[FEATURE] Add multiple preset inheritance (#204)

docs/config.rst

@@ -157,6 +157,8 @@ Presets support inheritance by defining a parent preset:
 .. code-block:: yaml
 
    presets:
+     custom_preset:
+       ...
      parent_preset:
        ...
      child_preset:
@@ -166,6 +168,19 @@ In the example above, ``child_preset`` inherits all fields defined in ``parent_p
 It is advantageous to use parent presets where possible to reduce duplicate yaml
 definitions.
 
+Presets also support inheritance from multiple presets:
+
+.. code-block:: yaml
+
+     child_preset:
+       preset:
+         - "custom_preset"
+         - "parent_preset"
+
+In this example, ``child_preset`` will inherit all fields from ``custom_preset``
+and ``parent_preset`` in that order. The bottom-most preset has the highest
+priority.
+
 -------------------------------------------------------------------------------
 
 

src/ytdl_sub/config/preset.py

@@ -6,6 +6,7 @@ from typing import List
 from typing import Optional
 from typing import Tuple
 from typing import Type
+from typing import TypeVar
 from typing import Union
 
 from mergedeep import mergedeep
@@ -27,6 +28,7 @@ from ytdl_sub.validators.string_formatter_validators import OverridesDictFormatt
 from ytdl_sub.validators.string_formatter_validators import OverridesStringFormatterValidator
 from ytdl_sub.validators.string_formatter_validators import StringFormatterValidator
 from ytdl_sub.validators.validators import DictValidator
+from ytdl_sub.validators.validators import StringListValidator
 from ytdl_sub.validators.validators import StringValidator
 from ytdl_sub.validators.validators import Validator
 
@@ -41,6 +43,8 @@ PRESET_KEYS = {
 
 
 class PresetPlugins:
+    _TPluginOptions = TypeVar("_TPluginOptions", bound=PluginOptions)
+
     def __init__(self):
         self.plugin_types: List[Type[Plugin]] = []
         self.plugin_options: List[PluginOptions] = []
@@ -61,6 +65,22 @@ class PresetPlugins:
         """
         return zip(self.plugin_types, self.plugin_options)
 
+    def get(self, plugin_type: Type[_TPluginOptions]) -> Optional[_TPluginOptions]:
+        """
+        Parameters
+        ----------
+        plugin_type
+            Fetch the plugin options for this type
+
+        Returns
+        -------
+        Options of this plugin if they exit. Otherwise, return None.
+        """
+        plugin_option_types = [type(plugin_options) for plugin_options in self.plugin_options]
+        if plugin_type in plugin_option_types:
+            return self.plugin_options[plugin_option_types.index(plugin_type)]
+        return None
+
 
 class DownloadStrategyValidator(StrictDictValidator):
     """
@@ -248,36 +268,40 @@ class Preset(StrictDictValidator):
                     self.__validate_override_string_formatter_validator(validator_value)
 
     def __merge_parent_preset_dicts_if_present(self, config: ConfigFile):
-        parent_presets = set()
         parent_preset_validator = self._validate_key_if_present(
-            key="preset", validator=StringValidator
+            key="preset", validator=StringListValidator
         )
-        parent_preset = parent_preset_validator.value if parent_preset_validator else None
 
-        while parent_preset:
+        if parent_preset_validator is None:
-            # Make sure the parent preset actually exists
+            return
-            if parent_preset not in config.presets.keys:
+
-                raise self._validation_exception(
+        for parent_preset in [preset.value for preset in parent_preset_validator.list]:
-                    f"preset '{parent_preset}' does not exist in the provided config. "
+            parent_presets = set()
-                    f"Available presets: {', '.join(config.presets.keys)}"
+
+            while parent_preset:
+                # Make sure the parent preset actually exists
+                if parent_preset not in config.presets.keys:
+                    raise self._validation_exception(
+                        f"preset '{parent_preset}' does not exist in the provided config. "
+                        f"Available presets: {', '.join(config.presets.keys)}"
+                    )
+
+                # Make sure we do not hit an infinite loop
+                if parent_preset in parent_presets:
+                    raise self._validation_exception(
+                        f"preset loop detected with the preset '{parent_preset}'"
+                    )
+
+                parent_preset_dict = copy.deepcopy(config.presets.dict[parent_preset])
+
+                parent_presets.add(parent_preset)
+                parent_preset = parent_preset_dict.get("preset")
+
+                # Override the parent preset with the contents of this preset
+                self._value = mergedeep.merge(
+                    parent_preset_dict, self._value, strategy=mergedeep.Strategy.REPLACE
                 )
 
