from __future__ import annotations

from decimal import Decimal

from .models import EconomicsSnapshot
from .usage import build_usage_summary


def build_cost_allocation(
    snapshot: EconomicsSnapshot,
    usage_records: list[dict],
) -> dict:
    usage = build_usage_summary(usage_records, snapshot.period)
    variable_ai = usage["total_ai_spend_eur"]
    fixed = snapshot.monthly_infrastructure_cost
    variable_processing = snapshot.monthly_payment_processing_cost
    total = fixed + variable_processing + variable_ai
    contribution = snapshot.monthly_revenue - total

    return {
        "period": snapshot.period,
        "currency": snapshot.currency,
        "fixed_costs_eur": fixed,
        "variable_processing_eur": variable_processing,
        "variable_ai_eur": variable_ai,
        "total_platform_cost_eur": total,
        "cost_floor_eur": snapshot.cost_per_member,
        "contribution_margin_eur": contribution,
        "contribution_margin_pct": snapshot.gross_margin_pct,
        "cost_per_member_eur": snapshot.cost_per_member,
        "active_members": snapshot.active_members,
    }