import type { MarkdownTree } from '../app/utils/markdown';
import { expect, test } from 'bun:test';
import { splitParagraphBreaks } from '../app/utils/markdown';

test('paragraph splitting preserves nested formatting without mutating a cached parser tree', () => {
    const tree = { nodes: [
        ['p', {}, 'before', ['br', {}], ['strong', {}, 'after']],
        ['blockquote', {}, 'one', ['br', {}], ['em', {}, 'two']],
    ] } as MarkdownTree;
    const original = structuredClone(tree);
    const result = splitParagraphBreaks(tree);
    expect(result.nodes).toEqual([
        ['p', {}, 'before'],
        ['p', {}, ['strong', {}, 'after']],
        ['blockquote', {}, ['p', {}, 'one'], ['p', {}, ['em', {}, 'two']]],
    ]);
    expect(tree).toEqual(original);
    expect(splitParagraphBreaks(tree)).toEqual(result);
});

test('br-free trees return by reference with no allocation', () => {
    const tree = { nodes: [
        ['p', {}, 'plain ', ['strong', {}, 'text']],
        ['ul', {}, ['li', {}, 'one'], ['li', {}, 'two']],
    ] } as MarkdownTree;
    expect(splitParagraphBreaks(tree)).toBe(tree);
});

test('single newlines still split into sibling paragraphs', () => {
    const tree = { nodes: [
        ['p', {}, 'line one', ['br', {}], 'line two'],
    ] } as MarkdownTree;
    expect(splitParagraphBreaks(tree).nodes).toEqual([
        ['p', {}, 'line one'],
        ['p', {}, 'line two'],
    ]);
});

test('nested changes rebuild only the affected path', () => {
    const tree = { nodes: [
        ['blockquote', {}, ['p', {}, 'kept']],
        ['p', {}, 'split', ['br', {}], 'me'],
    ] } as MarkdownTree;
    const result = splitParagraphBreaks(tree);
    expect(result).not.toBe(tree);
    expect(result.nodes[0]).toBe(tree.nodes[0]);
    expect(result.nodes).toEqual([
        ['blockquote', {}, ['p', {}, 'kept']],
        ['p', {}, 'split'],
        ['p', {}, 'me'],
    ]);
});