import { readdirSync, readFileSync, statSync } from 'node:fs';
import { join, relative } from 'node:path';

import { zipSync } from 'fflate';
import { describe, expect, it } from 'vitest';

import {
  ASSET_PLACEHOLDER_PREFIX,
  VaultError,
  extractFrontmatter,
  extractInlineTags,
  parseVaultZip,
  planFolders,
  planSlugs,
  planVaultImport,
} from './obsidian-vault';

const FIXTURE_DIR = join(__dirname, '../../../../fixtures/import/obsidian-vault');

/** Zips the checked-in fixture vault (also the e2e helper's job later, #119). */
function fixtureZip(extra: Record<string, Uint8Array> = {}): Uint8Array {
  const entries: Record<string, Uint8Array> = { ...extra };
  const walk = (dir: string): void => {
    for (const name of readdirSync(dir)) {
      const path = join(dir, name);
      if (statSync(path).isDirectory()) walk(path);
      else entries[relative(FIXTURE_DIR, path)] = new Uint8Array(readFileSync(path));
    }
  };
  walk(FIXTURE_DIR);
  return zipSync(entries);
}

function planFixture(mountDepth = 0, frontmatterMode: 'strip' | 'preserve' = 'strip') {
  return planVaultImport(fixtureZip(), {
    frontmatterMode,
    existingSlugs: new Set(),
    mountDepth,
  });
}

describe('parseVaultZip (issue #116)', () => {
  it('splits notes from assets and skips dot-directories', () => {
    const vault = parseVaultZip(fixtureZip());
    expect(vault.notes.map((n) => n.path)).toEqual([
      'Notizen/Über Uns',
      'Projekte/Projekt A',
      'Projekte/Projekt B',
      'Projekte/Tief/Ebene4/Ebene5/Tiefe Notiz',
      'Startseite',
      'Über Uns',
    ]);
    expect(vault.assets.map((a) => a.path)).toEqual(['media/teich.png', 'media/unterlagen.pdf']);
    expect(vault.assets[0]!.extension).toBe('png');
  });

  it('decodes UTF-8 entry names even without the ZIP UTF-8 flag (#127)', () => {
    // Real-world archivers often omit the UTF-8 flag; fflate then decodes
    // the name bytes as Latin-1 ("Fußball" → mojibake in page titles).
    // Build such a ZIP by zipping an ASCII placeholder of the same byte
    // length (keeps the flag clear) and patching in the raw UTF-8 bytes.
    const utf8Name = new TextEncoder().encode('Grüße.md');
    const placeholder = 'GrAABBe.md';
    expect(utf8Name.length).toBe(placeholder.length);
    const zipped = zipSync({ [placeholder]: new TextEncoder().encode('# Hallo') });
    const placeholderBytes = new TextEncoder().encode(placeholder);
    for (let i = 0; i <= zipped.length - placeholderBytes.length; i += 1) {
      if (placeholderBytes.every((byte, j) => zipped[i + j] === byte)) {
        zipped.set(utf8Name, i); // local header + central directory
      }
    }

    const vault = parseVaultZip(zipped);
    expect(vault.notes.map((n) => n.name)).toEqual(['Grüße']);
  });

  it('NFC-normalizes decomposed names so umlaut digraphs survive (#127)', () => {
    // macOS zips store umlauts decomposed (NFD): "\u00dc" as U + combining mark.
    const nfdName = 'U\u0308ber NFD.md';
    expect(nfdName.normalize('NFC')).not.toBe(nfdName); // really decomposed
    const vault = parseVaultZip(fixtureZip({ [nfdName]: new TextEncoder().encode('# NFD') }));
    const note = vault.notes.find((n) => n.path.includes('NFD'));
    expect(note?.name).toBe('\u00dcber NFD'); // precomposed
    const plan = planVaultImport(fixtureZip({ [nfdName]: new TextEncoder().encode('x') }), {
      frontmatterMode: 'strip',
      existingSlugs: new Set(),
      mountDepth: 0,
    });
    expect(plan.notes.map((n) => n.slug)).toContain('ueber-nfd');
  });

