import { QxReject, type ExactReference, type MutationKey } from "@quixos/camino-replica-core";
import { createRegistry, generic, type Contexts } from "./gen/qx.js";
const metadata = (ref: ExactReference) => ({
  ...ref,
  expectation: { kind: "interface" as const, id: "interface:org.quixos.presentation-state@1" as const },
});
const same = (a: ExactReference | null, b: ExactReference | null) =>
  a === null || b === null ? a === b : a.workspace === b.workspace && a.object === b.object;

// These source contracts also exist in assemblies with no closed navigation
// application. Generated Contexts contains only the applications actually used.
type NavigationInput = Contexts["attach"]["input"] & { occurrence: string };
type MetadataRequest = { receiver: ReturnType<typeof metadata>; input: null };
type NavigationMetadata = {
  "occurrence.get"(request: MetadataRequest): Promise<string>;
  "source.resolve"(request: MetadataRequest): Promise<ExactReference>;
  "parent.resolve"(request: MetadataRequest): Promise<ExactReference | null>;
  "attach.call"(
    request: { receiver: ReturnType<typeof metadata>; input: Contexts["attach"]["input"] },
    key: MutationKey,
  ): Promise<null>;
};
type CreateContext<Navigation extends ExactReference> = {
  receiver: ExactReference;
  input: NavigationInput;
  ports: {
    metadata: NavigationMetadata;
    factory: { "create.call"(input: { occurrence: string }, key: MutationKey): Promise<Navigation> };
  };
};
type EnsureContext = CreateContext<ExactReference> & {
  ports: {
    presentationMount: {
      "find.call"(request: {
        receiver: NavigationInput["presentationMount"];
        input: string;
      }): Promise<ReturnType<typeof metadata> | null>;
    };
  };
};

async function attach({ receiver, input, ports }: Contexts["attach"]) {
  const owner = (await ports.owner.resolve())[0]?.target ?? null;
  const parent = (await ports.parent.resolve())[0]?.target ?? null;
  if (owner) {
    if (!same(owner, input.presentationMount)) throw new QxReject("PRESENTATION_STATE_ALREADY_ATTACHED");
    if (!same(parent, input.parent)) throw new QxReject("OCCURRENCE_PARENT_MISMATCH");
    return null;
  }
  if (parent) throw new QxReject("UNATTACHED_PRESENTATION_PARENT");
  if (input.parent) {
    const parentOwner = await ports.metadata["presentationMount.resolve"]({ receiver: input.parent, input: null });
    if (!same(parentOwner, input.presentationMount)) throw new QxReject("PRESENTATION_PARENT_MISMATCH");
    await ports.parent.connect(input.parent, { key: "parent" });
  } else {
    if (await ports.presentationMount["root.resolve"]({ receiver: input.presentationMount, input: null }))
      throw new QxReject("PRESENTATION_ROOT_EXISTS");
    await ports.rootOf.connect(input.presentationMount, { key: "root" });
  }
  // The parent must already be attached. No operation reparents attached state,
  // so attachment cannot introduce a cycle, including through pending births.
  await ports.presentationMount["attach.call"](
    { receiver: input.presentationMount, input: metadata(receiver) },
    { key: "owner" },
  );
  return null;
}

async function create<Navigation extends ExactReference>({
  receiver,
  input,
  ports,
}: CreateContext<Navigation>): Promise<Navigation> {
  if (!input.occurrence || input.occurrence.length > 128) throw new QxReject("INVALID_OCCURRENCE");
  const navigation = await ports.factory["create.call"]({ occurrence: input.occurrence }, { key: "navigation" });
  if ((await ports.metadata["occurrence.get"]({ receiver: metadata(navigation), input: null })) !== input.occurrence)
    throw new QxReject("PRESENTATION_OCCURRENCE_MISMATCH");
  if (!same(await ports.metadata["source.resolve"]({ receiver: metadata(navigation), input: null }), receiver))
    throw new QxReject("PRESENTATION_SOURCE_MISMATCH");
  await ports.metadata["attach.call"](
    { receiver: metadata(navigation), input: { presentationMount: input.presentationMount, parent: input.parent } },
    { key: "attach" },
  );
  return navigation;
}
export const registry = createRegistry({
  copyEmpty: async ({ input, ports }) => {
    if (input !== null) throw new QxReject("PRESENTATION_HAS_NO_STATE");
    return {
      ...(await ports.presentationMount.create({ key: "copy" })),
      expectation: { kind: "interface", id: "interface:org.quixos.presentation-mount@1" },
    };
  },
  findEmpty: async () => null,
  attachEmpty: async () => {
    throw new QxReject("PRESENTATION_STATE_NOT_INSTALLED");
  },
  ...generic.allocate(allocate),
  copy,
  ...generic.create(create),
  find: async ({ input, ports }) =>
    (await ports.members.resolve()).find((entry) => entry.mapKey === input)?.target ?? null,
  ...generic.ensure(async ({ receiver, input, ports }: EnsureContext) => {
    const existing = await ports.presentationMount["find.call"]({
      receiver: input.presentationMount,
      input: input.occurrence,
    });
    if (existing) {
      if (!same(await ports.metadata["source.resolve"]({ receiver: existing, input: null }), receiver))
        throw new QxReject("PRESENTATION_SOURCE_MISMATCH");
      if (!same(await ports.metadata["parent.resolve"]({ receiver: existing, input: null }), input.parent))
        throw new QxReject("OCCURRENCE_PARENT_MISMATCH");
    } else {
      await create<ExactReference>({ receiver, input, ports });
    }
    return null;
  }),
  attach,
  claim: async ({ receiver, input, ports }) => {
    const request = { receiver: input, input: null };
    const owner = await ports.metadata["presentationMount.resolve"](request);
    if (owner) throw new QxReject("PRESENTATION_STATE_ALREADY_ATTACHED");
    const parent = await ports.metadata["parent.resolve"](request);
    if (parent) {
      if (!same(await ports.metadata["presentationMount.resolve"]({ receiver: parent, input: null }), receiver))
        throw new QxReject("PRESENTATION_PARENT_MISMATCH");
    } else if (!same((await ports.root.resolve())[0]?.target ?? null, input)) {
      throw new QxReject("PRESENTATION_ROOT_MISMATCH");
    }
    const occurrence = await ports.metadata["occurrence.get"](request);
    if (!occurrence || occurrence.length > 128) throw new QxReject("INVALID_OCCURRENCE");
    await ports.members.connect({ target: input, mapKey: occurrence }, { key: "member" });
    return null;
  },
  createPresentationMount: async ({ ports }) => ({
    ...(await ports.presentationMount.create({ key: "presentationMount" })),
    expectation: { kind: "interface", id: "interface:org.quixos.presentation-mount@1" },
  }),
});

