import { chars } from './utils.ts';
import Row from './row.ts';
import { getRuntime } from './runtime.ts';
import { Position, SCROLL_TAB_SIZE } from './mod.ts';

export class Document {
	#filename: string | null;
	#rows: Row[];
	dirty: boolean;

	private constructor() {
		this.#rows = [];
		this.#filename = null;
		this.dirty = false;
	}

	get numRows(): number {
		return this.#rows.length;
	}

	public static empty(): Document {
		return new Document();
	}

	public isEmpty(): boolean {
		return this.#rows.length === 0;
	}

	public async open(filename: string): Promise<Document> {
		const { file } = await getRuntime();

		// Clear any existing rows
		if (!this.isEmpty()) {
			this.#rows = [];
		}

		const rawFile = await file.openFile(filename);
		rawFile.split(/\r?\n/)
			.forEach((row) => this.appendRow(row));

		this.#filename = filename;
		this.dirty = false;

		return this;
	}

	public async save() {
		if (this.#filename === null) {
			return;
		}

		const { file } = await getRuntime();

		await file.saveFile(this.#filename, this.rowsToString());

		this.dirty = false;
	}

	public insert(at: Position, c: string): void {
		if (at.y === this.numRows) {
			this.appendRow(c);
		} else {
			this.#rows[at.y].insertChar(at.x, c);
			this.updateRow(this.#rows[at.y]);
		}

		this.dirty = true;
	}

	public row(i: number): Row | null {
		return this.#rows[i] ?? null;
	}

	public appendRow(s: string): void {
		const at = this.numRows;
		this.#rows[at] = new Row(s);
		this.updateRow(this.#rows[at]);

		this.dirty = true;
	}

	private updateRow(r: Row): void {
		r.render = chars(r.toString().replace('\t', ' '.repeat(SCROLL_TAB_SIZE)));
	}

	private rowsToString(): string {
		return this.#rows.map((r) => r.toString()).join('\n');
	}
}

export default Document;