#!/bin/bash
# database/scripts/configure-postgres.sh
#
# PostgreSQL Configuration Management Script
# Applies recommended settings based on system resources
# NOTE THIS FILE IS FOR REFERENCE PURPOSE ONLY SINCE WE ARE USING INSIDE A DOCKER CONTAINER
# - WE HAVE FIND ANOTHER WAY TO PROVISION THIS SHELL SCRIPT
# -- DO NOT USE
set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

echo "==================================================================="
echo "PostgreSQL Configuration Script for Aurganize V6.2"
echo "==================================================================="

# Check if running as root
if [[ $EUID -ne 0 ]]; then
   echo -e "${RED}This script must be run as root${NC}"
   exit 1
fi

# Detect PostgreSQL version
PG_VERSION=$(sudo -u postgres psql -t -c "SELECT version();" | grep -oP '\d+(?:\.\d+)?' | head -1 | cut -d. -f1)
echo -e "${GREEN}Detected PostgreSQL version: ${PG_VERSION}${NC}"

# Detect total RAM
TOTAL_RAM_KB=$(grep MemTotal /proc/meminfo | awk '{print $2}')
TOTAL_RAM_GB=$((TOTAL_RAM_KB / 1024 / 1024))
echo -e "${GREEN}Detected RAM: ${TOTAL_RAM_GB}GB${NC}"

# Calculate settings
SHARED_BUFFERS_GB=$((TOTAL_RAM_GB / 4))
EFFECTIVE_CACHE_GB=$((TOTAL_RAM_GB * 3 / 4))
WORK_MEM_MB=$(((TOTAL_RAM_GB - SHARED_BUFFERS_GB) * 1024 / 100 / 3))

echo ""
echo "Recommended settings:"
echo "  shared_buffers = ${SHARED_BUFFERS_GB}GB"
echo "  effective_cache_size = ${EFFECTIVE_CACHE_GB}GB"
echo "  work_mem = ${WORK_MEM_MB}MB"
echo ""

# Ask for confirmation
read -p "Apply these settings? (y/n) " -n 1 -r
echo
if [[ ! $REPLY =~ ^[Yy]$ ]]; then
    echo "Aborted."
    exit 0
fi

# Backup current config
CONFIG_FILE="/etc/postgresql/${PG_VERSION}/main/postgresql.conf"
BACKUP_FILE="${CONFIG_FILE}.backup.$(date +%Y%m%d_%H%M%S)"

echo -e "${YELLOW}Backing up config to: ${BACKUP_FILE}${NC}"
cp "${CONFIG_FILE}" "${BACKUP_FILE}"

# Apply settings
echo -e "${GREEN}Applying settings...${NC}"

sudo -u postgres psql -c "ALTER SYSTEM SET shared_buffers = '${SHARED_BUFFERS_GB}GB';"
sudo -u postgres psql -c "ALTER SYSTEM SET effective_cache_size = '${EFFECTIVE_CACHE_GB}GB';"
sudo -u postgres psql -c "ALTER SYSTEM SET work_mem = '${WORK_MEM_MB}MB';"
sudo -u postgres psql -c "ALTER SYSTEM SET maintenance_work_mem = '256MB';"
sudo -u postgres psql -c "ALTER SYSTEM SET random_page_cost = '1.1';"
sudo -u postgres psql -c "ALTER SYSTEM SET effective_io_concurrency = '200';"

# Restart PostgreSQL
echo -e "${YELLOW}Restarting PostgreSQL...${NC}"
systemctl restart postgresql

# Verify
echo -e "${GREEN}Configuration applied successfully!${NC}"
sudo -u postgres psql -c "SELECT name, setting, unit FROM pg_settings WHERE name IN ('shared_buffers', 'effective_cache_size', 'work_mem');"

echo ""
echo "==================================================================="
echo "Configuration complete!"
echo "Backup saved to: ${BACKUP_FILE}"
echo "==================================================================="