env: Use env platform if --platform wasn't given

Signed-off-by: Itamar Shalev <[email protected]>

Author: Itamar Shalev

README.md

@@ -95,17 +95,8 @@ export TLDR_PLATFORM=linux
 ```
 
 ### Platform
-The platform that tldr will use is determined by the `TLDR_PLATFORM` environment variable.
-If it is not set, the client will try to determine the platform automatically based on the system it is running on.
-The following values are supported:
-- `linux`
-- `windows`
-- `android`
-- `freebsd`
-- `netbsd`
-- `openbsd`
-- `osx`
-- `sunos`
+Determines the platform that tldr will use based on the `TLDR_PLATFORM` environment variable or system detection.
+For a complete list of supported platform values, refer to the help for the `--platform` option flag.
 
 ### Cache
 

tldr.py

@@ -56,12 +56,10 @@
     "osx": "osx",
     "sunos": "sunos",
     "win32": "windows",
-    "windows": "windows"
+    "windows": "windows",
+    "common": "common",
 }
 
-SUPPORTED_PLATFORMS = sorted(set(OS_DIRECTORIES.values()))
-
-
 class CacheNotExist(Exception):
     pass
 
@@ -204,24 +202,14 @@ def update_page_for_platform(
 
 
 def get_platform() -> str:
-    platform_env = os.environ.get('TLDR_PLATFORM', '').strip().lower()
-    if platform_env:
-        if platform_env in SUPPORTED_PLATFORMS:
-            return platform_env
-        else:
-            print(
-                f"Warning: '{platform_env}' is not a supported TLDR_PLATFORM env value."
-                "\nFalling back to auto-detection."
-            )
-
     for key in OS_DIRECTORIES:
         if sys.platform.startswith(key):
             return OS_DIRECTORIES[key]
     return 'linux'
 
 
 def get_platform_list() -> List[str]:
-    platforms = ['common'] + list(set(OS_DIRECTORIES.values()))
+    platforms = list(set(OS_DIRECTORIES.values()))
     current_platform = get_platform()
     platforms.remove(current_platform)
     platforms.insert(0, current_platform)
@@ -681,6 +669,17 @@ def main() -> None:
 
     options = parser.parse_args()
 
+
+    if options.platform is None:
+        platform_env = os.environ.get('TLDR_PLATFORM', '').strip().lower()
+        if platform_env in OS_DIRECTORIES:
+            options.platform = [platform_env]
+        elif platform_env:
+            print(
+                f"Warning: '{platform_env}' is not a supported TLDR_PLATFORM env value."
+                "\nFalling back to auto-detection."
+            )
+
     display_option_length = "long"
     if os.environ.get('TLDR_OPTIONS') == "short":
         display_option_length = "short"