import { describe, it, expect } from 'vitest';
import { parseTelemetry, computeDeviations, distHaversine, parsePrediction } from '$domain';
import type { TelemetryPoint, PredictionStage } from '$domain';

const points: TelemetryPoint[] = [
	{ latitude: 62.0, longitude: 129.0, altitude: 0, datetime: '2026-01-01T00:00:00Z', payload: '{}' },
	{
		latitude: 62.05,
		longitude: 129.1,
		altitude: 15000,
		datetime: '2026-01-01T00:30:00Z',
		payload: '{}'
	}
];

describe('parseTelemetry', () => {
	it('builds a flight path and takes the first sample as launch', () => {
		const t = parseTelemetry(points);
		expect(t.flight_path).toEqual([
			[62.0, 129.0, 0],
			[62.05, 129.1, 15000]
		]);
		expect(t.launch.latlng.lat).toBe(62.0);
		expect(t.datapoints).toHaveLength(2);
	});

	it('throws on an empty series', () => {
		expect(() => parseTelemetry([])).toThrow();
	});
});

describe('distHaversine', () => {
	it('is zero for identical points and ~343 km London→Paris', () => {
		expect(distHaversine({ lat: 55, lng: 37 }, { lat: 55, lng: 37 })).toBe(0);
		const d = distHaversine({ lat: 51.5074, lng: -0.1278 }, { lat: 48.8566, lng: 2.3522 });
		expect(d).toBeGreaterThan(340);
		expect(d).toBeLessThan(346);
	});
});

describe('computeDeviations', () => {
	// Prediction runs 00:00 → 01:30 along the same corridor as the telemetry.
	const stages: PredictionStage[] = [
		{
			stage: 'ascent',
			trajectory: [
				{ altitude: 0, datetime: '2026-01-01T00:00:00Z', latitude: 62.0, longitude: 129.0 },
				{ altitude: 30000, datetime: '2026-01-01T01:00:00Z', latitude: 62.1, longitude: 129.2 }
			]
		},
		{
			stage: 'descent',
			trajectory: [
				{ altitude: 30000, datetime: '2026-01-01T01:00:00Z', latitude: 62.1, longitude: 129.2 },
				{ altitude: 0, datetime: '2026-01-01T01:30:00Z', latitude: 62.05, longitude: 129.4 }
			]
		}
	];
	const prediction = parsePrediction(stages);

	it('matches each sample to the closest prediction point', () => {
		const devs = computeDeviations(points, prediction);
		expect(devs).toHaveLength(2);
		// First sample sits exactly on the predicted launch point.
		expect(devs[0].horizontal).toBeCloseTo(0, 6);
		expect(devs[0].vertical).toBe(0);
		// Second sample is offset from the prediction, both laterally and in altitude.
		expect(devs[1].horizontal).toBeGreaterThan(0);
		expect(devs[1].altActual).toBe(15000);
	});

	it('skips samples outside the prediction window', () => {
		const outside: TelemetryPoint[] = [
			{
				latitude: 62,
				longitude: 129,
				altitude: 0,
				datetime: '2025-12-31T00:00:00Z', // a day early
				payload: '{}'
			}
		];
		expect(computeDeviations(outside, prediction)).toHaveLength(0);
	});

	it('returns nothing without telemetry', () => {
		expect(computeDeviations([], prediction)).toEqual([]);
	});
});