From eb65da6377af7e1dab05621ff46987a7386eea00 Mon Sep 17 00:00:00 2001
From: Knut Ahlers <knut@ahlers.me>
Date: Sun, 20 Sep 2020 02:41:09 +0200
Subject: [PATCH] Add support for over/underlays

Signed-off-by: Knut Ahlers <knut@ahlers.me>
---
 cmd/streamdeck/config.go |  4 +++-
 cmd/streamdeck/main.go   | 23 ++++++++++-------------
 cmd/streamdeck/page.go   | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 14 deletions(-)
 create mode 100644 cmd/streamdeck/page.go

diff --git a/cmd/streamdeck/config.go b/cmd/streamdeck/config.go
index e149f0b..7810c9d 100644
--- a/cmd/streamdeck/config.go
+++ b/cmd/streamdeck/config.go
@@ -19,7 +19,9 @@ type config struct {
 }
 
 type page struct {
-	Keys map[int]keyDefinition `yaml:"keys"`
+	Keys     map[int]keyDefinition `yaml:"keys"`
+	Overlay  string                `yaml:"overlay"`
+	Underlay string                `yaml:"underlay"`
 }
 
 type keyDefinition struct {
diff --git a/cmd/streamdeck/main.go b/cmd/streamdeck/main.go
index f3b7184..a737620 100644
--- a/cmd/streamdeck/main.go
+++ b/cmd/streamdeck/main.go
@@ -167,7 +167,7 @@ func main() {
 				offTimer.Reset(userConfig.DisplayOffTime)
 			}
 
-			kd, ok := activePage.Keys[evt.Key]
+			kd, ok := activePage.GetKeyDefinitions(userConfig)[evt.Key]
 			if !ok {
 				continue
 			}
@@ -192,7 +192,7 @@ func main() {
 					continue
 				}
 
-				var nextPage = userConfig.DefaultPage
+				nextPage := userConfig.DefaultPage
 				if _, ok := userConfig.Pages[activePageName]; ok {
 					nextPage = activePageName
 				}
@@ -229,19 +229,16 @@ func togglePage(page string) error {
 	activePageCtx, activePageCtxCancel = context.WithCancel(context.Background())
 	sd.ClearAllKeys()
 
-	for idx := range activePage.Keys {
-		if activePage.Keys[idx].Display.Type == "" {
+	for idx, kd := range activePage.GetKeyDefinitions(userConfig) {
+		if kd.Display.Type == "" {
 			continue
 		}
 
-		go func(idx int) {
-			var (
-				kd        = activePage.Keys[idx]
-				keyLogger = log.WithFields(log.Fields{
-					"key":  idx,
-					"page": activePageName,
-				})
-			)
+		go func(idx int, kd keyDefinition) {
+			keyLogger := log.WithFields(log.Fields{
+				"key":  idx,
+				"page": activePageName,
+			})
 
 			if err := callDisplayElement(activePageCtx, idx, kd); err != nil {
 				keyLogger.WithError(err).Error("Unable to execute display element")
@@ -250,7 +247,7 @@ func togglePage(page string) error {
 					keyLogger.WithError(err).Error("Unable to execute error display element")
 				}
 			}
-		}(idx)
+		}(idx, kd)
 	}
 
 	return nil
diff --git a/cmd/streamdeck/page.go b/cmd/streamdeck/page.go
new file mode 100644
index 0000000..d9e6509
--- /dev/null
+++ b/cmd/streamdeck/page.go
@@ -0,0 +1,34 @@
+package main
+
+func (p page) GetKeyDefinitions(cfg config) map[int]keyDefinition {
+	var (
+		defMaps []map[int]keyDefinition
+		result  = make(map[int]keyDefinition)
+	)
+
+	// First process underlay if defined
+	if p.Underlay != "" {
+		defMaps = append(defMaps, cfg.Pages[p.Underlay].Keys)
+	}
+
+	// Process current definition
+	defMaps = append(defMaps, p.Keys)
+
+	// Last process overlay if defined
+	if p.Overlay != "" {
+		defMaps = append(defMaps, cfg.Pages[p.Overlay].Keys)
+	}
+
+	// Assemble combination of keys
+	for _, pageDef := range defMaps {
+		for idx, kd := range pageDef {
+			if kd.Display.Type == "" {
+				continue
+			}
+
+			result[idx] = kd
+		}
+	}
+
+	return result
+}