-            # Make sure we do not hit an infinite loop
-            if parent_preset in parent_presets:
-                raise self._validation_exception(
-                    f"preset loop detected with the preset '{parent_preset}'"
-                )
-
-            parent_preset_dict = copy.deepcopy(config.presets.dict[parent_preset])
-
-            parent_presets.add(parent_preset)
-            parent_preset = parent_preset_dict.get("preset")
-
-            # Override the parent preset with the contents of this preset
-            self._value = mergedeep.merge(
-                parent_preset_dict, self._value, strategy=mergedeep.Strategy.REPLACE
-            )
-
     def __init__(self, config: ConfigFile, name: str, value: Any):
         super().__init__(name=name, value=value)
 

tests/unit/config/test_preset.py

@@ -4,13 +4,39 @@ import pytest
 
 from ytdl_sub.config.config_file import ConfigFile
 from ytdl_sub.config.preset import Preset
+from ytdl_sub.plugins.nfo_tags import NfoTagsOptions
 from ytdl_sub.utils.exceptions import StringFormattingVariableNotFoundException
+from ytdl_sub.utils.exceptions import ValidationException
 
 
 @pytest.fixture
 def config_file() -> ConfigFile:
     return ConfigFile(
-        name="config", value={"configuration": {"working_directory": "."}, "presets": {}}
+        name="config",
+        value={
+            "configuration": {"working_directory": "."},
+            "presets": {
+                "parent_preset_0": {"nfo_tags": {"tags": {"key-1": "preset_0"}}},
+                "parent_preset_1": {
+                    "preset": "parent_preset_0",
+                    "nfo_tags": {
+                        "nfo_name": "{uid}.nfo",
+                        "nfo_root": "root",
+                        "tags": {"key-2": "preset_1"},
+                    },
+                },
+                "parent_preset_2": {
+                    "nfo_tags": {
+                        "nfo_name": "{uid}.nfo",
+                        "nfo_root": "root",
+                        "tags": {"key-2": "preset_2", "key-3": "preset_2"},
+                    }
+                },
+                "preset_self_loop": {"preset": "preset_self_loop"},
+                "preset_loop_0": {"preset": "preset_loop_1"},
+                "preset_loop_1": {"preset": "preset_loop_0"},
+            },
+        },
     )
 
 
@@ -22,6 +48,14 @@ def output_options() -> Dict:
     }
 
 
+@pytest.fixture
+def youtube_video() -> Dict:
+    return {
+        "download_strategy": "video",
+        "video_url": "youtube.com/watch?v=123abc",
+    }
+
+
 class TestPreset:
     @pytest.mark.parametrize(
         "source, download_strategy",
@@ -48,21 +82,79 @@ class TestPreset:
             value={source: download_strategy, "output_options": output_options},
         )
 
-    def test_preset_with_override_variable(self, config_file, output_options):
+    def test_preset_with_override_variable(self, config_file, output_options, youtube_video):
         _ = Preset(
             config=config_file,
             name="test",
             value={
-                "youtube": {
+                "youtube": youtube_video,
-                    "download_strategy": "video",
-                    "video_url": "youtube.com/watch?v=123abc",
-                },
                 "output_options": {"output_directory": "dir", "file_name": "{dne_var}"},
                 "overrides": {"dne_var": "not dne"},
             },
         )
 