  it('rejects zip-slip paths, garbage, and oversized vaults', () => {
    expect(() => parseVaultZip(new Uint8Array([1, 2, 3]))).toThrowError(VaultError);
    expect(() =>
      parseVaultZip(fixtureZip({ '../evil.md': new TextEncoder().encode('x') })),
    ).toThrowError(/Illegal path/);
    expect(() => parseVaultZip(fixtureZip(), 64)).toThrowError(/too large/);
    try {
      parseVaultZip(fixtureZip(), 64);
    } catch (error) {
      expect((error as VaultError).code).toBe('import_vault_too_large');
    }
  });
});

describe('extractFrontmatter', () => {
  const note = '---\ntitle: X\ntags: [a, b/c]\n---\n\nBody.';

  it('strips the block and reads inline-array tags', () => {
    const result = extractFrontmatter(note, 'strip');
    expect(result.markdown).toBe('\nBody.');
    expect(result.tags).toEqual([['a'], ['b', 'c']]);
  });

  it('preserves the block as a yaml code fence', () => {
    const result = extractFrontmatter(note, 'preserve');
    expect(result.markdown).toContain('```yaml\ntitle: X\ntags: [a, b/c]\n```');
    expect(result.markdown.trimEnd().endsWith('Body.')).toBe(true);
  });

  it('reads block-list and scalar tag forms; leaves notes without frontmatter alone', () => {
    const block = extractFrontmatter('---\ntags:\n  - team\n  - "x/y"\n---\nHi', 'strip');
    expect(block.tags).toEqual([['team'], ['x', 'y']]);
    const scalar = extractFrontmatter('---\ntag: solo\n---\nHi', 'strip');
    expect(scalar.tags).toEqual([['solo']]);
    const none = extractFrontmatter('# Just a heading\n---\nnot frontmatter', 'strip');
    expect(none.markdown).toContain('# Just a heading');
    expect(none.tags).toEqual([]);
  });
});

describe('extractInlineTags', () => {
  it('collects nested tags, removes them, and never touches code or headings', () => {
    const result = extractInlineTags(
      '# Heading stays\n\nText #eins mitten im Satz und #a/b am Ende.\n' +
        'Code: `#nichttag` bleibt.\n\n```\n#auchkeintag\n```\n\nNummern #123 bleiben.',
    );
    expect(result.tags).toEqual([['eins'], ['a', 'b']]);
    expect(result.markdown).toContain('# Heading stays');
    expect(result.markdown).toContain('Text mitten im Satz und am Ende.');
    expect(result.markdown).toContain('`#nichttag`');
    expect(result.markdown).toContain('#auchkeintag');
    expect(result.markdown).toContain('#123');
  });
});

describe('planFolders / planSlugs', () => {
  it('merges the deepest folder levels beyond the budget', () => {
    const vault = parseVaultZip(fixtureZip());
    const { containers, parentKeyByNote } = planFolders(vault, 3);
    // Assets never create containers (no `media` here).
    expect(containers.map((c) => c.title)).toEqual([
      'Notizen',
      'Projekte',
      'Tief',
      'Ebene4/Ebene5',
    ]);
    expect(parentKeyByNote.get('Projekte/Tief/Ebene4/Ebene5/Tiefe Notiz')).toBe(
      'Projekte/Tief/Ebene4/Ebene5',
    );
    expect(parentKeyByNote.get('Startseite')).toBeNull();
  });

  it('suffixes collisions against existing and batch slugs deterministically', () => {
    const slugs = planSlugs(
      [
        { key: 'a', base: 'Über Uns' },
        { key: 'b', base: 'über uns' },
        { key: 'c', base: 'Taken' },
      ],
      new Set(['taken']),
    );
    expect(slugs.get('a')).toBe('ueber-uns');
    expect(slugs.get('b')).toBe('ueber-uns-2');
    expect(slugs.get('c')).toBe('taken-2');
  });
});