async function allocate<Navigation extends ExactReference>({
  input,
  ports,
}: {
  input: NavigationInput;
  ports: { source: { "create.call"(input: NavigationInput, key: MutationKey): Promise<Navigation> } };
}) {
  return metadata(await ports.source["create.call"](input, { key: "allocate" }));
}
async function copy({ receiver, input, ports }: Contexts["copy"]) {
  const members = (await ports.members.resolve()).map((entry) => entry.target);
  if (members.length > 512) throw new QxReject("PRESENTATION_COPY_LIMIT");
  const originalRoot = (await ports.root.resolve())[0]?.target ?? null;
  const requestedRoot = input ?? originalRoot;
  if (!requestedRoot && members.length) throw new QxReject("PRESENTATION_ROOT_MISSING");
  if (requestedRoot && !members.some((member) => same(member, requestedRoot)))
    throw new QxReject("PRESENTATION_COPY_ROOT_MISMATCH");
  const byId = new Map(members.map((member) => [member.object, member]));
  const children = new Map<string, typeof members>();
  for (const member of members) {
    const owner = await ports.metadata["presentationMount.resolve"]({ receiver: member, input: null });
    if (!same(owner, receiver)) throw new QxReject("PRESENTATION_OWNER_MISMATCH");
    const parent = await ports.metadata["parent.resolve"]({ receiver: member, input: null });
    if (parent) {
      if (!byId.has(parent.object)) throw new QxReject("PRESENTATION_PARENT_MISMATCH");
      const siblings = children.get(parent.object) ?? [];
      siblings.push(member);
      children.set(parent.object, siblings);
    } else if (!same(member, originalRoot)) throw new QxReject("PRESENTATION_ROOT_MISMATCH");
  }
  const queue = requestedRoot ? [requestedRoot] : [];
  const visited = new Set<string>();
  for (let index = 0; index < queue.length; index++) {
    const item = queue[index]!;
    if (visited.has(item.object)) throw new QxReject("PRESENTATION_CYCLE");
    visited.add(item.object);
    queue.push(...(children.get(item.object) ?? []).sort((a, b) => a.object.localeCompare(b.object)));
  }
  if (!input && queue.length !== members.length) throw new QxReject("PRESENTATION_DISCONNECTED_STATE");
  const presentationMount = {
    ...(await ports.presentationMount.create({ key: "presentationMount" })),
    expectation: { kind: "interface" as const, id: "interface:org.quixos.presentation-mount@1" as const },
  };
  const mapping: { source: (typeof members)[number]; target: (typeof members)[number] }[] = [];
  const copied = new Map<string, (typeof members)[number]>();
  for (const [index, source] of queue.entries()) {
    const originalParent = await ports.metadata["parent.resolve"]({ receiver: source, input: null });
    const parent = same(source, requestedRoot) ? null : copied.get(originalParent!.object)!;
    if (!same(source, requestedRoot) && !parent) throw new QxReject("PRESENTATION_COPY_PARENT_MISSING");
    const occurrence = await ports.metadata["occurrence.get"]({ receiver: source, input: null });
    const target = await ports.metadata["allocate.call"](
      { receiver: source, input: { presentationMount, occurrence, parent } },
      { key: "allocate:" + index },
    );
    copied.set(source.object, target);
    mapping.push({ source, target });
  }
  for (const [index, item] of mapping.entries())
    await ports.metadata["copyValues.call"](
      { receiver: item.source, input: { target: item.target, mapping } },
      { key: "values:" + index },
    );
  return presentationMount;
}