import type { RemoteExcalidrawElement } from "../../data/reconcile";
import { reconcileElements } from "../../data/reconcile";
import type {
  ExcalidrawElement,
  OrderedExcalidrawElement,
} from "../../element/types";
import { syncInvalidIndices } from "../../fractionalIndex";
import { randomInteger } from "../../random";
import type { AppState } from "../../types";
import { cloneJSON } from "../../utils";

type Id = string;
type ElementLike = {
  id: string;
  version: number;
  versionNonce: number;
  index: string;
};

type Cache = Record<string, ExcalidrawElement | undefined>;

const createElement = (opts: { uid: string } | ElementLike) => {
  let uid: string;
  let id: string;
  let version: number | null;
  let versionNonce: number | null = null;
  if ("uid" in opts) {
    const match = opts.uid.match(/^(\w+)(?::(\d+))?$/)!;
    id = match[1];
    version = match[2] ? parseInt(match[2]) : null;
    uid = version ? `${id}:${version}` : id;
  } else {
    ({ id, version, versionNonce } = opts);
    uid = id;
  }
  return {
    uid,
    id,
    version,
    versionNonce: versionNonce || randomInteger(),
  };
};

const idsToElements = (ids: (Id | ElementLike)[], cache: Cache = {}) => {
  return syncInvalidIndices(
    ids.reduce((acc, _uid) => {
      const { uid, id, version, versionNonce } = createElement(
        typeof _uid === "string" ? { uid: _uid } : _uid,
      );
      const cached = cache[uid];
      const elem = {
        id,
        version: version ?? 0,
        versionNonce,
        ...cached,
      } as ExcalidrawElement;
      // @ts-ignore
      cache[uid] = elem;
      acc.push(elem);
      return acc;
    }, [] as ExcalidrawElement[]),
  );
};

const test = <U extends `${string}:${"L" | "R"}`>(
  local: (Id | ElementLike)[],
  remote: (Id | ElementLike)[],
  target: U[],
) => {
  const cache: Cache = {};
  const _local = idsToElements(local, cache);
  const _remote = idsToElements(remote, cache);

  const reconciled = reconcileElements(
    cloneJSON(_local),
    cloneJSON(_remote) as RemoteExcalidrawElement[],
    {} as AppState,
  );

  const reconciledIds = reconciled.map((x) => x.id);
  const reconciledIndices = reconciled.map((x) => x.index);

  expect(target.length).equal(reconciled.length);
  expect(reconciledIndices.length).equal(new Set([...reconciledIndices]).size); // expect no duplicated indices
  expect(reconciledIds).deep.equal(
    target.map((uid) => {
      const [, id, source] = uid.match(/^(\w+):([LR])$/)!;
      const element = (source === "L" ? _local : _remote).find(
        (e) => e.id === id,
      )!;

      return element.id;
    }),
    "remote reconciliation",
  );

  // convergent reconciliation on the remote client
  try {
    expect(
      reconcileElements(
        cloneJSON(_remote),
        cloneJSON(_local as RemoteExcalidrawElement[]),
        {} as AppState,
      ).map((x) => x.id),
    ).deep.equal(reconciledIds, "convergent reconciliation");
  } catch (error: any) {
    console.error("local original", _remote);
    console.error("remote original", _local);
    throw error;
  }

  // bidirectional re-reconciliation on remote client
  try {
    expect(
      reconcileElements(
        cloneJSON(_remote),
        cloneJSON(reconciled as unknown as RemoteExcalidrawElement[]),
        {} as AppState,
      ).map((x) => x.id),
    ).deep.equal(reconciledIds, "local re-reconciliation");
  } catch (error: any) {
    console.error("local original", _remote);
    console.error("remote reconciled", reconciled);
    throw error;
  }
};

describe("elements reconciliation", () => {
  it("reconcileElements()", () => {
    // -------------------------------------------------------------------------
    //
    // in following tests, we pass:
    //  (1) an array of local elements and their version (:1, :2...)
    //  (2) an array of remote elements and their version (:1, :2...)
    //  (3) expected reconciled elements
    //
    // in the reconciled array:
    //  :L means local element was resolved
    //  :R means remote element was resolved
    //
    // if versions are missing, it defaults to version 0
    // -------------------------------------------------------------------------

