import { TestBed } from '@angular/core/testing';
import { describe, it, expect, vi, afterEach } from 'vitest';
import { Result } from '@shared/kernel/fp';
import { BLOB_PRESENTER, BlobPresenter } from '@shared/application/blob-presenter';
import { Brief, BriefDecisions, CaseContext, LetterBlock } from '@brief/domain/brief';
import { OrgTemplate } from '@brief/domain/org-template';
import {
  BRIEF_LOAD_FAILED,
  BriefAdapter,
  BriefLoadFailure,
  BriefView,
} from '@brief/infrastructure/brief.adapter';
import { LetterPreviewAdapter, PREVIEW_FAILED } from '@brief/infrastructure/letter-preview.adapter';
import { RevealBigNummerAdapter } from '@brief/infrastructure/reveal-bignummer.adapter';
import { BriefStore } from './brief.store';

const decisions: BriefDecisions = {
  canEdit: true,
  canApprove: true,
  canReject: true,
  canSend: true,
  canRevealBigNummer: true,
};

const brief: Brief = {
  briefId: 'b1',
  beroep: 'arts',
  templateId: 't1',
  placeholders: [],
  sections: [],
  status: { tag: 'draft' },
  drafterId: 'u1',
};

const orgTemplate: OrgTemplate = {
  subOrgId: 'cibg-registers',
  orgName: 'CIBG — Registers',
  returnAddress: 'Postbus 00000\n2500 AA Den Haag',
  footerContact: 'info@voorbeeld.example',
  footerLegal: 'KvK 00000000',
  signatureName: 'A. de Vries',
  signatureRole: 'Hoofd Registratie',
  signatureClosing: 'Met vriendelijke groet,',
  margins: { topMm: 25, rightMm: 25, bottomMm: 25, leftMm: 25 },
  version: 1,
};

const caseContext: CaseContext = {
  zorgverlenerNaam: 'Dr. A. (Anna) de Vries',
  bigNummer: '19012345601',
  beroep: 'arts',
  aanvraagReferentie: 'HER-2026-000842',
};

const view: BriefView = { brief, availablePassages: [], decisions, orgTemplate, caseContext };

/** A recording fake of BLOB_PRESENTER (RB-28/TE-006) — records every call instead of
    touching the DOM, so a spec can assert a command's success path directly. */
function fakeBlobPresenter() {
  const opened: Blob[] = [];
  const presenter: BlobPresenter = {
    open: (blob) => opened.push(blob),
    download: () => {
      throw new Error('not used by BriefStore');
    },
  };
  return { presenter, opened };
}

function setup(adapter: Partial<BriefAdapter>, blobPresenter?: BlobPresenter): BriefStore {
  TestBed.configureTestingModule({
    providers: [
      { provide: BriefAdapter, useValue: adapter },
      ...(blobPresenter ? [{ provide: BLOB_PRESENTER, useValue: blobPresenter }] : []),
    ],
  });
  return TestBed.inject(BriefStore);
}

describe('BriefStore action state (Idle | Busy | Failed)', () => {
  it('is Busy synchronously once a transition starts', async () => {
    const approved: BriefView = {
      ...view,
      brief: { ...brief, status: { tag: 'approved', approvedBy: 'u2', approvedAt: 't' } },
    };
    const store = setup({
      load: (): Promise<Result<BriefLoadFailure, BriefView>> =>
        Promise.resolve({ ok: true, value: view }),
      save: (): Promise<Result<string, BriefView>> => Promise.resolve({ ok: true, value: view }),
      approve: (): Promise<Result<string, BriefView>> =>
        Promise.resolve({ ok: true, value: approved }),
    });
    await store.load();

    const pending = store.approve();
    expect(store.busy()).toBe(true); // set synchronously, before any await resolves

    await pending; // settle before the test ends
  });

  it('settles to Idle on a successful transition', async () => {
    const approved: BriefView = {
      ...view,
      brief: { ...brief, status: { tag: 'approved', approvedBy: 'u2', approvedAt: 't' } },
    };
    const store = setup({
      load: (): Promise<Result<BriefLoadFailure, BriefView>> =>
        Promise.resolve({ ok: true, value: view }),
      save: (): Promise<Result<string, BriefView>> => Promise.resolve({ ok: true, value: view }),
      approve: (): Promise<Result<string, BriefView>> =>
        Promise.resolve({ ok: true, value: approved }),
    });
    await store.load();

