import os
import sqlite3
import pandas as pd

DATABASE_URL = os.getenv("DATABASE_URL", "")
DATABASE_PATH = os.getenv("DATABASE_PATH", "./proxy.db")

class DBConnectionWrapper:
    def __init__(self, conn, is_pg=False):
        self.conn = conn
        self.is_pg = is_pg

    def execute(self, query, params=()):
        if self.is_pg:
            query = query.replace("?", "%s")
        cursor = self.conn.cursor()
        cursor.execute(query, params)
        return cursor

    def commit(self):
        self.conn.commit()

    def close(self):
        self.conn.close()

def get_db_connection():
    if DATABASE_URL.startswith("postgres"):
        import psycopg2
        import psycopg2.extras
        conn = psycopg2.connect(DATABASE_URL, cursor_factory=psycopg2.extras.DictCursor)
        return DBConnectionWrapper(conn, is_pg=True)
    else:
        db_dir = os.path.dirname(DATABASE_PATH)
        if db_dir:
            os.makedirs(db_dir, exist_ok=True)
            
        # Add a timeout to handle concurrent initialization locks
        conn = sqlite3.connect(DATABASE_PATH, check_same_thread=False, timeout=15.0)
        conn.row_factory = sqlite3.Row
        return conn

def init_db() -> None:
    """Create the required database tables if they don't exist."""
    import time
    import sqlite3
    
    for attempt in range(5):
        try:
            conn = get_db_connection()
            try:
                is_pg = DATABASE_URL.startswith("postgres")
                
                id_type = "TEXT PRIMARY KEY"
                
                # Users table
                conn.execute(
                    """
                    CREATE TABLE IF NOT EXISTS users (
                        id TEXT PRIMARY KEY,
                        email TEXT UNIQUE NOT NULL,
                        password_hash TEXT NOT NULL,
                        created_at TEXT NOT NULL
                    )
                    """
                )
                # API Keys table
                conn.execute(
                    """
                    CREATE TABLE IF NOT EXISTS api_keys (
                        id TEXT PRIMARY KEY,
                        user_id TEXT NOT NULL,
                        key_hash TEXT NOT NULL,
                        prefix TEXT NOT NULL,
                        name TEXT,
                        created_at TEXT NOT NULL,
                        FOREIGN KEY(user_id) REFERENCES users(id)
                    )
                    """
                )
                # Requests table
                conn.execute(
                    f"""
                    CREATE TABLE IF NOT EXISTS requests (
                        id {id_type},
                        timestamp TEXT NOT NULL,
                        user_id TEXT,
                        prompt_text TEXT NOT NULL,
                        system_prompt TEXT,
                        score_heuristic REAL,
                        score_classifier REAL,
                        score_embedding REAL,
                        score_judge REAL,
                        final_score REAL NOT NULL,
                        action_taken TEXT NOT NULL,
                        triggered_layers TEXT NOT NULL,
                        matched_patterns TEXT,
                        judge_reason TEXT,
                        model TEXT,
                        processing_ms REAL,
                        FOREIGN KEY(user_id) REFERENCES users(id)
                    )
                    """
                )
                
                if is_pg:
                    try:
                        conn.execute("ALTER TABLE requests ALTER COLUMN id TYPE TEXT")
                    except Exception:
                        pass
                
                if not is_pg:
                    try:
                        conn.execute("ALTER TABLE requests ADD COLUMN user_id TEXT")
                    except Exception:
                        pass
                        
                conn.commit()
                return  # Success, exit the retry loop
            finally:
                conn.close()
                
        except sqlite3.OperationalError as e:
            if attempt < 4:
                print(f"SQLite concurrent init error (attempt {attempt+1}/5): {e}")
                time.sleep(1.5) # Wait for the other process to finish creating tables
            else:
                print(f"Failed to initialize database after 5 attempts: {e}")
                raise

def query_db_df(query: str, params: tuple = (), conn=None) -> pd.DataFrame:
    close_conn = False
    if conn is None:
        conn = get_db_connection()
        close_conn = True
        
    if DATABASE_URL.startswith("postgres"):
        query = query.replace("?", "%s")
        
    try:
        # Pandas requires the raw DBAPI connection object, not our wrapper
        raw_conn = conn.conn if hasattr(conn, "conn") else conn
        return pd.read_sql_query(query, raw_conn, params=params)
    except Exception as e:
        print(f"DB Error: {e}")
        return pd.DataFrame()
    finally:
        if close_conn:
            conn.close()