"""
Role detection service for identifying distinct speakers in text.
"""
import re
from typing import List, Set, Dict


class RoleDetector:
    """
    Service for detecting distinct speaker roles in text.
    
    Supports two pattern types:
    1. Colon pattern: "RoleName:" at the start of a line
    2. Bracket pattern: "[RoleName]" preceding dialogue
    """
    
    # Regex patterns for role detection
    COLON_PATTERN = r'^([A-Z][a-zA-Z\s]+?):\s'
    BRACKET_PATTERN = r'\[([A-Z][a-zA-Z\s]+?)\]'
    DEFAULT_ROLE = "Narrator"
    
    def detect_roles(self, text: str) -> List[Dict[str, str]]:
        """
        Analyzes text to identify distinct speaker roles.
        
        Args:
            text: Input text to analyze
            
        Returns:
            List of role dictionaries with 'id' and 'label' fields.
            Returns default "Narrator" role if no patterns found.
        """
        if not text or not text.strip():
            return [{"id": self.DEFAULT_ROLE, "label": self.DEFAULT_ROLE}]
        
        # Extract roles from both patterns
        colon_roles = self._extract_colon_pattern(text)
        bracket_roles = self._extract_bracket_pattern(text)
        
        # Combine and deduplicate
        all_roles = colon_roles.union(bracket_roles)
        
        # If no roles found, return default
        if not all_roles:
            return [{"id": self.DEFAULT_ROLE, "label": self.DEFAULT_ROLE}]
        
        # Convert to role dictionaries and sort for consistent ordering
        role_list = [
            {"id": role.strip(), "label": role.strip()}
            for role in sorted(all_roles)
        ]
        
        return role_list
    
    def _extract_colon_pattern(self, text: str) -> Set[str]:
        """
        Extracts roles from "RoleName:" pattern at line starts.
        
        Args:
            text: Input text to analyze
            
        Returns:
            Set of role names found
        """
        roles = set()
        pattern = re.compile(self.COLON_PATTERN, re.MULTILINE)
        
        for match in pattern.finditer(text):
            role_name = match.group(1).strip()
            if role_name:
                roles.add(role_name)
        
        return roles
    
    def _extract_bracket_pattern(self, text: str) -> Set[str]:
        """
        Extracts roles from "[RoleName]" pattern.
        
        Args:
            text: Input text to analyze
            
        Returns:
            Set of role names found
        """
        roles = set()
        pattern = re.compile(self.BRACKET_PATTERN)
        
        for match in pattern.finditer(text):
            role_name = match.group(1).strip()
            if role_name:
                roles.add(role_name)
        
        return roles