app/services/analysis_service.py

"""
Analysis Service
================
Main analysis orchestrator (Dependency Inversion + Open/Closed)
"""

import numpy as np
from typing import List, Dict
from collections import defaultdict

from app.models.model_loader import model_loader
from app.services.text_processor import TextProcessor
from app.services.gradient_service import GradientService
from app.services.html_generator import HTMLGenerator
from app.schemas.requests import AnalysisRequest
from app.schemas.responses import (
    AnalysisResponse, SentenceResult, WordScore,
    ToxicWordSummary, Statistics, SentimentLabel
)
from app.core.config import settings
from app.core.exceptions import AnalysisException


class AnalysisService:
    """
    Main analysis service
    
    Responsibilities:
    - Orchestrate analysis pipeline
    - Coordinate between services
    - Build response
    
    Dependencies:
    - TextProcessor: Text processing
    - GradientService: Gradient computation
    - HTMLGenerator: HTML generation
    """
    
    def __init__(self):
        self.text_processor = TextProcessor()
        self.gradient_service = GradientService()
        self.html_generator = HTMLGenerator()
    
    def analyze(self, request: AnalysisRequest) -> AnalysisResponse:
        """
        Analyze text for toxicity
        
        Args:
            request: Analysis request
            
        Returns:
            Analysis response
            
        Raises:
            AnalysisException: If analysis fails
        """
        try:
            # 1. Split into sentences
            sentences = self.text_processor.split_into_sentences(request.text)
            
            # 2. Analyze each sentence
            sentence_results = []
            for i, sent_info in enumerate(sentences, 1):
                sent_result = self._analyze_sentence(
                    sent_info,
                    i,
                    request.include_word_scores
                )
                sentence_results.append(sent_result)
            
            # 3. Generate statistics
            statistics = self._compute_statistics(sentence_results)
            
            # 4. Extract toxic words summary
            toxic_words_summary = self._extract_toxic_words_summary(sentence_results)
            
            # 5. Generate HTML if requested
            html_highlighted = None
            if request.include_html:
                html_highlighted = self.html_generator.generate_highlighted_html(
                    request.text,
                    [self._convert_to_dict(r) for r in sentence_results]
                )
            
            # 6. Determine overall label
            toxic_count = sum(1 for r in sentence_results if r.label == SentimentLabel.TOXIC)
            overall_label = SentimentLabel.TOXIC if toxic_count > 0 else SentimentLabel.CLEAN
            
            # 7. Build response
            return AnalysisResponse(
                success=True,
                text=request.text,
                overall_label=overall_label,
                toxic_sentence_count=toxic_count,
                clean_sentence_count=len(sentences) - toxic_count,
                total_sentences=len(sentences),
                sentences=sentence_results,
                toxic_words_summary=toxic_words_summary,
                statistics=statistics,
                html_highlighted=html_highlighted
            )
            
        except Exception as e:
            raise AnalysisException(detail=str(e))
    
    def _analyze_sentence(
        self,
        sent_info: Dict[str, any],
        sent_number: int,
        include_word_scores: bool
    ) -> SentenceResult:
        """Analyze single sentence"""
        sent_text = sent_info['text']
        
        # Extract words
        words = self.text_processor.extract_words(sent_text)
        
        if len(words) == 0:
            return SentenceResult(
                sentence_number=sent_number,
                text=sent_text,
                label=SentimentLabel.CLEAN,
                confidence=0.0,
                threshold=0.6,
                word_count=0,
                word_scores=[] if include_word_scores else None
            )
        
        # Tokenize
        encoding = model_loader.tokenizer(
            sent_text.lower().strip(),
            add_special_tokens=True,
            max_length=settings.MAX_LENGTH,
            padding='max_length',
            truncation=True,
            return_tensors='pt'
        )
        
        # Compute gradients
        gradient_scores, predicted_class, confidence = self.gradient_service.compute_integrated_gradients(
            model=model_loader.model,
            input_ids=encoding['input_ids'],
            attention_mask=encoding['attention_mask'],
            device=model_loader.device
        )
        
        # Get tokens
        tokens = model_loader.tokenizer.convert_ids_to_tokens(
            encoding['input_ids'][0].cpu().numpy()
        )
        valid_length = encoding['attention_mask'][0].sum().item()
        tokens = tokens[:valid_length]
        
        # Normalize gradients
        gradient_scores_norm = self.gradient_service.normalize_scores(gradient_scores)
        
        # Map to words
        word_scores = self._map_tokens_to_words(tokens, gradient_scores_norm, words)
        
        # Determine toxicity
        is_toxic = (predicted_class == 1)
        label = SentimentLabel.TOXIC if is_toxic else SentimentLabel.CLEAN
        
