import datetime
import uuid
import random
import pandas as pd
import numpy as np

class RevenueAnalyticsEngine:
    """
    A comprehensive Revenue Analytics Engine for tracking patent monetization.
    """

    def __init__(self, db_engine):
        """
        Initializes the RevenueAnalyticsEngine.

        Args:
            db_engine: A database engine object (e.g., SQLAlchemy engine)
                       to interact with the database.  For this example, we'll
                       simulate a database with Pandas DataFrames.
        """
        self.db_engine = db_engine
        self.usage_events = pd.DataFrame(columns=['event_id', 'timestamp', 'patent_id', 'customer_id', 'api_endpoint', 'processing_time_ms', 'billed', 'validation_type'])
        self.customers = pd.DataFrame(columns=['customer_id', 'name', 'contract_type', 'volume_discount', 'enterprise_discount', 'signup_date', 'churned'])
        self.invoices = pd.DataFrame(columns=['invoice_id', 'customer_id', 'issue_date', 'due_date', 'total_amount', 'paid'])
        self.metrics_aggregations = pd.DataFrame(columns=['date', 'metric_type', 'value'])
        self.pricing = {'validation_base': 1.0, 'validation_premium': 5.0}  # Example pricing

    def track_usage(self, patent_id, customer_id, api_endpoint, processing_time_ms, validation_type):
        """
        Tracks API usage events.

        Args:
            patent_id: The ID of the patent used.
            customer_id: The ID of the customer making the API call.
            api_endpoint: The API endpoint called.
            processing_time_ms: The processing time in milliseconds.
            validation_type: Type of validation (e.g., 'base', 'premium')
        """
        event_id = uuid.uuid4()
        timestamp = datetime.datetime.now()
        new_event = pd.DataFrame([{
            'event_id': event_id,
            'timestamp': timestamp,
            'patent_id': patent_id,
            'customer_id': customer_id,
            'api_endpoint': api_endpoint,
            'processing_time_ms': processing_time_ms,
            'billed': False,
            'validation_type': validation_type
        }])
        self.usage_events = pd.concat([self.usage_events, new_event], ignore_index=True)
        return event_id

    def calculate_bill(self, customer_id, validation_type):
        """
        Calculates the bill for a single validation event.

        Args:
            customer_id: The ID of the customer.
            validation_type: The type of validation.

        Returns:
            The bill amount.
        """
        customer = self.customers[self.customers['customer_id'] == customer_id]
        if customer.empty:
            return 0  # Customer not found

        contract_type = customer['contract_type'].values[0]
        volume_discount = customer['volume_discount'].values[0]
        enterprise_discount = customer['enterprise_discount'].values[0]

        base_price = self.pricing.get(f'validation_{validation_type}', self.pricing['validation_base'])

        # Apply discounts
        price = base_price * (1 - volume_discount) * (1 - enterprise_discount)

        return price

    def generate_invoice(self, customer_id, start_date, end_date):
        """
        Generates an invoice for a customer for a given period.

        Args:
            customer_id: The ID of the customer.
            start_date: The start date of the billing period.
            end_date: The end date of the billing period.

        Returns:
            The invoice ID.
        """
        usage_events = self.usage_events[
            (self.usage_events['customer_id'] == customer_id) &
            (self.usage_events['timestamp'] >= start_date) &
            (self.usage_events['timestamp'] <= end_date) &
            (self.usage_events['billed'] == False)
        ]

        if usage_events.empty:
            return None  # No usage for the period

        total_amount = 0
        for index, row in usage_events.iterrows():
            validation_type = row['validation_type']
            bill_amount = self.calculate_bill(customer_id, validation_type)
            total_amount += bill_amount
            self.usage_events.loc[index, 'billed'] = True

        invoice_id = uuid.uuid4()
        issue_date = datetime.datetime.now()
        due_date = issue_date + datetime.timedelta(days=30)

        new_invoice = pd.DataFrame([{
            'invoice_id': invoice_id,
            'customer_id': customer_id,
            'issue_date': issue_date,
            'due_date': due_date,
            'total_amount': total_amount,
            'paid': False
        }])
        self.invoices = pd.concat([self.invoices, new_invoice], ignore_index=True)
        return invoice_id

    def revenue_by_patent(self, start_date=None, end_date=None):
        """
        Calculates revenue generated by each patent.

        Args:
            start_date: Optional start date for the analysis.
            end_date: Optional end date for the analysis.

