const { setupDatabaseAndSynchronizer, switchClient, createNTestNotes, createNTestFolders, createNTestTags } = require('./testing/test-utils.js');
const reducer = require('./reducer').default;
const { defaultState, MAX_HISTORY } = require('./reducer');
const { ALL_NOTES_FILTER_ID } = require('./reserved-ids');

function initTestState(folders, selectedFolderIndex, notes, selectedNoteIndexes, tags = null, selectedTagIndex = null) {
	let state = defaultState;

	if (selectedFolderIndex != null) {
		state = reducer(state, { type: 'FOLDER_SELECT', id: folders[selectedFolderIndex].id });
	}
	if (folders != null) {
		state = reducer(state, { type: 'FOLDER_UPDATE_ALL', items: folders });
	}
	if (notes != null) {
		state = reducer(state, { type: 'NOTE_UPDATE_ALL', notes: notes, noteSource: 'test' });
	}
	if (selectedNoteIndexes != null) {
		const selectedIds = [];
		for (let i = 0; i < selectedNoteIndexes.length; i++) {
			selectedIds.push(notes[selectedNoteIndexes[i]].id);
		}
		state = reducer(state, { type: 'NOTE_SELECT', ids: selectedIds });
	}
	if (tags != null) {
		state = reducer(state, { type: 'TAG_UPDATE_ALL', items: tags });
	}
	if (selectedTagIndex != null) {
		state = reducer(state, { type: 'TAG_SELECT', id: tags[selectedTagIndex].id });
	}

	return state;
}

function goToNote(notes, selectedNoteIndexes, state) {
	if (selectedNoteIndexes != null) {
		const selectedIds = [];
		for (let i = 0; i < selectedNoteIndexes.length; i++) {
			selectedIds.push(notes[selectedNoteIndexes[i]].id);
		}
		state = reducer(state, { type: 'NOTE_SELECT', ids: selectedIds });
	}
	return state;
}

function goBackWard(state) {
	if (!state.backwardHistoryNotes.length)	return state;
	state = reducer(state, {
		type: 'HISTORY_BACKWARD',
	});
	return state;
}

function goForward(state) {
	if (!state.forwardHistoryNotes.length)	return state;
	state = reducer(state, {
		type: 'HISTORY_FORWARD',
	});
	return state;
}

function createExpectedState(items, keepIndexes, selectedIndexes) {
	const expected = { items: [], selectedIds: [] };

	for (let i = 0; i < selectedIndexes.length; i++) {
		expected.selectedIds.push(items[selectedIndexes[i]].id);
	}
	for (let i = 0; i < keepIndexes.length; i++) {
		expected.items.push(items[keepIndexes[i]]);
	}
	return expected;
}

function getIds(items, indexes = null) {
	const ids = [];
	for (let i = 0; i < items.length; i++) {
		if (indexes == null || i in indexes) {
			ids.push(items[i].id);
		}
	}
	return ids;
}

describe('reducer', function() {

	beforeEach(async (done) => {
		await setupDatabaseAndSynchronizer(1);
		await switchClient(1);

		done();
	});

	// tests for NOTE_DELETE
	it('should delete selected note', (async () => {
		// create 1 folder
		const folders = await createNTestFolders(1);
		// create 5 notes
		const notes = await createNTestNotes(5, folders[0]);
		// select the 1st folder and the 3rd note
		let state = initTestState(folders, 0, notes, [2]);

		// test action
		// delete the third note
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[2].id });

		// expect that the third note is missing, and the 4th note is now selected
		const expected = createExpectedState(notes, [0,1,3,4], [3]);

		// check the ids of all the remaining notes
		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		// check the ids of the selected notes
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete selected note at top', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [1]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[0].id });

		const expected = createExpectedState(notes, [1,2,3,4], [1]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete last remaining note', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(1, folders[0]);
		let state = initTestState(folders, 0, notes, [0]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[0].id });

		const expected = createExpectedState(notes, [], []);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete selected note at bottom', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [4]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[4].id });

		const expected = createExpectedState(notes, [0,1,2,3], [3]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete note when a note below is selected', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [3]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[1].id });

		const expected = createExpectedState(notes, [0,2,3,4], [3]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete note when a note above is selected', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [1]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[3].id });

		const expected = createExpectedState(notes, [0,1,2,4], [1]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete selected notes', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [1,2]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[1].id });
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[2].id });

		const expected = createExpectedState(notes, [0,3,4], [3]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete note when a notes below it are selected', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [3,4]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[1].id });

		const expected = createExpectedState(notes, [0,2,3,4], [3,4]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete note when a notes above it are selected', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [1,2]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[3].id });

		const expected = createExpectedState(notes, [0,1,2,4], [1,2]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete notes at end', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [3,4]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[3].id });
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[4].id });

		const expected = createExpectedState(notes, [0,1,2], [2]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should delete notes when non-contiguous selection', (async () => {
		const folders = await createNTestFolders(1);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 0, notes, [0,2,4]);

