"""
Knowledge Graph DB - Basis-Modul
SQLite-basierte Graph-Datenbank fuer pathOS Audit
"""
import sqlite3
import json
import os
from pathlib import Path

DB_PATH = Path(__file__).parent / "pathos.db"
SCHEMA_PATH = Path(__file__).parent / "schema.sql"


def get_db():
    """Verbindung zur DB herstellen, Schema anlegen falls noetig."""
    db = sqlite3.connect(str(DB_PATH))
    db.row_factory = sqlite3.Row
    db.execute("PRAGMA journal_mode=WAL")
    db.execute("PRAGMA foreign_keys=ON")
    # Schema anlegen
    with open(SCHEMA_PATH, "r", encoding="utf-8") as f:
        db.executescript(f.read())
    return db


def upsert_node(db, node_id, node_type, name, summary=None, properties=None, source=None):
    """Node einfuegen oder aktualisieren."""
    props_json = json.dumps(properties, ensure_ascii=False) if properties else None
    db.execute("""
        INSERT INTO nodes (id, type, name, summary, properties, source, updated_at)
        VALUES (?, ?, ?, ?, ?, ?, datetime('now'))
        ON CONFLICT(id) DO UPDATE SET
            type=excluded.type, name=excluded.name, summary=excluded.summary,
            properties=excluded.properties, source=excluded.source, updated_at=datetime('now')
    """, (node_id, node_type, name, summary, props_json, source))


def add_edge(db, source_id, target_id, relation, properties=None, source=None):
    """Kante hinzufuegen (Duplikate werden vermieden)."""
    props_json = json.dumps(properties, ensure_ascii=False) if properties else None
    # Pruefen ob schon existiert
    existing = db.execute(
        "SELECT id FROM edges WHERE source_id=? AND target_id=? AND relation=?",
        (source_id, target_id, relation)
    ).fetchone()
    if existing:
        db.execute(
            "UPDATE edges SET properties=?, source=?, updated_at=datetime('now') WHERE id=?",
            (props_json, source, existing["id"])
        )
    else:
        db.execute(
            "INSERT INTO edges (source_id, target_id, relation, properties, source, updated_at) VALUES (?, ?, ?, ?, ?, datetime('now'))",
            (source_id, target_id, relation, props_json, source)
        )


def upsert_summary(db, summary_id, topic, content, detail_path=None, tags=None):
    """Zusammenfassung einfuegen oder aktualisieren."""
    db.execute("""
        INSERT INTO summaries (id, topic, content, detail_path, tags, updated_at)
        VALUES (?, ?, ?, ?, ?, datetime('now'))
        ON CONFLICT(id) DO UPDATE SET
            topic=excluded.topic, content=excluded.content,
            detail_path=excluded.detail_path, tags=excluded.tags, updated_at=datetime('now')
    """, (summary_id, topic, content, detail_path, tags))
    # FTS aktualisieren
    db.execute("INSERT INTO summaries_fts(summaries_fts) VALUES('rebuild')")


def add_fact(db, subject, predicate, value, confidence="confirmed", source=None, date=None):
    """Fakt hinzufuegen."""
    db.execute(
        "INSERT INTO facts (subject, predicate, value, confidence, source, date, updated_at) VALUES (?, ?, ?, ?, ?, ?, datetime('now'))",
        (subject, predicate, value, confidence, source, date)
    )
    db.execute("INSERT INTO facts_fts(facts_fts) VALUES('rebuild')")


def search_summaries(db, query, limit=5):
    """Volltextsuche in Zusammenfassungen."""
    # FTS5 Query escapen: Woerter mit Anfuehrungszeichen schuetzen
    safe_query = " ".join(f'"{w}"' for w in query.split())
    results = db.execute("""
        SELECT s.id, s.topic, s.content, s.detail_path, s.tags
        FROM summaries_fts fts
        JOIN summaries s ON s.rowid = fts.rowid
        WHERE summaries_fts MATCH ?
        LIMIT ?
    """, (safe_query, limit)).fetchall()
    return [dict(r) for r in results]


def search_facts(db, query, limit=10):
    """Volltextsuche in Fakten."""
    safe_query = " ".join(f'"{w}"' for w in query.split())
    results = db.execute("""
        SELECT f.subject, f.predicate, f.value, f.confidence, f.source, f.date
        FROM facts_fts fts
        JOIN facts f ON f.rowid = fts.rowid
        WHERE facts_fts MATCH ?
        LIMIT ?
    """, (safe_query, limit)).fetchall()
    return [dict(r) for r in results]


def get_node_context(db, node_id):
    """Alle Infos zu einem Node + seine Beziehungen."""
    node = db.execute("SELECT * FROM nodes WHERE id=?", (node_id,)).fetchone()
    if not node:
        return None
    edges_out = db.execute(
        "SELECT e.relation, n.name, n.type, e.properties FROM edges e JOIN nodes n ON n.id=e.target_id WHERE e.source_id=?",
        (node_id,)
    ).fetchall()
    edges_in = db.execute(
        "SELECT e.relation, n.name, n.type, e.properties FROM edges e JOIN nodes n ON n.id=e.source_id WHERE e.target_id=?",
        (node_id,)
    ).fetchall()
    return {
        "node": dict(node),
        "outgoing": [dict(e) for e in edges_out],
        "incoming": [dict(e) for e in edges_in]
    }