/**
 * embed-collection-filter.test.ts — Tests for the collection-filter plumbing
 * shipped under i-ofojj7dy:
 *
 *   - getPendingEmbeddingDocs(db, collection) filters at the SQL layer
 *   - getHashesNeedingEmbedding(db, collection) filters at the SQL layer
 *   - generateEmbeddings({ collection }) only embeds matching docs
 *
 * Uses an in-memory SQLite + stub EmbeddingProvider — no node-llama-cpp.
 */

import { describe, test, expect, beforeEach, afterEach } from "vitest";
import { mkdtempSync, rmSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";

import {
  createStore,
  generateEmbeddings,
  getHashesNeedingEmbedding,
  type Store,
} from "../src/store.js";
import type {
  EmbeddingProvider,
  ProviderEmbedding,
  ProviderHealth,
} from "../src/embedding/provider.js";

// ─────────────────────────── Stub provider ───────────────────────────────────

class StubProvider implements EmbeddingProvider {
  readonly kind = "openai" as const;
  readonly modelId: string;
  readonly dim: number;
  embedBatchCalls = 0;
  totalTextsEmbedded = 0;
  // Snapshot the per-doc collection labels we received via the chunk stream.
  // generateEmbeddings hands us the chunk text only, but we can correlate
  // back through `docsProcessed` count in the result. For this test we only
  // assert on the result counts.
  constructor(modelId: string, dim = 4) {
    this.modelId = modelId;
    this.dim = dim;
  }
  getModelId(): string { return this.modelId; }
  getDimensions(): number | undefined { return this.dim; }
  async healthcheck(): Promise<ProviderHealth> {
    return { ok: true, model: this.modelId, dimensions: this.dim };
  }
  async embed(text: string): Promise<ProviderEmbedding | null> {
    this.totalTextsEmbedded++;
    return { embedding: this.fakeEmbed(text), model: this.modelId };
  }
  async embedBatch(texts: string[]): Promise<(ProviderEmbedding | null)[]> {
    this.embedBatchCalls++;
    this.totalTextsEmbedded += texts.length;
    return texts.map((t) => ({ embedding: this.fakeEmbed(t), model: this.modelId }));
  }
  async dispose(): Promise<void> {}
  private fakeEmbed(text: string): number[] {
    return Array.from({ length: this.dim }, (_, i) => (text.length + i) * 0.01);
  }
}

// ─────────────────────────── Test setup ──────────────────────────────────────

let workDir: string;
let store: Store;

beforeEach(() => {
  workDir = mkdtempSync(join(tmpdir(), "qmd-embed-filter-test-"));
  process.env.INDEX_PATH = join(workDir, "index.sqlite");
  store = createStore(process.env.INDEX_PATH);

  const now = "2026-05-13T00:00:00Z";

  // Three distinct content hashes, three distinct collections — one doc each.
  // The body has to be non-empty so chunkDocumentByTokens emits ≥1 chunk/doc.
  const bodies: Record<string, string> = {
    hashA: "Alpha collection body content here that is long enough to chunk.",
    hashB: "Beta collection body text there with different vocabulary to chunk.",
    hashC: "Gamma collection body words yonder packing unique tokens to chunk.",
  };
  for (const [hash, body] of Object.entries(bodies)) {
    store.db
      .prepare(`INSERT INTO content (hash, doc, created_at) VALUES (?, ?, ?)`)
      .run(hash, body, now);
  }
  // doc-per-collection mapping
  const insertDoc = (hash: string, collection: string, path: string) => {
    store.db
      .prepare(
        `INSERT INTO documents (hash, collection, path, title, created_at, modified_at, active) VALUES (?, ?, ?, ?, ?, ?, ?)`,
      )
      .run(hash, collection, path, path, now, now, 1);
  };
  insertDoc("hashA", "alpha", "a.md");
  insertDoc("hashB", "beta", "b.md");
  insertDoc("hashC", "gamma", "c.md");
});

afterEach(() => {
  try {
    store.close();
  } catch { /* ignore */ }
  delete process.env.INDEX_PATH;
  rmSync(workDir, { recursive: true, force: true });
});

