/*+ MAX_EXECUTION_TIME(8000) */

-- Simple historical alarms query: get all alarms in time period
-- Filter by priority, location, and time range - that's it

SELECT 
  a.id AS ID,
  a.eventtime AS StartTimestamp,
  (SELECT MIN(clr.eventtime) 
   FROM alarm_events clr USE INDEX (idx_alarm_events_eventid)
   WHERE clr.eventid = a.eventid 
     AND clr.eventtype IN (1, 2)
     AND clr.id > a.id
  ) AS EndTimestamp,
  TIME_FORMAT(SEC_TO_TIME(TIMESTAMPDIFF(SECOND, a.eventtime, 
    COALESCE(
      (SELECT MIN(clr.eventtime) 
       FROM alarm_events clr USE INDEX (idx_alarm_events_eventid)
       WHERE clr.eventid = a.eventid 
         AND clr.eventtype IN (1, 2)
         AND clr.id > a.id
      ), 
      NOW()
    )
  )), '%H:%i:%s') AS Duration,
  CONCAT(REPLACE(a.displaypath, '_', '-'), ' ', SUBSTRING_INDEX(a.source, ':/alm:', -1)) AS Description,
  
  CASE a.priority
    WHEN 0 THEN 'Diagnostic'
    WHEN 1 THEN 'Low'
    WHEN 2 THEN 'Medium'
    WHEN 3 THEN 'High'
    WHEN 4 THEN 'Critical'
    ELSE 'Unknown'
  END AS Priority,

  IFNULL(tag.strValue, '') AS Tag,
  
  -- Use myLocation property directly (99.96% coverage) - MUCH faster than parsing tags!
  IFNULL(loc.strValue, '') AS Location,
  
  CASE 
    WHEN a.priority = 3 THEN 'Alarms-Styles/High'
    WHEN a.priority = 2 THEN 'Alarms-Styles/Medium'
    WHEN a.priority = 1 THEN 'Alarms-Styles/Low'
    WHEN a.priority = 0 THEN 'Alarms-Styles/Diagnostic'
    ELSE 'Alarms-Styles/NoAlarm'
  END AS Style

FROM alarm_events a FORCE INDEX (idx_alarm_events_type_time_id)
LEFT JOIN alarm_event_data tag FORCE INDEX (idx_alarm_event_data_lookup)
  ON tag.id = a.id AND tag.propname = 'myTag'
LEFT JOIN alarm_event_data loc FORCE INDEX (idx_alarm_event_data_lookup)
  ON loc.id = a.id AND loc.propname = 'myLocation'

WHERE 
  a.eventtype = 0
  AND a.displaypath NOT LIKE '%System Startup%'
  AND a.source NOT LIKE '%System Startup%'
  AND a.displaypath NOT LIKE '%System Shutdown%'
  AND a.source NOT LIKE '%System Shutdown%'
  AND a.eventtime >= :starttime
  AND a.eventtime < :endtime
  -- Exclude active alarms: only show alarms that have been cleared
  -- Check if a later clear/ack event exists for this eventid
  AND EXISTS (
    SELECT 1 
    FROM alarm_events clr USE INDEX (idx_alarm_events_eventid)
    WHERE clr.eventid = a.eventid 
      AND clr.eventtype IN (1, 2)
      AND clr.id > a.id
    LIMIT 1
  )

  -- Priority filter: Only evaluate priority conditions when parameter is provided
  AND (
       :priority IS NULL OR :priority = '' OR :priority = 0
    OR (
      :priority IS NOT NULL AND :priority != '' AND :priority != 0 AND (
        (:priority = 3 AND a.priority = 3)
    OR (:priority = 2 AND a.priority BETWEEN 2 AND 3)
    OR (:priority = 1 AND a.priority BETWEEN 1 AND 3)
      )
    )
  )

  -- LOCATION FILTER
  AND (
        (:location = 'all' 
            AND (loc.strValue LIKE '%MCM01%' OR loc.strValue LIKE '%MCM02%')
        )
     OR (:location <> 'all' 
            AND loc.strValue LIKE CONCAT('%', :location, '%')
        )
  )

ORDER BY a.eventtime DESC;