    test(["A:1", "B:1", "C:1"], ["B:2"], ["A:L", "B:R", "C:L"]);
    test(["A:1", "B:1", "C"], ["B:2", "A:2"], ["B:R", "A:R", "C:L"]);
    test(["A:2", "B:1", "C"], ["B:2", "A:1"], ["A:L", "B:R", "C:L"]);
    test(["A:1", "C:1"], ["B:1"], ["A:L", "B:R", "C:L"]);
    test(["A", "B"], ["A:1"], ["A:R", "B:L"]);
    test(["A"], ["A", "B"], ["A:L", "B:R"]);
    test(["A"], ["A:1", "B"], ["A:R", "B:R"]);
    test(["A:2"], ["A:1", "B"], ["A:L", "B:R"]);
    test(["A:2"], ["B", "A:1"], ["A:L", "B:R"]);
    test(["A:1"], ["B", "A:2"], ["B:R", "A:R"]);
    test(["A"], ["A:1"], ["A:R"]);
    test(["A", "B:1", "D"], ["B", "C:2", "A"], ["C:R", "A:R", "B:L", "D:L"]);

    // some of the following tests are kinda arbitrary and they're less
    // likely to happen in real-world cases
    test(["A", "B"], ["B:1", "A:1"], ["B:R", "A:R"]);
    test(["A:2", "B:2"], ["B:1", "A:1"], ["A:L", "B:L"]);
    test(["A", "B", "C"], ["A", "B:2", "G", "C"], ["A:L", "B:R", "G:R", "C:L"]);
    test(["A", "B", "C"], ["A", "B:2", "G"], ["A:R", "B:R", "C:L", "G:R"]);
    test(
      ["A:2", "B:2", "C"],
      ["D", "B:1", "A:3"],
      ["D:R", "B:L", "A:R", "C:L"],
    );
    test(
      ["A:2", "B:2", "C"],
      ["D", "B:2", "A:3", "C"],
      ["D:R", "B:L", "A:R", "C:L"],
    );
    test(
      ["A", "B", "C", "D", "E", "F"],
      ["A", "B:2", "X", "E:2", "F", "Y"],
      ["A:L", "B:R", "X:R", "C:L", "E:R", "D:L", "F:L", "Y:R"],
    );

    // fractional elements (previously annotated)
    test(
      ["A", "B", "C"],
      ["A", "B", "X", "Y", "Z"],
      ["A:R", "B:R", "C:L", "X:R", "Y:R", "Z:R"],
    );

    test(["A"], ["X", "Y"], ["A:L", "X:R", "Y:R"]);
    test(["A"], ["X", "Y", "Z"], ["A:L", "X:R", "Y:R", "Z:R"]);
    test(["A", "B"], ["C", "D", "F"], ["A:L", "C:R", "B:L", "D:R", "F:R"]);

    test(
      ["A", "B", "C", "D"],
      ["C:1", "B", "D:1"],
      ["A:L", "C:R", "B:L", "D:R"],
    );
    test(
      ["A", "B", "C"],
      ["X", "A", "Y", "B", "Z"],
      ["X:R", "A:R", "Y:R", "B:L", "C:L", "Z:R"],
    );
    test(
      ["B", "A", "C"],
      ["X", "A", "Y", "B", "Z"],
      ["X:R", "A:R", "C:L", "Y:R", "B:R", "Z:R"],
    );
    test(["A", "B"], ["A", "X", "Y"], ["A:R", "B:L", "X:R", "Y:R"]);
    test(
      ["A", "B", "C", "D", "E"],
      ["A", "X", "C", "Y", "D", "Z"],
      ["A:R", "B:L", "X:R", "C:R", "Y:R", "D:R", "E:L", "Z:R"],
    );
    test(
      ["X", "Y", "Z"],
      ["A", "B", "C"],
      ["A:R", "X:L", "B:R", "Y:L", "C:R", "Z:L"],
    );
    test(
      ["X", "Y", "Z"],
      ["A", "B", "C", "X", "D", "Y", "Z"],
      ["A:R", "B:R", "C:R", "X:L", "D:R", "Y:L", "Z:L"],
    );
    test(
      ["A", "B", "C", "D", "E"],
      ["C", "X", "A", "Y", "D", "E:1"],
      ["B:L", "C:L", "X:R", "A:R", "Y:R", "D:R", "E:R"],
    );
    test(
      ["C:1", "B", "D:1"],
      ["A", "B", "C:1", "D:1"],
      ["A:R", "B:R", "C:R", "D:R"],
    );

    test(
      ["C:1", "B", "D:1"],
      ["A", "B", "C:2", "D:1"],
      ["A:R", "B:L", "C:R", "D:L"],
    );

    test(
      ["A", "B", "C", "D"],
      ["A", "C:1", "B", "D:1"],
      ["A:L", "C:R", "B:L", "D:R"],
    );