		// test action
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[0].id });
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[2].id });
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[4].id });

		const expected = createExpectedState(notes, [1,3], [1]);

		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	// tests for FOLDER_DELETE
	it('should delete selected notebook', (async () => {
		const folders = await createNTestFolders(5);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 2, notes, [2]);

		// test action
		state = reducer(state, { type: 'FOLDER_DELETE', id: folders[2].id });

		const expected = createExpectedState(folders, [0,1,3,4], [3]);

		expect(getIds(state.folders)).toEqual(getIds(expected.items));
		expect(state.selectedFolderId).toEqual(expected.selectedIds[0]);
	}));

	it('should delete notebook when a book above is selected', (async () => {
		const folders = await createNTestFolders(5);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 1, notes, [2]);

		// test action
		state = reducer(state, { type: 'FOLDER_DELETE', id: folders[2].id });

		const expected = createExpectedState(folders, [0,1,3,4], [1]);

		expect(getIds(state.folders)).toEqual(getIds(expected.items));
		expect(state.selectedFolderId).toEqual(expected.selectedIds[0]);
	}));

	it('should delete notebook when a book below is selected', (async () => {
		const folders = await createNTestFolders(5);
		const notes = await createNTestNotes(5, folders[0]);
		let state = initTestState(folders, 4, notes, [2]);

		// test action
		state = reducer(state, { type: 'FOLDER_DELETE', id: folders[2].id });

		const expected = createExpectedState(folders, [0,1,3,4], [4]);

		expect(getIds(state.folders)).toEqual(getIds(expected.items));
		expect(state.selectedFolderId).toEqual(expected.selectedIds[0]);
	}));

	// tests for TAG_DELETE
	it('should delete selected tag', (async () => {
		const tags = await createNTestTags(5);
		let state = initTestState(null, null, null, null, tags, [2]);

		// test action
		state = reducer(state, { type: 'TAG_DELETE', id: tags[2].id });

		const expected = createExpectedState(tags, [0,1,3,4], [3]);

		expect(getIds(state.tags)).toEqual(getIds(expected.items));
		expect(state.selectedTagId).toEqual(expected.selectedIds[0]);
	}));

	it('should delete tag when a tag above is selected', (async () => {
		const tags = await createNTestTags(5);
		let state = initTestState(null, null, null, null, tags, [2]);

		// test action
		state = reducer(state, { type: 'TAG_DELETE', id: tags[4].id });

		const expected = createExpectedState(tags, [0,1,2,3], [2]);

		expect(getIds(state.tags)).toEqual(getIds(expected.items));
		expect(state.selectedTagId).toEqual(expected.selectedIds[0]);
	}));

	it('should delete tag when a tag below is selected', (async () => {
		const tags = await createNTestTags(5);
		let state = initTestState(null, null, null, null, tags, [2]);

		// test action
		state = reducer(state, { type: 'TAG_DELETE', id: tags[0].id });

		const expected = createExpectedState(tags, [1,2,3,4], [2]);

		expect(getIds(state.tags)).toEqual(getIds(expected.items));
		expect(state.selectedTagId).toEqual(expected.selectedIds[0]);
	}));

	it('should select all notes', (async () => {
		const folders = await createNTestFolders(2);
		const notes = [];
		for (let i = 0; i < folders.length; i++) {
			notes.push(...await createNTestNotes(3, folders[i]));
		}

		let state = initTestState(folders, 0, notes.slice(0,3), [0]);

		let expected = createExpectedState(notes, [0,1,2], [0]);

		expect(state.notes.length).toEqual(expected.items.length);
		expect(getIds(state.notes.slice(0,4))).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);

		// test action
		state = reducer(state, { type: 'NOTE_SELECT_ALL' });

		expected = createExpectedState(notes.slice(0,3), [0,1,2], [0,1,2]);
		expect(getIds(state.notes)).toEqual(getIds(expected.items));
		expect(state.selectedNoteIds).toEqual(expected.selectedIds);
	}));

	it('should remove deleted note from history', (async () => {

		// create 1 folder
		const folders = await createNTestFolders(1);
		// create 5 notes
		const notes = await createNTestNotes(5, folders[0]);
		// select the 1st folder and the 1st note
		let state = initTestState(folders, 0, notes, [0]);

