#!/usr/bin/env bash

# Variables
SCRIPT_PATH="/usr/local/bin/website_monitor.sh"
SERVICE_NAME="sitechecks"
SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"
JSON_FILE="/etc/${SERVICE_NAME}/sites.json"
LOG_FILE="/var/log/${SERVICE_NAME}.log"

# Function: Install the monitoring script
install_monitor_script() {
    echo "Copying the monitoring script to ${SCRIPT_PATH}..."
    cat << 'EOF' > "$SCRIPT_PATH"
#!/usr/bin/env bash

# Files
INPUT_FILE="/etc/sitechecks/sites.json"
LOG_FILE="/var/log/sitechecks.log"

# Curl options
CURL_OPTS=(
    --silent
    --max-time 10
    --location
    --max-redirs 10
    --fail
    --output /dev/null
)

# Function: Describe HTTP status codes
http_status_description() {
    local status="$1"
    case "$status" in
        200) echo "OK" ;;
        301) echo "Moved Permanently" ;;
        302) echo "Found" ;;
        400) echo "Bad Request" ;;
        401) echo "Unauthorized" ;;
        403) echo "Forbidden" ;;
        404) echo "Not Found" ;;
        408) echo "Request Timeout" ;;
        429) echo "Too Many Requests" ;;
        500) echo "Internal Server Error" ;;
        502) echo "Bad Gateway" ;;
        503) echo "Service Unavailable" ;;
        504) echo "Gateway Timeout" ;;
        *) echo "Unknown Status" ;;
    esac
}

# Function: Check website availability
check_site() {
    local site="$1"
    curl "${CURL_OPTS[@]}" --write-out "%{http_code}" "$site" 2>/dev/null
}

# Main function: Monitor websites
monitor_sites() {
    local urls=$(jq -r '.urls[]' "$INPUT_FILE")

    if [[ -z "$urls" ]]; then
        echo "[$(date)] Error: No URLs found in the input file." >> "$LOG_FILE"
        exit 1
    fi

    for site in $urls; do
        status=$(check_site "$site")
        description=$(http_status_description "$status")

        # Log the result
        echo "[$(date)] URL: $site - Status: $status ($description)" >> "$LOG_FILE"

        # Log errors only
        if [[ "$status" != "200" ]]; then
            echo "[$(date)] Error with URL: $site - Status: $status ($description)" >> "$LOG_FILE"
        fi
    done
}

monitor_sites
EOF

    chmod +x "$SCRIPT_PATH"
    echo "Monitoring script installed."
}

# Function: Create JSON configuration file
create_json_config() {
    echo "Creating JSON configuration file at ${JSON_FILE}..."
    mkdir -p "$(dirname "$JSON_FILE")"
    cat << 'EOF' > "$JSON_FILE"
{
    "urls": [
        "https://example.com",
        "https://example.org"
    ]
}
EOF
    echo "JSON configuration file created."
}

# Function: Create systemd service file
create_service_file() {
    echo "Creating systemd service file at ${SERVICE_FILE}..."
    cat << EOF > "$SERVICE_FILE"
[Unit]
Description=Website Monitoring Service
After=network.target

[Service]
ExecStart=$SCRIPT_PATH
Restart=on-failure
WorkingDirectory=/usr/local/bin
StandardOutput=append:$LOG_FILE
StandardError=append:$LOG_FILE

[Install]
WantedBy=multi-user.target
EOF

    echo "Systemd service file created."
}

# Function: Enable and start the service
enable_and_start_service() {
    echo "Enabling and starting the service ${SERVICE_NAME}..."
    systemctl daemon-reload
    systemctl enable "${SERVICE_NAME}"
    systemctl start "${SERVICE_NAME}"
    echo "Service ${SERVICE_NAME} is now running."
}

# Main installation process
install_monitor_script
create_json_config
create_service_file
enable_and_start_service

echo "Installation completed."