. "$BST_LIB"
require ifup ifupdown/present

# ifupdown ships ifup and ifdown (a hard link to the same binary, dispatching on
# argv[0]) plus the interfaces(5) parser. Everything below drives a sample
# interfaces file in a scratch dir via -i, with --state-dir pointing at that same
# scratch dir, so the suite never reads or writes the live /etc/network/interfaces
# or /run/network/ifstate. --no-scripts keeps the /etc/network/if-*.d hooks out:
# run-parts hooks are not part of what this port delivers, and a hook that resolves
# a hostname would trap in static-glibc __nss_module_load (BRINTOS-77).

tmp=${TMPDIR:-/tmp}/bst-ifupdown.$$
mkdir -p "$tmp"
cfg="$tmp/interfaces"
IF="ifup -i $cfg --state-dir $tmp --no-scripts"
ID="ifdown -i $cfg --state-dir $tmp --no-scripts"

cat > "$cfg" <<'EOF'
auto lo
iface lo inet loopback

allow-hotplug bst0
iface bst0 inet static
	address 10.99.0.1
	netmask 255.255.255.0
EOF

command -v ifdown >/dev/null 2>&1 \
  && bst_ok ifupdown/ifdown-present \
  || bst_notok ifupdown/ifdown-present "ifdown missing (recipe installs it as a hard link to ifup)"

# `ifup -V` prints "<argv0> version <PV>" -- the binary names itself, not the
# package, so the needle is "ifup version" and not "ifupdown".
check_out ifupdown/version "ifup version" sh -c 'ifup -V 2>&1'

# --- interfaces(5) parsing, via the dry run (-n) -----------------------------
# With -n, execute.c prints each command it *would* run to stderr and runs
# nothing, so this asserts the parse and the address->command conversion without
# needing the interface to exist.
check    ifupdown/parse-dryrun  sh -c "$IF -n bst0 >/dev/null 2>&1"
check_out ifupdown/dryrun-addr  "10.99.0.1"            sh -c "$IF -n bst0 2>&1"
check_out ifupdown/dryrun-mask  "10.99.0.1/255.255.255.0" sh -c "$IF -n bst0 2>&1"
check_out ifupdown/dryrun-link  "ip link set dev bst0" sh -c "$IF -n bst0 2>&1"
# The static `down` sequence flushes and downs the link.
check_out ifupdown/dryrun-down  "ip addr del"          sh -c "$ID -n bst0 2>&1"

# An interface with no stanza is an error, not a silent success.
check_rc ifupdown/unknown-iface 1 sh -c "$IF -n nosuchif0 >/dev/null 2>&1"

# A malformed stanza must fail the parse rather than be skipped.
bad="$tmp/interfaces.bad"
printf 'iface bst9 inet static\n\taddress\n' > "$bad"
check_rc ifupdown/parse-error 1 \
  sh -c "ifup -i $bad --state-dir $tmp --no-scripts -n bst9 >/dev/null 2>&1"

# --- real state transitions (not a dry run) ---------------------------------
# `iface lo inet loopback` is the one stanza whose up/down commands are guarded
# by `if (!iface_is_lo())`, so ifup/ifdown on lo run NO kernel command while still
# taking the full real path: fcntl(F_SETLKW) on the state lock, and the
# read/modify/write of ifstate. That makes it a safe on-target exercise of the
# machinery the dry run skips.
check ifupdown/state-up sh -c "$IF lo >/dev/null 2>&1"
check_out ifupdown/state-file "lo=lo" sh -c "cat $tmp/ifstate 2>&1"
# A second ifup is a no-op that says so (rc is non-zero; the message is the point).
check_out ifupdown/state-already "already configured" sh -c "$IF lo 2>&1 || true"
check ifupdown/state-down sh -c "$ID lo >/dev/null 2>&1"
check ifupdown/state-cleared sh -c "! grep -q '^lo=' $tmp/ifstate 2>/dev/null"

# --- dummy interface, up then down ------------------------------------------
# The ticket's deliverable: bring a real interface up from the interfaces file
# and back down, checking the address lands and is withdrawn. Needs `ip` and a
# kernel that can create a dummy link; both are probed, and a kernel without
# dummy support is reported as skip (a coverage gap to close) rather than a
# failure of ifupdown.
if ! command -v ip >/dev/null 2>&1; then
	bst_skip ifupdown/dummy-up   "iproute2 ip not installed on this image"
	bst_skip ifupdown/dummy-down "iproute2 ip not installed on this image"
elif ! ip link add bst0 type dummy >/dev/null 2>&1; then
	bst_skip ifupdown/dummy-up   "kernel cannot create a dummy link (no CONFIG_DUMMY)"
	bst_skip ifupdown/dummy-down "kernel cannot create a dummy link (no CONFIG_DUMMY)"
else
	check_out ifupdown/dummy-up "10.99.0.1" \
	  sh -c "$IF bst0 >/dev/null 2>&1; ip -4 addr show dev bst0 2>&1"
	check ifupdown/dummy-down \
	  sh -c "$ID bst0 >/dev/null 2>&1; ! ip -4 addr show dev bst0 2>/dev/null | grep -q 10.99.0.1"
	ip link del bst0 >/dev/null 2>&1
fi

rm -rf "$tmp"