import { TestBed } from '@angular/core/testing';
import { vi } from '../../testing/vitest-compat';
import { CalendarSettingsService } from './calendar-settings-service';
import { CalendarService, SelectableDayType } from './calendar-service';
import { RuleService, RuleType } from './rule-service';
import { UserInputService } from './user-input-service';
import { createPlanningCalculation, type PlanningOutcome } from './leave-planner.service';
import { PlanningDurationService } from './planning-duration.service';
import { PlanningCalculationService } from './planning-calculation.service';
import { OPTIMIZATION_PRESETS } from './planning-objectives';

describe('Planning duration estimate', () => {
	beforeEach(() => {
		localStorage.clear();
		localStorage.setItem('vacationRules', '{"version":1,"rules":[]}');
		TestBed.inject(CalendarSettingsService).setPlanningDates('2024-01-01', '2024-12-31');
		TestBed.inject(UserInputService).updateBalances(() => [
			{
				id: 'cp',
				type: SelectableDayType.CP,
				numberOfDays: 30,
				availableDate: new Date('2024-01-01T00:00:00'),
				expiryDate: new Date('2024-12-31T00:00:00'),
			},
		]);
	});

	afterEach(() => {
		TestBed.resetTestingModule();
		localStorage.clear();
	});

	it('offers a coarse seconds range on the first launch without calculating', () => {
		const duration = TestBed.inject(PlanningDurationService);
		expect(duration.estimate()).toEqual({ minimum: 1, maximum: 2, unit: 'seconds' });
		expect(TestBed.inject(PlanningCalculationService).isCalculating()).toBe(false);
		expect(TestBed.inject(PlanningCalculationService).accepted()).toBeNull();
		expect(TestBed.inject(RuleService).rules).toEqual([]);
	});

	it('estimates and calibrates optimization rules without a requested leave quantity', () => {
		const rules = TestBed.inject(RuleService);
		rules.addRule({
			id: 'loss',
			name: 'Loss',
			type: RuleType.OPTIMIZATION,
			enabled: true,
			force: 'preference',
			configuration: structuredClone(OPTIMIZATION_PRESETS.unplacedAtRisk),
		});
		const duration = TestBed.inject(PlanningDurationService);
		expect(Number.isFinite(duration.estimate()!.maximum)).toBe(true);
		duration.recordCompletion(TestBed.inject(PlanningCalculationService).request()!, 20_000);
		expect(duration.estimate()).toEqual({ minimum: 10, maximum: 60, unit: 'seconds' });
	});

	it('updates for dates, balances and active rules without requesting a calculation', () => {
		const duration = TestBed.inject(PlanningDurationService);
		const settings = TestBed.inject(CalendarSettingsService);
		const input = TestBed.inject(UserInputService);
		const initial = duration.estimate()!;
		settings.setPlanningDates('2024-01-01', '2026-12-31');
		const longer = duration.estimate()!;
		expect(longer.maximum).toBeGreaterThan(initial.maximum);
		input.updateBalances((balances) =>
			balances.map((balance) => ({ ...balance, numberOfDays: 120 })),
		);
		const moreLeave = duration.estimate()!;
		expect(moreLeave.maximum).toBeGreaterThan(longer.maximum);
		const rules = TestBed.inject(RuleService);
		rules.addRule({
			id: 'window',
			name: 'Spring',
			type: RuleType.TIME_WINDOW,
			enabled: true,
			force: 'obligation',
			startDate: new Date('2024-04-01T00:00:00'),
			endDate: new Date('2024-04-30T00:00:00'),
			placeDays: 15,
			placeType: SelectableDayType.CP,
		});
		expect(duration.estimate()!.maximum).toBeGreaterThan(moreLeave.maximum);
		rules.toggleRule('window');
		expect(duration.estimate()).toEqual(moreLeave);
		settings.setPlanningDates('2026-12-31', '2024-01-01');
		expect(duration.estimate()).toBeNull();
		expect(TestBed.inject(PlanningCalculationService).isCalculating()).toBe(false);
		expect(TestBed.inject(PlanningCalculationService).accepted()).toBeNull();
	});

	it('refines the submitted configuration using elapsed calendar time and displays minutes for a long wait', () => {
		const duration = TestBed.inject(PlanningDurationService);
		const submitted = TestBed.inject(PlanningCalculationService).request()!;
		duration.recordCompletion(submitted, 120_000);
		expect(duration.estimate()).toEqual({ minimum: 1, maximum: 6, unit: 'minutes' });
	});

