#!/usr/bin/env bash
# OpenAPI compatibility check (M3): fails when the current spec is not backwards
# compatible with the one at the last m*/v* tag: removed route or method, removed
# response field, changed field type, new required request param/field, removed
# enum value. Tags that predate openapi.json pass with a note.
#
#   scripts/openapi-check.sh                 spec from `nmon openapi`, else ./openapi.json
#   OPENAPI_NEW=file.json scripts/openapi-check.sh   compare this file instead
#   OPENAPI_BASE_TAG=m2 ...                  compare against this tag instead of the latest
# Needs: go, git.
set -uo pipefail
ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
cd "$ROOT"
TMP="$(mktemp -d)"
trap 'rm -rf "$TMP"' EXIT

NEW="${OPENAPI_NEW:-}"
if [ -z "$NEW" ]; then
	if go run ./cmd/nmon openapi >"$TMP/new.json" 2>"$TMP/gen.err" && [ -s "$TMP/new.json" ]; then
		NEW="$TMP/new.json"
	elif [ -f openapi.json ]; then
		echo "note: 'nmon openapi' unavailable; using openapi.json"
		NEW=openapi.json
	else
		echo "FAIL: no openapi spec (nmon openapi failed and openapi.json is missing)"; cat "$TMP/gen.err"; exit 1
	fi
fi

# Latest m*/v* tag by version order (m2 < m10 < v1.0.0 is not assumed; the newest by tag date wins).
TAG="${OPENAPI_BASE_TAG:-$(git tag --list 'm*' 'v*' --sort=-creatordate 2>/dev/null | head -n 1)}"
if [ -z "$TAG" ]; then
	echo "openapi-check: PASS (no m*/v* tag to compare against)"; exit 0
fi
if ! git show "$TAG:openapi.json" >"$TMP/old.json" 2>/dev/null; then
	echo "openapi-check: PASS (note: $TAG has no openapi.json yet, nothing to compare against)"; exit 0
fi

if go run ./internal/openapidiff/cmd/openapidiff "$TMP/old.json" "$NEW"; then
	echo "openapi-check: PASS (compatible with $TAG)"
else
	echo "openapi-check: FAIL (incompatible with $TAG)"; exit 1
fi