From 27064a9c61637235f0fbfec00162842ec54eddf6 Mon Sep 17 00:00:00 2001
From: xelast418 <alex@ajas.nz>
Date: Wed, 20 Sep 2023 20:50:37 +1200
Subject: [PATCH] Adds support for extending a calendar config with another
 calendar config.

---
 README.md          | 16 ++++++++++++++
 app/tools/tools.py | 52 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)

diff --git a/README.md b/README.md
index 4059092..03043f8 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,11 @@ The JSON configuration file should look like the following.
 
 ```json
 [
+    {
+        "conf": true,
+        "extends": "str",
+        "extendFail": "str",
+    },
     {
         "url":"str",
         "name":"str",
@@ -104,9 +109,20 @@ Only the `url` and the `name` field are mandatory.
 - `redactAs`: Replaces the content of the field with the specified string
   
 If multiple calendars are specified in the configuration list, their events will be merged in the resulting ics feed.
+The first dataset with {"conf": true,} specifies options that are globally applied to all calenders in the conf. Omit this set to disable. Options
+- `extends`: string specifying the name (excluding .json) of another config file to extend.
+- `extendFail`: string speciying the action to take if an extend fails, either "fail" or "ignore". Default is "fail".
 
 ## Usage
 Once the config file is created, the corresponding HTTP endpoint is accessible.  For example, if the file `app/config/my-calendar.json` contains the configuration, the HTTP endpoint will be `http://localhost:8088/my-calendar`.
 
+A config can extend another config file, to do this the extended config should contain begin with`{
+        "conf": true,
+        "extends": <name of calendar>,
+        "extendFail": "fail",
+    },`
+For an extend to work calendars MUST share the same name between the configs
+An extending config cannot remove data from a base calendar but can modify fields
+
 ## Limitations
 Currently, the application only merges events of the ics feeds, the alarms and todos are not supported.  
diff --git a/app/tools/tools.py b/app/tools/tools.py
index 91f253d..ca5ec91 100644
--- a/app/tools/tools.py
+++ b/app/tools/tools.py
@@ -348,6 +348,26 @@ def process(path: str, from_cache: bool = True) -> Calendar:
         data = []
 
         for entry in config:
+            if entry.get("conf", False) == True:
+                if entry.get("extends", None) is not None:
+                    try:
+                        o = "app/config/" + sanitize_filename(entry["extends"]) + ".json"
+                        print("Try to open " + o)
+                        file = open(o, "r")
+                        baseConfig = json.loads(file.read())
+                        file.close()
+                        extendingConfig = config
+                        try:
+                            config = merge_json(baseConfig, extendingConfig)
+                        except:
+                            config = extendingConfig
+                        
+                    except:
+                        if entry.get("extendFail", "fail") == "fail":
+                            raise FileNotFoundError("The calendar is not cached")
+                        else:
+                            pass
+                continue
 
             cal = load_cal(entry)
 
@@ -448,3 +468,35 @@ def horodate(cal: Calendar, prefix='') -> Calendar:
             if event.description is not None else prefix + ' ' + now
 
     return cal
+
+def merge_json(base, extention):
+    """Merges two config files by updating the value of base with the values in extention.
+    
+    
+    :param base: the base config file
+    :type base: dict
+    
+    :param extention: the config file to merge with the base
+    :type extention: dict
+    
+    :return: the merged config file
+    :rtype: dict
+    
+    """
+    
+    newJson = base.copy()
+    
+    def update_json(target, source):
+        
+        for key, value in source.items():
+            if isinstance(value, dict) and key in target and isinstance(target[key], dict):
+                update_json(target[key], value)
+            else:
+                target[key] = value
+
+    for dataset in newJson:
+        for dset in extention:
+            if newJson["name"] == dset["name"]:
+                update_json(newJson, dset)
+    
+    return newJson
\ No newline at end of file