    await store.approve();
    expect(store.busy()).toBe(false);
    expect(store.lastError()).toBeNull();
  });

  it('goes Busy then Failed on a failing transition, surfacing the error', async () => {
    const store = setup({
      load: (): Promise<Result<BriefLoadFailure, BriefView>> =>
        Promise.resolve({ ok: true, value: view }),
      save: (): Promise<Result<string, BriefView>> => Promise.resolve({ ok: true, value: view }),
      approve: (): Promise<Result<string, BriefView>> =>
        Promise.resolve({ ok: false, error: 'niet toegestaan' }),
    });
    await store.load();

    await store.approve();
    expect(store.busy()).toBe(false);
    expect(store.lastError()).toBe('niet toegestaan');
  });

  it('a subsequent successful transition clears a prior Failed state', async () => {
    let approveResult: Result<string, BriefView> = { ok: false, error: 'eerste poging mislukt' };
    const store = setup({
      load: (): Promise<Result<BriefLoadFailure, BriefView>> =>
        Promise.resolve({ ok: true, value: view }),
      save: (): Promise<Result<string, BriefView>> => Promise.resolve({ ok: true, value: view }),
      approve: (): Promise<Result<string, BriefView>> => Promise.resolve(approveResult),
    });
    await store.load();

    await store.approve();
    expect(store.lastError()).toBe('eerste poging mislukt');

    approveResult = {
      ok: true,
      value: {
        ...view,
        brief: { ...brief, status: { tag: 'approved', approvedBy: 'u2', approvedAt: 't' } },
      },
    };
    await store.approve();
    expect(store.busy()).toBe(false);
    expect(store.lastError()).toBeNull();
  });
});

// --- WP-27: undo/redo history + rejection diff ---

function block(id: string, text: string): LetterBlock {
  return {
    type: 'freeText',
    blockId: id,
    content: { paragraphs: [{ nodes: [{ type: 'text', text }] }] },
  };
}
const kern = (blocks: LetterBlock[]) => ({
  sectionKey: 'kern',
  title: 'Kern',
  required: true,
  locked: false,
  blocks,
});
const filledBrief: Brief = { ...brief, sections: [kern([block('local-1', 'x')])] };
const filledView: BriefView = { ...view, brief: filledBrief };

function loadedBrief(store: BriefStore): Brief {
  const s = store.model();
  if (s.tag !== 'Loaded') throw new Error('not loaded');
  return s.brief;
}

async function loadedStore(over: Partial<BriefAdapter> = {}): Promise<BriefStore> {
  // Untyped return (inferred as the narrow `{ ok: true; value }` literal) so this one
  // helper satisfies both `load` (error channel `BriefLoadFailure`) and `save` (error
  // channel `string`) — it only ever produces the `ok: true` branch.
  const ok = (v: BriefView) => Promise.resolve({ ok: true, value: v } as const);
  const store = setup({ load: () => ok(filledView), save: () => ok(filledView), ...over });
  await store.load();
  return store;
}

describe('BriefStore undo/redo history', () => {
  it('starts with nothing to undo', async () => {
    // Given a freshly loaded brief.
    // When no edit has happened yet...
    const store = await loadedStore();

    // Then there is nothing to undo.
    expect(store.canUndo()).toBe(false);
  });

  it('records an edit and makes it undoable', async () => {
    // Given a loaded brief with one block.
    const store = await loadedStore();

    // When a block is removed...
    store.edit({ tag: 'BlockRemoved', blockId: 'local-1' });

    // Then the block is gone and the edit becomes undoable.
    expect(loadedBrief(store).sections[0].blocks.length).toBe(0);
    expect(store.canUndo()).toBe(true);
  });

  it('undo reverts the edit and enables redo', async () => {
    // Given a brief with one recorded edit (a removed block).
    const store = await loadedStore();
    store.edit({ tag: 'BlockRemoved', blockId: 'local-1' });

    // When the edit is undone...
    store.undo();