		// select second note
		state = goToNote(notes, [1], state);
		// select third note
		state = goToNote(notes, [2], state);
		// select fourth note
		state = goToNote(notes, [3], state);

		// expect history to contain first, second and third note
		expect(state.backwardHistoryNotes.length).toEqual(3);
		expect(getIds(state.backwardHistoryNotes)).toEqual(getIds(notes.slice(0, 3)));

		// delete third note
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[2].id });

		// expect history to not contain third note
		expect(getIds(state.backwardHistoryNotes)).not.toContain(notes[2].id);
	}));

	it('should remove all notes of a deleted notebook from history', (async () => {
		const folders = await createNTestFolders(2);
		const notes = [];
		for (let i = 0; i < folders.length; i++) {
			notes.push(...await createNTestNotes(3, folders[i]));
		}

		let state = initTestState(folders, 0, notes.slice(0,3), [0]);
		state = goToNote(notes, [1], state);
		state = goToNote(notes, [2], state);


		// go to second folder
		state = reducer(state, { type: 'FOLDER_SELECT', id: folders[1].id });
		expect(getIds(state.backwardHistoryNotes)).toEqual(getIds(notes.slice(0, 3)));

		// delete the first folder
		state = reducer(state, { type: 'FOLDER_DELETE', id: folders[0].id });

		expect(getIds(state.backwardHistoryNotes)).toEqual([]);
	}));

	it('should maintain history correctly when going backward and forward', (async () => {
		const folders = await createNTestFolders(2);
		const notes = [];
		for (let i = 0; i < folders.length; i++) {
			notes.push(...await createNTestNotes(5, folders[i]));
		}

		let state = initTestState(folders, 0, notes.slice(0,5), [0]);
		state = goToNote(notes, [1], state);
		state = goToNote(notes, [2], state);
		state = goToNote(notes, [3], state);
		state = goToNote(notes, [4], state);

		expect(getIds(state.backwardHistoryNotes)).toEqual(getIds(notes.slice(0, 4)));

		state = goBackWard(state);
		expect(getIds(state.backwardHistoryNotes)).toEqual(getIds(notes.slice(0,3)));
		expect(getIds(state.forwardHistoryNotes)).toEqual(getIds(notes.slice(4, 5)));

		state = goBackWard(state);
		expect(getIds(state.backwardHistoryNotes)).toEqual(getIds(notes.slice(0,2)));
		// because we push the last seen note to stack.
		expect(getIds(state.forwardHistoryNotes)).toEqual(getIds([notes[4], notes[3]]));

		state = goForward(state);
		expect(getIds(state.backwardHistoryNotes)).toEqual(getIds(notes.slice(0,3)));
		expect(getIds(state.forwardHistoryNotes)).toEqual(getIds([notes[4]]));

		state = goForward(state);
		expect(getIds(state.backwardHistoryNotes)).toEqual(getIds(notes.slice(0,4)));
		expect(getIds(state.forwardHistoryNotes)).toEqual([]);
	}));

	it('should remember the last seen note of a notebook', (async () => {
		const folders = await createNTestFolders(2);
		const notes = [];
		for (let i = 0; i < folders.length; i++) {
			notes.push(...await createNTestNotes(5, folders[i]));
		}

		let state = initTestState(folders, 0, notes.slice(0,5), [0]);

		state = goToNote(notes, [1], state);
		state = goToNote(notes, [2], state);
		state = goToNote(notes, [3], state);
		state = goToNote(notes, [4], state); // last seen note is notes[4]
		// go to second folder
		state = reducer(state, { type: 'FOLDER_SELECT', id: folders[1].id });
		state = goToNote(notes, [5], state);
		state = goToNote(notes, [6], state);

		// return to first folder
		state = reducer(state, { type: 'FOLDER_SELECT', id: folders[0].id });

		expect(state.lastSelectedNotesIds.Folder[folders[0].id]).toEqual([notes[4].id]);

		// return to second folder
		state = reducer(state, { type: 'FOLDER_SELECT', id: folders[1].id });
		expect(state.lastSelectedNotesIds.Folder[folders[1].id]).toEqual([notes[6].id]);

