From dd9581ac43d1f6fb4c4da69904a2c30812d2ddb8 Mon Sep 17 00:00:00 2001
From: Chris Mackey <chris@mackeyarchitecture.com>
Date: Mon, 23 Dec 2019 14:01:48 -0800
Subject: [PATCH] feat(config): Add config module

I added this mostly so that we use a consistent location to download EPW files to. I have verified that this module will work well on both Windows and Unix-based systems.
---
 ladybug/config.json  |   4 ++
 ladybug/config.py    | 121 +++++++++++++++++++++++++++++++++++++++++++
 tests/config_test.py |  11 ++++
 3 files changed, 136 insertions(+)
 create mode 100644 ladybug/config.json
 create mode 100644 ladybug/config.py
 create mode 100644 tests/config_test.py

diff --git a/ladybug/config.json b/ladybug/config.json
new file mode 100644
index 00000000..060a62b7
--- /dev/null
+++ b/ladybug/config.json
@@ -0,0 +1,4 @@
+{
+    "__comment__": "Add full paths to folders (eg. C:/epw_data, /usr/local/epw_data).",
+    "default_epw_folder": ""
+}
\ No newline at end of file
diff --git a/ladybug/config.py b/ladybug/config.py
new file mode 100644
index 00000000..28396a73
--- /dev/null
+++ b/ladybug/config.py
@@ -0,0 +1,121 @@
+"""Ladybug configurations.
+
+Import this into every module where access configurations are needed.
+
+Usage:
+    from ladybug.config import folders
+    print(folders.default_epw_folder)
+    folders.default_epw_folder = "C:/epw_data"
+"""
+import os
+import sys
+import json
+
+
+class Folders(object):
+    """Ladybug folders.
+
+    Args:
+        config_file: The path to the config.json file from which folders are loaded.
+            If None, the config.json module included in this package will be used.
+            Default: None.
+        mute: If False, the paths to the various folders will be printed as they
+            are found. If True, no printing will occur upon initialization of this
+            class. Default: True.
+
+    Properties:
+        * default_epw_folder
+        * config_file
+        * mute
+    """
+
+    def __init__(self, config_file=None, mute=True):
+        # set the mute value
+        self.mute = bool(mute)
+
+        # load paths from the config JSON file 
+        self.config_file  = config_file
+
+    @property
+    def default_epw_folder(self):
+        """Get or set the path to the default folder where EPW files are stored."""
+        return self._default_epw_folder
+    
+    @default_epw_folder.setter
+    def default_epw_folder(self, path):
+        if not path:  # check the default location for epw files
+            path = self._find_default_epw_folder()
+
+        self._default_epw_folder = path
+
+        if not self.mute and self._default_epw_folder:
+            print('Path to the default epw folder is set to: '
+                  '{}'.format(self._default_epw_folder))
+    
+    @property 
+    def config_file(self):
+        """Get or set the path to the config.json file from which folders are loaded.
+        
+        Setting this to None will result in using the config.json module included
+        in this package.
+        """
+        return self._config_file
+
+    @config_file.setter
+    def config_file(self, cfg):
+        if cfg is None:
+            cfg = os.path.join(os.path.dirname(__file__), 'config.json')
+        self._load_from_file(cfg)
+        self._config_file = cfg
+
+    def _load_from_file(self, file_path):
+        """Set all of the the properties of this object from a config JSON file.
+        
+        Args:
+            file_path: Path to a JSON file containing the file paths. A sample of this
+                JSON is the config.json file within this package.
+        """
+        # check the default file path
+        assert os.path.isfile(file_path), \
+            ValueError('No file found at {}'.format(file_path))
+
+        # set the default paths to be all blank
+        default_path = {
+            "default_epw_folder": r''
+        }
+
+        with open(file_path, 'r') as cfg:
+            try:
+                paths = json.load(cfg)
+            except Exception as e:
+                print('Failed to load paths from {}.\nThey will be set to defaults '
+                      'instead\n{}'.format(file_path, e))
+            else:
+                for key, p in paths.items():
+                    if not key.startswith('__') and p.strip():
+                        default_path[key] = p.strip()
+
+        # set paths for the default_epw_folder
+        self.default_epw_folder = default_path["default_epw_folder"]
+
+    @staticmethod
+    def _find_default_epw_folder():
+        """Find the the default EPW folder in its usual location.
+        
+        An attempt will be made to create the directory if it does not already exist.
+        """
+        try:  # windows
+            sim_folder = os.path.join(os.environ['USERPROFILE'], 'ladybug')
+        except KeyError:  # mac and linux
+            sim_folder = os.path.join(os.environ['HOME'], 'ladybug')
+        if not os.path.isdir(sim_folder):
+            try:
+                os.makedirs(sim_folder)
+            except Exception as e:
+                raise OSError('Failed to create default epw '
+                              'folder: %s\n%s' % (sim_folder, e))
+        return sim_folder
+
+
+"""Object possesing all key folders within the configuration."""
+folders = Folders()
diff --git a/tests/config_test.py b/tests/config_test.py
new file mode 100644
index 00000000..cbbe24ca
--- /dev/null
+++ b/tests/config_test.py
@@ -0,0 +1,11 @@
+# coding=utf-8
+from ladybug.config import folders
+
+import pytest
+
+
+def test_config_init():
+    """Test the initialization of the config module and basic properties."""
+    assert hasattr(folders, 'default_epw_folder')
+    assert isinstance(folders.default_epw_folder, str)
+    
\ No newline at end of file