refactor(analyzer): redefine *_analyzer into steps

- update imports and names
- define step as a protocol
- extract analyzer function from classes

analyzer/libretime_analyzer/steps/analyze_replaygain.py

@@ -1,47 +1,42 @@
 import re
 import subprocess
+from typing import Any, Dict
 
 from loguru import logger
 
-from .analyzer import Analyzer
+REPLAYGAIN_EXECUTABLE = "replaygain"  # From the rgain3 python package
 
 
-class ReplayGainAnalyzer(Analyzer):
-    """This class extracts the ReplayGain using a tool from the python-rgain package."""
+def analyze_replaygain(filename: str, metadata: Dict[str, Any]):
+    """Extracts the Replaygain loudness normalization factor of a track.
+    :param filename: The full path to the file to analyzer
+    :param metadata: A metadata dictionary where the results will be put
+    :return: The metadata dictionary
+    """
+    """ The -d flag means do a dry-run, ie. don't modify the file directly.
+    """
+    command = [REPLAYGAIN_EXECUTABLE, "-d", filename]
+    try:
+        results = subprocess.check_output(
+            command,
+            stderr=subprocess.STDOUT,
+            close_fds=True,
+            universal_newlines=True,
+        )
+        gain_match = (
+            r"Calculating Replay Gain information \.\.\.(?:\n|.)*?:([\d.-]*) dB"
+        )
+        replaygain = re.search(gain_match, results).group(1)
+        metadata["replay_gain"] = float(replaygain)
 
-    REPLAYGAIN_EXECUTABLE = "replaygain"  # From the rgain3 python package
+    except OSError as e:  # replaygain was not found
+        logger.warning(
+            "Failed to run: %s - %s. %s"
+            % (command[0], e.strerror, "Do you have python-rgain installed?")
+        )
+    except subprocess.CalledProcessError as e:  # replaygain returned an error code
+        logger.warning("%s %s %s", e.cmd, e.output, e.returncode)
+    except Exception as e:
+        logger.warning(e)
 
-    @staticmethod
-    def analyze(filename, metadata):
-        """Extracts the Replaygain loudness normalization factor of a track.
-        :param filename: The full path to the file to analyzer
-        :param metadata: A metadata dictionary where the results will be put
-        :return: The metadata dictionary
-        """
-        """ The -d flag means do a dry-run, ie. don't modify the file directly.
-        """
-        command = [ReplayGainAnalyzer.REPLAYGAIN_EXECUTABLE, "-d", filename]
-        try:
-            results = subprocess.check_output(
-                command,
-                stderr=subprocess.STDOUT,
-                close_fds=True,
-                universal_newlines=True,
-            )
-            gain_match = (
-                r"Calculating Replay Gain information \.\.\.(?:\n|.)*?:([\d.-]*) dB"
-            )
-            replaygain = re.search(gain_match, results).group(1)
-            metadata["replay_gain"] = float(replaygain)
-
-        except OSError as e:  # replaygain was not found
-            logger.warning(
-                "Failed to run: %s - %s. %s"
-                % (command[0], e.strerror, "Do you have python-rgain installed?")
-            )
-        except subprocess.CalledProcessError as e:  # replaygain returned an error code
-            logger.warning("%s %s %s", e.cmd, e.output, e.returncode)
-        except Exception as e:
-            logger.warning(e)
-
-        return metadata
+    return metadata