Implement smart file resolving

src/wireviz/wv_helper.py

@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 
 from typing import List
+from pathlib import Path
 import re
 
 awg_equiv_table = {
@@ -117,3 +118,20 @@ def aspect_ratio(image_src):
     except Exception as error:
         print(f'aspect_ratio(): {type(error).__name__}: {error}')
     return 1 # Assume 1:1 when unable to read actual image size
+
+def smart_file_resolve(filename, possible_paths):
+    filename = Path(filename)
+    if filename.is_absolute():
+        if filename.exists():
+            return filename
+        else:
+            raise Exception(f'{filename} does not exist.')
+    else:  # sarch all possible paths in decreasing order of precedence
+        possible_paths = [Path(path).resolve() for path in possible_paths]
+        for possible_path in possible_paths:
+            resolved_path = (possible_path / filename).resolve()
+            if (resolved_path).exists():
+                return resolved_path
+        else:
+            raise Exception(f'{filename} was not found in any of the following locations: \n' +
+                            '\n'.join([str(x) for x in possible_paths]))