import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';

const mockSaveFn = vi.fn<(blockId: string, text: string) => Promise<void>>();

const { createBlockAutoSave } = await import('../useBlockAutoSave.svelte');

describe('createBlockAutoSave', () => {
	beforeEach(() => {
		vi.useFakeTimers();
		mockSaveFn.mockClear();
		mockSaveFn.mockResolvedValue(undefined);
	});

	afterEach(() => {
		vi.useRealTimers();
	});

	it('getSaveState returns idle initially', () => {
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		expect(as.getSaveState('block-1')).toBe('idle');
	});

	it('debounce coalesces multiple changes — saves once after 1500ms', async () => {
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		as.handleTextChange('block-1', 'text 1');
		as.handleTextChange('block-1', 'text 2');
		as.handleTextChange('block-1', 'text 3');
		await vi.advanceTimersByTimeAsync(1500);
		expect(mockSaveFn).toHaveBeenCalledTimes(1);
		expect(mockSaveFn).toHaveBeenCalledWith('block-1', 'text 3');
	});

	it('handles concurrent blocks independently', async () => {
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		as.handleTextChange('block-1', 'hello');
		as.handleTextChange('block-2', 'world');
		await vi.advanceTimersByTimeAsync(1500);
		expect(mockSaveFn).toHaveBeenCalledTimes(2);
	});

	it('sets save state to saving then saved on success', async () => {
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		as.handleTextChange('block-1', 'text');
		vi.advanceTimersByTime(1500);
		expect(as.getSaveState('block-1')).toBe('saving');
		await Promise.resolve();
		expect(as.getSaveState('block-1')).toBe('saved');
	});

	it('sets save state to error on save failure', async () => {
		mockSaveFn.mockRejectedValue(new Error('save failed'));
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		as.handleTextChange('block-1', 'text');
		await vi.advanceTimersByTimeAsync(1500);
		expect(as.getSaveState('block-1')).toBe('error');
	});

	it('handleRetry saves with provided current text', async () => {
		mockSaveFn.mockRejectedValueOnce(new Error('first fails'));
		mockSaveFn.mockResolvedValueOnce(undefined);
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		as.handleTextChange('block-1', 'original');
		await vi.advanceTimersByTimeAsync(1500);
		expect(as.getSaveState('block-1')).toBe('error');
		await as.handleRetry('block-1', 'original');
		expect(mockSaveFn).toHaveBeenCalledTimes(2);
		expect(as.getSaveState('block-1')).toBe('saved');
	});

	it('clearBlock removes all state for a block', () => {
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		as.handleTextChange('block-1', 'text');
		as.clearBlock('block-1');
		expect(as.getSaveState('block-1')).toBe('idle');
	});

	it('destroy clears all pending timers so no save occurs', async () => {
		const as = createBlockAutoSave({ saveFn: mockSaveFn, documentId: 'doc-1' });
		as.handleTextChange('block-1', 'text');
		as.destroy();
		await vi.advanceTimersByTimeAsync(2000);
		expect(mockSaveFn).not.toHaveBeenCalled();
	});
});