[Huge] Util Refactor, Dashboard Improvements, Hass.io Auth API, Better Validation Errors, Conditions, Custom Platforms, Substitutions (#234)

* Implement custom sensor platform

* Update

* Ethernet

* Lint

* Fix

* Login page

* Rename cookie secret

* Update manifest

* Update cookie check logic

* Favicon

* Fix

* Favicon manifest

* Fix

* Fix

* Fix

* Use hostname

* Message

* Temporary commit for screenshot

* Automatic board selection

* Undo temporary commit

* Update esphomeyaml-edge

* In-dashboard editing and hosting files locally

* Update esphomeyaml-edge

* Better ANSI color escaping

* Message

* Lint

* Download Efficiency

* Fix gitlab

* Fix

* Rename extra_libraries to libraries

* Add example

* Update README.md

* Update README.md

* Update README.md

* HassIO -> Hass.io

* Updates

* Add update available notice

* Update

* Fix substitutions

* Better error message

* Re-do dashboard ANSI colors

* Only include FastLED if user says so

* Autoscroll logs

* Remove old checks

* Use safer RedirectText

* Improvements

* Fix

* Use enviornment variable

* Use http://hassio/host/info

* Fix conditions

* Update platformio versions

* Revert "Use enviornment variable"

This reverts commit 7f038eb5d2.

* Fix

* README update

* Temp

* Better invalid config messages

* Platformio debug

* Improve error messages

* Debug

* Remove debug

* Multi Conf

* Update

* Better paths

* Remove unused

* Fixes

* Lint

* lib_ignore

* Try fix platformio colors

* Fix dashboard scrolling

* Revert

* Lint

* Revert

esphomeyaml/components/substitutions.py

@@ -0,0 +1,135 @@
+import logging
+import re
+
+import voluptuous as vol
+
+from esphomeyaml import core
+import esphomeyaml.config_validation as cv
+from esphomeyaml.core import EsphomeyamlError
+
+_LOGGER = logging.getLogger(__name__)
+
+CONF_SUBSTITUTIONS = 'substitutions'
+
+VALID_SUBSTITUTIONS_CHARACTERS = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' \
+                                 '0123456789_'
+
+
+def validate_substitution_key(value):
+    value = cv.string(value)
+    if not value:
+        raise vol.Invalid("Substitution key must not be empty")
+    if value[0] == '$':
+        value = value[1:]
+    if value[0].isdigit():
+        raise vol.Invalid("First character in substitutions cannot be a digit.")
+    for char in value:
+        if char not in VALID_SUBSTITUTIONS_CHARACTERS:
+            raise vol.Invalid(
+                u"Substitution must only consist of upper/lowercase characters, the underscore "
+                u"and numbers. The character '{}' cannot be used".format(char))
+    return value
+
+
+CONFIG_SCHEMA = vol.Schema({
+    validate_substitution_key: cv.string_strict,
+})
+
+
+def to_code(config):
+    pass
+
+
+VARIABLE_PROG = re.compile('\\$([{0}]+|\\{{[{0}]*\\}})'.format(VALID_SUBSTITUTIONS_CHARACTERS))
+
+
+def _expand_substitutions(substitutions, value, path):
+    if u'$' not in value:
+        return value
+
+    orig_value = value
+
+    i = 0
+    while True:
+        m = VARIABLE_PROG.search(value, i)
+        if not m:
+            # Nothing more to match. Done
+            break
+
+        i, j = m.span(0)
+        name = m.group(1)
+        if name.startswith(u'{') and name.endswith(u'}'):
+            name = name[1:-1]
+        if name not in substitutions:
+            _LOGGER.warn(u"Found '%s' (see %s) which looks like a substitution, but '%s' was not "
+                         u"declared", orig_value, u'->'.join(str(x) for x in path), name)
+            i = j
+            continue
+
+        sub = substitutions[name]
+        tail = value[j:]
+        value = value[:i] + sub
+        i = len(value)
+        value += tail
+    return value
+
+
+def _substitute_item(substitutions, item, path):
+    if isinstance(item, list):
+        for i, it in enumerate(item):
+            sub = _substitute_item(substitutions, it, path + [i])
+            if sub is not None:
+                item[i] = sub
+    elif isinstance(item, dict):
+        replace_keys = []
+        for k, v in item.iteritems():
+            if path or k != CONF_SUBSTITUTIONS:
+                sub = _substitute_item(substitutions, k, path + [k])
+                if sub is not None:
+                    replace_keys.append((k, sub))
+            sub = _substitute_item(substitutions, v, path + [k])
+            if sub is not None:
+                item[k] = sub
+        for old, new in replace_keys:
+            item[new] = item[old]
+            del item[old]
+    elif isinstance(item, str):
+        sub = _expand_substitutions(substitutions, item, path)
+        if sub != item:
+            return sub
+    elif isinstance(item, core.Lambda):
+        sub = _expand_substitutions(substitutions, item.value, path)
+        if sub != item:
+            item.value = sub
+    return None
+
+
+def do_substitution_pass(config):
+    if CONF_SUBSTITUTIONS not in config:
+        return config
+
+    substitutions = config[CONF_SUBSTITUTIONS]
+    if not isinstance(substitutions, dict):
+        raise EsphomeyamlError(u"Substitutions must be a key to value mapping, got {}"
+                               u"".format(type(substitutions)))
+
+    key = ''
+    try:
+        replace_keys = []
+        for key, value in substitutions.iteritems():
+            sub = validate_substitution_key(key)
+            if sub != key:
+                replace_keys.append((key, sub))
+            substitutions[key] = cv.string_strict(value)
+        for old, new in replace_keys:
+            substitutions[new] = substitutions[old]
+            del substitutions[old]
+    except vol.Invalid as err:
+        err.path.append(key)
+
+        raise EsphomeyamlError(u"Error while parsing substitutions: {}".format(err))
+
+    config[CONF_SUBSTITUTIONS] = substitutions
+    _substitute_item(substitutions, config, [])
+
+    return config