From b11d5f6799b04585bfe28f35f8eda8e174a90e00 Mon Sep 17 00:00:00 2001
From: Jim Bauwens <jimbauwens@gmail.com>
Date: Sun, 23 May 2021 22:57:48 +0200
Subject: [PATCH] Allow segments in a light partition to be reversed (#1484)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
---
 esphome/components/partition/light.py          | 15 +++++++++++++--
 esphome/components/partition/light_partition.h | 16 +++++++++++++---
 esphome/const.py                               |  1 +
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/esphome/components/partition/light.py b/esphome/components/partition/light.py
index 202481b936..c366aea033 100644
--- a/esphome/components/partition/light.py
+++ b/esphome/components/partition/light.py
@@ -1,7 +1,14 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.components import light
-from esphome.const import CONF_FROM, CONF_ID, CONF_SEGMENTS, CONF_TO, CONF_OUTPUT_ID
+from esphome.const import (
+    CONF_FROM,
+    CONF_ID,
+    CONF_SEGMENTS,
+    CONF_TO,
+    CONF_OUTPUT_ID,
+    CONF_REVERSED,
+)
 
 partitions_ns = cg.esphome_ns.namespace("partition")
 AddressableSegment = partitions_ns.class_("AddressableSegment")
@@ -28,6 +35,7 @@ CONFIG_SCHEMA = light.ADDRESSABLE_LIGHT_SCHEMA.extend(
                     cv.Required(CONF_ID): cv.use_id(light.AddressableLightState),
                     cv.Required(CONF_FROM): cv.positive_int,
                     cv.Required(CONF_TO): cv.positive_int,
+                    cv.Optional(CONF_REVERSED, default=False): cv.boolean,
                 },
                 validate_from_to,
             ),
@@ -43,7 +51,10 @@ def to_code(config):
         var = yield cg.get_variable(conf[CONF_ID])
         segments.append(
             AddressableSegment(
-                var, conf[CONF_FROM], conf[CONF_TO] - conf[CONF_FROM] + 1
+                var,
+                conf[CONF_FROM],
+                conf[CONF_TO] - conf[CONF_FROM] + 1,
+                conf[CONF_REVERSED],
             )
         )
 
diff --git a/esphome/components/partition/light_partition.h b/esphome/components/partition/light_partition.h
index 8085c43720..11589ee539 100644
--- a/esphome/components/partition/light_partition.h
+++ b/esphome/components/partition/light_partition.h
@@ -8,20 +8,25 @@ namespace partition {
 
 class AddressableSegment {
  public:
-  AddressableSegment(light::LightState *src, int32_t src_offset, int32_t size)
-      : src_(static_cast<light::AddressableLight *>(src->get_output())), src_offset_(src_offset), size_(size) {}
+  AddressableSegment(light::LightState *src, int32_t src_offset, int32_t size, bool reversed)
+      : src_(static_cast<light::AddressableLight *>(src->get_output())),
+        src_offset_(src_offset),
+        size_(size),
+        reversed_(reversed) {}
 
   light::AddressableLight *get_src() const { return this->src_; }
   int32_t get_src_offset() const { return this->src_offset_; }
   int32_t get_size() const { return this->size_; }
   int32_t get_dst_offset() const { return this->dst_offset_; }
   void set_dst_offset(int32_t dst_offset) { this->dst_offset_ = dst_offset; }
+  bool is_reversed() const { return this->reversed_; }
 
  protected:
   light::AddressableLight *src_;
   int32_t src_offset_;
   int32_t size_;
   int32_t dst_offset_;
+  bool reversed_;
 };
 
 class PartitionLightOutput : public light::AddressableLight {
@@ -72,7 +77,12 @@ class PartitionLightOutput : public light::AddressableLight {
     // offset within the segment
     int32_t seg_off = index - seg.get_dst_offset();
     // offset within the src
-    int32_t src_off = seg.get_src_offset() + seg_off;
+    int32_t src_off;
+    if (seg.is_reversed())
+      src_off = seg.get_src_offset() + seg.get_size() - seg_off - 1;
+    else
+      src_off = seg.get_src_offset() + seg_off;
+
     auto view = (*seg.get_src())[src_off];
     view.raw_set_color_correction(&this->correction_);
     return view;
diff --git a/esphome/const.py b/esphome/const.py
index a70fefa648..e93d2b7d25 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -471,6 +471,7 @@ CONF_RESTORE_STATE = "restore_state"
 CONF_RESTORE_VALUE = "restore_value"
 CONF_RETAIN = "retain"
 CONF_REVERSE_ACTIVE_ENERGY = "reverse_active_energy"
+CONF_REVERSED = "reversed"
 CONF_RGB_ORDER = "rgb_order"
 CONF_RGBW = "rgbw"
 CONF_RISING_EDGE = "rising_edge"