create(
        model=model_name,
        messages=[
            {"role": "system", "content": system_instruction_json},
            {"role": "user", "content": user_content}
        ],
        max_tokens=max_tokens,
        timeout=timeout
    )
    raw_text = completion.choices[0].message.content or ""
    json_data = extract_and_parse_json(raw_text)
    return pydantic_cls.model_validate(json_data)


@shared_task(bind=True, max_retries=3, default_retry_delay=10)
def evaluate_ad_with_ai(self, evaluation_id):
    """
    Asynchronously evaluates a single ad using OpenAI's gpt-4o-mini / OpenRouter model
    against the specific CrawlTask search criteria.
    """
    try:
        evaluation = AdEvaluation.objects.get(pk=evaluation_id)
    except AdEvaluation.DoesNotExist:
        return

    ad = evaluation.ad
    task = evaluation.crawl_task
    api_key = os.getenv('OPENAI_API_KEY')

    # Fallback if OpenAI API Key is missing
    if not api_key or any(k in api_key for k in ['placeholder', 'your_openai_api_key', 'your-openai-api-key-here']):
        evaluation.is_flagged = False
        evaluation.reason = "AI Evaluation skipped: OpenAI API key is not configured."
        evaluation.confidence = 0.0
        evaluation.save()
        return

    try:
        # Support OpenRouter keys seamlessly
        client_kwargs = {"api_key": api_key}
        if api_key.startswith("sk-or-"):
            client_kwargs["base_url"] = "https://openrouter.ai/api/v1"

        client = OpenAI(**client_kwargs)

        system_instruction = (
            "You are an expert Iranian market analyst. Your job is to read listing descriptions "
            "and decide if they match specific target criteria. You MUST reply using the structured JSON response format "
            "with Persian strings."
        )

        user_content = (
            f"User Search Criteria: {task.detection_prompt}\n\n"
            f"Ad Title: {ad.title}\n"
            f"Ad Price: {ad.price or 'Not specified'}\n"
            f"Ad Category: {ad.category or 'Not specified'}\n"
            f"Ad Description:\n{ad.description}"
        )

        default_model = "openrouter/free" if api_key.startswith("sk-or-") else "gpt-4o-mini"
        model_name = os.getenv("OPENAI_MODEL", default_model)

        result = call_llm_with_structured_fallback(
            client=client,
            model_name=model_name,
            system_instruction=system_instruction,
            user_content=user_content,
            pydantic_cls=AdEvaluationResult,
            max_tokens=2500,
            timeout=35
        )

        evaluation.is_flagged = result.is_flagged
        evaluation.reason = result.reason
        evaluation.confidence = result.confidence
        evaluation.save()

        # Update run stats on successful AI flagging
        if result.is_flagged:
            from crawler.models import CrawlRun
            from django.db.models import F
            latest_run = CrawlRun.objects.filter(crawl_task=task).order_by('-started_at').first()
            if latest_run:
                latest_run.ads_flagged_count = F('ads_flagged_count') + 1
                latest_run.save(update_fields=['ads_flagged_count'])

            # Send telegram channel notification if configured
            if task.telegram_channel_id:
                send_telegram_notification.delay(evaluation.id)

    except AuthenticationError as auth_err:
        evaluation.is_flagged = False
        evaluation.reason = "AI Evaluation failed: Invalid or incorrect OpenAI API key."
        evaluation.confidence = 0.0
        evaluation.save()
    except Exception as e:
        # Retry in case of API rate limits or network issues
        try:
            self.retry(exc=e)
        except self.MaxRetriesExceededError:
            evaluation.is_flagged = False
            evaluation.reason = f"AI Evaluation failed: {str(e)}"
            evaluation.confidence = 0.0
            evaluation.save()


@shared_task(bind=True, max_retries=3, default_retry_delay=10)
def evaluate_ad_batch_with_ai(self, evaluation_ids):
    """
    Asynchronously evaluates a batch of ads in a single LLM API call.
    """
    if not evaluation_ids:
        return

    evaluations = list(AdEvaluation.objects.filter(id__in=evaluation_ids).select_related('ad', 'crawl_task'))
    if not evaluations:
        return

    api_key = os.getenv('OPENAI_API_KEY')
    if not api_key or any(k in api_key for k in ['placeholder', 'your_openai_api_key', 'your-openai-api-key-here']):
        for ev in evaluations:
            ev.is_flagged = False
            ev.reason = "AI Evaluation skipped: OpenAI API key is not configured."
            ev.confidence = 0.0
            ev.save()
        return

    task = evaluations[0].crawl_task
    try:
        client_kwargs = {"api_key": api_key}
        if api_key.startswith("sk-or-"):
            client_kwargs["base_url"] = "https://openrouter.ai/api/v1"

        client = OpenAI(**client_kwargs)

