#!/bin/bash
# Quant Engine Shadow Copy Hot Deploy Script
# To be executed on Hz-Prod-01 Remote Server

set -e

DEPLOY_BASE="/home/kjh2064/deployments"
ACTIVE_LINK="/home/kjh2064/quantengine_active"
TMP_ARCHIVE="/home/kjh2064/tmp/quantengine.tar.gz"

TIMESTAMP=$(date +%Y%m%d_%H%M%S)
TARGET_DIR="${DEPLOY_BASE}/quantengine_${TIMESTAMP}"

echo "========================================="
echo "Starting Shadow Copy Hot Deploy [${TIMESTAMP}]"
echo "========================================="

# 1. Ensure directories exist
mkdir -p "${DEPLOY_BASE}"
mkdir -p "${TARGET_DIR}"

# 2. Extract build artifact to unique shadow directory
if [ -f "${TMP_ARCHIVE}" ]; then
    echo "Extracting build artifact to ${TARGET_DIR}..."
    tar -xzf "${TMP_ARCHIVE}" -C "${TARGET_DIR}"
    rm -f "${TMP_ARCHIVE}"
else
    echo "ERROR: Deployment archive not found at ${TMP_ARCHIVE}"
    exit 1
fi

# 3. Swap symbolic link atomically
echo "Swapping symbolic link dynamically..."
ln -sfn "${TARGET_DIR}" "${ACTIVE_LINK}"

# 4. Restart Systemd service (requires passwordless sudo reload or specific policy)
echo "Restarting Systemd service..."
sudo systemctl restart quantengine

# 5. Clean up old deployments (keep last 5)
echo "Cleaning up obsolete deployments..."
cd "${DEPLOY_BASE}"
ls -dt quantengine_* | tail -n +6 | while read -r old_dir; do
    echo "Removing old release: ${old_dir}"
    rm -rf "${old_dir}"
done

echo "========================================="
echo "Deployment successfully completed!"
echo "Active Version: $(readlink -f ${ACTIVE_LINK})"
echo "========================================="