#!/usr/bin/env bash
# Suramadu compresses nothing on the fly - AbstractResourceHandler serves a
# precompressed sibling when one is already next to the file, and the plain file
# otherwise. So a missing sibling is not a slow path, it is an uncompressed one,
# and the only thing standing between our webFolder and ~70KB on every cold load
# is that these files get written at build time.
#
# What is checked: the siblings appear, they are smaller than their source, a
# file that does not compress gets none rather than a bigger one, and the
# already-compressed assets are left alone.
set -uo pipefail

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
SCRIPT="$ROOT/suramadu/precompress-web.sh"
TMP="$(mktemp -d)"
trap 'rm -rf "$TMP"' EXIT

fail=0
check() { if "${@:2}"; then echo "ok    $1"; else echo "FAIL  $1"; fail=1; fi; }
not() { ! "$@"; }

[ -x "$SCRIPT" ] || { echo "FAIL  $SCRIPT is missing or not executable"; exit 1; }
for tool in gzip brotli; do
  command -v "$tool" >/dev/null || {
    echo "SKIP  test-precompress-web: no $tool in this environment"; exit 0; }
done

W="$TMP/web"
mkdir -p "$W/fonts"
# Compressible, and long enough that the gzip header cannot eat the win.
rep() { local i; for ((i = 0; i < 400; i++)); do printf '%s\n' "$2"; done > "$1"; }
rep "$W/big.js"    'function hexIsVisible(a,b){return a===b;}'
rep "$W/big.css"   '.hex { color: #4c8dff; }'
rep "$W/page.html" '<p>lorem hex</p>'
# Incompressible, in a file the extension list matches: random bytes, so the
# sibling comes out bigger than the source and has to be dropped.
head -c 4096 /dev/urandom > "$W/noise.svg"
# Already compressed, and not in the extension list either.
head -c 4096 /dev/urandom > "$W/fonts/a.woff2"

DIR="$W" bash "$SCRIPT" > "$TMP/out" 2>&1
check "the script succeeds" test $? -eq 0

for f in big.js big.css page.html; do
  check "$f gets a .gz" test -f "$W/$f.gz"
  check "$f gets a .br" test -f "$W/$f.br"
  check "$f.gz is smaller than $f" \
    bash -c '[ "$(wc -c < "$1.gz")" -lt "$(wc -c < "$1")" ]' _ "$W/$f"
  check "$f.br is smaller than $f" \
    bash -c '[ "$(wc -c < "$1.br")" -lt "$(wc -c < "$1")" ]' _ "$W/$f"
done

# A sibling the handler would serve to send *more* bytes than the plain file is
# worse than none, so it is deleted rather than shipped.
check "an incompressible file gets no .gz" not test -f "$W/noise.svg.gz"
check "an incompressible file gets no .br" not test -f "$W/noise.svg.br"

# woff2 is already compressed and is not in the extension list; a .gz of it
# would be bigger than the font.
check "fonts are left alone" not test -f "$W/fonts/a.woff2.gz"

# Running twice must not compound - siblings are rebuilt from the source, and
# are never themselves treated as input.
before="$(wc -c < "$W/big.js.gz")"
DIR="$W" bash "$SCRIPT" >/dev/null 2>&1
check "a second run is idempotent" test "$(wc -c < "$W/big.js.gz")" -eq "$before"
check "siblings are not compressed again" not test -f "$W/big.js.gz.gz"

check "it reports what it did" grep -q "precompressed 4 file(s)" "$TMP/out"

# An empty directory is a build that silently shipped nothing.
mkdir -p "$TMP/empty"
DIR="$TMP/empty" bash "$SCRIPT" >/dev/null 2>&1
check "an empty web folder fails the build" test $? -ne 0

exit "$fail"