From 808e3be324590425ad831c7d7e7c80d3680686bf Mon Sep 17 00:00:00 2001
From: Stanislav Meduna <stano@meduna.org>
Date: Sat, 3 Apr 2021 04:00:41 +0200
Subject: [PATCH] Add the display.is_displaying_page condition (#1646)

* display: add the display.is_displaying_page condition

* use maybe_simple_value for page_id

* add test
---
 esphome/components/display/__init__.py      | 25 ++++++++++++++++++++-
 esphome/components/display/display_buffer.h | 14 ++++++++++++
 tests/test1.yaml                            |  7 ++++++
 3 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/esphome/components/display/__init__.py b/esphome/components/display/__init__.py
index f72ec88fae..fe8bc9bd7c 100644
--- a/esphome/components/display/__init__.py
+++ b/esphome/components/display/__init__.py
@@ -2,7 +2,7 @@ import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome import core, automation
 from esphome.automation import maybe_simple_id
-from esphome.const import CONF_ID, CONF_LAMBDA, CONF_PAGES, CONF_ROTATION
+from esphome.const import CONF_ID, CONF_LAMBDA, CONF_PAGES, CONF_PAGE_ID, CONF_ROTATION
 from esphome.core import coroutine, coroutine_with_priority
 
 IS_PLATFORM_COMPONENT = True
@@ -19,6 +19,9 @@ DisplayPageShowNextAction = display_ns.class_(
 DisplayPageShowPrevAction = display_ns.class_(
     "DisplayPageShowPrevAction", automation.Action
 )
+DisplayIsDisplayingPageCondition = display_ns.class_(
+    "DisplayIsDisplayingPageCondition", automation.Condition
+)
 
 DISPLAY_ROTATIONS = {
     0: display_ns.DISPLAY_ROTATION_0_DEGREES,
@@ -125,6 +128,26 @@ def display_page_show_previous_to_code(config, action_id, template_arg, args):
     yield cg.new_Pvariable(action_id, template_arg, paren)
 
 
+@automation.register_condition(
+    "display.is_displaying_page",
+    DisplayIsDisplayingPageCondition,
+    cv.maybe_simple_value(
+        {
+            cv.GenerateID(CONF_ID): cv.use_id(DisplayBuffer),
+            cv.Required(CONF_PAGE_ID): cv.use_id(DisplayPage),
+        },
+        key=CONF_PAGE_ID,
+    ),
+)
+def display_is_displaying_page_to_code(config, condition_id, template_arg, args):
+    paren = yield cg.get_variable(config[CONF_ID])
+    page = yield cg.get_variable(config[CONF_PAGE_ID])
+    var = cg.new_Pvariable(condition_id, template_arg, paren)
+    cg.add(var.set_page(page))
+
+    yield var
+
+
 @coroutine_with_priority(100.0)
 def to_code(config):
     cg.add_global(display_ns.using)
diff --git a/esphome/components/display/display_buffer.h b/esphome/components/display/display_buffer.h
index 5a63441e2d..71a6189990 100644
--- a/esphome/components/display/display_buffer.h
+++ b/esphome/components/display/display_buffer.h
@@ -296,6 +296,8 @@ class DisplayBuffer {
 
   void set_pages(std::vector<DisplayPage *> pages);
 
+  const DisplayPage *get_active_page() const { return this->page_; }
+
   /// Internal method to set the display rotation with.
   void set_rotation(DisplayRotation rotation);
 
@@ -448,5 +450,17 @@ template<typename... Ts> class DisplayPageShowPrevAction : public Action<Ts...>
   DisplayBuffer *buffer_;
 };
 
+template<typename... Ts> class DisplayIsDisplayingPageCondition : public Condition<Ts...> {
+ public:
+  DisplayIsDisplayingPageCondition(DisplayBuffer *parent) : parent_(parent) {}
+
+  void set_page(DisplayPage *page) { this->page_ = page; }
+  bool check(Ts... x) override { return this->parent_->get_active_page() == this->page_; }
+
+ protected:
+  DisplayBuffer *parent_;
+  DisplayPage *page_;
+};
+
 }  // namespace display
 }  // namespace esphome
diff --git a/tests/test1.yaml b/tests/test1.yaml
index e9b4cdf67c..41f688e4e8 100644
--- a/tests/test1.yaml
+++ b/tests/test1.yaml
@@ -1760,6 +1760,13 @@ interval:
           btn_left_state = ((uint32_t) id(btn_left)->get_value()  +  63 * (uint32_t)btn_left_state) >> 6;
 
           id(btn_left)->set_threshold(btn_left_state * 0.9);
+      - if:
+          condition:
+            display.is_displaying_page:
+              id: display1
+              page_id: page1
+          then:
+            - logger.log: 'Seeing page 1'
 
 color:
   - id: kbx_red