#!/bin/bash
# =============================================================================
# SAP HANA Monitoring Library - Shared Functions
# =============================================================================

# Initialize script with common setup
# Usage: init_script "SCRIPT_NAME"
# Sets up: SCRIPT_DIR, SCRIPT_NAME, LOG_FILE, LOCK_DIR
init_script() {
    SCRIPT_NAME="$1"
    SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" &>/dev/null && pwd)"
    
    # Load configuration
    source "${SCRIPT_DIR}/hana.conf"
    
    # Setup logging
    LOG_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" &>/dev/null && pwd)"
    LOG_FILE="${LOG_DIR}/hana_monitor.log"
    
    # Setup lock directory
    LOCK_DIR="/tmp"
}

# Acquire lock for script execution
# Usage: acquire_lock "SCRIPT_NAME"
# Returns: 0 on success, 1 on failure (already running)
acquire_lock() {
    local script_name="$1"
    local lock_file="${LOCK_DIR}/hana_${script_name}.lock"
    
    if [ -e "$lock_file" ]; then
        log_message "$script_name" "Script is already running. Exiting."
        return 1
    fi
    
    touch "$lock_file"
    return 0
}

# Release lock
# Usage: release_lock "SCRIPT_NAME"
release_lock() {
    local script_name="$1"
    local lock_file="${LOCK_DIR}/hana_${script_name}.lock"
    if [ -f "$lock_file" ]; then
        rm -f "$lock_file"
    fi
}

# Logging function with script name prefix
# Usage: log_message "SCRIPT_NAME" "message"
log_message() {
    local script_name="$1"
    local message="$2"
    local timestamp=$(date "+%Y-%m-%d %H:%M:%S")
    echo "[${timestamp}] [${script_name}] ${message}" | tee -a "${LOG_FILE}"
}

# Send notification via ntfy
# Usage: send_notification "TITLE" "MESSAGE"
send_notification() {
    local title="$1"
    local message="$2"
    local hostname=$(hostname)
    local full_message="[${COMPANY_NAME} | ${hostname}] ${message}"
    
    if [ -n "$NTFY_TOKEN" ] && [ -n "$NTFY_TOPIC_URL" ]; then
        curl -H "Authorization: Bearer ${NTFY_TOKEN}" -H "Title: ${title}" -d "${full_message}" "${NTFY_TOPIC_URL}" > /dev/null 2>&1
        log_message "NOTIFY" "Notification sent: ${title}"
    else
        log_message "NOTIFY" "Ntfy not configured, skipping notification"
    fi
}

# Send alert notification
# Usage: send_alert "SCRIPT_NAME" "TITLE_PREFIX" "MESSAGE"
send_alert() {
    local script_name="$1"
    local title_prefix="$2"
    local message="$3"
    send_notification "${title_prefix} Alert" "🚨 Critical: ${message}"
    log_message "$script_name" "ALERT: ${message}"
}

# Execute SQL query as HANA user
# Usage: execute_hana_sql "SQL_QUERY"
# Returns: SQL output on stdout, returns 0 on success, 1 on failure
execute_hana_sql() {
    local sql_query="$1"
    local output
    
    output=$(su - "$HANA_USER" -c "$HDBSQL_PATH -U $HANA_USER_KEY -j -a -x \"$sql_query\"" 2>&1)
    local sql_status=$?
    
    if [ $sql_status -ne 0 ]; then
        log_message "SQL" "ERROR: Failed to execute SQL query. Exit code: ${sql_status}"
        echo "$output" >&2
        return 1
    fi
    
    echo "$output"
    return 0
}

# Execute SQL query and return result (for single-value queries)
# Usage: execute_hana_sql_query "SQL_QUERY"
# Returns: Query result on stdout, returns 0 on success, 1 on failure
execute_hana_sql_query() {
    local sql_query="$1"
    local output
    
    output=$(execute_hana_sql "$sql_query")
    local sql_status=$?
    
    if [ $sql_status -ne 0 ]; then
        return 1
    fi
    
    # Clean output: remove quotes and whitespace
    echo "$output" | tr -d '"' | xargs
    return 0
}

# Get disk usage percentage for a directory
# Usage: get_disk_usage_percentage "/path/to/dir"
# Returns: Usage percentage as integer (without % sign)
get_disk_usage_percentage() {
    local dir="$1"
    if [ ! -d "$dir" ]; then
        echo "0"
        return
    fi
    df "$dir" 2>/dev/null | awk 'NR==2 {gsub(/%/,"",$5); print $5}'
}