Refactor Wi-Fi log download

Use MAVLink LOG_REQUEST_DATA and LOG_DATA for download log instead of console.
Make Wi-Fi download default way of downloading the log.
Make `log` command only print the header and `log dump` dump the log.

tools/log.py

@@ -3,21 +3,49 @@
 # Download flight log remotely and save to file
 
 import os
+import time
 import datetime
+import struct
+from pymavlink.dialects.v20.common import MAVLink_log_data_message
 from pyflix import Flix
 
 DIR = os.path.dirname(os.path.realpath(__file__))
-
 flix = Flix()
 
 print('Downloading log...')
-lines = flix.cli('log').splitlines()
 
-# sort by timestamp
-header = lines.pop(0)
-lines.sort(key=lambda line: float(line.split(',')[0]))
+header = flix.cli('log')
+print('Received header:\n- ' + '\n- '.join(header.split(',')))
+
+records = []
+
+def on_record(msg: MAVLink_log_data_message):
+    global stop
+    stop = time.time() + 1  # extend timeout
+    records.append([])
+    i = 0
+    data = bytes(msg.data)
+    while i + 4 <= msg.count:
+        records[-1].append(struct.unpack('<f', data[i:i+4])[0])
+        i += 4
+
+stop = time.time() + 3
+flix.on('mavlink.LOG_DATA', on_record)
+flix.mavlink.log_request_data_send(flix.system_id, 0, 0, 0, 0xFFFFFFFF)
+
+while time.time() < stop:
+    time.sleep(1)
+
+flix.off(on_record)
+
+records.sort(key=lambda record: record[0])
+records = [record for record in records if record[0] != 0]
+
+print(f'Received records: {len(records)}')
 
 log = open(f'{DIR}/log/{datetime.datetime.now().isoformat()}.csv', 'wb')
-content = header.encode() + b'\n' + b'\n'.join(line.encode() for line in lines)
-log.write(content)
+log.write(header.encode() + b'\n')
+for record in records:
+    line = ','.join(f'{value}' for value in record)
+    log.write(line.encode() + b'\n')
 print(f'Written {os.path.relpath(log.name, os.curdir)}')