From dd571fc3ea1387402a8241aaafd330dd38a6c0c5 Mon Sep 17 00:00:00 2001
From: Markus Zolliker <markus.zolliker@psi.ch>
Date: Wed, 21 May 2025 09:49:50 +0200
Subject: [PATCH] improve set_instrument and get_experiment

- do not predate when setting instrument to '0'
- join chunks with the same device
---
 seinflux.py | 41 +++++++++++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/seinflux.py b/seinflux.py
index 2f03360..b900ee2 100644
--- a/seinflux.py
+++ b/seinflux.py
@@ -7,11 +7,17 @@ ETERNITY = 1e10
 
 
 def fmtime(t):
+    if t is None:
+        return ' ' * 19
     if t >= ETERNITY:
         return '-' * 19
     return time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(int(t)))
 
 
+def sameday(ts1, ts2):
+    return time.localtime(ts1)[:3] == time.localtime(ts2)[:3]
+
+
 def summarize_tags(curves, remove_multiple=False):
     """summarize tags
 
@@ -315,7 +321,7 @@ class SEHistory(InfluxDBWrapper):
         for key, rows in by_key.items():
             devices = {}
             current = {}
-            combi = None
+            prevcombi = None
             chunk = None
             for ts, flag, stream, device, _ in rows:
                 ts = max(start, int(ts))
@@ -324,17 +330,22 @@ class SEHistory(InfluxDBWrapper):
                 else:
                     devices.pop(stream, None)
                 devcombi = tuple(zip(*sorted(devices.items())))
-                if devcombi != combi:
-                    if combi:
+                if devcombi != prevcombi:
+                    if prevcombi:  # device(s) removed
                         prevend = min(ts, chunk[1])
                         if prevend - chunk[0] < gap:
-                            current.pop(combi)
+                            current.pop(prevcombi)
                         else:
                             chunk[1] = prevend
-                    if devcombi:
+                    if devcombi:  # device(s) added
                         chunks = current.setdefault(devcombi, [])
-                        if chunks and time.localtime(chunks[-1][0])[:3] == time.localtime(ts)[:3]:
-                            # merge when started at the same day
+                        if chunks:
+                            prevbeg, prevend = chunks[-1]
+                            # merge when joining or started at the same day
+                            merge = prevend + gap < ts or sameday(prevbeg, ts)
+                        else:
+                            merge = False
+                        if merge:
                             chunk = chunks[-1]
                             chunk[1] = ETERNITY
                         else:
@@ -342,7 +353,7 @@ class SEHistory(InfluxDBWrapper):
                             chunks.append(chunk)
                     else:
                         chunk = None
-                    combi = devcombi
+                    prevcombi = devcombi
             if current:
                 result[key] = current
         return result
@@ -372,24 +383,26 @@ class SEHistory(InfluxDBWrapper):
                     instrument = None if ins == '0' else ins
         return instrument, lastts
 
-    def set_instrument(self, stream, value, ts=None, **tags):
+    def set_instrument(self, stream, instrument, ts=None, **tags):
         """set stream and instrument on or off
 
         :param stream: the uri of the stream
-        :param value: instrument, "0" to unassign the instrument or None when switching the stream off
+        :param instrument: or "0" to unassign the instrument or None when switching the stream off
         :param ts: the time or None when now
         """
-        flag = value is not None
-        if flag:
+        flag = instrument is not None
+        if flag and instrument != '0':
+            # in case an real instrument is given and no instrument is assigned yet
+            # we predate the assignment to the start of the stream
             try:
                 previns, prevts = self.get_instrument(stream, ts, **tags)
-                if prevts is not None and (previns is None or (ts or 1e10) < prevts):
+                if prevts is not None and (previns is None or (ts or ETERNITY) < prevts):
                     ts = prevts + 0.001
             except Exception as e:
                 print(f'Exception in get_instrument {e!r}')
         tags['stream'] = stream
         if flag:
-            tags['instrument'] = value
+            tags['instrument'] = instrument
         self._add_point('_stream_', 'on', flag, ts, tags)
 
     def remove_experiment(self, stream, ts=None, **tags):