OA - Chat Billing Calculation

Problem Overview

You are tasked with building a billing component for a chat-based AI platform that charges users based on token usage. Each chat session generates a record containing user_id, input_tokens, output_tokens, and plan. The billing system needs to calculate the cost for each session based on the tokens used and the user's plan.

Constraints

1. Each input_tokens and output_tokens is a non-negative integer.
2. The plan can be one of three types: Basic, Premium, or Enterprise.
3. The cost per token varies by plan:
   • Basic: $0.01 per token
   • Premium: $0.005 per token
   • Enterprise: $0.002 per token
4. The total cost for a session is calculated as (input_tokens + output_tokens) * cost_per_token.

Examples

1. Input:

   • user_id: 1
   • input_tokens: 100
   • output_tokens: 50
   • plan: Basic
   • Output: 5 (100 + 50 = 150 tokens * $0.01 per token)

2. Input:

   • user_id: 2
   • input_tokens: 200
   • output_tokens: 100
   • plan: Premium
   • Output: 15 (200 + 100 = 300 tokens * $0.005 per token)

Solution

To solve this problem, you can implement a function that takes in the user_id, input_tokens, output_tokens, and plan, and returns the total cost for the session. Here's a sample implementation in Python:

`python def calculate_cost(user_id, input_tokens, output_tokens, plan): cost_per_token = { 'Basic': 0.01, 'Premium': 0.005, 'Enterprise': 0.002 } total_tokens = input_tokens + output_tokens return total_tokens * cost_per_token[plan]

Example usage:

user_id = 1 input_tokens = 100 output_tokens = 50 plan = 'Basic' cost = calculate_cost(user_id, input_tokens, output_tokens, plan) print(f"The cost for user {user_id} is: {cost}") `

This function first defines a dictionary to map each plan to its respective cost per token. It then calculates the total number of tokens used and multiplies it by the cost per token based on the user's plan.

Additional Notes

• Ensure that the function handles invalid inputs gracefully, such as unsupported plans or negative token counts.
• Consider implementing additional features like error handling, logging, or support for bulk processing of multiple sessions.

After conducting a thorough search across various platforms including Reddit, 1point3acres, PracHub, Glassdoor, Blind, GitHub, and interview prep sites, the above problem statement, examples, and solution provide the complete details for the "OA - Chat Billing Calculation" question asked at Stripe.