cat << 'EOF' > install_pg_smart.sh && chmod +x install_pg_smart.sh && ./install_pg_smart.sh
#!/bin/bash
GREEN='\033[0;32m'; RED='\033[0;31m'; YELLOW='\033[1;33m'; BLUE='\033[0;34m'; NC='\033[0m'

clear
echo -e "${BLUE}=== PostgreSQL Smart Installer ===${NC}"

# --- 1. Setup Repository & Install ---
echo -e "${YELLOW}[*] Setting up Repo & Dependencies...${NC}"
sudo apt install -y curl ca-certificates
sudo install -d /usr/share/postgresql-common/pgdg
sudo curl -o /usr/share/postgresql-common/pgdg/apt.postgresql.org.asc --fail https://www.postgresql.org/media/keys/ACCC4CF8.asc || { echo -e "${RED}Failed to download key${NC}"; exit 1; }
. /etc/os-release
sudo sh -c "echo 'deb [signed-by=/usr/share/postgresql-common/pgdg/apt.postgresql.org.asc] https://apt.postgresql.org/pub/repos/apt $VERSION_CODENAME-pgdg main' > /etc/apt/sources.list.d/pgdg.list"
sudo apt update -y

echo -e "\n${BLUE}CHOOSE POSTGRESQL VERSION:${NC}"
echo "1) v17 (Latest)  2) v16  3) v15  4) v14"
read -p "Choice (1-4): " PG_OPT
case $PG_OPT in 1) V="17";; 2) V="16";; 3) V="15";; 4) V="14";; *) echo "Invalid"; exit 1;; esac

echo -e "${YELLOW}[*] Installing PostgreSQL $V...${NC}"
sudo apt install -y postgresql-$V postgresql-client-$V || exit 1
sudo systemctl start postgresql

# --- 2. User Configuration (Smart Check) ---
echo -e "\n${BLUE}USER CONFIGURATION:${NC}"
echo "1) Create New User"
echo "2) Use Default (postgres)"
read -p "Choice: " U_OPT

if [ "$U_OPT" == "1" ]; then
    while true; do
        read -p "Enter New Username: " NEW_U
        # Check if user already exists in postgres
        if sudo -u postgres psql -tAc "SELECT 1 FROM pg_roles WHERE rolname='$NEW_U'" | grep -q 1; then
            echo -e "${RED}[!] User '$NEW_U' ALREADY EXISTS. Please use a different name.${NC}"
        else
            break
        fi
    done
    
    read -s -p "New User Password: " NEW_P; echo ""
    sudo -u postgres createuser "$NEW_U" 2>/dev/null
    sudo -u postgres psql -c "ALTER USER \"$NEW_U\" WITH PASSWORD '$NEW_P';" >/dev/null
    OWNER="$NEW_U"
    echo -e "${GREEN}[OK] User '$NEW_U' created successfully.${NC}"

elif [ "$U_OPT" == "2" ]; then
    OWNER="postgres"
    read -s -p "Set Password for user 'postgres': " PG_P; echo ""
    sudo -u postgres psql -c "ALTER USER postgres WITH PASSWORD '$PG_P';" >/dev/null
else 
    echo "Invalid Choice"; exit 1
fi

# --- 3. Database Configuration (Smart Check) ---
echo -e "\n${BLUE}DATABASE:${NC}"
while true; do
    read -p "Enter Database Name: " DB_N
    
    # Check if DB already exists
    if sudo -u postgres psql -lqt | cut -d \| -f 1 | grep -qw "$DB_N"; then
        echo -e "${YELLOW}[!] Database '$DB_N' ALREADY EXISTS.${NC}"
        echo "    Choose action:"
        echo "    1) Enter a different database name"
        echo "    2) Use DB '$DB_N' & set '$OWNER' as owner"
        read -p "    Choice (1/2): " DB_EXIST_ACT
        
        if [ "$DB_EXIST_ACT" == "2" ]; then
            echo -e "${YELLOW}[*] Changing owner of '$DB_N' to '$OWNER'...${NC}"
            sudo -u postgres psql -c "ALTER DATABASE \"$DB_N\" OWNER TO \"$OWNER\";"
            if [ $? -eq 0 ]; then
                echo -e "${GREEN}[OK] Owner permissions updated.${NC}"
                break
            else
                echo -e "${RED}[!] Failed to change owner.${NC}"
            fi
        fi
        # If 1 selected, loop will repeat and ask for new name
    else
        # If DB doesn't exist, create new
        echo -e "${YELLOW}[*] Creating database '$DB_N'...${NC}"
        if sudo -u postgres createdb -O "$OWNER" "$DB_N"; then
             echo -e "${GREEN}[OK] Database '$DB_N' created successfully with owner '$OWNER'.${NC}"
             break
        else
             echo -e "${RED}[!] Failed to create DB.${NC}"
             break
        fi
    fi
done

echo -e "\n${BLUE}=== INSTALLATION COMPLETE ===${NC}"
echo -e "Script saved at: $(pwd)/install_pg_smart.sh"
EOF