	it('calibrates against the submitted snapshot even when the form has since changed', () => {
		const duration = TestBed.inject(PlanningDurationService);
		const submitted = TestBed.inject(PlanningCalculationService).request()!;
		TestBed.inject(CalendarSettingsService).setPlanningDates('2024-01-01', '2026-12-31');
		duration.recordCompletion(submitted, 20_000);
		expect(duration.estimate()!.maximum).toBeGreaterThan(60);
		TestBed.inject(CalendarSettingsService).setPlanningDates('2024-01-01', '2024-12-31');
		expect(duration.estimate()).toEqual({ minimum: 10, maximum: 60, unit: 'seconds' });
	});

	it('calibrates the same configuration after Date rules become ISO strings in the immutable snapshot', () => {
		TestBed.inject(RuleService).addRule({
			id: 'future-rule',
			name: 'Outside the historical horizon',
			type: RuleType.TIME_WINDOW,
			force: 'preference',
			enabled: true,
			startDate: new Date(2026, 3, 1),
			endDate: new Date(2026, 3, 30),
			placeDays: 60,
			placeType: SelectableDayType.CP,
		});
		const duration = TestBed.inject(PlanningDurationService);
		const calculation = createPlanningCalculation(
			TestBed.inject(PlanningCalculationService).request()!,
		);
		duration.recordCompletion(calculation.snapshot, 20_000);
		expect(duration.estimate()).toEqual({ minimum: 10, maximum: 60, unit: 'seconds' });
	});

	it('uses recent typical waits rather than an isolated slow calculation, and resets on a fresh visit', () => {
		const duration = TestBed.inject(PlanningDurationService);
		const submitted = TestBed.inject(PlanningCalculationService).request()!;
		for (const elapsed of [20_000, 25_000, 900_000])
			duration.recordCompletion(submitted, elapsed);
		expect(duration.estimate()).toEqual({ minimum: 12, maximum: 75, unit: 'seconds' });
		TestBed.resetTestingModule();
		expect(TestBed.inject(PlanningDurationService).estimate()).toEqual({
			minimum: 1,
			maximum: 2,
			unit: 'seconds',
		});
	});

	it.each([0, -1, NaN, Infinity])('ignores unusable elapsed measurements: %s', (elapsed) => {
		const duration = TestBed.inject(PlanningDurationService);
		const initial = duration.estimate();
		duration.recordCompletion(TestBed.inject(PlanningCalculationService).request()!, elapsed);
		expect(duration.estimate()).toEqual(initial);
	});
});

describe('Indicative wait progress', () => {
	let now: number;
	let startedAt: number;
	let progress: (stage: string) => void;
	let resolve: (outcome: PlanningOutcome) => void;
	let reject: (error: Error) => void;
	let duration: PlanningDurationService;
	let calculations: PlanningCalculationService;

	/** Starts a calculation whose expected wait is exactly `expectedMs`. */
	function start(expectedMs: number): void {
		duration['calibration'].set([]);
		duration.recordCompletion(calculations.request()!, expectedMs);
		startedAt = now;
		calculations.start();
		TestBed.tick();
	}

	function at(elapsedMs: number) {
		now = startedAt + elapsedMs;
		vi.advanceTimersByTime(250);
		return duration.wait();
	}

	beforeEach(() => {
		localStorage.clear();
		localStorage.setItem('vacationRules', '{"version":1,"rules":[]}');
		vi.useFakeTimers();
		now = 1_000;
		vi.spyOn(performance, 'now').mockImplementation(() => now);
		TestBed.configureTestingModule({
			providers: [
				{
					provide: CalendarService,
					useValue: {
						createPlanningCalculation: (request: { progress: typeof progress }) => {
							progress = request.progress;
							return {
								cancel: () => undefined,
								snapshot: { rules: [], labels: {}, declaredDays: [] },
								outcome: new Promise<PlanningOutcome>((res, rej) => {
									resolve = res;
									reject = rej;
								}),
								explanation: new Promise(() => undefined),
								explanationError: new Promise(() => undefined),
							};
						},
					},
				},
			],
		});
		TestBed.inject(CalendarSettingsService).setPlanningDates('2024-01-01', '2024-12-31');
		duration = TestBed.inject(PlanningDurationService);
		calculations = TestBed.inject(PlanningCalculationService);
	});

