import { describe, it, expect } from "vitest";
import { distanceKm } from "./geo";
import {
  rankNearbyCustomers,
  DEFAULT_RADIUS_KM,
  type NearbyCandidate,
} from "./visit-matching";

/**
 * Fixtures are anchored on Sibanye Driefontein (Carletonville) — the
 * same part of the West Rand the real customer base sits in, so the
 * latitude-dependent longitude scaling in `distanceKm` is exercised at
 * a realistic value rather than at the equator.
 */
const ORIGIN = [-26.4, 27.4] as const;

/** ~1 km north of ORIGIN (1 degree of latitude ≈ 111.19 km). */
const ONE_KM_NORTH = { lat: -26.4 + 1 / 111.19, lon: 27.4 };
/** ~3 km north of ORIGIN — outside a 2 km radius. */
const THREE_KM_NORTH = { lat: -26.4 + 3 / 111.19, lon: 27.4 };

function candidate(over: Partial<NearbyCandidate> & { id: string }): NearbyCandidate {
  return {
    customer: `Customer ${over.id}`,
    coordinates: { lat: ORIGIN[0], lon: ORIGIN[1] },
    rep: "",
    companyName: null,
    ...over,
  };
}

describe("rankNearbyCustomers", () => {
  it("returns customers inside the radius and drops those outside it", () => {
    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      customers: [
        candidate({ id: "near", coordinates: ONE_KM_NORTH }),
        candidate({ id: "far", coordinates: THREE_KM_NORTH }),
      ],
    });

    expect(result.map((r) => r.id)).toEqual(["near"]);
  });

  it("skips Null Island customers rather than placing them off West Africa", () => {
    // This is the state of all 616 customers before the pin tool /
    // capture-on-visit runs, so it is the common case, not an edge case.
    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      customers: [
        candidate({ id: "unset", coordinates: { lat: 0, lon: 0 } }),
        candidate({ id: "pinned" }),
      ],
    });

    expect(result.map((r) => r.id)).toEqual(["pinned"]);
  });

  it("skips customers whose coordinates field is missing entirely", () => {
    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      customers: [
        candidate({ id: "null-coords", coordinates: null }),
        candidate({ id: "undef-coords", coordinates: undefined }),
        candidate({ id: "pinned" }),
      ],
    });

    expect(result.map((r) => r.id)).toEqual(["pinned"]);
  });

  it("puts the signed-in rep's own customers first, then sorts by distance", () => {
    // Inside a 2 km radius everyone is on the same mine property, so
    // distance is mostly noise — the rep came to see *their* accounts.
    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      repId: "rep-tiaan",
      customers: [
        candidate({ id: "other-closest", rep: "rep-chris" }),
        candidate({ id: "mine-far", rep: "rep-tiaan", coordinates: ONE_KM_NORTH }),
        candidate({ id: "mine-close", rep: "rep-tiaan" }),
      ],
    });

    expect(result.map((r) => r.id)).toEqual([
      "mine-close",
      "mine-far",
      "other-closest",
    ]);
  });

  it("marks which rows belong to the signed-in rep", () => {
    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      repId: "rep-tiaan",
      customers: [
        candidate({ id: "mine", rep: "rep-tiaan" }),
        candidate({ id: "theirs", rep: "rep-chris" }),
      ],
    });

    expect(result.find((r) => r.id === "mine")?.isMine).toBe(true);
    expect(result.find((r) => r.id === "theirs")?.isMine).toBe(false);
  });

  it("treats every row as not-mine when no rep is signed in", () => {
    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      customers: [candidate({ id: "a", rep: "rep-tiaan" })],
    });

    expect(result[0].isMine).toBe(false);
  });

  it("reports distance in metres-precision kilometres", () => {
    const [row] = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      customers: [candidate({ id: "a", coordinates: ONE_KM_NORTH })],
    });

    expect(row.distanceKm).toBeCloseTo(1, 2);
  });

  it("carries the company name through for display", () => {
    const [row] = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 2,
      customers: [
        candidate({ id: "a", customer: "DANIE GREYLING", companyName: "Sibanye - Driefontein" }),
      ],
    });

    expect(row.name).toBe("DANIE GREYLING");
    expect(row.companyName).toBe("Sibanye - Driefontein");
  });

  it("includes a customer sitting exactly on the radius boundary", () => {
    // A rep parked exactly `radiusKm` from a pin should still see it —
    // excluding the boundary makes the radius setting feel arbitrary.
    // The radius is taken from the measured distance so this asserts the
    // exact `<=` boundary rather than an approximated one.
    const exactDistance = distanceKm(ORIGIN, [
      ONE_KM_NORTH.lat,
      ONE_KM_NORTH.lon,
    ]);

    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: exactDistance,
      customers: [candidate({ id: "boundary", coordinates: ONE_KM_NORTH })],
    });

    expect(result.map((r) => r.id)).toEqual(["boundary"]);
  });

  it("excludes a customer just outside the radius", () => {
    const exactDistance = distanceKm(ORIGIN, [
      ONE_KM_NORTH.lat,
      ONE_KM_NORTH.lon,
    ]);

    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: exactDistance - 0.001,
      customers: [candidate({ id: "boundary", coordinates: ONE_KM_NORTH })],
    });

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

  it("falls back to the default radius when given a non-positive one", () => {
    // A misconfigured settings row must not silently match every
    // customer in the country (radius 0 → nothing, negative → nothing).
    const result = rankNearbyCustomers({
      origin: ORIGIN,
      radiusKm: 0,
      customers: [candidate({ id: "near", coordinates: ONE_KM_NORTH })],
    });

    expect(DEFAULT_RADIUS_KM).toBe(2);
    expect(result.map((r) => r.id)).toEqual(["near"]);
  });

  it("returns an empty list rather than throwing on no candidates", () => {
    expect(
      rankNearbyCustomers({ origin: ORIGIN, radiusKm: 2, customers: [] })
    ).toEqual([]);
  });
});