describe('planVaultImport (the whole transform)', () => {
  it('rewrites every link form to final slugs', () => {
    const plan = planFixture();
    const note = (path: string) => plan.notes.find((n) => n.key === `note:${path}`)!;

    const start = note('Startseite');
    // Basename link → resolved slug with the original name as display.
    expect(start.markdown).toContain('[[projekt-a|Projekt A]]');
    // Full-path link keeps its display text.
    expect(start.markdown).toContain('[[projekt-b|Das zweite Projekt]]');
    // Duplicate basename: lexicographically first path (Notizen/Über Uns) wins.
    expect(start.markdown).toContain('[[ueber-uns|Über Uns]]');
    expect(note('Notizen/Über Uns').slug).toBe('ueber-uns');
    expect(note('Über Uns').slug).toBe('ueber-uns-2');
    // Unresolvable → phantom out of the slugified name.
    expect(start.markdown).toContain('[[fehlt-noch|Fehlt Noch]]');
    // Heading link strips the fragment.
    expect(note('Projekte/Projekt B').markdown).toContain('[[projekt-a|Projekt A]]');
  });

  it('turns image embeds into placeholders and other files into attachments', () => {
    const plan = planFixture();
    const a = plan.notes.find((n) => n.key === 'note:Projekte/Projekt A')!;
    expect(a.markdown).toContain(`![teich.png](${ASSET_PLACEHOLDER_PREFIX}media/teich.png)`);
    expect(a.imageAssets).toEqual(['media/teich.png']);

    const b = plan.notes.find((n) => n.key === 'note:Projekte/Projekt B')!;
    expect(b.markdown).toContain('*unterlagen.pdf*');
    expect(b.attachmentAssets).toEqual(['media/unterlagen.pdf']);
    // Code spans and fences survive untouched.
    expect(b.markdown).toContain('`[[NichtLink]] #nichttag`');
    expect(b.markdown).toContain('[[AuchKeinLink]] #auchkeintag');

    // A relative standard-markdown image resolves too.
    const about = plan.notes.find((n) => n.key === 'note:Über Uns')!;
    expect(about.markdown).toContain(`![Logo](${ASSET_PLACEHOLDER_PREFIX}media/teich.png)`);

    expect([...plan.referencedAssets].sort()).toEqual(['media/teich.png', 'media/unterlagen.pdf']);
  });

  it('collects frontmatter and inline tags per note', () => {
    const plan = planFixture();
    const a = plan.notes.find((n) => n.key === 'note:Projekte/Projekt A')!;
    expect(a.tags).toEqual([['projekt'], ['status', 'aktiv']]);
    expect(a.markdown).not.toContain('#status/aktiv');
    expect(a.markdown).not.toContain('tags: [projekt');

    const start = plan.notes.find((n) => n.key === 'note:Startseite')!;
    expect(start.tags).toEqual([['willkommen']]);
  });

  it('honors the preserve frontmatter mode', () => {
    const plan = planFixture(0, 'preserve');
    const a = plan.notes.find((n) => n.key === 'note:Projekte/Projekt A')!;
    expect(a.markdown).toContain('```yaml');
    expect(a.markdown).toContain('title: Projekt A');
  });

  it('budgets container levels from the mount depth', () => {
    // Mount at depth 0 (pond root): 5 container levels available — the deep
    // path (4 folders) fits unmerged.
    const roomy = planFixture(0);
    expect(roomy.containers.map((c) => c.title)).toContain('Ebene5');

    // Mount at depth 2: 3 container levels — the deepest two merge.
    const tight = planFixture(2);
    expect(tight.containers.map((c) => c.title)).toContain('Ebene4/Ebene5');
    const deep = tight.notes.find((n) => n.key.includes('Tiefe Notiz'))!;
    expect(deep.parentKey).toBe('container:Projekte/Tief/Ebene4/Ebene5');
    // Containers stay parents-before-children.
    const keys = tight.containers.map((c) => c.key);
    for (const container of tight.containers) {
      if (container.parentKey) {
        expect(keys.indexOf(container.parentKey)).toBeLessThan(keys.indexOf(container.key));
      }
    }
  });
});