        system_instruction = (
            "You are an expert Iranian market analyst. Your job is to evaluate a batch of ad listings "
            "against the target search criteria. You MUST reply with a structured JSON object containing "
            "evaluations for each ad ID provided, using Persian text for the reasons."
        )

        ads_text = []
        for index, ev in enumerate(evaluations, 1):
            ads_text.append(
                f"--- Ad #{index} ---\n"
                f"Evaluation ID: {ev.id}\n"
                f"Title: {ev.ad.title}\n"
                f"Price: {ev.ad.price or 'Not specified'}\n"
                f"Category: {ev.ad.category or 'Not specified'}\n"
                f"Description:\n{ev.ad.description[:2500]}\n"
            )

        user_content = (
            f"Target Search Criteria: {task.detection_prompt}\n\n"
            "Evaluate each of the following ads:\n"
            + "\n".join(ads_text)
        )

        default_model = "openrouter/free" if api_key.startswith("sk-or-") else "gpt-4o-mini"
        model_name = os.getenv("OPENAI_MODEL", default_model)

        parsed = call_llm_with_structured_fallback(
            client=client,
            model_name=model_name,
            system_instruction=system_instruction,
            user_content=user_content,
            pydantic_cls=BatchAdEvaluationResult,
            max_tokens=8000,
            timeout=90
        )

        res_map = {}
        for idx, res in enumerate(parsed.results):
            eval_id_str = str(res.evaluation_id).strip()
            res_map[eval_id_str] = res
            res_map[str(idx)] = res
            res_map[f"Ad #{idx + 1}"] = res
            res_map[f"#{idx + 1}"] = res

        flagged_count = 0
        for idx, ev in enumerate(evaluations):
            ev_id_str = str(ev.id).strip()
            res = res_map.get(ev_id_str)
            if not res and idx < len(parsed.results):
                res = parsed.results[idx]

            if res:
                ev.is_flagged = res.is_flagged
                ev.reason = res.reason
                ev.confidence = res.confidence
            else:
                ev.is_flagged = False
                ev.reason = "Evaluation result omitted in batch response."
                ev.confidence = 0.0
            ev.save()

            if ev.is_flagged:
                flagged_count += 1
                if task.telegram_channel_id:
                    send_telegram_notification.delay(ev.id)

        if flagged_count > 0:
            from crawler.models import CrawlRun
            from django.db.models import F
            latest_run = CrawlRun.objects.filter(crawl_task=task).order_by('-started_at').first()
            if latest_run:
                latest_run.ads_flagged_count = F('ads_flagged_count') + flagged_count
                latest_run.save(update_fields=['ads_flagged_count'])

    except Exception as e:
        # Fallback to individual evaluations if batch call fails
        for ev in evaluations:
            evaluate_ad_with_ai.delay(ev.id)


@shared_task(bind=True, max_retries=3, default_retry_delay=15)
def send_telegram_notification(self, evaluation_id):
    """
    Sends an HTML formatted alert message to the target Telegram Channel
    notifying them of a flagged ad.
    """
    try:
        evaluation = AdEvaluation.objects.get(pk=evaluation_id)
    except AdEvaluation.DoesNotExist:
        return

    ad = evaluation.ad
    task = evaluation.crawl_task
    token = os.getenv('TELEGRAM_BOT_TOKEN')
    channel = task.telegram_channel_id

    if not token or not channel:
        return

    # Escape HTML to prevent telegram parsing errors
    title_esc = html.escape(ad.title)
    price_esc = html.escape(ad.price or 'مشخص نشده')
    cat_esc = html.escape(ad.category or 'مشخص نشده')
    reason_esc = html.escape(evaluation.reason or '')

    message_html = (
        f"🔔 <b>آگهی پرچم‌گذاری شده دیوار</b>\n\n"
        f"📌 <b>عنوان:</b> {title_esc}\n"
        f"💰 <b>قیمت:</b> {price_esc}\n"
        f"🗂 <b>دسته‌بندی:</b> {cat_esc}\n\n"
        f"🤖 <b>علت انتخاب AI:</b>\n{reason_esc}\n\n"
        f"🔗 <a href='{ad.url}'>مشاهده آگهی در دیوار</a>"
    )

    url = f"https://api.telegram.org/bot{token}/sendMessage"
    payload = {
        'chat_id': channel,
        'text': message_html,
        'parse_mode': 'HTML'
    }

    try:
        res = requests.post(url, json=payload, timeout=10)
        if res.status_code == 200:
            NotificationLog.objects.create(
                evaluation=evaluation,
                channel_id=channel,
                status='SENT'
            )
        else:
            raise Exception(f"Telegram API responded with code {res.status_code}: {res.text}")
    except Exception as e:
        try:
            self.retry(exc=e)
        except self.MaxRetriesExceededError:
            NotificationLog.objects.create(
                evaluation=evaluation,
                channel_id=channel,
                status='FAILED',
                error_message=str(e)
            )