Add cursor position conversions

frontend/obsidian-plugin/src/utils/line-and-column-to-position.test.ts

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+import { lineAndColumnToPosition } from "./line-and-column-to-position";
+
+describe("lineAndColumnToPosition", () => {
+	it("should return the correct position for the first line", () => {
+		const text = "Hello\nWorld";
+		const position = lineAndColumnToPosition(text, 0, 3);
+		expect(position).toBe(3);
+	});
+
+	it("should return the correct position for the second line", () => {
+		const text = "Hello\nWorld";
+		const position = lineAndColumnToPosition(text, 1, 2);
+		expect(position).toBe(8);
+	});
+
+	it("should return the correct position for an empty string", () => {
+		const text = "";
+		const position = lineAndColumnToPosition(text, 0, 0);
+		expect(position).toBe(0);
+	});
+
+	it("should handle a single-line string correctly", () => {
+		const text = "SingleLine";
+		const position = lineAndColumnToPosition(text, 0, 5);
+		expect(position).toBe(5);
+	});
+
+	it("should handle multi-line strings with varying lengths", () => {
+		const text = "Line1\nLongerLine2\nShort3";
+		const position = lineAndColumnToPosition(text, 2, 4);
+		expect(position).toBe(22);
+	});
+
+	it("should throw an error if the line number is out of range", () => {
+		const text = "Line1\nLine2";
+		expect(() => lineAndColumnToPosition(text, 3, 0)).toThrow();
+	});
+
+	it("should throw an error if the column number is out of range", () => {
+		const text = "Line1\nLine2";
+		expect(() => lineAndColumnToPosition(text, 1, 10)).toThrow();
+	});
+});

frontend/obsidian-plugin/src/utils/line-and-column-to-position.ts

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+/**
+ * Converts line and column coordinates to an absolute character position in a text string.
+ *
+ * @param line - The zero-based line number
+ * @param column - The zero-based column number
+ * @param text - The text string to calculate position in
+ * @returns The absolute character position (zero-based index) in the text string
+ * @throws Error if line number is out of range
+ * @throws Error if column number is out of range
+ */
+export function lineAndColumnToPosition(
+	text: string,
+	line: number,
+	column: number
+): number {
+	const lines = text.split("\n");
+
+	if (line >= lines.length) {
+		throw new Error(`Line number ${line} is out of range.`);
+	}
+
+	if (column > lines[line].length) {
+		throw new Error(`Column number ${column} is out of range.`);
+	}
+
+	let position = 0;
+	for (let i = 0; i < line; i++) {
+		position += lines[i].length + 1;
+	}
+
+	position += column;
+
+	return position;
+}

frontend/obsidian-plugin/src/utils/position-to-line-and-column.test.ts

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+import { positionToLineAndColumn } from "./position-to-line-and-column";
+
+describe("positionToLineAndColumn", () => {
+	test("converts position to line and column in a single line text", () => {
+		const text = "Hello, world!";
+		expect(positionToLineAndColumn(text, 0)).toEqual({
+			line: 0,
+			column: 1
+		});
+		expect(positionToLineAndColumn(text, 7)).toEqual({
+			line: 0,
+			column: 8
+		});
+		expect(positionToLineAndColumn(text, 12)).toEqual({
+			line: 0,
+			column: 13
+		});
+	});
+
+	test("converts position to line and column in multi-line text", () => {
+		const text = "First line\nSecond line\nThird line";
+		expect(positionToLineAndColumn(text, 0)).toEqual({
+			line: 0,
+			column: 1
+		});
+		expect(positionToLineAndColumn(text, 10)).toEqual({
+			line: 0,
+			column: 11
+		});
+		expect(positionToLineAndColumn(text, 15)).toEqual({
+			line: 1,
+			column: 5
+		});
+		expect(positionToLineAndColumn(text, 26)).toEqual({
+			line: 2,
+			column: 4
+		});
+	});
+
+	test("handles positions at line breaks", () => {
+		const text = "Line\nBreak";
+		expect(positionToLineAndColumn(text, 4)).toEqual({
+			line: 0,
+			column: 5
+		});
+		expect(positionToLineAndColumn(text, 5)).toEqual({
+			line: 1,
+			column: 1
+		});
+	});
+
+	test("handles empty input", () => {
+		expect(positionToLineAndColumn("", 0)).toEqual({ line: 0, column: 1 });
+	});
+
+	test("handles positions at the end of text", () => {
+		const text = "End";
+		expect(positionToLineAndColumn(text, 3)).toEqual({
+			line: 0,
+			column: 4
+		});
+	});
+
+	test("throws error for position out of range", () => {
+		const text = "Short text";
+		expect(() => positionToLineAndColumn(text, 15)).toThrow();
+		expect(() => positionToLineAndColumn(text, -1)).toThrow();
+	});
+});

frontend/obsidian-plugin/src/utils/position-to-line-and-column.ts

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+/**
+ * Converts a character position in text to line and column numbers.
+ *
+ * @param text The text content to analyze
+ * @param position The character position to convert
+ * @returns An object containing line and column numbers (0-based index for line, 1-based index for column)
+ * @throws Will throw an error if the position is negative or exceeds the text length
+ */
+export function positionToLineAndColumn(
+	text: string,
+	position: number
+): { line: number; column: number } {
+	if (position < 0) {
+		throw new Error("Position cannot be negative");
+	}
+
+	if (position > text.length) {
+		throw new Error(
+			`Position ${position} exceeds text length ${text.length}`
+		);
+	}
+
+	const textUpToPosition = text.substring(0, position);
+	const lines = textUpToPosition.split("\n");
+
+	const line = lines.length - 1; // 0-based index
+	const column = lines[lines.length - 1].length + 1; // 1-based index
+
+	return { line, column };
+}