From ccc4074f4872881d795aa56851483f3e4a034b49 Mon Sep 17 00:00:00 2001
From: belligerentbeagle <ethan.wei@u.nus.edu>
Date: Sat, 13 Apr 2024 01:52:39 +0800
Subject: [PATCH 1/2] Add PUML Implementation Diagram for Command History

---
 docs/DeveloperGuide.md                        |  8 ++++-
 .../CommandHistorySequenceDiagram.puml        | 35 +++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 docs/diagrams/CommandHistorySequenceDiagram.puml

diff --git a/docs/DeveloperGuide.md b/docs/DeveloperGuide.md
index dda421e186f..4d1004a3b3b 100644
--- a/docs/DeveloperGuide.md
+++ b/docs/DeveloperGuide.md
@@ -221,7 +221,13 @@ This section describes some noteworthy details on how certain features are imple
 
 ### Command History Retrieval
 
-**TODO**
+Let's consider the scenario where the user wants to retrieve the last command executed. The user can do this by 
+pressing the <span class="badge bg-light text-dark"><i class="fa-regular fa-square-caret-up"></i> UP</span> key on 
+the keyboard. 
+
+The <span class="badge bg-light text-dark"><i class="fa-regular fa-square-caret-up"></i> UP</span> key press event is captured by the `CommandBox` class, which then 
+retrieves the last command from the `CommandHistory` Singleton object.
+<puml src="diagrams/CommandHistorySequenceDiagram.puml" alt="Command History Sequence Diagram" />
 
 {{ newPage }}
 
diff --git a/docs/diagrams/CommandHistorySequenceDiagram.puml b/docs/diagrams/CommandHistorySequenceDiagram.puml
new file mode 100644
index 00000000000..937b06019cd
--- /dev/null
+++ b/docs/diagrams/CommandHistorySequenceDiagram.puml
@@ -0,0 +1,35 @@
+@startuml
+!include style.puml
+skinparam ArrowFontStyle plain
+
+box Command History UI_COLOR_T2
+participant ":CommandBox" as Model UI_COLOR_T3
+participant ":CommandHistory" as ModelCH UI_COLOR_T3
+end box
+
+[-> Model : keyPress(e)
+activate Model
+
+Model -> Model : handleKeyPressEvent(e)
+Model -> Model : handleArrowKeyPress(e)
+activate Model
+Model -> ModelCH : getInstance()
+activate ModelCH
+ModelCH --> Model :
+deactivate ModelCH
+
+Model -> ModelCH : getCommandHistory(direction)
+activate ModelCH
+
+ModelCH -> ModelCH :
+ModelCH -> ModelCH :
+ModelCH -> ModelCH :
+ModelCH --> Model : previousCommand
+deactivate ModelCH
+
+Model -> Model : setText(previousCommand)
+
+[<-- Model
+deactivate Model
+
+@enduml

From 690aa2dff65d11a1b5ba90daaab7106e165c09f7 Mon Sep 17 00:00:00 2001
From: belligerentbeagle <ethan.wei@u.nus.edu>
Date: Sat, 13 Apr 2024 14:58:32 +0800
Subject: [PATCH 2/2] Improve clarity

---
 docs/diagrams/CommandHistorySequenceDiagram.puml | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/docs/diagrams/CommandHistorySequenceDiagram.puml b/docs/diagrams/CommandHistorySequenceDiagram.puml
index 937b06019cd..79ff5e3036a 100644
--- a/docs/diagrams/CommandHistorySequenceDiagram.puml
+++ b/docs/diagrams/CommandHistorySequenceDiagram.puml
@@ -21,9 +21,6 @@ deactivate ModelCH
 Model -> ModelCH : getCommandHistory(direction)
 activate ModelCH
 
-ModelCH -> ModelCH :
-ModelCH -> ModelCH :
-ModelCH -> ModelCH :
 ModelCH --> Model : previousCommand
 deactivate ModelCH