"""
FILE: app/services/edge_registry.py
DESCRIPTION: Single Source of Truth für Kanten-Typen. Parst '01_edge_vocabulary.md'.
             Implementiert WP-22 Teil B (Registry & Validation).
"""
import re
import os
import json
import logging
from typing import Dict, Optional, Set

logger = logging.getLogger(__name__)

class EdgeRegistry:
    _instance = None

    def __new__(cls):
        if cls._instance is None:
            cls._instance = super(EdgeRegistry, cls).__new__(cls)
            cls._instance.initialized = False
        return cls._instance

    def __init__(self):
        if self.initialized: return
        # Pfad korrespondiert mit dem Frontmatter Pfad in 01_edge_vocabulary.md
        self.vocab_path = "01_User_Manual/01_edge_vocabulary.md"
        self.unknown_log_path = "data/logs/unknown_edges.jsonl"
        self.canonical_map: Dict[str, str] = {} # alias -> canonical
        self.valid_types: Set[str] = set()
        self._load_vocabulary()
        self.initialized = True

    def _load_vocabulary(self):
        """Parst die Markdown-Tabelle in 01_edge_vocabulary.md"""
        # Fallback Suche, falls das Skript aus Root oder app ausgeführt wird
        candidates = [
            self.vocab_path,
            os.path.join("..", self.vocab_path),
            "vault/01_User_Manual/01_edge_vocabulary.md"
        ]
        
        found_path = None
        for p in candidates:
            if os.path.exists(p):
                found_path = p
                break
        
        if not found_path:
            logger.warning(f"Edge Vocabulary not found (checked: {candidates}). Registry empty.")
            return

        # Regex für Tabellenzeilen: | **canonical** | alias, alias | ...
        # Matcht: | **caused_by** | ausgelöst_durch, wegen |
        pattern = re.compile(r"\|\s*\*\*([a-z_]+)\*\*\s*\|\s*([^|]+)\|")

        try:
            with open(found_path, "r", encoding="utf-8") as f:
                for line in f:
                    match = pattern.search(line)
                    if match:
                        canonical = match.group(1).strip()
                        aliases_str = match.group(2).strip()
                        
                        self.valid_types.add(canonical)
                        self.canonical_map[canonical] = canonical # Self-ref
                        
                        # Aliases parsen
                        if aliases_str and "Kein Alias" not in aliases_str:
                            aliases = [a.strip() for a in aliases_str.split(",") if a.strip()]
                            for alias in aliases:
                                # Clean up user inputs (e.g. remove backticks if present)
                                clean_alias = alias.replace("`", "")
                                self.canonical_map[clean_alias] = canonical
            
            logger.info(f"EdgeRegistry loaded: {len(self.valid_types)} canonical types from {found_path}.")

        except Exception as e:
            logger.error(f"Failed to parse Edge Vocabulary: {e}")

    def resolve(self, edge_type: str) -> str:
        """
        Normalisiert Kanten-Typen. Loggt unbekannte Typen, verwirft sie aber nicht (Learning System).
        """
        if not edge_type:
            return "related_to"

        clean_type = edge_type.lower().strip().replace(" ", "_")
        
        # 1. Lookup
        if clean_type in self.canonical_map:
            return self.canonical_map[clean_type]
        
        # 2. Unknown Handling
        self._log_unknown(clean_type)
        return clean_type # Pass-through (nicht verwerfen, aber loggen)

    def _log_unknown(self, edge_type: str):
        """Schreibt unbekannte Typen in ein Append-Only Log für Review."""
        try:
            os.makedirs(os.path.dirname(self.unknown_log_path), exist_ok=True)
            # Einfaches JSONL Format
            entry = {"unknown_type": edge_type, "status": "new"}
            with open(self.unknown_log_path, "a", encoding="utf-8") as f:
                f.write(json.dumps(entry) + "\n")
        except Exception:
            pass # Silent fail bei Logging, darf Ingestion nicht stoppen

# Singleton Accessor
registry = EdgeRegistry()