Group exception events by device

device-exception-events-i.php

<?php

$reports = array(
	['device_id'=>'D523C45F', 'vehicle_reg_no'=>'UAB 158G', 'event_id'=>'41', 'event'=>'panic_emergency', 'reported_at'=>'2018-09-19 14:10:58', ], 
	['device_id'=>'D523C45F', 'vehicle_reg_no'=>'UAB 158G', 'event_id'=>'41', 'event'=>'panic_emergency', 'reported_at'=>'2018-09-19 14:10:50', ],
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-19 13:34:58', ], 
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-19 13:24:58', ], 
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-19 13:14:57', ], 
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-14 20:19:03', ], 
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'56', 'event'=>'ext_power_disconnected', 'reported_at'=>'2018-09-14 20:11:45', ], 
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-13 13:40:30', ], 
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-13 13:30:30', ], 
	['device_id'=>'2F3C4790', 'vehicle_reg_no'=>'KCG 785H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-13 00:01:41', ], 
	['device_id'=>'C61233EF', 'vehicle_reg_no'=>'TAZ 849H', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-18 15:37:46', ], 
	['device_id'=>'1EC23C62', 'vehicle_reg_no'=>'RAW 856S', 'event_id'=>'305', 'event'=>'turning_over_speeding', 'reported_at'=>'2018-09-19 16:48:57', ], 
	['device_id'=>'1EC23C62', 'vehicle_reg_no'=>'RAW 856S', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-19 14:52:37', ], 
	['device_id'=>'1EC23C62', 'vehicle_reg_no'=>'RAW 856S', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-19 14:37:37', ], 
	['device_id'=>'1EC23C62', 'vehicle_reg_no'=>'RAW 856S', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-19 14:22:36', ],  
	['device_id'=>'4523C6A0', 'vehicle_reg_no'=>'SSD 451A', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-14 16:35:29', ], 
	['device_id'=>'4523C6A0', 'vehicle_reg_no'=>'SSD 451A', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-14 16:34:29', ], 
	['device_id'=>'4523C6A0', 'vehicle_reg_no'=>'SSD 451A', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-14 16:33:29', ], 
	['device_id'=>'4523C6A0', 'vehicle_reg_no'=>'SSD 451A', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-14 16:32:29', ], 
	['device_id'=>'4523C6A0', 'vehicle_reg_no'=>'SSD 451A', 'event_id'=>'276', 'event'=>'excessive_idle', 'reported_at'=>'2018-09-14 16:31:29', ], 
);

$devices = [];

// print json_encode(['reports' => $reports]);
// exit();

foreach($reports as $report) {

  $device_idx = array_search($report['device_id'], array_column($devices, 'id'));

  if(is_numeric($device_idx)) {

    $event = array(
      'id' => $report['event_id'],
      'name' => $report['event'],
      'reported_at' => $report['reported_at'],
    );
    
    $devices[$device_idx]['events'][] = $event;

    continue;
  }

  $device = array(
    'id' => $report['device_id'],
    'vehicle' => $report['vehicle_reg_no'],
  );

  $event = array(
    'id' => $report['event_id'],
    'name' => $report['event'],
    'reported_at' => $report['reported_at'],
  );

  $device['events'][] = $event;
  $devices[] = $device;
}

print json_encode(['devices' => $devices]);