    // Then the block is back, and redo becomes available.
    expect(loadedBrief(store).sections[0].blocks.length).toBe(1);
    expect(store.canRedo()).toBe(true);
  });

  it('redo reapplies the undone edit', async () => {
    // Given an edit that was undone.
    const store = await loadedStore();
    store.edit({ tag: 'BlockRemoved', blockId: 'local-1' });
    store.undo();

    // When it is redone...
    store.redo();

    // Then the edit is reapplied.
    expect(loadedBrief(store).sections[0].blocks.length).toBe(0);
  });

  it('a no-op edit does not clear the redo future', async () => {
    // Given an undone edit, with redo available.
    const store = await loadedStore();
    store.edit({ tag: 'BlockRemoved', blockId: 'local-1' });
    store.undo(); // back to 1 block, redo available

    // When an edit that changes nothing (an unknown block) is applied...
    store.edit({ tag: 'BlockRemoved', blockId: 'does-not-exist' });

    // Then the no-op leaves no dead history step — redo is still available.
    expect(store.canRedo()).toBe(true);
  });

  it('a new edit clears the redo future', async () => {
    const store = await loadedStore();
    store.edit({ tag: 'FreeTextBlockAdded', sectionKey: 'kern' });
    store.undo();
    expect(store.canRedo()).toBe(true);
    store.edit({ tag: 'FreeTextBlockAdded', sectionKey: 'kern' });
    expect(store.canRedo()).toBe(false);
  });

  it('caps history at 50 snapshots', async () => {
    const store = await loadedStore();
    for (let i = 0; i < 55; i++) store.edit({ tag: 'FreeTextBlockAdded', sectionKey: 'kern' });
    let undos = 0;
    while (store.canUndo()) {
      store.undo();
      undos++;
    }
    expect(undos).toBe(50);
  });
});

describe('BriefStore rejection diff', () => {
  it('captures the rejected letter and diffs a subsequent edit against it', async () => {
    const submitted: Brief = {
      ...filledBrief,
      status: { tag: 'submitted', submittedBy: 'u', submittedAt: 't' },
    };
    const rejected: Brief = {
      ...filledBrief,
      status: { tag: 'rejected', rejectedBy: 'u2', rejectedAt: 't', comments: 'nee' },
    };
    const ok = (v: BriefView) => Promise.resolve({ ok: true, value: v } as const);
    const store = setup({
      load: () => ok({ ...filledView, brief: submitted }),
      save: () => ok(filledView),
      reject: () => ok({ ...filledView, brief: rejected }),
    });
    await store.load();
    await store.reject('nee');
    expect(store.hasRejectionDiff()).toBe(false); // nothing changed yet

    store.edit({
      tag: 'BlockContentEdited',
      blockId: 'local-1',
      content: { paragraphs: [{ nodes: [{ type: 'text', text: 'CHANGED' }] }] },
    });
    expect(store.blockDiffs().get('local-1')).toBe('changed');
    expect(store.removedSinceReject()).toBe(0);
  });
});

describe('BriefStore.previewLetter', () => {
  afterEach(() => vi.restoreAllMocks());

  it('opens the composed letter via BLOB_PRESENTER on success (RB-28)', async () => {
    const { presenter, opened } = fakeBlobPresenter();
    const store = setup(
      {
        load: (): Promise<Result<BriefLoadFailure, BriefView>> =>
          Promise.resolve({ ok: true, value: view }),
      },
      presenter,
    );
    await store.load();
    const blob = new Blob(['<html></html>'], { type: 'text/html' });
    vi.spyOn(TestBed.inject(LetterPreviewAdapter), 'preview').mockResolvedValue({
      ok: true,
      value: blob,
    });

    await store.previewLetter();
    expect(opened).toEqual([blob]);
    expect(store.lastError()).toBeNull();
  });

  it('surfaces the error without opening a tab on failure', async () => {
    const { presenter, opened } = fakeBlobPresenter();
    const store = setup(
      {
        load: (): Promise<Result<BriefLoadFailure, BriefView>> =>
          Promise.resolve({ ok: true, value: view }),
      },
      presenter,
    );
    await store.load();
    vi.spyOn(TestBed.inject(LetterPreviewAdapter), 'preview').mockResolvedValue({
      ok: false,
      error: PREVIEW_FAILED,
    });

    await store.previewLetter();
    expect(opened).toHaveLength(0);
    expect(store.lastError()).toBe(PREVIEW_FAILED);
  });
});

describe('BriefStore.revealBigNummer (PRD-0002 §5c)', () => {
  afterEach(() => vi.restoreAllMocks());

