"""
Median computation for vote parameters.

Computes the element-wise median of (vinf, a, b, c, d, e) across all active votes.
This parametric median is chosen over geometric median because:
- It's transparent and politically explainable
- The result is itself a valid set of Bézier parameters
"""

import numpy as np
from dataclasses import dataclass


@dataclass
class VoteParams:
    """The 6 citizen-adjustable parameters."""
    vinf: float
    a: float
    b: float
    c: float
    d: float
    e: float


def compute_median(votes: list[VoteParams]) -> VoteParams | None:
    """
    Compute element-wise median of vote parameters.

    Returns None if no votes provided.
    """
    if not votes:
        return None

    vinfs = [v.vinf for v in votes]
    a_s = [v.a for v in votes]
    b_s = [v.b for v in votes]
    c_s = [v.c for v in votes]
    d_s = [v.d for v in votes]
    e_s = [v.e for v in votes]

    return VoteParams(
        vinf=float(np.median(vinfs)),
        a=float(np.median(a_s)),
        b=float(np.median(b_s)),
        c=float(np.median(c_s)),
        d=float(np.median(d_s)),
        e=float(np.median(e_s)),
    )