-    def test_preset_error__source_variable_does_not_exist(self, config_file, output_options):
+    def test_preset_parent(self, config_file, output_options, youtube_video):
+        preset = Preset(
+            config=config_file,
+            name="test",
+            value={
+                "preset": "parent_preset_1",
+                "youtube": youtube_video,
+                "output_options": output_options,
+                "nfo_tags": {"tags": {"key-2": "this-preset"}},
+            },
+        )
+
+        nfo_options: NfoTagsOptions = preset.plugins.get(NfoTagsOptions)
+        tags_string_dict = {
+            key: formatter.format_string for key, formatter in nfo_options.tags.string_tags.items()
+        }
+
+        assert tags_string_dict == {"key-1": "preset_0", "key-2": "this-preset"}
+
+    def test_preset_multiple_parents(self, config_file, output_options, youtube_video):
+        preset = Preset(
+            config=config_file,
+            name="test",
+            value={
+                "preset": ["parent_preset_1", "parent_preset_2"],
+                "youtube": youtube_video,
+                "output_options": output_options,
+                "nfo_tags": {"tags": {"key-3": "this-preset"}},
+            },
+        )
+
+        nfo_options: NfoTagsOptions = preset.plugins.get(NfoTagsOptions)
+        tags_string_dict = {
+            key: formatter.format_string for key, formatter in nfo_options.tags.string_tags.items()
+        }
+
+        assert tags_string_dict == {
+            "key-1": "preset_0",
+            "key-2": "preset_1",
+            "key-3": "this-preset",
+        }
+
+    @pytest.mark.parametrize(
+        "parent_preset", ["preset_self_loop", "preset_loop_0", "preset_loop_1"]
+    )
+    def test_preset_error__parent_loop(
+        self, config_file, output_options, youtube_video, parent_preset
+    ):
+        with pytest.raises(ValidationException, match="preset loop detected"):
+            _ = Preset(
+                config=config_file,
+                name="test",
+                value={
+                    "preset": parent_preset,
+                    "youtube": youtube_video,
+                    "output_options": output_options,
+                },
+            )
+
+    def test_preset_error__source_variable_does_not_exist(
+        self, config_file, output_options, youtube_video
+    ):
         with pytest.raises(
             StringFormattingVariableNotFoundException,
             match="Format variable 'dne_var' does not exist",
@@ -71,15 +163,14 @@ class TestPreset:
                 config=config_file,
                 name="test",
                 value={
-                    "youtube": {
+                    "youtube": youtube_video,
-                        "download_strategy": "video",
-                        "video_url": "youtube.com/watch?v=123abc",
-                    },
                     "output_options": {"output_directory": "dir", "file_name": "{dne_var}"},
                 },
             )
 
-    def test_preset_error__override_variable_does_not_exist(self, config_file, output_options):
+    def test_preset_error__override_variable_does_not_exist(
+        self, config_file, output_options, youtube_video
+    ):
         with pytest.raises(
             StringFormattingVariableNotFoundException,
             match="Override variable 'dne_var' does not exist",
@@ -88,15 +179,14 @@ class TestPreset:
                 config=config_file,
                 name="test",
                 value={
-                    "youtube": {
+                    "youtube": youtube_video,
-                        "download_strategy": "video",
-                        "video_url": "youtube.com/watch?v=123abc",
-                    },
                     "output_options": {"output_directory": "{dne_var}", "file_name": "file"},
                 },
             )
 
-    def test_preset_error__dict_source_variable_does_not_exist(self, config_file, output_options):
+    def test_preset_error__dict_source_variable_does_not_exist(
+        self, config_file, output_options, youtube_video
+    ):
         with pytest.raises(
             StringFormattingVariableNotFoundException,
             match="Format variable 'dne_var' does not exist",
@@ -105,10 +195,7 @@ class TestPreset:
                 config=config_file,
                 name="test",
                 value={
-                    "youtube": {
+                    "youtube": youtube_video,
-                        "download_strategy": "video",
-                        "video_url": "youtube.com/watch?v=123abc",
-                    },
                     "output_options": {"output_directory": "dir", "file_name": "file"},
                     "nfo_tags": {
                         "nfo_name": "the nfo name",
@@ -118,7 +205,9 @@ class TestPreset:
                 },
             )
 
-    def test_preset_error__dict_override_variable_does_not_exist(self, config_file, output_options):
+    def test_preset_error__dict_override_variable_does_not_exist(
+        self, config_file, output_options, youtube_video
+    ):
         with pytest.raises(
             StringFormattingVariableNotFoundException,
             match="Override variable 'dne_var' does not exist",
@@ -127,10 +216,7 @@ class TestPreset:
                 config=config_file,
                 name="test",
                 value={
-                    "youtube": {
+                    "youtube": youtube_video,
-                        "download_strategy": "video",
-                        "video_url": "youtube.com/watch?v=123abc",
-                    },
                     "output_options": {"output_directory": "dir", "file_name": "file"},
                     "output_directory_nfo_tags": {
                         "nfo_name": "the nfo name",