/**
 * v0.31 Phase 6 — migration v45 embedding dim resolution.
 *
 * Pins:
 *   - Migration uses HALFVEC on PGLite (recent pgvector bundled)
 *   - Dimension is resolved from config.embedding_dimensions, NOT
 *     hardcoded to 1536
 *   - HNSW index uses halfvec_cosine_ops (matching opclass)
 *   - Idempotent re-init does not re-create the column with a different shape
 */

import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
import { PGLiteEngine } from '../src/core/pglite-engine.ts';
import { configureGateway, resetGateway } from '../src/core/ai/gateway.ts';

let engine: PGLiteEngine;

beforeAll(async () => {
  engine = new PGLiteEngine();
  await engine.connect({});
  await engine.initSchema();
});

afterAll(async () => {
  await engine.disconnect();
});

describe('migration v45 facts column shape', () => {
  test('embedding column is HALFVEC (or VECTOR fallback) — not a different type', async () => {
    const rows = await engine.executeRaw<{ udt_name: string }>(
      `SELECT udt_name FROM information_schema.columns
       WHERE table_name = 'facts' AND column_name = 'embedding'`,
    );
    expect(rows.length).toBe(1);
    // HALFVEC on pgvector >= 0.7 (PGLite bundles this); falls back to VECTOR
    // on older Postgres. Either is acceptable.
    expect(['halfvec', 'vector']).toContain(rows[0].udt_name);
  });

  test('embedding dim matches the gateway-configured dim (not hardcoded 1536)', async () => {
    // The migration reads config.embedding_dimensions. PGLite's schema-init
    // seeds that to __EMBEDDING_DIMS__ replaced with the gateway dim (1536
    // by default). The dim used for the column must match.
    const dimRows = await engine.executeRaw<{ value: string }>(
      `SELECT value FROM config WHERE key = 'embedding_dimensions'`,
    );
    const expectedDim = dimRows.length > 0 ? parseInt(dimRows[0].value, 10) : 1536;

    // For the actual column type-modifier, query pg_attribute via atttypmod
    // (decoded by format_type).
    const formatRows = await engine.executeRaw<{ format_type: string }>(
      `SELECT format_type(atttypid, atttypmod) AS format_type
       FROM pg_attribute
       WHERE attrelid = 'facts'::regclass AND attname = 'embedding'`,
    );
    expect(formatRows.length).toBe(1);
    const formatStr = formatRows[0].format_type;
    // Shape: "halfvec(1536)" or "vector(1536)" — extract the parenthesized dim.
    const m = formatStr.match(/\((\d+)\)/);
    expect(m).not.toBeNull();
    expect(parseInt(m![1], 10)).toBe(expectedDim);
  });

  test('HNSW index uses opclass matching the column type', async () => {
    const rows = await engine.executeRaw<{ indexdef: string }>(
      `SELECT indexdef FROM pg_indexes
       WHERE tablename = 'facts' AND indexname = 'idx_facts_embedding_hnsw'`,
    );
    expect(rows.length).toBe(1);
    const def = rows[0].indexdef;
    // Either halfvec_cosine_ops (HALFVEC column) or vector_cosine_ops (fallback).
    expect(def).toMatch(/(halfvec_cosine_ops|vector_cosine_ops)/);
    // And the opclass must agree with the column type.
    const colRows = await engine.executeRaw<{ udt_name: string }>(
      `SELECT udt_name FROM information_schema.columns
       WHERE table_name = 'facts' AND column_name = 'embedding'`,
    );
    if (colRows[0].udt_name === 'halfvec') {
      expect(def).toContain('halfvec_cosine_ops');
    } else {
      expect(def).toContain('vector_cosine_ops');
    }
  });

  test('idempotent: re-running initSchema does not change the column type', async () => {
    const before = await engine.executeRaw<{ udt_name: string }>(
      `SELECT udt_name FROM information_schema.columns
       WHERE table_name = 'facts' AND column_name = 'embedding'`,
    );
    await engine.initSchema();
    const after = await engine.executeRaw<{ udt_name: string }>(
      `SELECT udt_name FROM information_schema.columns
       WHERE table_name = 'facts' AND column_name = 'embedding'`,
    );
    expect(after[0].udt_name).toBe(before[0].udt_name);
  });

});

describe('migration v45/v55 large-dim HNSW policy', () => {
  let largeDimEngine: PGLiteEngine;

  beforeAll(async () => {
    configureGateway({
      embedding_model: 'litellm:custom-4096d',
      embedding_dimensions: 4096,
      env: { ...process.env },
    });

    largeDimEngine = new PGLiteEngine();
    await largeDimEngine.connect({});
    await largeDimEngine.initSchema();
  });

  afterAll(async () => {
    await largeDimEngine.disconnect();
    resetGateway();
  });

  test('4096d init skips unsupported HNSW indexes but keeps vector columns', async () => {
    const formatRows = await largeDimEngine.executeRaw<{ format_type: string }>(
      `SELECT format_type(atttypid, atttypmod) AS format_type
       FROM pg_attribute
       WHERE attrelid = 'facts'::regclass AND attname = 'embedding'`,
    );
    expect(formatRows[0]?.format_type).toMatch(/(halfvec|vector)\(4096\)/);

    const indexRows = await largeDimEngine.executeRaw<{ exists: boolean }>(
      `SELECT EXISTS (
         SELECT 1 FROM pg_indexes
         WHERE tablename = 'facts'
           AND indexname = 'idx_facts_embedding_hnsw'
       ) AS exists`,
    );
    expect(indexRows[0]?.exists).toBe(false);

    const queryCacheFormatRows = await largeDimEngine.executeRaw<{ format_type: string }>(
      `SELECT format_type(atttypid, atttypmod) AS format_type
       FROM pg_attribute
       WHERE attrelid = 'query_cache'::regclass AND attname = 'embedding'`,
    );
    expect(queryCacheFormatRows[0]?.format_type).toMatch(/(halfvec|vector)\(4096\)/);

    const queryCacheIndexRows = await largeDimEngine.executeRaw<{ exists: boolean }>(
      `SELECT EXISTS (
         SELECT 1 FROM pg_indexes
         WHERE tablename = 'query_cache'
           AND indexname = 'idx_query_cache_embedding_hnsw'
       ) AS exists`,
    );
    expect(queryCacheIndexRows[0]?.exists).toBe(false);
  }, 60000);
});