#!/bin/bash
# =============================================================================
# SAP HANA Statement Queue Monitoring Script
# Checks for queued SQL statements
# =============================================================================

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" &>/dev/null && pwd)"
SCRIPT_NAME="hana_queue"

# Load configuration
source "${SCRIPT_DIR}/hana.conf"
source "${SCRIPT_DIR}/hana_lib.sh"

# Acquire lock
LOCK_FILE=$(acquire_lock "$SCRIPT_NAME")
if [ $? -ne 0 ]; then
    exit 1
fi
trap 'release_lock "$LOCK_FILE"' EXIT

log_message "$SCRIPT_NAME" "Starting statement queue check..."

# SQL Query for statement queue
STATEMENT_QUEUE_SQL="SELECT COUNT(*) FROM M_SERVICE_THREADS WHERE THREAD_TYPE = 'SqlExecutor' AND THREAD_STATE = 'Queueing';"

# Check if hdbsql is available
if [ ! -x "$HDBSQL_PATH" ]; then
    log_message "$SCRIPT_NAME" "ERROR: hdbsql not found or not executable at ${HDBSQL_PATH}"
    send_notification_if_changed "$SCRIPT_NAME" "hana_hdbsql_path_queue" "HANA Monitor Error" "hdbsql not found or not executable at ${HDBSQL_PATH}" "true" "HDBSQL_ERROR"
    exit 1
fi

# Execute SQL query as HANA user with improved error handling
queue_result=$(su - "$HANA_USER" -c "$HDBSQL_PATH -U $HANA_USER_KEY -j -a -x \"$STATEMENT_QUEUE_SQL\"" 2>&1)
sql_status=$?

if [ $sql_status -ne 0 ]; then
    log_message "$SCRIPT_NAME" "ERROR: Failed to execute queue query. Exit code: ${sql_status}"
    send_notification_if_changed "$SCRIPT_NAME" "hana_queue_query_error" "HANA Queue Error" "Failed to execute queue query. Exit code: ${sql_status}" "true" "QUERY_ERROR"
    exit 1
fi

# Clear any previous query error state
send_notification_if_changed "$SCRIPT_NAME" "hana_queue_query_error" "HANA Statement Queue" "Queue query successful." "false" "OK"

# Parse queue count
queue_count=$(echo "$queue_result" | tr -d '"' | xargs)

# Validate queue count is a number
if ! [[ "$queue_count" =~ ^[0-9]+$ ]]; then
    log_message "$SCRIPT_NAME" "WARNING: Could not retrieve HANA statement queue count. Got: '${queue_count}'. Skipping check."
    send_notification_if_changed "$SCRIPT_NAME" "hana_statement_queue_check_fail" "HANA Monitor Warning" "Could not retrieve statement queue count. Got: '${queue_count}'" "true" "QUEUE_CHECK_FAIL"
else
    # Clear any previous check failure state
    send_notification_if_changed "$SCRIPT_NAME" "hana_statement_queue_check_fail" "HANA Monitor Warning" "Statement queue check is working." "false" "OK"
    log_message "$SCRIPT_NAME" "Current statement queue length: ${queue_count}"
    
    # Get breach count from state
    breach_count=$(get_state "statement_queue_breach_count")
    breach_count=${breach_count:-0}

    if [ "$queue_count" -gt "$STATEMENT_QUEUE_THRESHOLD" ]; then
        breach_count=$((breach_count + 1))
        log_message "$SCRIPT_NAME" "Statement queue is above threshold (${queue_count} > ${STATEMENT_QUEUE_THRESHOLD}). Consecutive breach count: ${breach_count}/${STATEMENT_QUEUE_CONSECUTIVE_RUNS}."
    else
        if [ "$breach_count" -gt 0 ]; then
            log_message "$SCRIPT_NAME" "Statement queue returned to normal. Resetting breach count from ${breach_count} to 0."
        fi
        breach_count=0
    fi
    set_state "statement_queue_breach_count" "$breach_count"

    if [ "$breach_count" -ge "$STATEMENT_QUEUE_CONSECUTIVE_RUNS" ]; then
        message="Statement queue has been over ${STATEMENT_QUEUE_THRESHOLD} for ${breach_count} checks. Current count: ${queue_count}."
        send_notification_if_changed "$SCRIPT_NAME" "hana_statement_queue_status" "HANA Statement Queue" "$message" "true" "ALERT:${queue_count}"
    else
        message="Statement queue is normal. Current count: ${queue_count}."
        send_notification_if_changed "$SCRIPT_NAME" "hana_statement_queue_status" "HANA Statement Queue" "$message" "false" "OK"
    fi
fi

log_message "$SCRIPT_NAME" "Statement queue check complete."