import json
import logging
from typing import Any, Dict, Optional

logger = logging.getLogger("ExamGraph")

def safe_parse(parser_obj, text: str, question_no: int) -> Optional[Dict[str, Any]]:
    if not text or text.strip() in ("null", "None", ""):
        logger.warning(f"[Parse] q{question_no}: empty/null response")
        return None
    
    last_error = None
    
    # Try direct parse
    try:
        result = parser_obj.parse(text)
        return result.model_dump() if hasattr(result, "model_dump") else result
    except Exception as e:
        last_error = e
        logger.debug(f"[Parse] q{question_no}: direct parse failed, trying extraction")
    
    # Try to extract JSON from text (LLM may have wrapped it in prose)
    try:
        # look for {...} pattern
        start = text.rfind("{")
        end = text.rfind("}") + 1
        if start >= 0 and end > start:
            json_str = text[start:end]
            json_obj = json.loads(json_str)
            result = parser_obj.parse(json.dumps(json_obj))
            return result.model_dump() if hasattr(result, "model_dump") else result
    except Exception as e:
        last_error = e
        logger.debug(f"[Parse] q{question_no}: json extraction failed")
    
    # Last resort: if it looks like partial JSON, mark for regen
    error_msg = str(last_error) if last_error else "unknown"
    logger.error(f"[Parse] q{question_no}: failed all attempts: {error_msg}")
    return None

def categorize_error(error_str: str) -> str:
    err = error_str.lower()
    if "timeout" in err:
        return "timeout"
    elif "json" in err or "invalid" in err:
        return "invalid_json"
    elif "field required" in err or "missing" in err:
        return "missing_field"
    elif "none" in err or "null" in err:
        return "null"
    return "unknown"