From f3d8ed2e45bc4500996e6c82395347efe5eb4219 Mon Sep 17 00:00:00 2001
From: Suhas <sugas182@gmail.com>
Date: Sun, 24 Jan 2021 11:08:47 -0500
Subject: [PATCH] implement recursive config overrides

---
 jrnl/args.py     | 10 +++++-----
 jrnl/override.py | 25 +++++++++++++++++++++----
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/jrnl/args.py b/jrnl/args.py
index d991783f..99489b74 100644
--- a/jrnl/args.py
+++ b/jrnl/args.py
@@ -330,11 +330,11 @@ def parse_args(args=[]):
         help="""
         Override configured key-value pairs with CONFIG_KV_PAIR for this command invocation only. 
 
-        Examples: 
-        - Use a different editor for this jrnl entry, call: 
-            jrnl --config-override '{"editor": "nano"}' 
-        - Override color selections
-            jrnl --config-override '{"colors.body":"blue", "colors.title": "green"}
+        Examples: \n
+        \t - Use a different editor for this jrnl entry, call: \n
+            \t jrnl --config-override '{"editor": "nano"}' \n
+        \t - Override color selections\n
+           \t jrnl --config-override '{"colors.body":"blue", "colors.title": "green"}
         """,
     )
 
diff --git a/jrnl/override.py b/jrnl/override.py
index 09de4258..8da034f9 100644
--- a/jrnl/override.py
+++ b/jrnl/override.py
@@ -1,8 +1,25 @@
-import logging 
+# import logging 
 def apply_overrides(overrides: dict, base_config: dict) -> dict:
     config = base_config.copy() 
-    for k in overrides:
-        logging.debug("Overriding %s from %s to %s" % (k, config[k], overrides[k]))
-        config[k] = overrides[k]
+    for k in overrides: 
+        nodes = k.split('.') 
+        config = recursively_apply(config, nodes, overrides[k]) 
+    return config 
 
+
+def recursively_apply(config: dict, nodes: list, override_value) -> dict:
+    """Recurse through configuration and apply overrides at the leaf of the config tree 
+    
+    See: https://stackoverflow.com/a/47276490 for algorithm
+
+    Args:
+        config (dict): loaded configuration from YAML
+        nodes (list): vector of override keys; the length of the vector indicates tree depth 
+        override_value (str): runtime override passed from the command-line
+    """
+    key = nodes[0] 
+    config[key] = override_value \
+        if len(nodes) == 1 \
+        else \
+        recursively_apply(config[key] if key in config else {}, nodes[1:], override_value)
     return config 
\ No newline at end of file