import sqlite_utils
from datetime import datetime
import os
import json
from typing import Dict, Optional, Any

DB_PATH = os.path.join(os.path.dirname(os.path.dirname(__file__)), "articles.db")

def get_db():
    """Returns a connection to the SQLite database."""
    db = sqlite_utils.Database(DB_PATH)
    
    # Create table if not exists
    if "articles" not in db.table_names():
        db["articles"].create({
            "url": str,
            "title": str,
            "author": str,
            "publication": str,
            "markdown_content": str,
            "json_state": str, # Raw Apollo/JSON-LD state
            "html_content": str,
            "last_scraped": str,
            "source": str, # 'apollo', 'json-ld', 'html', 'archive', 'vision'
            "embedding": str # JSON string of float list
        }, pk="url")
        
        # Enable Full Text Search
        db["articles"].enable_fts(["title", "markdown_content", "author"])
        
    return db

def save_article(data: Dict[str, Any]):
    """Saves or updates an article in the database."""
    db = get_db()
    
    # Prepare record
    record = {
        "url": data.get("url"),
        "title": data.get("title"),
        "author": data.get("author", {}).get("name") if isinstance(data.get("author"), dict) else data.get("author"),
        "publication": data.get("publication"),
        "markdown_content": data.get("markdownContent"),
        "json_state": json.dumps(data.get("json_state", {})),
        "html_content": data.get("html_debug", "")[:100000], # Truncate if too huge
        "last_scraped": datetime.now().isoformat(),
        "source": data.get("source", "unknown"),
        "embedding": json.dumps(data.get("embedding")) if data.get("embedding") else None
    }
    
    # Validation: Don't save if it looks like an error page
    content = record.get("markdown_content", "")
    if "Apologies, but something went wrong" in content or "500" in content and len(content) < 500:
        print(f"Refusing to save invalid article: {record['url']}")
        return

    # Upsert
    db["articles"].upsert(record, pk="url")

def get_article(url: str) -> Optional[Dict[str, Any]]:
    """Retrieves an article from the database."""
    db = get_db()
    try:
        record = db["articles"].get(url)
        if record:
            # Parse JSON state back
            try:
                record["json_state"] = json.loads(record["json_state"])
            except:
                record["json_state"] = {}
                
            # Map back to expected format
            return {
                "url": record["url"],
                "title": record["title"],
                "author": {"name": record["author"]},
                "publication": record["publication"],
                "markdownContent": record["markdown_content"],
                "json_state": record["json_state"],
                "source": record["source"],
                "cached": True
            }
    except sqlite_utils.db.NotFoundError:
        return None
    return None

def is_fresh(url: str, max_age_hours: int = 24) -> bool:
    """Checks if the cached article is fresh enough."""
    article = get_article(url)
    if not article:
        return False
        
    db = get_db()
    record = db["articles"].get(url)
    last_scraped = datetime.fromisoformat(record["last_scraped"])
    age = (datetime.now() - last_scraped).total_seconds() / 3600
    
    return age < max_age_hours

def search_similar(query_embedding: list, limit: int = 5) -> list:
    """
    Searches for similar articles using cosine similarity.
    Note: This is a brute-force implementation in Python.
    """
    import numpy as np
    
    db = get_db()
    results = []
    
    # Fetch all embeddings
    # In a real production system, use a Vector DB
    rows = db.query("SELECT url, title, embedding FROM articles WHERE embedding IS NOT NULL")
    
    query_vec = np.array(query_embedding)
    norm_query = np.linalg.norm(query_vec)
    
    for row in rows:
        try:
            emb = json.loads(row["embedding"])
            vec = np.array(emb)
            norm_vec = np.linalg.norm(vec)
            
            if norm_vec == 0 or norm_query == 0:
                continue
                
            similarity = np.dot(query_vec, vec) / (norm_query * norm_vec)
            results.append({
                "url": row["url"],
                "title": row["title"],
                "similarity": float(similarity)
            })
        except:
            continue
            
    # Sort by similarity desc
    results.sort(key=lambda x: x["similarity"], reverse=True)
    return results[:limit]