#!/bin/sh
#
# Check that watching a process's file descriptors works as expected when
# given multiple arguments.

# Allow all tests to be skipped, e.g. during a release build
test "${SKIP_ALL_TESTS}" = "1" && exit 77

true "${testSubject:?not set - call this from 'make check'}"
true "${workFile1:?not set - call this from 'make check'}"
true "${workFile2:?not set - call this from 'make check'}"
true "${workFile3:?not set - call this from 'make check'}"
true "${workFile4:?not set - call this from 'make check'}"

# Skip the test if "-d" is not available.
if ! "${testSubject}" -h | grep -Fq ' -d'; then
	echo "no \`--watchfd' / \`-d' option on this platform"
	exit 77
fi

seq 1 100 > "${workFile1}"
seq 1 300 > "${workFile2}"

# Run two background processes to perform a few reads from a file.
#
# Each one only starts doing anything once the PV process below has started
# (the workFile3 check).
true > "${workFile3}"
(
while test -e "${workFile3}" && ! test -s "${workFile3}"; do sleep 0.1; done
sleep 1
# shellcheck disable=SC2034 # line is deliberately unused
read -r line <&8
sleep 1
) <&- 8<"${workFile1}" &
pid1=$!

(
while test -e "${workFile3}" && ! test -s "${workFile3}"; do sleep 0.1; done
sleep 1
# shellcheck disable=SC2034 # line is deliberately unused
read -r line <&9
sleep 1
) <&- 9<"${workFile2}" &
pid2=$!

sleep 0.1
"${testSubject}" -P "${workFile3}" -f -i 0.5 -d "${pid1}" "${pid2}" >/dev/null 2>"${workFile4}"

# Skip the test if "-d" does not work.
if grep -Fq ' -d: not available' "${workFile4}"; then
	echo "no \`--watchfd' / \`-d' option on this platform"
	exit 77
fi

# Process the output to make it easier to handle.
# NB "ESC [ A" is "cursor up", we turn that into "-" and a newline.
tr '\r' '\n' < "${workFile4}" | sed 's/.\[A/-!/g' | tr '!' '\n' > "${workFile1}"

# We should see at least 2 file positions for fd 8.
positionsReported="$(awk '/^[0-9 ]+: *8:/ {print $3}' < "${workFile1}" | sort -n | uniq)"
differentNumbers="$(printf "%s\n" "${positionsReported}" | grep -Ec .)"
if ! test "${differentNumbers}" -gt 1; then
	printf "%s\n" "Expected at least 2 different numbers to be output for fd 8"
	printf "%s:\n%s\n" "Positions reported" "${positionsReported}"
	printf "%s: %s\n" "Number of different values seen" "${differentNumbers}"
	printf "%s\n" "Raw output:"
	cat "${workFile1}"
	exit 1
fi

# We should see at least 2 file positions for fd 9.
positionsReported="$(awk '/^[0-9 ]+: *9:/ {print $3}' < "${workFile1}" | sort -n | uniq)"
differentNumbers="$(printf "%s\n" "${positionsReported}" | grep -Ec .)"
if ! test "${differentNumbers}" -gt 1; then
	printf "%s\n" "Expected at least 2 different numbers to be output for fd 9"
	printf "%s:\n%s\n" "Positions reported" "${positionsReported}"
	printf "%s: %s\n" "Number of different values seen" "${differentNumbers}"
	printf "%s\n" "Raw output:"
	cat "${workFile1}"
	exit 1
fi

# We should see the last 6 characters of fd 8's filename appear.
lastChars="$(printf "%s\n" "${workFile1}" | rev | cut -b1-6 | rev)"
if ! grep -Fq "${lastChars}:" < "${workFile1}"; then
	printf "%s\n" "Expected to see a filename for fd 8"
	printf "%s\n" "Raw output:"
	cat "${workFile1}"
	exit 1
fi
# We should see the last 6 characters of fd 9's filename appear.
lastChars="$(printf "%s\n" "${workFile2}" | rev | cut -b1-6 | rev)"
if ! grep -Fq "${lastChars}:" < "${workFile1}"; then
	printf "%s\n" "Expected to see a filename for fd 9"
	printf "%s\n" "Raw output:"
	cat "${workFile1}"
	exit 1
fi

exit 0