#!/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
if ! acquire_lock "$SCRIPT_NAME"; then
    exit 1
fi
trap 'release_lock "$SCRIPT_NAME"' EXIT

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

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

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

# Execute SQL query
queue_result=$(execute_hana_sql_query "$STATEMENT_QUEUE_SQL")
sql_status=$?

if [ $sql_status -ne 0 ]; then
    log_message "$SCRIPT_NAME" "ERROR: Failed to execute queue query."
    send_alert "$SCRIPT_NAME" "HANA Queue Error" "Failed to execute queue query."
    exit 1
fi

# 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}'."
    send_alert "$SCRIPT_NAME" "HANA Monitor Warning" "Could not retrieve statement queue count."
    exit 1
fi

log_message "$SCRIPT_NAME" "Current statement queue length: ${queue_count}"

# Get breach count from state file
breach_count_file="${STATE_DIR}/statement_queue_breach_count"
breach_count=0
if [ -f "$breach_count_file" ]; then
    breach_count=$(cat "$breach_count_file")
fi

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 ${breach_count} to 0."
    fi
    breach_count=0
fi
echo "$breach_count" > "$breach_count_file"

if [ "$breach_count" -ge "$STATEMENT_QUEUE_CONSECUTIVE_RUNS" ]; then
    message="Statement queue has been over ${STATEMENT_QUEUE_THRESHOLD} for ${breach_count} checks. Current count: ${queue_count}."
    send_alert "$SCRIPT_NAME" "HANA Statement Queue" "$message"
    exit 1
else
    log_message "$SCRIPT_NAME" "Statement queue is normal. Current count: ${queue_count}."
fi

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