    test(
      ["A", "B", "C", "D"],
      ["C", "X", "B", "Y", "A", "Z"],
      ["C:R", "D:L", "X:R", "B:R", "Y:R", "A:R", "Z:R"],
    );

    test(
      ["A", "B", "C", "D"],
      ["A", "B:1", "C:1"],
      ["A:R", "B:R", "C:R", "D:L"],
    );

    test(
      ["A", "B", "C", "D"],
      ["A", "C:1", "B:1"],
      ["A:R", "C:R", "B:R", "D:L"],
    );

    test(
      ["A", "B", "C", "D"],
      ["A", "C:1", "B", "D:1"],
      ["A:R", "C:R", "B:R", "D:R"],
    );

    test(["A:1", "B:1", "C"], ["B:2"], ["A:L", "B:R", "C:L"]);
    test(["A:1", "B:1", "C"], ["B:2", "C:2"], ["A:L", "B:R", "C:R"]);
    test(["A", "B"], ["A", "C", "B", "D"], ["A:R", "C:R", "B:R", "D:R"]);
    test(["A", "B"], ["B", "C", "D"], ["A:L", "B:R", "C:R", "D:R"]);
    test(["A", "B"], ["C", "D"], ["A:L", "C:R", "B:L", "D:R"]);
    test(["A", "B"], ["A", "B:1"], ["A:L", "B:R"]);
    test(["A:2", "B"], ["A", "B:1"], ["A:L", "B:R"]);
    test(["A:2", "B:2"], ["B:1"], ["A:L", "B:L"]);
    test(["A:2", "B:2"], ["B:1", "C"], ["A:L", "B:L", "C:R"]);
    test(["A:2", "B:2"], ["A", "C", "B:1"], ["A:L", "B:L", "C:R"]);

    // concurrent convergency
    test(["A", "B", "C"], ["A", "B", "D"], ["A:R", "B:R", "C:L", "D:R"]);
    test(["A", "B", "E"], ["A", "B", "D"], ["A:R", "B:R", "D:R", "E:L"]);
    test(
      ["A", "B", "C"],
      ["A", "B", "D", "E"],
      ["A:R", "B:R", "C:L", "D:R", "E:R"],
    );
    test(
      ["A", "B", "E"],
      ["A", "B", "D", "C"],
      ["A:R", "B:R", "D:R", "E:L", "C:R"],
    );
    test(["A", "B"], ["B", "D"], ["A:L", "B:R", "D:R"]);
    test(["C", "A", "B"], ["C", "B", "D"], ["C:R", "A:L", "B:R", "D:R"]);
  });

  it("test identical elements reconciliation", () => {
    const testIdentical = (
      local: ElementLike[],
      remote: ElementLike[],
      expected: Id[],
    ) => {
      const ret = reconcileElements(
        local as unknown as OrderedExcalidrawElement[],
        remote as unknown as RemoteExcalidrawElement[],
        {} as AppState,
      );

      if (new Set(ret.map((x) => x.id)).size !== ret.length) {
        throw new Error("reconcileElements: duplicate elements found");
      }

      expect(ret.map((x) => x.id)).to.deep.equal(expected);
    };

    // identical id/version/versionNonce/index
    // -------------------------------------------------------------------------

    testIdentical(
      [{ id: "A", version: 1, versionNonce: 1, index: "a0" }],
      [{ id: "A", version: 1, versionNonce: 1, index: "a0" }],
      ["A"],
    );
    testIdentical(
      [
        { id: "A", version: 1, versionNonce: 1, index: "a0" },
        { id: "B", version: 1, versionNonce: 1, index: "a0" },
      ],
      [
        { id: "B", version: 1, versionNonce: 1, index: "a0" },
        { id: "A", version: 1, versionNonce: 1, index: "a0" },
      ],
      ["A", "B"],
    );

    // actually identical (arrays and element objects)
    // -------------------------------------------------------------------------

    const elements1 = [
      {
        id: "A",
        version: 1,
        versionNonce: 1,
        index: "a0",
      },
      {
        id: "B",
        version: 1,
        versionNonce: 1,
        index: "a0",
      },
    ];

    testIdentical(elements1, elements1, ["A", "B"]);
    testIdentical(elements1, elements1.slice(), ["A", "B"]);
    testIdentical(elements1.slice(), elements1, ["A", "B"]);
    testIdentical(elements1.slice(), elements1.slice(), ["A", "B"]);

    const el1 = {
      id: "A",
      version: 1,
      versionNonce: 1,
      index: "a0",
    };
    const el2 = {
      id: "B",
      version: 1,
      versionNonce: 1,
      index: "a0",
    };
    testIdentical([el1, el2], [el2, el1], ["A", "B"]);
  });
});