From 4296930dae002af8b043df7a9c999701a215a93d Mon Sep 17 00:00:00 2001
From: "Timothy J. Warren" <tim@timshome.page>
Date: Mon, 13 Nov 2023 14:46:04 -0500
Subject: [PATCH] Start of documents

---
 README.md                     | 16 +++++----
 src/common/editor/ansi.ts     |  1 +
 src/common/editor/document.ts | 49 ++++++++++++++++++++++++++
 src/common/editor/editor.ts   | 65 ++++++++++++++++++++++-------------
 4 files changed, 100 insertions(+), 31 deletions(-)
 create mode 100644 src/common/editor/document.ts

diff --git a/README.md b/README.md
index 975fd77..c05c319 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,15 @@
 # Scroll
 
-Making a text editor in Typescript based on Kilo (Script + Kilo = Scroll).
-This runs on [Bun](https://bun.sh/) and [Deno](https://deno.com/). 
+Making a text editor in Typescript based on Kilo (Script + Kilo = Scroll). This
+runs on [Bun](https://bun.sh/) and [Deno](https://deno.com/).
 
 To simplify running, I'm using [Just](https://github.com/casey/just)
-* Bun: `just bun-run`
-* Deno: `just deno-run`
+
+- Bun: `just bun-run`
+- Deno: `just deno-run`
 
 ## Development Notes
-* Runtime differences are adapted into a common interface
-* Runtime implementations are in the `src/deno` and `src/bun` folders
-* The main implementation is in `src/common`
\ No newline at end of file
+
+- Runtime differences are adapted into a common interface
+- Runtime implementations are in the `src/deno` and `src/bun` folders
+- The main implementation is in `src/common`
diff --git a/src/common/editor/ansi.ts b/src/common/editor/ansi.ts
index bb5c20a..aa4d616 100644
--- a/src/common/editor/ansi.ts
+++ b/src/common/editor/ansi.ts
@@ -14,6 +14,7 @@ export enum KeyCommand {
 	ArrowLeft = ANSI_PREFIX + 'D',
 	PageUp = ANSI_PREFIX + '5~',
 	PageDown = ANSI_PREFIX + '6~',
+	Delete = ANSI_PREFIX + '3~',
 
 	// These keys have several possible escape sequences
 	Home = 'LineHome',
diff --git a/src/common/editor/document.ts b/src/common/editor/document.ts
new file mode 100644
index 0000000..b5cfbd1
--- /dev/null
+++ b/src/common/editor/document.ts
@@ -0,0 +1,49 @@
+import { chars } from '../utils.ts';
+
+export class Row {
+	chars: string[] = [];
+
+	constructor(s: string = '') {
+		this.chars = chars(s);
+	}
+
+	public toString(): string {
+		return this.chars.join('');
+	}
+}
+
+export class Document {
+	#rows: Row[];
+
+	private constructor() {
+		this.#rows = [];
+	}
+
+	get numrows(): number {
+		return this.#rows.length;
+	}
+
+	public static empty(): Document {
+		return new Document();
+	}
+
+	public static open(): Document {
+		const doc = new Document();
+		const line = 'Hello, World!';
+		const row = new Row(line);
+
+		doc.#rows.push(row);
+
+		return doc;
+	}
+
+	public getRow(i: number): Row | null {
+		if (this.#rows[i] !== undefined) {
+			return this.#rows[i];
+		}
+
+		return null;
+	}
+}
+
+export default Document;
diff --git a/src/common/editor/editor.ts b/src/common/editor/editor.ts
index e2288ed..809a401 100644
--- a/src/common/editor/editor.ts
+++ b/src/common/editor/editor.ts
@@ -1,11 +1,13 @@
 import Ansi, { KeyCommand } from './ansi.ts';
 import Buffer from './buffer.ts';
+import Document from './document.ts';
 import { ctrl_key, IPoint, ITerminalSize, truncate, VERSION } from '../mod.ts';
 
 export class Editor {
 	#buffer: Buffer;
 	#screen: ITerminalSize;
 	#cursor: IPoint;
+	#document: Document;
 	constructor(terminalSize: ITerminalSize) {
 		this.#buffer = new Buffer();
 		this.#screen = terminalSize;
@@ -13,6 +15,7 @@ export class Editor {
 			x: 0,
 			y: 0,
 		};
+		this.#document = Document.open();
 	}
 
 	// --------------------------------------------------------------------------
@@ -114,33 +117,47 @@ export class Editor {
 	}
 
 	private drawRows(): void {
-		this.drawPlaceholderRows();
-	}
-
-	private drawPlaceholderRows(): void {
 		for (let y = 0; y < this.#screen.rows; y++) {
-			if (y === Math.trunc(this.#screen.rows / 2)) {
-				const message = `Kilo editor -- version ${VERSION}`;
-				const messageLen = (message.length > this.#screen.cols)
-					? this.#screen.cols
-					: message.length;
-				let padding = Math.trunc((this.#screen.cols - messageLen) / 2);
-				if (padding > 0) {
-					this.#buffer.append('~');
-					padding -= 1;
-
-					this.#buffer.append(' '.repeat(padding));
-				}
-
-				this.#buffer.append(truncate(message, messageLen));
+			if (y >= this.#document.numrows) {
+				this.drawPlaceholderRow(y);
 			} else {
-				this.#buffer.append('~');
-			}
-
-			this.#buffer.append(Ansi.ClearLine);
-			if (y < this.#screen.rows - 1) {
-				this.#buffer.appendLine('');
+				this.drawFileRow(y);
 			}
 		}
 	}
+
+	private drawFileRow(_y: number): void {
+		const row = this.#document.getRow(0);
+		let len = row?.chars.length ?? 0;
+		if (len > this.#screen.cols) {
+			len = this.#screen.cols;
+		}
+
+		this.#buffer.appendLine(truncate(row!.toString(), len));
+	}
+
+	private drawPlaceholderRow(y: number): void {
+		if (y === Math.trunc(this.#screen.rows / 2)) {
+			const message = `Kilo editor -- version ${VERSION}`;
+			const messageLen = (message.length > this.#screen.cols)
+				? this.#screen.cols
+				: message.length;
+			let padding = Math.trunc((this.#screen.cols - messageLen) / 2);
+			if (padding > 0) {
+				this.#buffer.append('~');
+				padding -= 1;
+
+				this.#buffer.append(' '.repeat(padding));
+			}
+
+			this.#buffer.append(truncate(message, messageLen));
+		} else {
+			this.#buffer.append('~');
+		}
+
+		this.#buffer.append(Ansi.ClearLine);
+		if (y < this.#screen.rows - 1) {
+			this.#buffer.appendLine('');
+		}
+	}
 }