  // Loaded with a MASKED BIG-nummer, as the server ships it by default.
  const maskedView: BriefView = {
    ...view,
    caseContext: { ...caseContext, bigNummer: '********601' },
  };

  it('swaps the masked value for the revealed one on success', async () => {
    const store = setup({ load: () => Promise.resolve({ ok: true, value: maskedView }) });
    await store.load();
    expect(store.caseContext()?.bigNummer).toBe('********601');
    vi.spyOn(TestBed.inject(RevealBigNummerAdapter), 'reveal').mockResolvedValue({
      ok: true,
      value: '19012345601',
    });

    await store.revealBigNummer();
    expect(store.caseContext()?.bigNummer).toBe('19012345601');
    expect(store.lastError()).toBeNull();
  });

  it('keeps the value masked and surfaces the error on failure', async () => {
    const store = setup({ load: () => Promise.resolve({ ok: true, value: maskedView }) });
    await store.load();
    vi.spyOn(TestBed.inject(RevealBigNummerAdapter), 'reveal').mockResolvedValue({
      ok: false,
      error: 'geweigerd',
    });

    await store.revealBigNummer();
    expect(store.caseContext()?.bigNummer).toBe('********601'); // unchanged
    expect(store.lastError()).toBe('geweigerd');
  });
});

describe('BriefStore.flushPending (CanDeactivate guard / beforeunload)', () => {
  const okSave = () =>
    vi.fn(() => Promise.resolve({ ok: true, value: filledView } as Result<string, BriefView>));

  it('flushes a pending debounced edit immediately and clears the pending flag', async () => {
    const save = okSave();
    const store = await loadedStore({ save });
    expect(store.hasPendingSave()).toBe(false);

    store.edit({ tag: 'FreeTextBlockAdded', sectionKey: 'kern' });
    expect(store.hasPendingSave()).toBe(true); // 600ms debounce armed, not yet fired

    await store.flushPending();
    expect(save).toHaveBeenCalledTimes(1); // no timer wait needed
    expect(store.hasPendingSave()).toBe(false); // timer consumed
  });

  it('is a no-op when no edit is pending', async () => {
    const save = okSave();
    const store = await loadedStore({ save });
    await store.flushPending();
    expect(save).not.toHaveBeenCalled();
  });
});

// --- RB-22 (CQ-007 expand half): a 404 from GET /brief tolerates by calling the
// existing reset() command, exactly once. Today's backend never 404s (RB-23 adds
// that); this fake adapter is what exercises the branch until then. ---

describe('BriefStore.load — 404 tolerance (RB-22)', () => {
  const notFound: Result<BriefLoadFailure, BriefView> = { ok: false, error: { tag: 'notFound' } };
  const resetOk: Result<string, BriefView> = { ok: true, value: view };

  it('a 404 drives exactly one reset(), which populates the store', async () => {
    // Given GET /brief 404s (no brief exists yet) and reset() succeeds.
    const load = vi.fn(() => Promise.resolve(notFound));
    const reset = vi.fn(() => Promise.resolve(resetOk));
    const store = setup({ load, reset });

    // When the store loads...
    await store.load();

    // Then reset() ran exactly once, and the store ends up loaded from its result.
    expect(reset).toHaveBeenCalledTimes(1);
    expect(store.model().tag).toBe('Loaded');
  });

  it('a second 404 does not drive a second reset()', async () => {
    // Given every load() attempt 404s (e.g. the brief still fails to appear).
    const load = vi.fn(() => Promise.resolve(notFound));
    const reset = vi.fn(() => Promise.resolve(resetOk));
    const store = setup({ load, reset });

    // When the store loads twice...
    await store.load();
    await store.load();

    // Then reset() ran exactly once — the once-only bound holds across calls, not
    // just within one — and the second 404 surfaces as an ordinary load failure.
    expect(reset).toHaveBeenCalledTimes(1);
    expect(store.model()).toEqual({ tag: 'Failed', reason: BRIEF_LOAD_FAILED });
  });
});