[FEATURE:] Add nester management

src/nester/exceptions/__init__.py

@@ -0,0 +1,3 @@
+"""
+This module provides Nester with various custom exceptions to handle run-time errors.
+"""

src/nester/exceptions/management_excs.py

@@ -0,0 +1,8 @@
+"""Custom Exceptions for Nester's project management utility."""
+
+
+class UnknownDistroException(Exception):
+    """Exception to handle in the event that a linux distribution cannot be identified or does not have a known package manager."""
+
+    def __init__(self, message: str):
+        super().__init__(message)

src/nester/management/__init__.py

@@ -0,0 +1 @@
+"""This module implements all aspects of Nester's project management."""

src/nester/management/manage_dependencies.py

@@ -0,0 +1,35 @@
+"""This module provides logic to allow Nester to manage dependencies."""
+
+import subprocess
+
+from . import utils
+
+
+def add_dependency(language: str, dependency: str) -> None:
+    """
+    Add dependency to current project.
+
+    Adds a dependency to a project and adds it to the list of dependencies for the project's language.\n
+    E.g the pyproject.toml etc.
+
+    :param language: The language of the project.
+    :param dependency: The name of the dependency to add.
+    """
+    match language:
+        case "py":
+            if utils.check_pip_installed():
+                subprocess.run("pip").args("install").args(dependency)
+                # TODO Add dependency logging!
+            else:
+                print("Error: Dependency cannot be added. Pip is not installed!")
+
+
+def remove_dependency(dependency: str) -> None:
+    """
+    Remove a given dependency.
+
+    Remove a given dependency from a project.
+
+    :param dependency: The dependency to remove.
+    """
+    pass

src/nester/management/utils.py

@@ -0,0 +1,94 @@
+"""This module provides frequently used code to the wider management module."""
+
+import os
+import platform
+import subprocess
+
+from ..exceptions import management_excs
+
+PACKAGE_MANAGERS: list[str] = ["zypper", "apt", "apt-get", "dnf", "packman"]
+
+
+def check_pip_installed() -> bool:
+    """Verify pip is installed on the current system."""
+    try:
+        subprocess.run("pip", check=True)
+    except subprocess.CalledProcessError:
+        return False
+
+    return True
+
+
+def get_package_manager() -> str | None:
+    """
+    Check what package manager is installed.
+
+    Attempts to identify the system Nester is installed on.
+    If it cannot identify the system it will raise an exception.
+
+    :return package_manager: name of the system's package manager
+    """
+    package_manager: str | None = None
+    system: str = platform.system()
+
+    match system:
+        case "Linux":
+            package_manager = identify_linux_package_manager()
+        case "Darwin":
+            package_manager = "brew"
+        case "Windows":
+            package_manager = "winget"
+
+    return package_manager
+
+
+def identify_linux_package_manager() -> str | None:
+    """
+    Will attempt to identify the distribution's package manager by brute forcing all known package manager.
+
+    Will raise a UnknownDistroExcpetion if the package manager cannot be identified.
+
+    :return pkgmgr: The Package Manager from the list of known package managers
+    """
+    for pkgmgr in PACKAGE_MANAGERS:
+        try:
+            subprocess.run(pkgmgr)
+        except subprocess.CalledProcessError:
+            raise management_excs.UnknownDistroException(
+                "Error: Distribution could not be identified."
+            )
+        return pkgmgr
+
+    return None
+
+
+def check_for_virtualenv(project_name: str) -> bool:
+    """
+    Check a project for a virtual environment.
+
+    This function checks whether a given project has a virtualenv directory.
+
+    :param project_name: The name of the project to check.
+    :return: Whether the given project has a virtualenv.
+    """
+
+    return False
+
+
+def select_dependency_source(language: str) -> str:
+    """
+    Select the source of the project's dependencies according to its language.
+
+    Different programming languages have different ways of installing dependencies.\n
+    Python uses ```pip```, Ruby uses ```gem``` etc. This function selects the appropriate way of installing dependencies
+    using a given programming language.
+
+    :param language: The language the project is written in.
+    """
+    match language:
+        case "py":
+            return "pip"
+        case "rb":
+            return "gem"
+    # TODO
+    pass

src/nester/tui.py

@@ -76,7 +76,7 @@ def interactive_mode() -> None:
                 choices: List[str] = ["---Abort---"]
                 projects = nester_log.find_all_projects()
 
-                if projects is not None:
+                if projects != []:
                     for project in projects:
                         choices.append(project)
                 else: