Implement backwards/forwards searching

src/common/document.ts

@@ -1,10 +1,53 @@
 import Row from './row.ts';
 import { arrayInsert } from './fns.ts';
 import { getRuntime } from './runtime.ts';
-import { Position } from './types.ts';
+import { Position, SearchDirection } from './types.ts';
+import { KeyCommand } from './ansi.ts';
+
+class Search {
+	public lastMatch: number = -1;
+	public current: number = -1;
+	public direction: SearchDirection = SearchDirection.Forward;
+
+	public parseInput(key: string) {
+		switch (key) {
+			case KeyCommand.ArrowRight:
+			case KeyCommand.ArrowDown:
+				this.direction = SearchDirection.Forward;
+				break;
+
+			case KeyCommand.ArrowLeft:
+			case KeyCommand.ArrowUp:
+				this.direction = SearchDirection.Backward;
+				break;
+
+			default:
+				this.lastMatch = -1;
+				this.direction = SearchDirection.Forward;
+		}
+
+		if (this.lastMatch === -1) {
+			this.direction = SearchDirection.Forward;
+		}
+
+		this.current = this.lastMatch;
+	}
+
+	public getNextRow(rowCount: number): number {
+		this.current += this.direction;
+		if (this.current === -1) {
+			this.current = rowCount - 1;
+		} else if (this.current === rowCount) {
+			this.current = 0;
+		}
+
+		return this.current;
+	}
+}
 
 export class Document {
 	#rows: Row[];
+	#search: Search;
 
 	/**
 	 * Has the document been modified?
@@ -13,6 +56,7 @@ export class Document {
 
 	private constructor() {
 		this.#rows = [];
+		this.#search = new Search();
 		this.dirty = false;
 	}
 
@@ -53,15 +97,24 @@ export class Document {
 		this.dirty = false;
 	}
 
+	public resetFind() {
+		this.#search = new Search();
+	}
+
 	public find(
 		q: string,
-		offset: Position = Position.default(),
+		key: string,
 	): Position | null {
-		let i = offset.y;
+		this.#search.parseInput(key);
+
+		let i = 0;
 		for (; i < this.numRows; i++) {
-			const possible = this.#rows[i].find(q, offset.x);
+			const current = this.#search.getNextRow(this.numRows);
+
+			const possible = this.#rows[current].find(q);
 			if (possible !== null) {
-				return Position.at(possible, i);
+				this.#search.lastMatch = current;
+				return Position.at(possible, current);
 			}
 		}
 

src/common/editor.ts

@@ -302,14 +302,15 @@ class Editor {
 		const savedOffset = Position.from(this.#offset);
 
 		const query = await this.prompt(
-			'Search: %s (ESC to cancel)',
+			'Search: %s (Use ESC/Arrows/Enter)',
 			(query: string, key: string) => {
 				if (key === KeyCommand.Enter || key === KeyCommand.Escape) {
+					this.#document.resetFind();
 					return;
 				}
 
 				if (query !== null && query.length > 0) {
-					const pos = this.#document.find(query);
+					const pos = this.#document.find(query, key);
 					if (pos !== null) {
 						this.#cursor = pos;
 					} else {