import { ConflictException, INestApplication, NotFoundException } from '@nestjs/common';
import { MAX_PAGE_DEPTH } from '@dorfteich/shared';
import { PrismaClient, User } from '@prisma/client';
import { afterAll, beforeAll, describe, expect, it } from 'vitest';

import { createTestApp } from '../testing/test-app';
import { createTestPrisma, grantOwnerAdmin, hasTestDb, uniqueSuffix } from '../testing/test-db';
import { PagesService } from './pages.service';

/**
 * Page hierarchy (issue #106): create-under-parent, reparent via reposition,
 * cycle/depth rejection, and the permission rule that a child of an unreadable
 * parent lists with `parentId: null` (no hidden-page id ever leaks).
 */
describe.skipIf(!hasTestDb)('Page hierarchy (db, issue #106)', () => {
  let app: INestApplication;
  let prisma: PrismaClient;
  let pages: PagesService;
  const suffix = uniqueSuffix();
  let owner: User;
  let reader: User;
  let pondId: string;
  let secretLabelId: string;

  async function createChain(titles: string[]): Promise<string[]> {
    const ids: string[] = [];
    for (const [index, title] of titles.entries()) {
      const page = await pages.create(owner, pondId, {
        title,
        parentId: index === 0 ? null : ids[index - 1],
      });
      ids.push(page.id);
    }
    return ids;
  }

  beforeAll(async () => {
    prisma = createTestPrisma();
    app = await createTestApp();
    pages = app.get(PagesService);

    owner = await prisma.user.create({
      data: {
        username: `tree-owner-${suffix}`,
        email: `tree-owner-${suffix}@example.test`,
        displayName: 'Tree Owner',
      },
    });
    reader = await prisma.user.create({
      data: {
        username: `tree-reader-${suffix}`,
        email: `tree-reader-${suffix}@example.test`,
        displayName: 'Tree Reader',
      },
    });
    const pond = await prisma.pond.create({
      data: {
        slug: `tree-pond-${suffix}`,
        name: 'Tree Pond',
        type: 'SHARED',
        ownerId: owner.id,
      },
    });
    pondId = pond.id;
    await grantOwnerAdmin(prisma, pondId, owner.id);

    // Reader grants BEFORE any permission resolution touches the pond — the
    // PondPermissionCache would otherwise serve the pre-grant state.
    const secret = await prisma.label.create({
      data: { pondId, name: 'secret', color: '#334455' },
    });
    secretLabelId = secret.id;
    await prisma.roleGrant.createMany({
      data: [
        {
          pondId,
          subjectType: 'USER',
          subjectId: reader.id,
          role: 'READER',
          scopeType: 'POND',
          effect: 'ALLOW',
          createdBy: owner.id,
        },
        {
          pondId,
          subjectType: 'USER',
          subjectId: reader.id,
          role: 'READER',
          scopeType: 'LABEL',
          scopeId: secret.id,
          effect: 'DENY',
          createdBy: owner.id,
        },
      ],
    });
  });

  afterAll(async () => {
    await prisma.roleGrant.deleteMany({ where: { pondId } });
    await prisma.label.deleteMany({ where: { pondId } });
    await prisma.page.deleteMany({ where: { pondId } });
    await prisma.pond.deleteMany({ where: { id: pondId } });
    await prisma.user.deleteMany({ where: { id: { in: [owner.id, reader.id] } } });
    await prisma.$disconnect();
    await app.close();
  });

  it('creates a page under a parent and at the root', async () => {
    const root = await pages.create(owner, pondId, { title: 'Root' });
    expect(root.parentId).toBeNull();

    const child = await pages.create(owner, pondId, { title: 'Child', parentId: root.id });
    expect(child.parentId).toBe(root.id);

    const list = await pages.list(owner, pondId);
    expect(list.find((p) => p.id === child.id)?.parentId).toBe(root.id);
    expect(list.find((p) => p.id === root.id)?.parentId).toBeNull();
  });

  it('rejects an unknown, foreign, or trashed parent as 404', async () => {
    await expect(
      pages.create(owner, pondId, { title: 'Orphan', parentId: 'no-such-page' }),
    ).rejects.toBeInstanceOf(NotFoundException);

