test(calendar): regression oracle vs calapi 2020-2040 (0 season mismatches)

Caught + fixed an Advent-start bug: anchor on Christmas Eve, not Dec 25, so
years where Dec 25 is a Sunday don't lose the first week of Advent. Rank-class
diffs (324) are informational — the initial sanctoral dataset is partial.

1 files changed, 35 insertions, 0 deletions

diff --git a/scripts/build-oracle.sh b/scripts/build-oracle.sh
new file mode 100755
index 0000000..2d5b329
--- /dev/null
+++ b/scripts/build-oracle.sh
@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# build-oracle.sh — generate the regression oracle snapshot for the calendar
+# engine by fetching the authoritative General Roman Calendar from calapi
+# (calendarium-romanum) month by month, 2020-2040.
+#
+# NOT run by `go test`. Requires network + curl + jq. Run from the repo root:
+#   scripts/build-oracle.sh
+# Writes internal/calendar/testdata/oracle-2020-2040.json as
+#   { "YYYY-MM-DD": {"season": "...", "rank_num": N.N}, ... }
+# where season/rank_num are the top celebration's (celebrations[0]).
+set -euo pipefail
+
+base="http://calapi.inadiutorium.cz/api/v0/en/calendars/general-en"
+out="internal/calendar/testdata/oracle-2020-2040.json"
+mkdir -p "$(dirname "$out")"
+tmp="$(mktemp)"
+
+echo "{" > "$tmp"
+first=1
+for y in $(seq 2020 2040); do
+  for m in $(seq 1 12); do
+    month_json="$(curl -sf "$base/$y/$m")"
+    # emit  "date": {"season":..., "rank_num":...}  for each day, comma-separated
+    rows="$(printf '%s' "$month_json" | jq -r '.[] | "\(.date)\t\(.season)\t\(.celebrations[0].rank_num)"')"
+    while IFS=$'\t' read -r date season rank; do
+      [ -n "$date" ] || continue
+      if [ "$first" -eq 1 ]; then first=0; else printf ",\n" >> "$tmp"; fi
+      printf '  "%s": {"season": "%s", "rank_num": %s}' "$date" "$season" "$rank" >> "$tmp"
+    done <<< "$rows"
+  done
+  echo "  ...$y done" >&2
+done
+printf "\n}\n" >> "$tmp"
+mv "$tmp" "$out"
+echo "wrote $out" >&2