#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import fdb
from pathlib import Path

# ================== CONFIG ==================
DB_PATH = r"u:\MEDICUS 3\data\medicus.FDB"
HOST = "localhost"
USER = "sysdba"
PASSWORD = "masterkey"
LOG_FILE = Path("dropped_tables_with_deps.txt")
# ============================================

con = fdb.connect(
    host=HOST,
    database=DB_PATH,
    user=USER,
    password=PASSWORD,
    charset="WIN1250",
)
cur = con.cursor()

print("🔍 Checking tables for emptiness and dependencies...")

# All user tables
cur.execute("""
    SELECT TRIM(rdb$relation_name)
    FROM rdb$relations
    WHERE rdb$system_flag = 0
    ORDER BY 1
""")
tables = [r[0] for r in cur.fetchall()]

dropped = []
skipped = []

def drop_fk_constraints_referring_to(table_name: str):
    # Find all FKs that reference this table (PK or UNIQUE)
    cur.execute(f"""
        SELECT TRIM(rc.rdb$relation_name), TRIM(rc.rdb$constraint_name)
        FROM rdb$relation_constraints rc
        JOIN rdb$ref_constraints ref ON ref.rdb$constraint_name = rc.rdb$constraint_name
        JOIN rdb$relation_constraints pk ON pk.rdb$constraint_name = ref.rdb$const_name_uq
        WHERE rc.rdb$constraint_type = 'FOREIGN KEY'
          AND UPPER(pk.rdb$relation_name) = '{table_name.upper()}'
    """)
    for fk_table, fk_name in cur.fetchall():
        stmt = f'ALTER TABLE {fk_table} DROP CONSTRAINT {fk_name}'
        try:
            print(f"   🔧 Dropping FK {fk_name} in {fk_table}")
            con.execute_immediate(stmt)
            con.commit()  # commit each FK drop
        except Exception as e:
            print(f"      ⚠️  Could not drop FK {fk_name} in {fk_table}: {e}")
            con.rollback()

for t in tables:
    try:
        # Count rows
        cur.execute(f"SELECT COUNT(*) FROM {t}")
        count = cur.fetchone()[0]
        if count > 0:
            continue

        print(f"\n🧹 {t} → empty")

        # 1) Drop FKs that reference this table
        drop_fk_constraints_referring_to(t)

        # 2) Try to drop the table itself
        try:
            con.execute_immediate(f"DROP TABLE {t}")
            con.commit()  # commit this table drop
            dropped.append(t)
            print(f"   ✅ Dropped table {t}")
        except Exception as e:
            print(f"   ⚠️  Could not drop {t}: {e}")
            con.rollback()
            skipped.append(t)

    except Exception as e:
        print(f"⚠️  Skipping {t}: {e}")

con.close()

LOG_FILE.write_text("\n".join(dropped), encoding="utf-8")
print("\n✅ Done.")
print(f"Total dropped: {len(dropped)}")
print(f"Skipped: {len(skipped)}")
print(f"List saved to {LOG_FILE.resolve()}")