# genesis/graph_tools.py
import os
import logging
from neo4j import GraphDatabase, basic_auth

# =========================
# CONFIG
# =========================
NEO4J_URI = os.getenv("NEO4J_URI")
NEO4J_USER = os.getenv("NEO4J_USER")
NEO4J_PASSWORD = os.getenv("NEO4J_PASSWORD")

driver = None

# =========================
# INIT CONNECTION
# =========================
def init_driver():
    """Initialize Neo4j driver if credentials are set."""
    global driver
    if NEO4J_URI and NEO4J_USER and NEO4J_PASSWORD:
        try:
            driver = GraphDatabase.driver(
                NEO4J_URI,
                auth=basic_auth(NEO4J_USER, NEO4J_PASSWORD)
            )
            logging.info("[Neo4j] Connected successfully.")
        except Exception as e:
            logging.error(f"[Neo4j] Connection failed: {e}")
            driver = None
    else:
        logging.info("[Neo4j] No URI/user/password set — skipping connection.")
        driver = None

# Call on import
init_driver()

def is_connected():
    """Check if driver is active and ready."""
    return driver is not None and hasattr(driver, "session")

# =========================
# QUERY FUNCTIONS
# =========================
def run_query(cypher, params=None):
    """Run a read/write Cypher query safely."""
    if not is_connected():
        logging.warning("[Neo4j] No active connection — returning empty result.")
        return []
    try:
        with driver.session() as session:
            return list(session.run(cypher, params or {}))
    except Exception as e:
        logging.error(f"[Neo4j] Query failed: {e}")
        return []

def write_data(cypher, params=None):
    """Write data to Neo4j (CREATE/MERGE)."""
    if not is_connected():
        logging.warning("[Neo4j] No active connection — skipping write.")
        return False
    try:
        with driver.session() as session:
            session.run(cypher, params or {})
        return True
    except Exception as e:
        logging.error(f"[Neo4j] Write failed: {e}")
        return False

# =========================
# BULK GRAPH CREATION
# =========================
def save_graph_data(nodes, edges):
    """
    Save nodes and edges to Neo4j.
    nodes: list of dicts {id, label, type}
    edges: list of dicts {source, target, type}
    """
    if not is_connected():
        logging.warning("[Neo4j] No active connection — skipping graph save.")
        return False

    try:
        with driver.session() as session:
            # Create nodes
            for node in nodes:
                session.run(
                    """
                    MERGE (n:Entity {id: $id})
                    SET n.label = $label, n.type = $type
                    """,
                    node
                )
            # Create edges
            for edge in edges:
                session.run(
                    """
                    MATCH (a:Entity {id: $source})
                    MATCH (b:Entity {id: $target})
                    MERGE (a)-[r:RELATION {type: $type}]->(b)
                    """,
                    edge
                )
        logging.info("[Neo4j] Graph data saved successfully.")
        return True
    except Exception as e:
        logging.error(f"[Neo4j] Error saving graph data: {e}")
        return False

# =========================
# CLEANUP
# =========================
def close_driver():
    """Close Neo4j driver."""
    global driver
    if driver:
        driver.close()
        driver = None
        logging.info("[Neo4j] Connection closed.")