# app/neo4j_utils.py

from neo4j import GraphDatabase
from flask import current_app

class Neo4jHandler:
    def __init__(self, uri=None, user=None, password=None):
        # We read from current_app.config if nothing is passed in explicitly.
        # If you already set NEO4J_URI / NEO4J_USER / NEO4J_PASSWORD in your config.py, 
        # these defaults will be overridden by those values automatically.
        uri     = uri    or current_app.config.get("NEO4J_URI", "bolt://nip_neo4j:7687")
        user    = user   or current_app.config.get("NEO4J_USER", "neo4j")
        pw      = password or current_app.config.get("NEO4J_PASSWORD", "your_password_here")

        self.driver = GraphDatabase.driver(uri, auth=(user, pw))

    def close(self):
        self.driver.close()

    def create_plant_node(self, uuid: str, name: str = "Unknown"):
        """
        MERGE a Plant node by UUID. On create, set its name.
        We strip() and strip('"') in case the CSV had extra quotes or spaces around the UUID.
        """
        if not uuid:
            print("[⚠️] Skipped node creation: missing UUID")
            return

        # Remove surrounding quotes or whitespace
        uuid_clean = uuid.strip().strip('"')
        name_clean = (name or "Unknown").strip()

        print(f"[ℹ️] (Neo4j) MERGE Plant node → uuid='{uuid_clean}', name='{name_clean}'")
        try:
            with self.driver.session() as session:
                session.run(
                    """
                    MERGE (p:Plant {uuid: $uuid})
                    ON CREATE SET p.name = $name
                    """,
                    uuid=uuid_clean,
                    name=name_clean
                )
        except Exception as e:
            print(f"[❌] Neo4j node creation failed for UUID={uuid_clean}: {e}")

    def create_lineage(self, child_uuid: str, parent_uuid: str):
        """
        MATCH both child and parent by UUID, then MERGE a LINEAGE relationship.
        Again, strip() any extraneous quotes or whitespace.
        """
        if not child_uuid or not parent_uuid:
            print(f"[⚠️] Skipped lineage creation: missing UUID(s) ({child_uuid!r} → {parent_uuid!r})")
            return

        child_clean  = child_uuid.strip().strip('"')
        parent_clean = parent_uuid.strip().strip('"')

        print(f"[ℹ️] (Neo4j) Attempting to MERGE LINEAGE → child='{child_clean}', parent='{parent_clean}'")
        try:
            with self.driver.session() as session:
                result = session.run(
                    """
                    MATCH (c:Plant {uuid: $child_uuid})
                    MATCH (p:Plant {uuid: $parent_uuid})
                    MERGE (c)-[r:LINEAGE]->(p)
                    RETURN type(r) AS rel_type
                    """,
                    child_uuid=child_clean,
                    parent_uuid=parent_clean
                )
                record = result.single()
                if record and record.get("rel_type") == "LINEAGE":
                    print(f"[✅] (Neo4j) Created LINEAGE → {child_clean} → {parent_clean}")
                else:
                    print(f"[⚠️] (Neo4j) No LINEAGE created (nodes may not match) → {child_clean} → {parent_clean}")
        except Exception as e:
            print(f"[❌] Neo4j lineage creation failed: {e}")

    def debug_check_node(self, uuid: str):
        """
        Utility: check whether a Plant node with this UUID exists in Neo4j.
        """
        uuid_clean = uuid.strip().strip('"')
        with self.driver.session() as session:
            result = session.run(
                "MATCH (p:Plant {uuid: $uuid}) RETURN p",
                uuid=uuid_clean
            )
            record = result.single()
            if record:
                print(f"[✅] (Neo4j) Node '{uuid_clean}' exists.")
            else:
                print(f"[❌] (Neo4j) Node '{uuid_clean}' NOT found.")

def get_neo4j_handler() -> Neo4jHandler:
    """
    Factory: read NEO4J_URI / NEO4J_USER / NEO4J_PASSWORD from current_app.config.
    """
    uri      = current_app.config.get("NEO4J_URI", "bolt://nip_neo4j:7687")
    user     = current_app.config.get("NEO4J_USER", "neo4j")
    password = current_app.config.get("NEO4J_PASSWORD", "your_password_here")
    return Neo4jHandler(uri, user, password)