#!/bin/bash

set -euo pipefail

if [[ $# -ne 1 ]]; then
   echo "$0 {bf}"
   exit 1
fi
TOOL=$1
TEST_DIR=$(mktemp -d)

# Delete temporary directory and exit with nonzero status.
function die
{
   echo "$1"
   rm -rf "$TEST_DIR"
   exit 1
}

# Run tool against input file and compare against expected output.
function run_test
{
   "$TOOL" "$TEST_DIR/code.txt" "$TEST_DIR/input.txt" > "$TEST_DIR/actual.txt" \
      || die "$1 (file, run)"

   diff -q "$TEST_DIR/expected.txt" "$TEST_DIR/actual.txt" \
      || die "$1 (file, diff)"

   "$TOOL" - "$TEST_DIR/input.txt" < "$TEST_DIR/code.txt" \
      > "$TEST_DIR/actual.txt" \
      || die "$1 (stdin, run)"

   diff -q "$TEST_DIR/expected.txt" "$TEST_DIR/actual.txt" \
      || die "$1 (stdin, diff)"
}

# Check for error conditions.
function run_error_test
{
   "$TOOL" "$TEST_DIR/code.txt" > "$TEST_DIR/error.txt" 2>&1 \
      && die "$1 (unexpected success)"

   grep -qF "$2" "$TEST_DIR/error.txt" || die "$1 (missing error message)"
}


# Try reading nonexistent files.
run_error_test "$LINENO: nonexistent code" "Error loading program"

touch "$TEST_DIR/code.txt"
"$TOOL" "$TEST_DIR/code.txt" "$TEST_DIR/no_such_file.txt" \
   > "$TEST_DIR/error.txt" 2>&1 \
   && die "$LINENO: nonexistent data (unexpected success)"
grep -qF "Error opening" "$TEST_DIR/error.txt" \
   || die "$LINENO: nonexistent data (missing error message)"

# Try empty input.
touch "$TEST_DIR/input.txt"
touch "$TEST_DIR/expected.txt"
run_test "$LINENO: empty"

# Try successful cases.
echo "+++++ +++++ +++++ +++++ +++++ +++++ +++." > "$TEST_DIR/code.txt"
echo -n "!" > "$TEST_DIR/expected.txt"
run_test "$LINENO: output"

echo "+++++ +++++ +++++ +++++ +++++ +++++ +++ >++[<.>-]" > "$TEST_DIR/code.txt"
echo -n "!!" > "$TEST_DIR/expected.txt"
run_test "$LINENO: loop"

echo "++++[>++++[>++++<-]<-]>>+." > "$TEST_DIR/code.txt"
echo -n "A" > "$TEST_DIR/expected.txt"
run_test "$LINENO: nested loop"

perl -e 'print ">" x 9999, "+" x 65, "."' > "$TEST_DIR/code.txt"
run_test "$LINENO: large tape"

echo "[+.]>[+[.]] >>++--[+.]--++[+.]" > "$TEST_DIR/code.txt"
echo -n "" > "$TEST_DIR/expected.txt"
run_test "$LINENO: skip block"

echo "<<>> ++++ ++++[>++++<-] >+ >><< ." > "$TEST_DIR/code.txt"
echo -n "!" > "$TEST_DIR/expected.txt"
run_test "$LINENO: lazy bounds check"

echo ",+[-.,+]" > "$TEST_DIR/code.txt"
echo "copy" > "$TEST_DIR/input.txt"
echo "copy" > "$TEST_DIR/expected.txt"
run_test "$LINENO: read input"

# Try failure cases.
echo "[" > "$TEST_DIR/code.txt"
run_error_test "$LINENO: unmatched ]" "Unmatched ["

echo "]" > "$TEST_DIR/code.txt"
run_error_test "$LINENO: unmatched ]" "Unmatched ]"

echo "<+" > "$TEST_DIR/code.txt"
run_error_test "$LINENO: operating on negative address" "negative address"

echo "<." > "$TEST_DIR/code.txt"
run_error_test "$LINENO: output from negative address" "negative address"

echo "." > "$TEST_DIR/code.txt"
run_error_test "$LINENO: uninitialized output (empty)" "uninitialized"

echo "+>." > "$TEST_DIR/code.txt"
run_error_test "$LINENO: uninitialized output (out of bounds)" "uninitialized"

rm -rf "$TEST_DIR"
exit 0