import { describe, it, expect } from "vitest";
import {
  detectStops,
  DEFAULT_STOP_RADIUS_METRES,
  DEFAULT_MIN_STOP_MINUTES,
  type Breadcrumb,
} from "./visit-stops";

/** Sibanye Driefontein-ish, matching the rest of the geo fixtures. */
const BASE_LAT = -26.4;
const BASE_LON = 27.4;

/** Metres → degrees of latitude (1° ≈ 111,195 m on a 6371 km sphere). */
function metresNorth(metres: number): number {
  return BASE_LAT + metres / 111195;
}

function crumb(
  minutesFromStart: number,
  over: Partial<Breadcrumb> = {}
): Breadcrumb {
  return {
    fixedAt: new Date(
      Date.UTC(2026, 8, 4, 7, 0, 0) + minutesFromStart * 60_000
    ).toISOString(),
    lat: BASE_LAT,
    lon: BASE_LON,
    ignition: false,
    speedKmh: 0,
    ...over,
  };
}

describe("detectStops", () => {
  it("returns nothing for an empty trail", () => {
    expect(detectStops([])).toEqual([]);
  });

  it("returns nothing for a single fix — a point has no duration", () => {
    expect(detectStops([crumb(0)])).toEqual([]);
  });

  it("collapses a parked vehicle into one stop", () => {
    const stops = detectStops([crumb(0), crumb(5), crumb(10), crumb(15)]);

    expect(stops).toHaveLength(1);
    expect(stops[0]).toMatchObject({
      durationMinutes: 15,
      fixCount: 4,
      startedAt: "2026-09-04T07:00:00.000Z",
      endedAt: "2026-09-04T07:15:00.000Z",
    });
  });

  it("absorbs GPS jitter rather than splitting a stop into several", () => {
    // A stationary tracker wanders tens of metres between fixes. Without
    // a radius this would read as four separate visits.
    const stops = detectStops([
      crumb(0, { lat: metresNorth(0) }),
      crumb(5, { lat: metresNorth(40) }),
      crumb(10, { lat: metresNorth(-30) }),
      crumb(15, { lat: metresNorth(25) }),
    ]);

    expect(stops).toHaveLength(1);
    expect(stops[0].fixCount).toBe(4);
  });

  it("does not invent a stop for a vehicle driving straight through", () => {
    const stops = detectStops([
      crumb(0, { lat: metresNorth(0), speedKmh: 60, ignition: true }),
      crumb(5, { lat: metresNorth(4000), speedKmh: 80, ignition: true }),
      crumb(10, { lat: metresNorth(9000), speedKmh: 75, ignition: true }),
    ]);

    expect(stops).toEqual([]);
  });

  it("splits two visits separated by travel", () => {
    const stops = detectStops([
      crumb(0),
      crumb(20),
      // 5 km away — a different site.
      crumb(60, { lat: metresNorth(5000) }),
      crumb(90, { lat: metresNorth(5000) }),
    ]);

    expect(stops).toHaveLength(2);
    expect(stops[0].durationMinutes).toBe(20);
    expect(stops[1].durationMinutes).toBe(30);
  });

  it("drops stops shorter than the minimum — a gate queue is not a visit", () => {
    const stops = detectStops(
      [crumb(0), crumb(3)],
      { minDurationMinutes: 10 }
    );

    expect(stops).toEqual([]);
  });

  it("sorts an out-of-order trail before analysing it", () => {
    // PocketBase paging does not guarantee order, and a poller retry can
    // insert an older fix after a newer one.
    const stops = detectStops([crumb(15), crumb(0), crumb(10), crumb(5)]);

    expect(stops).toHaveLength(1);
    expect(stops[0].startedAt).toBe("2026-09-04T07:00:00.000Z");
    expect(stops[0].endedAt).toBe("2026-09-04T07:15:00.000Z");
  });

  it("reports the centroid of the fixes as the stop position", () => {
    const stops = detectStops([
      crumb(0, { lat: metresNorth(0) }),
      crumb(10, { lat: metresNorth(100) }),
    ]);

    expect(stops[0].lat).toBeCloseTo(metresNorth(50), 6);
    expect(stops[0].lon).toBeCloseTo(BASE_LON, 6);
  });

  it("measures against the stop's anchor so a slow crawl cannot chain into one stop", () => {
    // Each fix is 100 m from the previous one — inside the radius — but
    // the vehicle covers 500 m overall. A running-centroid comparison
    // would drift along with it and report one long stationary stop.
    const stops = detectStops([
      crumb(0, { lat: metresNorth(0) }),
      crumb(10, { lat: metresNorth(100) }),
      crumb(20, { lat: metresNorth(200) }),
      crumb(30, { lat: metresNorth(300) }),
      crumb(40, { lat: metresNorth(400) }),
      crumb(50, { lat: metresNorth(500) }),
    ]);

    expect(stops.length).toBeGreaterThan(1);
  });

  it("flags the longest reporting gap inside a stop", () => {
    // Underground or in a signal shadow the tracker goes quiet. Two fixes
    // two hours apart at the same place *probably* mean the vehicle sat
    // there — but it could also have left and come back. The report has
    // to be able to say so rather than assert a confident 2-hour visit.
    const stops = detectStops([crumb(0), crumb(120), crumb(125)]);

    expect(stops).toHaveLength(1);
    expect(stops[0].longestGapMinutes).toBe(120);
  });

  it("reports a zero gap for evenly-polled stops", () => {
    const stops = detectStops([crumb(0), crumb(5), crumb(10)]);
    expect(stops[0].longestGapMinutes).toBe(5);
  });

  it("marks a stop as ignition-off only when every fix agrees", () => {
    const parked = detectStops([
      crumb(0, { ignition: false }),
      crumb(15, { ignition: false }),
    ]);
    expect(parked[0].ignitionOff).toBe(true);

    const idling = detectStops([
      crumb(0, { ignition: false }),
      crumb(15, { ignition: true }),
    ]);
    expect(idling[0].ignitionOff).toBe(false);
  });

  it("reports ignitionOff as false when the device has no ignition wire", () => {
    // `--` from FleetAI parses to null. Unknown must not read as "parked",
    // which would overstate confidence in the visit.
    const stops = detectStops([
      crumb(0, { ignition: null }),
      crumb(15, { ignition: null }),
    ]);

    expect(stops[0].ignitionOff).toBe(false);
  });

  it("ignores fixes with an unparseable timestamp", () => {
    const stops = detectStops([
      crumb(0),
      { ...crumb(5), fixedAt: "not a date" },
      crumb(15),
    ]);

    expect(stops).toHaveLength(1);
    expect(stops[0].fixCount).toBe(2);
  });

  it("de-duplicates repeated fixes at the same instant", () => {
    // The poller keys on fix time, but a retry or a clock wobble can
    // still land the same fix twice.
    const stops = detectStops([crumb(0), crumb(0), crumb(15)]);
    expect(stops[0].fixCount).toBe(2);
  });

  it("exposes usable defaults", () => {
    expect(DEFAULT_STOP_RADIUS_METRES).toBe(150);
    expect(DEFAULT_MIN_STOP_MINUTES).toBe(5);
  });
});