        Returns:
            A Pandas DataFrame with revenue by patent.
        """

        filtered_invoices = self.invoices
        if start_date:
            filtered_invoices = filtered_invoices[filtered_invoices['issue_date'] >= start_date]
        if end_date:
            filtered_invoices = filtered_invoices[filtered_invoices['issue_date'] <= end_date]

        if filtered_invoices.empty:
            return pd.DataFrame(columns=['patent_id', 'revenue'])

        patent_revenue = {}
        for index, row in self.usage_events.iterrows():
             if row['billed']:
                invoice_id = self.invoices[(self.invoices['customer_id'] == row['customer_id']) & (self.invoices['issue_date'] >= start_date) & (self.invoices['issue_date'] <= end_date)]['invoice_id'].values
                if len(invoice_id) > 0:
                    customer_id = row['customer_id']
                    validation_type = row['validation_type']
                    bill_amount = self.calculate_bill(customer_id, validation_type)
                    patent_id = row['patent_id']
                    if patent_id in patent_revenue:
                        patent_revenue[patent_id] += bill_amount
                    else:
                        patent_revenue[patent_id] = bill_amount

        patent_revenue_df = pd.DataFrame(list(patent_revenue.items()), columns=['patent_id', 'revenue'])
        return patent_revenue_df

    def revenue_by_customer(self, start_date=None, end_date=None):
        """
        Calculates revenue generated by each customer.

        Args:
            start_date: Optional start date for the analysis.
            end_date: Optional end date for the analysis.

        Returns:
            A Pandas DataFrame with revenue by customer.
        """
        filtered_invoices = self.invoices
        if start_date:
            filtered_invoices = filtered_invoices[filtered_invoices['issue_date'] >= start_date]
        if end_date:
            filtered_invoices = filtered_invoices[filtered_invoices['issue_date'] <= end_date]

        customer_revenue = filtered_invoices.groupby('customer_id')['total_amount'].sum().reset_index()
        return customer_revenue

    def daily_revenue_trend(self, start_date=None, end_date=None):
        """
        Calculates the daily revenue trend.

        Args:
            start_date: Optional start date for the analysis.
            end_date: Optional end date for the analysis.

        Returns:
            A Pandas DataFrame with daily revenue trend.
        """
        filtered_invoices = self.invoices
        if start_date:
            filtered_invoices = filtered_invoices[filtered_invoices['issue_date'] >= start_date]
        if end_date:
            filtered_invoices = filtered_invoices[filtered_invoices['issue_date'] <= end_date]

        daily_revenue = filtered_invoices.groupby(filtered_invoices['issue_date'].dt.date)['total_amount'].sum().reset_index()
        daily_revenue.rename(columns={'issue_date': 'date', 'total_amount': 'revenue'}, inplace=True)
        return daily_revenue

    def cohort_analysis(self, cohort_period='monthly'):
        """
        Performs cohort analysis based on signup date.

        Args:
            cohort_period: 'monthly' or 'weekly'

        Returns:
            A Pandas DataFrame with cohort analysis results.
        """
        if self.customers.empty:
            return pd.DataFrame()

        # Create cohort groups based on signup date
        if cohort_period == 'monthly':
            self.customers['cohort_group'] = self.customers['signup_date'].dt.to_period('M')
        elif cohort_period == 'weekly':
            self.customers['cohort_group'] = self.customers['signup_date'].dt.to_period('W')
        else:
            raise ValueError("Invalid cohort period. Choose 'monthly' or 'weekly'.")

        # Calculate retention rate
        cohort_data = self.customers.groupby('cohort_group')['customer_id'].nunique().reset_index()
        cohort_data.rename(columns={'customer_id': 'total_customers'}, inplace=True)

        # Calculate active customers each period
        retention = self.customers.groupby(['cohort_group', 'churned'])['customer_id'].nunique().unstack(fill_value=0)
        retention['retained'] = retention[False]
        retention = retention[['retained']]
        retention.reset_index(inplace=True)

        cohort_analysis = pd.merge(cohort_data, retention, on='cohort_group', how='left')
        cohort_analysis['retention_rate'] = cohort_analysis['retained'] / cohort_analysis['total_customers']
        return cohort_analysis

    def calculate_cost_per_validation(self, patent_id=None):
        """
        Calculates the cost per validation for a given patent or overall.

        Args:
            patent_id: Optional patent ID to filter by.

        Returns:
            The cost per validation.
        """
        # This would require integration with a cost tracking system.
        # For now, we'll simulate it with a fixed cost per validation.
        fixed_cost_per_validation = 0.1  # Example: $0.1 per validation
        if patent_id:
            validation_count = len(self.usage_events[self.usage_events['patent_id'] == patent_id])
        else:
            validation_count = len(self.usage_events)

        if validation_count == 0:
            return 0

        return fixed_cost_per_validation

    def calculate_profit_margin(self, patent_id=None):
        """
        Calculates the profit margin for a given patent or overall.

        Args:
            patent_id: Optional patent ID to filter by.

