#!/usr/bin/env bash
set -euo pipefail

TEST_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
QEMU_DIR="$(cd "$TEST_DIR/.." && pwd)"
SCRATCH="$(mktemp -d "${TMPDIR:-/tmp}/busybox-fetch.XXXXXX")"
trap 'rm -rf "$SCRATCH"' EXIT

FAKE_BIN="$SCRATCH/bin"
FAKE_CURL_COUNT="$SCRATCH/curl-count"
mkdir -p "$FAKE_BIN" "$SCRATCH/qemu"
printf 'good payload' > "$SCRATCH/good"
sha256sum "$SCRATCH/good" | awk '{print $1}' > "$SCRATCH/qemu/busybox.sha256"

FAKE_CURL="$FAKE_BIN/curl"
apply_fake_curl() {
  chmod 0755 "$FAKE_CURL"
  export PATH="$FAKE_BIN:$PATH"
  export FAKE_CURL_COUNT FAKE_CURL_MODE
}

# The path is resolved at runtime from this file's location.
# shellcheck disable=SC1091
source "$QEMU_DIR/lib.sh"
QEMU_DIR="$SCRATCH/qemu"
# Read by qemu_get_busybox from the sourced helper.
# shellcheck disable=SC2034
BB_URL="https://invalid.example/busybox"

# These single-quoted lines are the literal source of the fake curl program.
# shellcheck disable=SC2016
printf '%s\n' '#!/bin/sh' \
  'count=0' \
  '[ ! -f "$FAKE_CURL_COUNT" ] || count=$(cat "$FAKE_CURL_COUNT")' \
  'count=$((count + 1))' \
  'printf "%s\n" "$count" > "$FAKE_CURL_COUNT"' \
  'out=' \
  'while [ "$#" -gt 0 ]; do' \
  '  if [ "$1" = "-o" ]; then shift; out="$1"; fi' \
  '  shift' \
  'done' \
  '[ -n "$out" ] || exit 2' \
  'if [ "$FAKE_CURL_MODE" = "flaky" ] && [ "$count" -gt 1 ]; then' \
  '  printf "good payload" > "$out"' \
  'else' \
  '  printf "bad payload" > "$out"' \
  'fi' > "$FAKE_CURL"

FAKE_CURL_MODE=flaky
apply_fake_curl
OUT="$SCRATCH/flaky" qemu_get_busybox
test "$(cat "$FAKE_CURL_COUNT")" = 2
test "$(sha256sum "$BB" | awk '{print $1}')" = "$(cat "$QEMU_DIR/busybox.sha256")"

printf '0\n' > "$FAKE_CURL_COUNT"
FAKE_CURL_MODE=bad
apply_fake_curl
if (OUT="$SCRATCH/always-bad" qemu_get_busybox) >"$SCRATCH/failure.log" 2>&1; then
  echo "FAIL: an unverified download was accepted" >&2
  exit 1
fi
test "$(cat "$FAKE_CURL_COUNT")" = 3
test ! -e "$SCRATCH/always-bad/busybox-armv7l"
grep -q 'after 3 verified attempts' "$SCRATCH/failure.log"

printf '0\n' > "$FAKE_CURL_COUNT"
mkdir -p "$SCRATCH/cached"
cp "$SCRATCH/good" "$SCRATCH/cached/busybox-armv7l"
OUT="$SCRATCH/cached" qemu_get_busybox
test "$(cat "$FAKE_CURL_COUNT")" = 0

echo "busybox fetch tests passed"