	}));

	it('should ensure that history is free of adjacent duplicates', (async () => {
		// create 1 folder
		const folders = await createNTestFolders(1);
		// create 5 notes
		const notes = await createNTestNotes(5, folders[0]);
		// select the 1st folder and the 1st note
		let state = initTestState(folders, 0, notes, [0]);

		// backward = 0 1 2 3 2 3 2 3 2 3 2
		// forward =
		// current = 3
		state = goToNote(notes, [1], state);
		state = goToNote(notes, [2], state);
		state = goToNote(notes, [3], state);
		state = goToNote(notes, [2], state);
		state = goToNote(notes, [3], state);
		state = goToNote(notes, [2], state);
		state = goToNote(notes, [3], state);
		state = goToNote(notes, [2], state);
		state = goToNote(notes, [3], state);
		state = goToNote(notes, [2], state);
		state = goToNote(notes, [3], state);

		// backward = 0 1 2 3 2 3 2 3 2 3
		// forward = 3
		// current = 2
		state = goBackWard(state);

		// backward = 0 1 2 3 2 3 2 3 2
		// forward = 3 2
		// current = 3
		state = goBackWard(state);

		// backward = 0 1 2 3 2 3 2 3
		// forward = 3 2 3
		// current = 2
		state = goBackWard(state);

		// backward = 0 1 2 3 2 3 2
		// forward = 3 2 3 2
		// current = 3
		state = goBackWard(state);

		expect(state.backwardHistoryNotes.map(n=>n.id)).toEqual([notes[0], notes[1], notes[2], notes[3], notes[2], notes[3], notes[2]].map(n=>n.id));
		expect(state.forwardHistoryNotes.map(n=>n.id)).toEqual([notes[3], notes[2], notes[3], notes[2]].map(n=>n.id));
		expect(state.selectedNoteIds).toEqual([notes[3].id]);

		// delete third note
		state = reducer(state, { type: 'NOTE_DELETE', id: notes[2].id });

		// if adjacent duplicates not removed
		// backward = 0 1 3 3
		// forward = 3 3
		// current = 3

		// if adjacent duplicates are removed
		// backward = 0 1 3
		// forward = 3
		// current = 3

		// Expected: adjacent duplicates are removed and latest history does not contain current note
		// backward = 0 1
		// forward =
		// current = 3
		expect(state.backwardHistoryNotes.map(x => x.id)).toEqual([notes[0].id, notes[1].id]);
		expect(state.forwardHistoryNotes.map(x => x.id)).toEqual([]);
		expect(state.selectedNoteIds).toEqual([notes[3].id]);
	}));

	it('should ensure history max limit is maintained', (async () => {
		const folders = await createNTestFolders(1);
		// create 5 notes
		const notes = await createNTestNotes(5, folders[0]);
		// select the 1st folder and the 1st note
		let state = initTestState(folders, 0, notes, [0]);

		for (let i = 0; i < 2 * MAX_HISTORY; i++) {
			state = goToNote(notes, [i % 5], state);
		}

		expect(state.backwardHistoryNotes.length).toEqual(MAX_HISTORY);
		expect(state.forwardHistoryNotes.map(x => x.id)).toEqual([]);

		for (let i = 0; i < 2 * MAX_HISTORY; i++) {
			state = goBackWard(state);
		}

		expect(state.backwardHistoryNotes).toEqual([]);
		expect(state.forwardHistoryNotes.length).toEqual(MAX_HISTORY);

		for (let i = 0; i < 2 * MAX_HISTORY; i++) {
			state = goForward(state);
		}

		expect(state.backwardHistoryNotes.length).toEqual(MAX_HISTORY);
		expect(state.forwardHistoryNotes.map(x => x.id)).toEqual([]);
	}));

	it('should not change folders when all notes filter is on', async () => {
		const folders = await createNTestFolders(2);
		const notes = [];
		for (let i = 0; i < folders.length; i++) {
			notes.push(...await createNTestNotes(1, folders[i]));
		}
		// initialize state with no folders selected
		let state = initTestState(folders, null, notes.slice(0,2), null);

		// turn on 'All Notes' filter
		state = reducer(state, { type: 'SMART_FILTER_SELECT', id: ALL_NOTES_FILTER_ID });

		// change folder
		state = reducer(state, { type: 'FOLDER_AND_NOTE_SELECT', folderId: folders[1].id, noteId: notes[1].id });

		expect(state.selectedFolderId).toEqual(null);
		expect(state.selectedNoteIds[0]).toEqual(notes[1].id);
	});
});