import { Category } from '@/types/category';
import { describe, expect, it } from 'vitest';

import {
    categorySelectionState,
    toggleCategorySelection,
} from './category-tree';

function category(id: string, parent_id: string | null): Category {
    return {
        id,
        name: id,
        icon: 'Tag',
        color: 'gray',
        type: 'expense',
        cashflow_direction: 'hidden',
        parent_id,
    } as Category;
}

// food ──┬─ groceries ── coffee
//        └─ restaurants
// drinks (root)
const categories: Category[] = [
    category('food', null),
    category('groceries', 'food'),
    category('restaurants', 'food'),
    category('coffee', 'groceries'),
    category('drinks', null),
];

const stateOf = (id: string, selected: string[]) =>
    categorySelectionState(id, new Set(selected), categories);

describe('categorySelectionState', () => {
    it('marks a category and its descendants checked when the parent is selected', () => {
        expect(stateOf('food', ['food'])).toBe('checked');
        expect(stateOf('groceries', ['food'])).toBe('checked');
        expect(stateOf('coffee', ['food'])).toBe('checked');
        expect(stateOf('drinks', ['food'])).toBe('unchecked');
    });

    it('marks ancestors indeterminate when only a descendant is selected', () => {
        expect(stateOf('food', ['coffee'])).toBe('indeterminate');
        expect(stateOf('groceries', ['coffee'])).toBe('indeterminate');
        expect(stateOf('coffee', ['coffee'])).toBe('checked');
    });
});

describe('toggleCategorySelection', () => {
    it('selecting a parent collapses to a single id covering the subtree', () => {
        expect(toggleCategorySelection([], 'food', categories)).toEqual([
            'food',
        ]);
    });

    it('unselecting one child keeps its siblings selected', () => {
        const result = toggleCategorySelection(
            ['food'],
            'restaurants',
            categories,
        );

        expect(result).not.toContain('food');
        expect(result).not.toContain('restaurants');
        expect(stateOf('groceries', result)).toBe('checked');
        expect(stateOf('restaurants', result)).toBe('unchecked');
        expect(stateOf('food', result)).toBe('indeterminate');
    });

    it('re-selecting a sibling does not auto-collapse to the parent, but clicking the parent does', () => {
        const partial = toggleCategorySelection(
            ['food'],
            'restaurants',
            categories,
        );
        const reselected = toggleCategorySelection(
            partial,
            'restaurants',
            categories,
        );

        // Both children selected individually; the parent is not auto-added.
        expect(reselected).not.toContain('food');
        expect(stateOf('groceries', reselected)).toBe('checked');
        expect(stateOf('restaurants', reselected)).toBe('checked');

        // Clicking the parent collapses the whole subtree to a single id.
        expect(toggleCategorySelection(reselected, 'food', categories)).toEqual(
            ['food'],
        );
    });

    it('selecting a single child never pulls in its parent', () => {
        const result = toggleCategorySelection([], 'coffee', categories);

        expect(result).toEqual(['coffee']);
        expect(stateOf('groceries', result)).toBe('indeterminate');
        expect(stateOf('food', result)).toBe('indeterminate');
    });
});