        Returns:
            The profit margin.
        """
        revenue = 0
        if patent_id:
            revenue_data = self.revenue_by_patent(start_date=datetime.datetime(2023, 1, 1), end_date=datetime.datetime.now())
            if not revenue_data.empty:
                revenue = revenue_data[revenue_data['patent_id']==patent_id]['revenue'].values[0]
        else:
            revenue = self.invoices['total_amount'].sum()

        cost = self.calculate_cost_per_validation(patent_id) * len(self.usage_events)
        if revenue == 0:
            return 0
        profit_margin = (revenue - cost) / revenue
        return profit_margin

    def calculate_customer_lifetime_value(self, customer_id):
        """
        Calculates the customer lifetime value (CLTV).
        This is a simplified CLTV calculation.

        Args:
            customer_id: The ID of the customer.

        Returns:
            The estimated CLTV.
        """
        customer_revenue = self.revenue_by_customer(start_date=self.customers[self.customers['customer_id'] == customer_id]['signup_date'].values[0], end_date=datetime.datetime.now())
        if customer_revenue.empty:
            return 0
        avg_monthly_revenue = customer_revenue['total_amount'].mean()
        customer_lifespan_months = 36  # Assuming a 3-year lifespan
        churn_rate = 0.1 # Assuming a 10% churn rate

        cltv = (avg_monthly_revenue * customer_lifespan_months) / (1 + churn_rate)
        return cltv

    def predict_churn(self, customer_id):
        """
        Predicts whether a customer is likely to churn.
        (This is a placeholder for a real churn prediction model).

        Args:
            customer_id: The ID of the customer.

        Returns:
            True if the customer is predicted to churn, False otherwise.
        """
        # Simulate churn prediction based on random chance.
        # A real implementation would use machine learning models.
        return random.random() < 0.2  # 20% chance of churn prediction

    def generate_sample_data(self, num_customers=5, num_events=20):
      """
      Generates sample data for testing purposes.
      """
      self.customers = pd.DataFrame({
          'customer_id': [uuid.uuid4() for _ in range(num_customers)],
          'name': [f'Customer {i}' for i in range(num_customers)],
          'contract_type': ['standard'] * num_customers,
          'volume_discount': [0.05] * num_customers,
          'enterprise_discount': [0.0] * num_customers,
          'signup_date': [datetime.datetime.now() - datetime.timedelta(days=random.randint(30, 365)) for _ in range(num_customers)],
          'churned': [False] * num_customers
      })

      patents = ['patent1', 'patent2', 'patent3']
      api_endpoints = ['/validate', '/analyze']
      validation_types = ['base', 'premium']

      for _ in range(num_events):
          customer_id = random.choice(self.customers['customer_id'].tolist())
          patent_id = random.choice(patents)
          api_endpoint = random.choice(api_endpoints)
          processing_time_ms = random.randint(100, 500)
          validation_type = random.choice(validation_types)

          self.track_usage(patent_id, customer_id, api_endpoint, processing_time_ms, validation_type)

    def run_simulation(self):
      """
      Runs a simulation to demonstrate the engine's capabilities.
      """
      self.generate_sample_data()

      # Generate invoices for all customers
      for customer_id in self.customers['customer_id']:
          invoice_id = self.generate_invoice(customer_id, datetime.datetime(2023, 1, 1), datetime.datetime.now())
          if invoice_id:
              print(f"Generated invoice {invoice_id} for customer {customer_id}")

      # Perform analytics queries
      print("\nRevenue by Patent:")
      print(self.revenue_by_patent())

      print("\nRevenue by Customer:")
      print(self.revenue_by_customer())

      print("\nDaily Revenue Trend:")
      print(self.daily_revenue_trend())

      print("\nCohort Analysis:")
      print(self.cohort_analysis())

      # Calculate optimization metrics
      print("\nCost per Validation:")
      print(self.calculate_cost_per_validation())

      print("\nProfit Margin:")
      print(self.calculate_profit_margin())

      customer_id = self.customers['customer_id'].iloc[0] #Grab first customer
      print(f"\nCustomer Lifetime Value for {customer_id}:")
      print(self.calculate_customer_lifetime_value(customer_id))

      print(f"\nChurn Prediction for {customer_id}:")
      print(self.predict_churn(customer_id))

# Example Usage (Simulated Database)
if __name__ == '__main__':
    # For demonstration, we'll simulate a database with Pandas DataFrames.
    # In a real application, replace this with a database engine (e.g., SQLAlchemy).
    class MockDBEngine:
        pass  # Replace with your actual database engine

    db_engine = MockDBEngine()
    engine = RevenueAnalyticsEngine(db_engine)
    engine.run_simulation()
