Adapt agipdlib.get_acq_rate to fetch rate from MDL control data

cal_tools/cal_tools/agipdlib.py

+from pathlib import Path
+from typing import Optional, Tuple
+
 import h5py
 import numpy as np
 import sharedmem
@@ -22,16 +25,49 @@ def get_num_cells(fname, loc, module):
         return options[np.argmin(dists)]
 
 
-def get_acq_rate(fname, loc, module):
-    with h5py.File(fname, "r") as f:
-        try:
-            pulses = \
-                np.squeeze(f[f"INSTRUMENT/{loc}/DET/{module}CH0:xtdf/image/pulseId"][:2])  # noqa
-            diff = pulses[1] - pulses[0]
-        except:
-            diff = 0
-        options = {8: 0.5, 4: 1.1, 2: 2.2, 1: 4.5}
-        return options.get(diff, None)
+def get_acq_rate(slow_paths: Tuple[str, str],
+                 fast_paths: Tuple[str, str, int]) -> Optional[float]:
+    """Get the acquisition rate from said detector module.
+
+    If the data is available from the middlelayer FPGA_COMP device, then it is
+    retrieved from there. If not, the rate is calculated from two different pulses
+    time.
+
+    The first entry is deliberatly not used, as the detector just began operating,
+    and it might have skipped a train.
+
+    :param slow_paths: in which file and h5 path to look for slow data.
+                       The first string is the filename with complete path,
+                       the second string is the key `karabo_id_control`
+
+    :param fast_paths: in which module file and h5 path to look for pulses.
+                       The first string is the filename with complete path,
+                       the second string is the module device name `karabo_id`,
+                       the third parameter is the module number, used to navigate
+                       through the h5 file structure.
+
+    :return acq_rate: the acquisition rate. If not found in either files, return None.
+    """
+    # Attempt to look for acquisition rate in slow data
+    slow_data_file, karabo_id_control = slow_paths
+    slow_data_file = Path(slow_data_file)
+    if slow_data_file.exists():  
+        slow_data_path = f'CONTROL/{karabo_id_control}/MDL/FPGA_COMP/bunchStructure/repetitionRate/value'  # noqa
+        with h5py.File(slow_data_file, "r") as fin:
+            if slow_data_path in fin:
+                return fin[slow_data_path][3]
+
+    # Compute acquisition rate from fast data
+    fast_data_file, karabo_id, module = fast_paths
+    fast_data_file = Path(fast_data_file)
+    if fast_data_file.exists():
+        fast_data_path = f'INSTRUMENT/{karabo_id}/DET/{module}CH0:xtdf/image/pulseId'
+        with h5py.File(fast_data_file) as fin:
+            if fast_data_path in fin:
+                pulses = np.squeeze(fin[fast_data_path][1:3])
+                diff = pulses[1] - pulses[0]
+                options = {8: 0.5, 4: 1.1, 2: 2.2, 1: 4.5}
+                return options.get(diff, None)
 
 
 def get_gain_setting(fname, h5path_ctrl):