from snowflake.connector import connect  # type: ignore[import-untyped]
from datetime import datetime
import os
import json
from dotenv import load_dotenv

# 🔑 Load .env file
load_dotenv()
# -----------------------------
# Snowflake connection config
# -----------------------------

def get_snowflake_connection():
    conn = connect(
        user=os.getenv("SNOWFLAKE_USER"),
        password=os.getenv("SNOWFLAKE_PASSWORD"),
        account=os.getenv("SNOWFLAKE_ACCOUNT"),
        role=os.getenv("SNOWFLAKE_ROLE"),
        warehouse=os.getenv("SNOWFLAKE_WAREHOUSE"),
        database=os.getenv("SNOWFLAKE_DATABASE"),
        schema=os.getenv("SNOWFLAKE_SCHEMA")
    )
    return conn

# -----------------------------
# Fetch Employee Details
# -----------------------------
def get_employee(employee_id: str):
    """Fetch employee details from Snowflake."""
    print("get_employee called")
    conn = get_snowflake_connection()
    cur = conn.cursor()
    try:
        cur.execute("""
            SELECT employee_id, country, employment_status
            FROM employees
            WHERE employee_id = %s
        """, (employee_id,))
        row = cur.fetchone()
        if not row:
            return {"error": f"Employee '{employee_id}' not found"}
        
        employee = {
            "employee_id": row[0],
            "country": row[1],
            "employment_status": row[2]
        }

        if employee["employment_status"] != "active":
            return {"error": f"Employee '{employee_id}' is not active"}

        # Fetch leave balances
        cur.execute("""
            SELECT leave_type, balance
            FROM leave_balances
            WHERE employee_id = %s
        """, (employee_id,))
        balances = {r[0]: r[1] for r in cur.fetchall()}
        employee["leave_balances"] = balances

        return employee
    finally:
        cur.close()
        conn.close()


# -----------------------------
# Fetch Leave Policy
# -----------------------------
def get_leave_policy(country: str, leave_type: str):
    """Fetch leave policy from Snowflake."""
    print("get_leave_policy called")
    conn = get_snowflake_connection()
    cur = conn.cursor()
    try:
        cur.execute("""
            SELECT policy
            FROM leave_policies
            WHERE country = %s AND leave_type = %s
        """, (country, leave_type))
        row = cur.fetchone()
        if not row:
            # fetch available leave types
            cur.execute("""
                SELECT leave_type
                FROM leave_policies
                WHERE country = %s
            """, (country,))
            leave_types = [r[0] for r in cur.fetchall()]
            return {
                "error": f"Leave type '{leave_type}' not found",
                "available_leave_types": leave_types
            }
        # policy is VARIANT JSON in Snowflake (may be dict or JSON string)
        raw = row[0]
        if isinstance(raw, dict):
            return raw
        if isinstance(raw, str):
            return json.loads(raw)
        return dict(raw)
    finally:
        cur.close()
        conn.close()


# -----------------------------
# Check Leave Eligibility
# -----------------------------
def check_leave_eligibility(employee_id: str, leave_type: str, requested_days: int):
    """Check if employee is eligible to take leave."""
    print("check_leave_eligibility called")
    if requested_days <= 0:
        return {"eligible": False, "reason": "Requested leave days must be > 0"}

    employee = get_employee(employee_id)
    if "error" in employee:
        return employee

    country = employee["country"]
    policy = get_leave_policy(country, leave_type)
    if "error" in policy:
        return policy

    balance = employee["leave_balances"].get(leave_type, 0)

    # Max consecutive days
    if "max_consecutive_days" in policy:
        if requested_days > policy["max_consecutive_days"]:
            return {
                "eligible": False,
                "reason": f"Maximum consecutive days allowed for {leave_type} is {policy['max_consecutive_days']}"
            }

    # Annual allowance
    if "annual_allowance" in policy:
        if requested_days > policy["annual_allowance"]:
            return {
                "eligible": False,
                "reason": "Requested days exceed annual allowance"
            }

    # Available balance
    if requested_days > balance:
        return {
            "eligible": False,
            "reason": "Insufficient leave balance",
            "available_balance": balance
        }

    return {
        "eligible": True,
        "employee_id": employee_id,
        "leave_type": leave_type,
        "approved_days": requested_days,
        "remaining_balance": balance - requested_days
    }