#!/usr/bin/env bash
# test_nginx_cache.sh — verify the phase-1 edge cache actually caches.
#
# Sequence :
#   1. Pre-flight : nginx-cache reachable + /health returns 200.
#   2. Curl a fixed URL twice. First request must be MISS, second
#      must be HIT. Surfaces via the X-Cache-Status response header.
#   3. Verify the cache directory has at least one entry on disk.
#
# Run on the Incus host that owns the nginx-cache container, OR
# from a workstation that can reach nginx-cache.lxd:80. The test
# uses a public bucket path so it doesn't need MinIO credentials.
#
# v1.0.9 — phase-1 edge cache acceptance.
#
# Usage:
#   TEST_URL=http://nginx-cache.lxd/some-public-object.m4s \
#     bash infra/ansible/tests/test_nginx_cache.sh
#
# Exit codes :
#   0  — cache is working (MISS then HIT)
#   1  — cache not reachable
#   2  — second request did not return HIT
#   3  — required tool missing
set -euo pipefail

CACHE_HOST=${CACHE_HOST:-nginx-cache.lxd}
CACHE_PORT=${CACHE_PORT:-80}
TEST_URL=${TEST_URL:-http://${CACHE_HOST}:${CACHE_PORT}/health}
RUN_VIA_INCUS=${RUN_VIA_INCUS:-0}

log()  { printf '[%s] %s\n' "$(date +%H:%M:%S)" "$*" >&2; }
fail() { log "FAIL: $*"; exit "${2:-2}"; }

require() {
  command -v "$1" >/dev/null 2>&1 || fail "required tool missing on host: $1" 3
}

require curl
require date

# helper : run curl in the right context. If RUN_VIA_INCUS=1 the
# command runs inside the host (which can resolve .lxd hostnames).
do_curl() {
  if [ "$RUN_VIA_INCUS" = "1" ]; then
    incus exec nginx-cache -- curl -sS "$@"
  else
    curl -sS "$@"
  fi
}

# -----------------------------------------------------------------------------
# 1. Pre-flight — /health is alive.
# -----------------------------------------------------------------------------
log "step 0: pre-flight — GET ${CACHE_HOST}:${CACHE_PORT}/health"
health_url="http://${CACHE_HOST}:${CACHE_PORT}/health"
if ! body=$(do_curl --max-time 5 -o /dev/null -w "%{http_code}" "$health_url" 2>&1); then
  fail "cache not reachable at $health_url" 1
fi
if [ "$body" != "200" ]; then
  fail "cache /health returned HTTP $body, want 200" 1
fi

# -----------------------------------------------------------------------------
# 2. The ${TEST_URL} dance — first MISS, second HIT.
# -----------------------------------------------------------------------------
log "step 1: first request to $TEST_URL — expect MISS"
status1=$(do_curl --max-time 10 -o /dev/null -D - "$TEST_URL" 2>&1 \
  | tr -d '\r' | awk -F': ' 'tolower($1) == "x-cache-status" {print $2}' | tr -d ' ')
log "  X-Cache-Status: $status1"
if [ -z "$status1" ]; then
  fail "first response missing X-Cache-Status header — site config not applying ?" 2
fi

# A cacheable URL with no prior entry is MISS or EXPIRED. STALE means
# the upstream is unhealthy, which is a different bug — fail loud.
case "$status1" in
  MISS|EXPIRED|REVALIDATED|BYPASS) ;;
  HIT) log "  WARN: first request already HIT (a previous run cached it)" ;;
  STALE|UPDATING) fail "origin upstream unhealthy — got STALE on cold cache" 2 ;;
  *) fail "unexpected cache status on first request: $status1" 2 ;;
esac

log "step 2: second request to $TEST_URL — expect HIT"
sleep 1  # give nginx a moment to flush the entry to disk
status2=$(do_curl --max-time 10 -o /dev/null -D - "$TEST_URL" 2>&1 \
  | tr -d '\r' | awk -F': ' 'tolower($1) == "x-cache-status" {print $2}' | tr -d ' ')
log "  X-Cache-Status: $status2"

if [ "$status2" != "HIT" ]; then
  fail "second request returned X-Cache-Status=$status2, want HIT — cache config not effective" 2
fi

# -----------------------------------------------------------------------------
# 3. On-disk verification — at least one entry under the cache root.
# -----------------------------------------------------------------------------
log "step 3: verifying cache directory has on-disk entries"
if [ "$RUN_VIA_INCUS" = "1" ]; then
  count=$(incus exec nginx-cache -- bash -c "find /var/cache/nginx/veza -type f 2>/dev/null | wc -l" || echo 0)
  log "  on-disk entries: $count"
  if [ "$count" = "0" ]; then
    fail "cache directory is empty after a HIT — unexpected" 2
  fi
fi

log "PASS: edge cache MISS→HIT roundtrip OK (status1=$status1, status2=$status2)"
exit 0