app/sentiment.py

"""
The Tier 1 Intelligence Sieve.

This module uses a locally-hosted, finance-optimized transformer model (FinBERT)
to perform initial, high-speed sentiment analysis. It acts as a gatekeeper,
only escalating high-conviction events to the more powerful Tier 2 analyst.
"""
from transformers import pipeline
from threading import Lock

class SentimentEngine:
    """
    A thread-safe, high-performance sentiment analysis engine using a local model.
    Implemented as a singleton to ensure the model is loaded only once.
    """
    _instance = None
    _lock = Lock()

    def __new__(cls):
        with cls._lock:
            if cls._instance is None:
                print("🧠 [Tier 1] Initializing local sentiment model (FinBERT)... This may take a moment.")
                try:
                    cls._instance = super().__new__(cls)
                    # Using a model specifically fine-tuned on financial text for superior accuracy.
                    cls._instance.sentiment_pipeline = pipeline(
                        "sentiment-analysis",
                        model="ProsusAI/finbert"
                    )
                    print("✅ [Tier 1] FinBERT model is online and ready.")
                except Exception as e:
                    print(f"❌ CRITICAL: Failed to load local FinBERT model. Tier 1 filtering will be disabled. Error: {e}")
                    cls._instance.sentiment_pipeline = None
        return cls._instance

    def analyze(self, text: str) -> dict:
        """
        Analyzes text using the local model if available.
        Returns a dictionary with 'label' and 'score'.
        """
        if not self.sentiment_pipeline:
            return {"label": "neutral", "score": 0.0}
            
        try:
            # FinBERT labels are 'positive', 'negative', 'neutral'
            return self.sentiment_pipeline(text)[0]
        except Exception as e:
            print(f"Error in local sentiment analysis: {e}")
            return {"label": "neutral", "score": 0.0}

# Create a singleton instance that will be imported by the main app.
LocalSentimentFilter = SentimentEngine()