#!/bin/bash

set -euo pipefail

if [[ $# -ne 1 ]]; then
   echo "$0 {chop.rb}"
   exit 1
fi
SOURCE=$1
TEST_DIR=$(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
{
   ruby -w "$SOURCE" "$2" < "$TEST_DIR/input.txt" > "$TEST_DIR/actual.txt" \
      || die "$LINENO: $1 (pipe)"

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

   ruby -w "$SOURCE" "$2" "$TEST_DIR/input.txt" > "$TEST_DIR/actual.txt" \
      || die "$LINENO: $1 (arg1)"

   diff -q "$TEST_DIR/expected.txt" "$TEST_DIR/actual.txt" \
      || die "$LINENO: $1 (arg1 diff)"
}


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

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

# Chopping head off.
seq 10 > "$TEST_DIR/input.txt"
cp -f "$TEST_DIR/input.txt" "$TEST_DIR/expected.txt"
run_test "$LINENO: head 0" 0
seq 10 | tail -9 > "$TEST_DIR/expected.txt"
run_test "$LINENO: head 1" 1
seq 10 | tail -7 > "$TEST_DIR/expected.txt"
run_test "$LINENO: head 3" 3
echo -n "" > "$TEST_DIR/expected.txt"
run_test "$LINENO: head 10" 10
run_test "$LINENO: head 11" 11

# Chopping tail off.
cp -f "$TEST_DIR/input.txt" "$TEST_DIR/expected.txt"
seq 9 > "$TEST_DIR/expected.txt"
run_test "$LINENO: tail -1" -1
seq 7 > "$TEST_DIR/expected.txt"
run_test "$LINENO: tail -3" -3
echo -n "" > "$TEST_DIR/expected.txt"
run_test "$LINENO: tail -10" -10
run_test "$LINENO: tail -11" -11

# Try file without trailing newline.
echo -n -e "hoge\npiyo\nfuga" > "$TEST_DIR/input.txt"
cp -f "$TEST_DIR/input.txt" "$TEST_DIR/expected.txt"
run_test "$LINENO: missing end of line 0" 0
echo -n -e "piyo\nfuga" > "$TEST_DIR/expected.txt"
run_test "$LINENO: missing end of line 1" 1
echo -n "fuga" > "$TEST_DIR/expected.txt"
run_test "$LINENO: missing end of line 2" 2
echo -n "" > "$TEST_DIR/expected.txt"
run_test "$LINENO: missing end of line 3" 3
echo -n -e "hoge\npiyo\n" > "$TEST_DIR/expected.txt"
run_test "$LINENO: missing end of line -1" -1
echo -n -e "hoge\n" > "$TEST_DIR/expected.txt"
run_test "$LINENO: missing end of line -2" -2
echo -n "" > "$TEST_DIR/expected.txt"
run_test "$LINENO: missing end of line -3" -3

# Try a larger input file.
ruby <<'EOT' > "$TEST_DIR/input.txt"
srand(1)
20.times{
   (rand(4096) + 256).times{
      print((rand(95) + 32).chr)
   }
   print "\n"
}
EOT

cp -f "$TEST_DIR/input.txt" "$TEST_DIR/expected.txt"
run_test "$LINENO: large 0" 0
sed -e "1d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large 1" 1
sed -e "1,3d" "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large 3" 3
head -19 "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large -1" -1
head -17 "$TEST_DIR/input.txt" > "$TEST_DIR/expected.txt"
run_test "$LINENO: large -3" -3

rm -rf "$TEST_DIR"
exit 0