    const foreignPond = await prisma.pond.create({
      data: {
        slug: `tree-foreign-${suffix}`,
        name: 'Foreign',
        type: 'PERSONAL',
        ownerId: owner.id,
      },
    });
    await grantOwnerAdmin(prisma, foreignPond.id, owner.id);
    const foreignPage = await pages.create(owner, foreignPond.id, { title: 'Elsewhere' });
    await expect(
      pages.create(owner, pondId, { title: 'Crossing', parentId: foreignPage.id }),
    ).rejects.toBeInstanceOf(NotFoundException);

    const doomed = await pages.create(owner, pondId, { title: 'Doomed' });
    await pages.softDelete(owner, doomed.id);
    await expect(
      pages.create(owner, pondId, { title: 'Under trash', parentId: doomed.id }),
    ).rejects.toBeInstanceOf(NotFoundException);

    await prisma.page.deleteMany({ where: { pondId: foreignPond.id } });
    await prisma.roleGrant.deleteMany({ where: { pondId: foreignPond.id } });
    await prisma.pond.delete({ where: { id: foreignPond.id } });
  });

  it(`rejects nesting beyond ${MAX_PAGE_DEPTH} levels on create`, async () => {
    const chain = await createChain(
      Array.from({ length: MAX_PAGE_DEPTH }, (_, i) => `Deep ${i + 1}`),
    );
    await expect(
      pages.create(owner, pondId, { title: 'Too deep', parentId: chain[MAX_PAGE_DEPTH - 1] }),
    ).rejects.toBeInstanceOf(ConflictException);
  });

  it('reparents atomically through the position endpoint', async () => {
    const a = await pages.create(owner, pondId, { title: 'Move A' });
    const b = await pages.create(owner, pondId, { title: 'Move B' });
    const child = await pages.create(owner, pondId, { title: 'Move child', parentId: a.id });

    // Drag onto B: reparent + append, one call.
    const moved = await pages.reposition(owner, child.id, {
      afterId: b.id,
      beforeId: null,
      parentId: b.id,
    });
    expect(moved.parentId).toBe(b.id);

    // Back to the root with `parentId: null`.
    const rooted = await pages.reposition(owner, child.id, {
      afterId: null,
      beforeId: a.id,
      parentId: null,
    });
    expect(rooted.parentId).toBeNull();

    // An absent `parentId` keeps the current parent (plain reorder).
    const reordered = await pages.reposition(owner, child.id, { afterId: b.id, beforeId: null });
    expect(reordered.parentId).toBeNull();
  });

  it('rejects a move into the page own subtree as page_cycle', async () => {
    const [top, , grandchild] = await createChain(['Cycle 1', 'Cycle 2', 'Cycle 3']);
    let caught: unknown;
    await pages
      .reposition(owner, top!, { afterId: null, beforeId: null, parentId: grandchild! })
      .catch((error: unknown) => {
        caught = error;
      });
    expect(caught).toBeInstanceOf(ConflictException);
    expect((caught as ConflictException).getResponse()).toMatchObject({ code: 'page_cycle' });

    // Self-parenting is the trivial cycle.
    await expect(
      pages.reposition(owner, top!, { afterId: null, beforeId: null, parentId: top! }),
    ).rejects.toBeInstanceOf(ConflictException);
  });

  it('rejects a move that pushes the subtree past the depth limit', async () => {
    const deep = await createChain(['Limit 1', 'Limit 2', 'Limit 3', 'Limit 4']);
    const [subtreeTop] = await createChain(['Tall 1', 'Tall 2', 'Tall 3']);

    let caught: unknown;
    await pages
      .reposition(owner, subtreeTop!, { afterId: null, beforeId: null, parentId: deep[3]! })
      .catch((error: unknown) => {
        caught = error;
      });
    expect(caught).toBeInstanceOf(ConflictException);
    expect((caught as ConflictException).getResponse()).toMatchObject({
      code: 'page_depth_exceeded',
    });
  });

  it('nulls the parentId of a child whose parent the caller may not read', async () => {
    const hidden = await pages.create(owner, pondId, { title: 'Hidden parent' });
    await prisma.pageLabel.create({ data: { pageId: hidden.id, labelId: secretLabelId } });
    const child = await pages.create(owner, pondId, {
      title: 'Visible child',
      parentId: hidden.id,
    });

    const ownerList = await pages.list(owner, pondId);
    expect(ownerList.find((p) => p.id === child.id)?.parentId).toBe(hidden.id);

    const readerList = await pages.list(reader, pondId);
    expect(readerList.some((p) => p.id === hidden.id)).toBe(false);
    expect(readerList.find((p) => p.id === child.id)?.parentId).toBeNull();
  });
});