#!/usr/bin/env bash
# Test: cached file remains readable after network goes down
#
# Verifies that once a file has been pulled into the VFS cache, it can
# be read even when the connection to the remote NAS is severed.
set -euo pipefail
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
source "$SCRIPT_DIR/../harness/helpers.sh"
source "$SCRIPT_DIR/../harness/mock-nas.sh"

require_root
setup_test_env
trap teardown_test_env EXIT

# Start mock NAS and create a 1 MB test file
start_mock_nas
nas_create_file "landscape.jpg" 1024

# Generate default config
gen_config

# Start warpgate and wait for readiness
start_warpgate
wait_for_mount
wait_for_rc_api

# Read the file through the FUSE mount to cache it
cat "$TEST_MOUNT/landscape.jpg" > /dev/null
assert_cached "landscape.jpg"

# Save a checksum for verification after network goes down
expected_cksum=$(md5sum "$TEST_MOUNT/landscape.jpg" | awk '{print $1}')

# Sever the network link to the mock NAS
inject_network_down

# Read the file again — should succeed from local cache.
# Time the read and verify it completes quickly (< 2 seconds for 1 MB).
read_start=$SECONDS
actual_cksum=$(md5sum "$TEST_MOUNT/landscape.jpg" | awk '{print $1}')
read_elapsed=$(( SECONDS - read_start ))

if [[ "$actual_cksum" != "$expected_cksum" ]]; then
    echo "FAIL: checksum mismatch after network down" >&2
    echo "  expected: $expected_cksum" >&2
    echo "  actual:   $actual_cksum" >&2
    inject_network_up
    exit 1
fi

if [[ "$read_elapsed" -gt 2 ]]; then
    echo "FAIL: offline cache read took ${read_elapsed}s (expected < 2s for 1 MB)" >&2
    inject_network_up
    exit 1
fi

# Restore the network
inject_network_up

echo "PASS: $(basename "$0" .sh)"