#!/bin/bash

set -euo pipefail

if [[ $# -ne 1 ]]; then
   echo "$0 {slash}"
   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 and check output.
function run_test
{
   "$TOOL" "$2" < "$TEST_DIR/input.txt" > "$TEST_DIR/actual.txt" \
      || die "$LINENO: $1 (run)"

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


# Check help message.
"$TOOL" > "$TEST_DIR/help.txt" && die "$LINENO: unexpected success"
grep -qF "line_number" "$TEST_DIR/help.txt" \
   || die "$LINENO: missing help message"

# Test empty input.
touch "$TEST_DIR/input.txt"
touch "$TEST_DIR/expected.txt"
run_test "$LINENO: empty input 0" 0
run_test "$LINENO: empty input 1" 1
run_test "$LINENO: empty input 2" 2
run_test "$LINENO: empty input -1" -1
run_test "$LINENO: empty input -2" -2

# Slash specific lines (positive).
seq 10 > "$TEST_DIR/input.txt"
sed -e "1d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: slash 1" 1
sed -e "5d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: slash 5" 5
sed -e "10d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: slash 10" 10

# Slash specific lines (negative).
sed -e "10d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: slash -1" -1
sed -e "6d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: slash -5" -5
sed -e "1d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: slash -10" -10

# Slash outside of available range.
cp -f "$TEST_DIR/input.txt" "$TEST_DIR/expected.txt"
run_test "$LINENO: slash 11" 11
run_test "$LINENO: slash 999" 999
run_test "$LINENO: slash -11" -11
run_test "$LINENO: slash -999" -999

# Try consecutive blank lines.
perl -e 'print "\n" x 10' > "$TEST_DIR/input.txt"
head -9 "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: slash consecutive blanks 1" 1
run_test "$LINENO: slash consecutive blanks 5" 5
run_test "$LINENO: slash consecutive blanks 10" 10
run_test "$LINENO: slash consecutive blanks -1" -1
run_test "$LINENO: slash consecutive blanks -5" -5
run_test "$LINENO: slash consecutive blanks -10" -10

# Try file with missing newline at the end.
echo -e -n "hoge\npiyo\nfuga" > "$TEST_DIR/input.txt"
echo -e -n "piyo\nfuga" > "$TEST_DIR/expected.txt"
run_test "$LINENO: truncated 1" 1
run_test "$LINENO: truncated -3" -3
echo -e -n "hoge\nfuga" > "$TEST_DIR/expected.txt"
run_test "$LINENO: truncated 2" 2
run_test "$LINENO: truncated -2" -2
echo -e -n "hoge\npiyo\n" > "$TEST_DIR/expected.txt"
run_test "$LINENO: truncated 3" 3
run_test "$LINENO: truncated -1" -1

# Try a larger input file.
perl <<'EOT' > "$TEST_DIR/input.txt"
srand(1);
for($i = 0; $i < 20; $i++)
{
   for($j = int(rand(4096) + 256); $j > 0; $j--)
   {
      print chr(int(rand(95) + 32));
   }
   print "\n";
}
EOT
sed -e "1d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large 1" 1
sed -e "2d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large 2" 2
sed -e "10d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large 10" 10
sed -e "19d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large 19" 19
sed -e "20d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large 20" 20
cp -f "$TEST_DIR/input.txt" "$TEST_DIR/expected.txt"
run_test "$LINENO: large 100" 100

sed -e "20d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large -1" -1
sed -e "19d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large -2" -2
sed -e "11d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large -10" -10
sed -e "2d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large -19" -19
sed -e "1d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large -20" -20
cp -f "$TEST_DIR/input.txt" "$TEST_DIR/expected.txt"
run_test "$LINENO: large -100" -100

rm -rf "$TEST_DIR"
exit 0