#!/usr/bin/env bash
# Enforce the coverage ratchet: total statement coverage must not regress
# below a floor.
#
# This is a regression GUARD, not a vanity target -- deleting a covered test
# or adding uncovered code below the floor fails CI. The floor sits just below
# the measured current total (with a small noise margin) and is raised as the
# foundation test net grows; never chase the number for its own sake.
#
# Reads coverage.out (produced by `make cover`) and compares its total against
# FLOOR below. awk does the float compare so there is no `bc` dependency.
#
# Run locally: make cover-check   (or: make cover && bash scripts/check-coverage.sh)
# CI: the `coverage` step in .github/workflows/ci.yml runs `make cover-check`.
set -euo pipefail

# Ratchet floor, not a target. Raised 80 -> 83 at H1 close (measured total
# 84.8%); raise again as the net grows -- keep it below total with a margin.
FLOOR=83

ROOT="$(cd "$(dirname "$0")/.." && pwd)"
PROFILE="$ROOT/coverage.out"

if [ ! -f "$PROFILE" ]; then
  echo "check-coverage: $PROFILE not found -- run \`make cover\` first" >&2
  exit 1
fi

total="$(go tool cover -func="$PROFILE" | awk '/^total:/ {print $NF}' | tr -d '%')"
if [ -z "$total" ]; then
  echo "check-coverage: could not parse total coverage from $PROFILE" >&2
  exit 1
fi

if ! awk -v t="$total" -v f="$FLOOR" 'BEGIN { exit !(t+0 >= f+0) }'; then
  echo "check-coverage: total ${total}% is below floor ${FLOOR}% -- add tests or justify" >&2
  exit 1
fi

echo "check-coverage: total ${total}% >= floor ${FLOOR}% -- ratchet holds"