	afterEach(() => {
		TestBed.resetTestingModule();
		vi.useRealTimers();
		vi.restoreAllMocks();
		localStorage.clear();
	});

	it('climbs linearly to 95% at the expected wait, holds, then shows 100% on completion', () => {
		start(20_000);
		expect(at(0)).toEqual({
			percent: 0,
			remaining: { value: 20, unit: 'seconds' },
			overrun: false,
		});
		expect(at(10_000)).toMatchObject({ percent: 47, overrun: false });
		expect(at(19_999)).toMatchObject({ percent: 94, overrun: false });
		expect(at(20_000)).toEqual({ percent: 95, remaining: null, overrun: false });
		expect(at(600_000)).toEqual({ percent: 95, remaining: null, overrun: true });
		progress('complete');
		expect(duration.wait()).toEqual({ percent: 100, remaining: null, overrun: false });
	});

	it('shows the remaining time only for expected waits of at least 3 seconds', () => {
		start(2_999);
		expect(at(1_000)).toEqual({ percent: 31, remaining: null, overrun: false });
		expect(at(2_999)).toEqual({ percent: 95, remaining: null, overrun: false });
		resolve({ kind: 'PlanningIncomplete', completedStages: [], reasons: [] });
	});

	it.each([
		[2_999, { minimum: 1, maximum: 9, unit: 'seconds' }, 9_000],
		[20_000, { minimum: 10, maximum: 60, unit: 'seconds' }, 60_000],
		[300_000, { minimum: 2, maximum: 15, unit: 'minutes' }, 900_000],
	])(
		'warns of an overrun of a %i ms expected wait only past the top of the range shown before Calculate',
		(expectedMs, shown, topMs) => {
			start(expectedMs);
			expect(duration.estimate()).toEqual(shown);
			expect(at(expectedMs)).toEqual({ percent: 95, remaining: null, overrun: false });
			expect(at(topMs - 1)!.overrun).toBe(false);
			expect(at(topMs)!.overrun).toBe(true);
		},
	);

	it('rounds the remaining time to seconds, then 5-second steps, then minutes', () => {
		start(3_000);
		expect(at(0)!.remaining).toEqual({ value: 3, unit: 'seconds' });
		expect(at(2_100)!.remaining).toEqual({ value: 1, unit: 'seconds' });
		start(300_000);
		const left = (seconds: number) => at(300_000 - seconds * 1_000)!.remaining;
		expect(left(9.2)).toEqual({ value: 10, unit: 'seconds' });
		expect(left(12.4)).toEqual({ value: 10, unit: 'seconds' });
		expect(left(12.6)).toEqual({ value: 15, unit: 'seconds' });
		expect(left(57.4)).toEqual({ value: 55, unit: 'seconds' });
		expect(left(57.6)).toEqual({ value: 1, unit: 'minutes' });
		expect(left(149)).toEqual({ value: 2, unit: 'minutes' });
		expect(left(300)).toEqual({ value: 5, unit: 'minutes' });
	});

	it('keeps the expected wait frozen when the form or calibration change mid-calculation', () => {
		start(20_000);
		TestBed.inject(CalendarSettingsService).setPlanningDates('2024-01-01', '2028-12-31');
		duration.recordCompletion(calculations.request()!, 900_000);
		expect(at(10_000)).toMatchObject({ percent: 47, remaining: { value: 10 } });
	});

	it('never moves backwards when the planner repeats stages', () => {
		start(20_000);
		const percents = ['obligations', 'preference:a', 'dates', 'preference:a', 'dates'].map(
			(stage, index) => {
				progress(stage);
				return at(index * 5_000)!.percent;
			},
		);
		expect(percents).toEqual([...percents].sort((a, b) => a - b));
		expect(percents.at(-1)).toBe(95);
	});

	it('freezes on Cancel and never shows 100% after cancellation, incomplete outcomes or errors', async () => {
		start(20_000);
		at(10_000);
		calculations.cancel();
		TestBed.tick();
		progress('complete');
		expect(at(30_000)).toMatchObject({ percent: 47 });
		resolve({ kind: 'PlanningIncomplete', completedStages: [], reasons: [] });
		await Promise.resolve();
		expect(duration.wait()).toBeNull();
		start(20_000);
		at(25_000);
		reject(new Error('Worker failed'));
		await Promise.resolve();
		await Promise.resolve();
		expect(duration.wait()).toBeNull();
	});
});