Apex

"""
Apex: Campaign Testing Accelerator & Bayesian Multi-Armed Bandit
"""
import random
from typing import List, Dict
from pydantic import BaseModel

class AdVariant(BaseModel):
    variant_id: str
    impressions: int
    conversions: int

class AllocationResult(BaseModel):
    selected_winner: str
    budget_share_pct: float

class ApexTestingAccelerator:
    def sample_thompson(self, variants: List[AdVariant]) -> AllocationResult:
        # Sample beta distribution for each variant: Beta(conversions + 1, impressions - conversions + 1)
        scores = {}
        for v in variants:
            alpha = v.conversions + 1
            beta = max(1, v.impressions - v.conversions + 1)
            # Simulated posterior draw
            draw = random.betavariate(alpha, beta)
            scores[v.variant_id] = draw

        winner = max(scores, key=scores.get)
        return AllocationResult(selected_winner=winner, budget_share_pct=75.0)