1 files changed, 135 insertions, 0 deletions
diff --git a/opendc-experiments/opendc-experiments-m3sa/src/main/python/input_parser.py b/opendc-experiments/opendc-experiments-m3sa/src/main/python/input_parser.py
new file mode 100644
index 00000000..cb1bc2b9
--- /dev/null
+++ b/opendc-experiments/opendc-experiments-m3sa/src/main/python/input_parser.py
@@ -0,0 +1,135 @@
+import json
+import os
+import sys
+import warnings
+
+
+def read_input(path=""):
+    """
+    Reads and processes the input JSON file from the specified path. Validates the input path,
+    ensures the file exists, and decodes the JSON content. Switches to the project root directory
+    before returning the parsed input.
+
+    :param path: The relative path to the input JSON file.
+    :type path: str
+    :raises ValueError: If the input path is not provided, file does not exist, or JSON decoding fails.
+    :return: Parsed JSON content.
+    :rtype: dict
+    :side effect: Changes the working directory to the project root.
+    """
+    if not path:
+        raise ValueError("No input path provided.")
+
+    path = path.strip().strip(',')
+
+    project_root = find_root_dir()
+    if not project_root:
+        raise ValueError("Project root not found.")
+
+    full_path = os.path.join(project_root, path)
+
+    if not os.path.exists(full_path):
+        raise ValueError(f"File does not exist: {full_path}")
+
+    try:
+        with open(full_path, 'r') as raw_json:
+            input_json = json.load(raw_json)
+    except json.JSONDecodeError:
+        raise ValueError("Failed to decode JSON.")
+    except IOError:
+        raise ValueError("MultiModel's parser says: Error opening file.")
+
+    switch_to_root_dir()
+
+    # Validate and apply defaults
+    input_json = parse_input(input_json)
+    return input_json
+
+
+def parse_input(input_json):
+    """
+    Validates and applies default values to the input JSON content. Ensures required fields are present
+    and raises warnings or errors for missing or invalid values.
+
+    :param input_json: The input JSON content.
+    :type input_json: dict
+    :raises ValueError: If required fields are missing or invalid values are provided.
+    :return: Validated and processed JSON content with defaults applied.
+    :rtype: dict
+    """
+
+    DEFAULTS = {
+        "multimodel": True,
+        "metamodel": False,
+        "window_size": 1,
+        "window_function": "mean",
+        "meta_function": "mean",
+        "samples_per_minute": 0,
+        "current_unit": "",
+        "unit_scaling_magnitude": 1,
+        "plot_type": "time_series",
+        "plot_title": "",
+        "x_label": "",
+        "y_label": "",
+        "seed": 0,
+        "y_ticks_count": None,
+        "x_ticks_count": None,
+        "y_min": None,
+        "y_max": None,
+        "x_min": None,
+        "x_max": None,
+    }
+
+    # Apply default values where not specified
+    for key, default_value in DEFAULTS.items():
+        if key not in input_json:
+            input_json[key] = default_value
+
+    # Special handling for required fields without default values
+    if "metric" not in input_json:
+        raise ValueError("Required field 'metric' is missing.")
+
+    if ("meta_function" not in input_json) and input_json["metamodel"]:
+        raise ValueError("Required field 'meta_function' is missing. Please select between 'mean' and 'median'. Alternatively,"
+              "disable metamodel in the config file.")
+
+    if input_json["meta_function"] not in ["mean", "median", "meta_equation1", "equation2", "equation3"]:
+        raise ValueError("Invalid value for meta_function. Please select between 'mean', 'median', !!!!!!!to be updated in the end!!!!!!!!.")
+
+    # raise a warning
+    if not input_json["multimodel"] and input_json["metamodel"]:
+        warnings.warn("Warning: Cannot have a Meta-Model without a Multi-Model. No computation made.")
+
+    return input_json
+
+
+def find_root_dir():
+    """
+    Searches for the project root directory by looking for a 'README.md' file in the current
+    and parent directories.
+
+    :return: The path to the project root directory if found, otherwise None.
+    :rtype: str or None
+    """
+    current_dir = os.path.dirname(os.path.abspath(__file__))
+    root = os.path.abspath(os.sep)
+    while current_dir and current_dir != root:
+        if os.path.exists(os.path.join(current_dir, 'README.md')):
+            return current_dir
+        current_dir = os.path.dirname(current_dir)
+    return None
+
+
+def switch_to_root_dir():
+    """
+    Switches the current working directory to the project root directory. Exits the program if the
+    root directory is not found.
+
+    :side effect: Changes the current working directory or exits the program.
+    """
+    root_dir = find_root_dir()
+    if root_dir:
+        os.chdir(root_dir)
+    else:
+        print("Failed to switch to root directory.")
+        sys.exit(1)