#!/usr/bin/env bash
# Regression test for newest_matching_file() in tools/install.sh.
#
# The function used to pipe `ls -1t` into `head -1`. Under `set -o pipefail` head
# closes the pipe after the first line, ls dies on SIGPIPE, and the function returns
# 141 with no output -- so once a directory holds enough matches to fill a pipe
# buffer (~1600 names), "find the newest backup" starts failing the install instead
# of answering. Its callers assign it at top level under `set -e`, so a 141 aborts
# the run.
#
# The large-population case is the whole point: with two or three files the old code
# passes, which is why this went unnoticed.

set -euo pipefail

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
TMP="$(mktemp -d "${TMPDIR:-/tmp}/mosaic-newest-match-test-XXXXXX")"
trap 'rm -rf "$TMP"' EXIT

# Load just the function under test, with the same shell options install.sh runs under.
eval "$(sed -n '/^newest_matching_file()/,/^}/p' "$ROOT/tools/install.sh")"

POPULATED="$TMP/many"
mkdir -p "$POPULATED"
# Enough names to overflow a 64 KiB pipe buffer several times over.
for i in $(seq 1 5000); do
  : > "$POPULATED/mosaicstack-mosaic-0.0.${i}.tgz"
done
sleep 1
: > "$POPULATED/mosaicstack-mosaic-9.9.9.tgz"

echo "[test] the newest match is returned from a directory large enough to fill a pipe"
GOT="$(newest_matching_file "$POPULATED" 'mosaicstack-mosaic-*.tgz')"
[[ "$(basename "$GOT")" == "mosaicstack-mosaic-9.9.9.tgz" ]] || {
  echo "expected the newest tarball, got '${GOT}'" >&2
  exit 1
}

echo "[test] a large population does not make the lookup fail"
set +e
newest_matching_file "$POPULATED" 'mosaicstack-mosaic-*.tgz' >/dev/null
RC=$?
set -e
[[ "$RC" -eq 0 ]] || { echo "expected rc=0, got ${RC} (141 means the SIGPIPE regression is back)" >&2; exit 1; }

echo "[test] a small population still works"
SMALL="$TMP/few"
mkdir -p "$SMALL"
: > "$SMALL/mosaicstack-gateway-0.0.1.tgz"
sleep 1
: > "$SMALL/mosaicstack-gateway-0.0.2.tgz"
GOT="$(newest_matching_file "$SMALL" 'mosaicstack-gateway-*.tgz')"
[[ "$(basename "$GOT")" == "mosaicstack-gateway-0.0.2.tgz" ]] || {
  echo "expected the newer gateway tarball, got '${GOT}'" >&2
  exit 1
}

echo "[test] no match is an empty answer, not an error"
EMPTY="$TMP/none"
mkdir -p "$EMPTY"
set +e
GOT="$(newest_matching_file "$EMPTY" 'nothing-*.tgz')"
RC=$?
set -e
[[ "$RC" -eq 0 && -z "$GOT" ]] || { echo "expected empty output and rc=0, got '${GOT}' rc=${RC}" >&2; exit 1; }

echo "[test] a directory that does not exist is an empty answer, not an error"
set +e
GOT="$(newest_matching_file "$TMP/absent" 'nothing-*.tgz')"
RC=$?
set -e
[[ "$RC" -eq 0 && -z "$GOT" ]] || { echo "expected empty output and rc=0, got '${GOT}' rc=${RC}" >&2; exit 1; }

echo "[test] newest_matching_file tests passed"