From c61cbf4234cbfe76fc2db04600f17b07c4f4d2a3 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Thu, 11 Oct 2018 02:50:08 +0200
Subject: [PATCH] Start poking at a TerminalWidget.

---
 Widgets/Makefile           |  1 +
 Widgets/TerminalWidget.cpp | 69 ++++++++++++++++++++++++++++++++++++++
 Widgets/TerminalWidget.h   | 33 ++++++++++++++++++
 Widgets/test.cpp           |  7 ++--
 4 files changed, 106 insertions(+), 4 deletions(-)
 create mode 100644 Widgets/TerminalWidget.cpp
 create mode 100644 Widgets/TerminalWidget.h

diff --git a/Widgets/Makefile b/Widgets/Makefile
index 0ddb811396..11ed7e6b51 100644
--- a/Widgets/Makefile
+++ b/Widgets/Makefile
@@ -18,6 +18,7 @@ VFS_OBJS = \
     Painter.o \
     Label.o \
     Button.o \
+    TerminalWidget.o \
     test.o
 
 OBJS = $(AK_OBJS) $(VFS_OBJS)
diff --git a/Widgets/TerminalWidget.cpp b/Widgets/TerminalWidget.cpp
new file mode 100644
index 0000000000..9de00cd9c8
--- /dev/null
+++ b/Widgets/TerminalWidget.cpp
@@ -0,0 +1,69 @@
+#include "TerminalWidget.h"
+#include "Painter.h"
+
+TerminalWidget::TerminalWidget(Widget* parent)
+    : Widget(parent)
+{
+    setRect({ 100, 300, columns() * 8, rows() * 8 });
+    m_screen = new CharacterWithAttributes[rows() * columns() * 2]; 
+    for (unsigned row = 0; row < m_rows; ++row) {
+        for (unsigned column = 0; column < m_columns; ++column) {
+            at(row, column).character = ' ';
+            at(row, column).attribute = 0x07;
+        }
+    }
+    onReceive(String("Serenity/OS").toByteBuffer());
+}
+
+TerminalWidget::~TerminalWidget()
+{
+}
+
+CharacterWithAttributes& TerminalWidget::at(unsigned row, unsigned column)
+{
+    ASSERT(m_screen);
+    ASSERT(row < m_rows);
+    ASSERT(column < m_columns);
+    return m_screen[row * columns() + column];
+}
+
+void TerminalWidget::onPaint(PaintEvent&)
+{
+    Painter painter(*this);
+
+    painter.fillRect({ 0, 0, width(), height() }, Color(0, 0, 0));
+
+    char buf[2] = { 0, 0 };
+    for (unsigned row = 0; row < m_rows; ++row) {
+        int y = row * 8;
+        for (unsigned column = 0; column < m_columns; ++column) {
+            int x = column * 8;
+            buf[0] = at(row, column).character;
+            painter.drawText({ x, y, width(), 8 }, buf, Painter::TextAlignment::TopLeft, Color(0xa0, 0xa0, 0xa0));
+        }
+    }
+}
+
+void TerminalWidget::onReceive(const ByteBuffer& buffer)
+{
+    for (unsigned i = 0; i < buffer.size(); ++i) {
+        onReceive(buffer[i]);
+    }
+}
+
+void TerminalWidget::onReceive(byte ch)
+{
+    at(m_cursorRow, m_cursorColumn).character = ch;
+    printf("%2u,%2u -> ", m_cursorRow, m_cursorColumn);
+    if (++m_cursorColumn > m_columns) {
+        m_cursorColumn = 0;
+        if (m_cursorRow < (m_rows - 1)) {
+            ++m_cursorRow;
+        } else {
+            // FIXME: Scroll it!
+            ASSERT_NOT_REACHED();
+        }
+    }
+    printf("%2u,%2u\n", m_cursorRow, m_cursorColumn);
+}
+
diff --git a/Widgets/TerminalWidget.h b/Widgets/TerminalWidget.h
new file mode 100644
index 0000000000..ba77c5d10a
--- /dev/null
+++ b/Widgets/TerminalWidget.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include "Widget.h"
+#include <AK/ByteBuffer.h>
+
+struct CharacterWithAttributes {
+    byte character;
+    byte attribute;
+};
+
+class TerminalWidget final : public Widget {
+public:
+    explicit TerminalWidget(Widget* parent);
+    virtual ~TerminalWidget() override;
+
+    unsigned rows() const { return m_rows; }
+    unsigned columns() const { return m_columns; }
+    
+private:
+    CharacterWithAttributes& at(unsigned row, unsigned column);
+
+    virtual void onPaint(PaintEvent&) override;
+    void onReceive(const ByteBuffer&);
+    void onReceive(byte);
+
+    unsigned m_columns { 80 };
+    unsigned m_rows { 25 };
+
+    unsigned m_cursorRow { 0 };
+    unsigned m_cursorColumn { 0 };
+
+    CharacterWithAttributes* m_screen { nullptr };
+};
diff --git a/Widgets/test.cpp b/Widgets/test.cpp
index b6d437041a..60426f7268 100644
--- a/Widgets/test.cpp
+++ b/Widgets/test.cpp
@@ -3,6 +3,7 @@
 #include "RootWidget.h"
 #include "Label.h"
 #include "Button.h"
+#include "TerminalWidget.h"
 #include <cstdio>
 
 int main(int c, char** v)
@@ -31,13 +32,11 @@ int main(int c, char** v)
     l4->setRect(Rect(100, 160, 300, 20));
     l4->setText("!\"#$%&'()*+,-./:;<=>?@[\\]^_{|}~");
 
-    auto* l5 = new Label(&w);
-    l5->setRect(Rect(200, 200, 400, 50));
-    l5->setText("Welcome to the Serenity Operating System");
-
     auto* b = new Button(&w);
     b->setRect(Rect(10, 10, 100, 30));
     b->setCaption("Button!");
 
+    auto* t = new TerminalWidget(&w);
+
     return loop.exec();
 }