#!/bin/bash
#ensure we always start a "log" with the PID of this script
echo $$

set -euo pipefail

# Config
USER_ID=$(id -u)
SCRIPT_PID=$$
TIMESTAMP=$(date +"%Y%m%dT%H%M")
TEMPBASE="/tmp/xproxy-${USER_ID}-${SCRIPT_PID}"
SOCKET_DIR="${TEMPBASE}/xclock-demo"
SOCKET_PATH="${SOCKET_DIR}/X5"
CONTAINER_NAME="xclock-demo-${SCRIPT_PID}"
DISPLAY_NUM="5"
CONTAINER_SCRIPT="${TEMPBASE}/run.sh"

# Centralized log directory
LOGBASE="/tmp/x11proxy-logs-${USER_ID}"
mkdir -p "$LOGBASE"
LOGFILE="${LOGBASE}/xproxy-${SCRIPT_PID}-${TIMESTAMP}.log"

# Cleanup stale logs
cleanup_stale_logs() {
    echo "Scanning for stale xclock logs..."
    find "$LOGBASE" -type f -name "xproxy-*.log" | while read -r log; do
        pid=$(head -n 1 "$log")

        if ! kill -0 "$pid" 2>/dev/null; then
            echo "Removing stale log: $log"
            rm -f "$log"
        fi
    done
}

# Entry point: daemonize if not already
if [ "${1:-}" != "--daemon" ]; then
    cleanup_stale_logs
    echo "Launching X11 proxy and container in background..."
    # Launch self in background and prepend PID to log
    nohup "$0" --daemon 2>&1 > "$LOGFILE" &
    sleep 1 #let the pocess start (and echo any nohup warnings)
    echo "Started background process. Logs: $LOGFILE"
    exit 0
fi

trap cleanup EXIT
mkdir -p "$SOCKET_DIR"

# Function: start proxy
start_proxy() {
    mkdir -p "${SOCKET_DIR}"
    chmod 0700 "${SOCKET_DIR}"
    echo "Created socket directory: ${SOCKET_DIR}"

    ./x11proxy -proxy-socket "${SOCKET_PATH}" &
    PROXY_PID=$!
    echo "Started x11proxy (PID $PROXY_PID)"
    sleep 1
}

# Function: write container script
write_container_script() {
    cat > "$CONTAINER_SCRIPT" <<'EOF'
#!/bin/sh
set -e

apk update
apk add xclock font-misc-misc ttf-dejavu

SOCKET="/tmp/.X11-unix/X5"
SOCKET_UID=$(stat -c '%u' "$SOCKET")

echo "Socket owned by UID: $SOCKET_UID"

adduser -u "$SOCKET_UID" -D x11user
su x11user -c "whoami && xclock"
EOF

    chmod +x "$CONTAINER_SCRIPT"
    echo "Wrote container script: $CONTAINER_SCRIPT"
}

# Function: run container
run_container() {
    echo "Launching Alpine container with xclock..."
    docker run --rm -i \
        --name "${CONTAINER_NAME}" \
        -e DISPLAY=":${DISPLAY_NUM}" \
        -v "${SOCKET_DIR}:/tmp/.X11-unix" \
        -v "${CONTAINER_SCRIPT}:/run.sh" \
        alpine sh /run.sh
}

# Function: cleanup
cleanup() {
    echo "Cleaning up..."
    kill $PROXY_PID || true
    rm -rf "${TEMPBASE}"
    echo "Done."
}

# Run sequence
start_proxy
write_container_script
run_container
cleanup