from mcp.server.fastmcp import FastMCP
import sqlite3, json

mcp = FastMCP("EnterpriseData")

# In-memory SQLite
conn = sqlite3.connect(":memory:", check_same_thread=False)
cur = conn.cursor()

cur.execute("""
CREATE TABLE Customers(
    CustomerID INTEGER PRIMARY KEY AUTOINCREMENT,
    Name TEXT,
    Region TEXT,
    LastOrderDate TEXT
)
""")

cur.executemany(
    "INSERT INTO Customers (Name, Region, LastOrderDate) VALUES (?,?,?)",
    [
        ("Acme Corp", "Northeast", "2024-12-01"),
        ("Beta Inc", "West",      "2025-06-01"),
        ("Gamma Co", "Northeast", "2023-09-15"),
        ("Delta LLC", "South",    "2025-03-20"),
        ("Epsilon Ltd", "Northeast","2025-07-10"),
    ]
)
conn.commit()

@mcp.tool()
def query_database(sql: str) -> str:
    """Run SQL and return JSON rows."""
    try:
        cur.execute(sql)
        cols = [d[0] for d in cur.description or []]
        rows = [dict(zip(cols, r)) for r in cur.fetchall()]
        return json.dumps(rows)
    except Exception as e:
        return json.dumps({"error": str(e)})

if __name__ == "__main__":
    mcp.run(transport="stdio")