"""
Trunk Stability Push-Up rubric scorer — pure function, no model calls.

FMS Trunk Stability Push-Up Criteria:
- Score 3: body moves as one unit (rigid) with hands at forehead level (men)
           or chin level (women). No sag or segment lag.
- Score 2: body moves as one unit but with hands at chin (men) or clavicle (women).
- Score 1: unable to perform with hands lowered; body sags or segments.
- Score 0: PAIN (spinal extension clearing test) — never auto-scored.
"""
from __future__ import annotations

from formscout.types import BiomechFeatures, ScoreResult


def score_trunk_stability_pushup(features: BiomechFeatures) -> ScoreResult:
    """Pure rubric scorer for trunk stability push-up."""
    angles = features.angles
    alignments = features.alignments

    has_data = "max_sag_px" in angles
    if not has_data:
        return ScoreResult(
            score=1, rationale="Insufficient data: trunk rigidity not measurable",
            confidence=0.3, notes="missing key measurements",
        )

    body_rigid = alignments.get("body_rigid", False)
    no_sag = alignments.get("no_sag", False)
    hands_high = alignments.get("hands_at_forehead", False)

    rationale_parts = []

    if body_rigid and hands_high:
        score = 3
        rationale_parts.append("Body rigid as one unit, hands at forehead position")
    elif body_rigid or no_sag:
        score = 2
        if not hands_high:
            rationale_parts.append("rigid body but hands in lower position")
        else:
            rationale_parts.append("minor trunk variance detected")
        rationale_parts.insert(0, "Completed with regression")
    else:
        score = 1
        sag = angles.get("max_sag_px", 0)
        variance = angles.get("trunk_variance_px", 0)
        rationale_parts.append(f"Body sag detected ({sag:.0f}px), variance {variance:.1f}px")

    confidence = features.confidence * 0.8

    return ScoreResult(
        score=score, rationale="; ".join(rationale_parts),
        confidence=confidence, notes="",
    )