// ─────────────────────────── getHashesNeedingEmbedding ───────────────────────

describe("getHashesNeedingEmbedding with collection filter (i-ofojj7dy)", () => {
  test("returns total count when no collection passed", () => {
    expect(getHashesNeedingEmbedding(store.db)).toBe(3);
  });

  test("returns 1 when filtering to a single-doc collection", () => {
    expect(getHashesNeedingEmbedding(store.db, "alpha")).toBe(1);
    expect(getHashesNeedingEmbedding(store.db, "beta")).toBe(1);
    expect(getHashesNeedingEmbedding(store.db, "gamma")).toBe(1);
  });

  test("returns 0 when filter does not match any collection", () => {
    expect(getHashesNeedingEmbedding(store.db, "nonexistent")).toBe(0);
  });

  test("shared content hash counted per containing collection", () => {
    // Add a second doc that re-uses hashA but in collection "beta".
    const now = "2026-05-13T00:00:00Z";
    store.db
      .prepare(
        `INSERT INTO documents (hash, collection, path, title, created_at, modified_at, active) VALUES (?, ?, ?, ?, ?, ?, ?)`,
      )
      .run("hashA", "beta", "shared.md", "shared", now, now, 1);
    // Without filter, the DISTINCT count of pending hashes is still 3.
    expect(getHashesNeedingEmbedding(store.db)).toBe(3);
    // With filter, beta now contains 2 distinct hashes (hashA + hashB).
    expect(getHashesNeedingEmbedding(store.db, "beta")).toBe(2);
    // Alpha still owns just hashA.
    expect(getHashesNeedingEmbedding(store.db, "alpha")).toBe(1);
  });

  test("inactive docs are excluded from the filtered count", () => {
    store.db
      .prepare(`UPDATE documents SET active = 0 WHERE collection = 'beta'`)
      .run();
    expect(getHashesNeedingEmbedding(store.db, "beta")).toBe(0);
    // Other collections unaffected
    expect(getHashesNeedingEmbedding(store.db, "alpha")).toBe(1);
  });
});

// ─────────────────────────── generateEmbeddings filter ───────────────────────

describe("generateEmbeddings with collection filter (i-ofojj7dy)", () => {
  test("processes only documents in the named collection", async () => {
    const provider = new StubProvider("embeddinggemma", 4);
    const result = await generateEmbeddings(store, {
      embedProvider: provider,
      collection: "alpha",
      maxDocsPerBatch: 64,
    });
    expect(result.docsProcessed).toBe(1);
    expect(result.chunksEmbedded).toBeGreaterThan(0);
    expect(result.errors).toBe(0);
  });

  test("processes all documents when collection is omitted (legacy path)", async () => {
    const provider = new StubProvider("embeddinggemma", 4);
    const result = await generateEmbeddings(store, {
      embedProvider: provider,
      maxDocsPerBatch: 64,
    });
    expect(result.docsProcessed).toBe(3);
    expect(result.errors).toBe(0);
  });

  test("returns zero-result for unknown collection without throwing", async () => {
    const provider = new StubProvider("embeddinggemma", 4);
    const result = await generateEmbeddings(store, {
      embedProvider: provider,
      collection: "ghost",
    });
    // No docs to embed → returns early with the empty-result shape
    expect(result.docsProcessed).toBe(0);
    expect(result.chunksEmbedded).toBe(0);
    expect(result.errors).toBe(0);
    expect(provider.totalTextsEmbedded).toBe(0);
  });

  test("does not embed docs from sibling collections", async () => {
    // Embed only beta; verify alpha + gamma are STILL pending afterward.
    const provider = new StubProvider("embeddinggemma", 4);
    await generateEmbeddings(store, {
      embedProvider: provider,
      collection: "beta",
    });
    // alpha + gamma still need embeddings, beta does not
    expect(getHashesNeedingEmbedding(store.db, "alpha")).toBe(1);
    expect(getHashesNeedingEmbedding(store.db, "gamma")).toBe(1);
    expect(getHashesNeedingEmbedding(store.db, "beta")).toBe(0);
  });
});