        # Compute threshold
        threshold = self.gradient_service.compute_threshold(word_scores, is_toxic)
        
        # Build word scores
        word_score_objects = None
        if include_word_scores:
            word_score_objects = []
            for word_info, score in zip(words, word_scores):
                word_score_objects.append(WordScore(
                    word=word_info['word'],
                    score=float(score),
                    position={'start': word_info['start'], 'end': word_info['end']},
                    is_toxic=score > threshold and not self.text_processor.is_stop_word(word_info['word']),
                    is_stop_word=self.text_processor.is_stop_word(word_info['word'])
                ))
        
        return SentenceResult(
            sentence_number=sent_number,
            text=sent_text,
            label=label,
            confidence=float(confidence),
            threshold=float(threshold),
            word_count=len(words),
            word_scores=word_score_objects
        )
    
    def _map_tokens_to_words(
        self,
        tokens: List[str],
        token_scores: np.ndarray,
        original_words: List[Dict[str, any]]
    ) -> np.ndarray:
        """Map token scores to words"""
        clean_tokens = []
        clean_scores = []
        
        for token, score in zip(tokens, token_scores):
            if token not in ['<s>', '</s>', '<pad>', '<unk>']:
                clean_token = token.replace('_', '').replace('@@', '').strip()
                if clean_token and not self.text_processor.is_punctuation(clean_token):
                    clean_tokens.append(clean_token)
                    clean_scores.append(score)
        
        word_scores = []
        token_idx = 0
        
        for word_info in original_words:
            word = word_info['word'].lower()
            
            matching_scores = []
            temp_idx = token_idx
            accumulated = ""
            
            while temp_idx < len(clean_tokens):
                accumulated += clean_tokens[temp_idx]
                matching_scores.append(clean_scores[temp_idx])
                
                if accumulated == word:
                    token_idx = temp_idx + 1
                    break
                elif len(accumulated) >= len(word):
                    break
                
                temp_idx += 1
            
            word_scores.append(max(matching_scores) if matching_scores else 0.0)
        
        return np.array(word_scores)
    
    def _compute_statistics(self, sentence_results: List[SentenceResult]) -> Statistics:
        """Compute overall statistics"""
        all_scores = []
        toxic_words_count = 0
        
        for sent_result in sentence_results:
            if sent_result.word_scores:
                for ws in sent_result.word_scores:
                    all_scores.append(ws.score)
                    if ws.is_toxic:
                        toxic_words_count += 1
        
        if len(all_scores) == 0:
            return Statistics(
                total_words=0,
                toxic_words=0,
                mean_score=0.0,
                median_score=0.0,
                max_score=0.0,
                min_score=0.0
            )
        
        all_scores = np.array(all_scores)
        
        return Statistics(
            total_words=len(all_scores),
            toxic_words=toxic_words_count,
            mean_score=float(np.mean(all_scores)),
            median_score=float(np.median(all_scores)),
            max_score=float(np.max(all_scores)),
            min_score=float(np.min(all_scores))
        )
    
    def _extract_toxic_words_summary(
        self,
        sentence_results: List[SentenceResult]
    ) -> List[ToxicWordSummary]:
        """Extract summary of toxic words"""
        toxic_words_dict = defaultdict(lambda: {
            'max_score': 0.0,
            'occurrences': 0,
            'sentences': []
        })
        
        for sent_result in sentence_results:
            if sent_result.word_scores:
                for ws in sent_result.word_scores:
                    if ws.is_toxic:
                        word = ws.word
                        toxic_words_dict[word]['max_score'] = max(
                            toxic_words_dict[word]['max_score'],
                            ws.score
                        )
                        toxic_words_dict[word]['occurrences'] += 1
                        if sent_result.sentence_number not in toxic_words_dict[word]['sentences']:
                            toxic_words_dict[word]['sentences'].append(sent_result.sentence_number)
        
        # Convert to list and sort by score
        toxic_words_summary = [
            ToxicWordSummary(
                word=word,
                score=data['max_score'],
                occurrences=data['occurrences'],
                sentences=sorted(data['sentences'])
            )
            for word, data in toxic_words_dict.items()
        ]
        
        toxic_words_summary.sort(key=lambda x: x.score, reverse=True)
        
        return toxic_words_summary
    
    def _convert_to_dict(self, sent_result: SentenceResult) -> Dict[str, any]:
        """Convert SentenceResult to dict for HTML generator"""
        return {
            'sent_start': sent_result.word_scores[0].position['start'] if sent_result.word_scores and len(sent_result.word_scores) > 0 else 0,
            'sent_end': sent_result.word_scores[-1].position['end'] if sent_result.word_scores and len(sent_result.word_scores) > 0 else len(sent_result.text),
            'is_toxic': sent_result.label == SentimentLabel.TOXIC,
            'words': [{'word': ws.word, 'start': ws.position['start'], 'end': ws.position['end']} for ws in sent_result.word_scores] if sent_result.word_scores else [],
            'scores': [ws.score for ws in sent_result.word_scores] if sent_result.word_scores else [],
            'threshold': sent_result.threshold
        }


# Singleton instance
analysis_service = AnalysisService()