/**
 * Test the SQL logic for checking postgres_ai.pg_statistic view existence
 * across different permission scenarios.
 */
import { describe, test, expect } from "bun:test";

describe("postgres_ai.pg_statistic permission check SQL", () => {
  test("to_regclass() returns NULL when schema doesn't exist", () => {
    // Simulate the SQL check behavior
    const viewExists = null; // to_regclass('postgres_ai.pg_statistic') when schema doesn't exist
    const granted = viewExists !== null;

    expect(granted).toBe(false);
  });

  test("to_regclass() returns NULL when user lacks USAGE on schema", () => {
    // When user lacks USAGE on postgres_ai schema, to_regclass() returns NULL
    // even if the schema and view exist
    const viewExists = null; // to_regclass('postgres_ai.pg_statistic') when no USAGE
    const granted = viewExists !== null;

    expect(granted).toBe(false);
  });

  test("to_regclass() returns oid when view exists and user has access", () => {
    // When user has USAGE on schema and view exists
    const viewExists = 12345; // to_regclass('postgres_ai.pg_statistic') returns oid
    const granted = viewExists !== null;

    expect(granted).toBe(true);
  });

  test("has_table_privilege is skipped (returns null) when view doesn't exist", () => {
    const viewExists = null;
    const selectGranted = viewExists === null ? null : true; // skipped

    expect(selectGranted).toBeNull();
  });

  test("has_table_privilege is checked when view exists", () => {
    const viewExists = 12345;
    const userHasSelect = true;
    const selectGranted = viewExists === null ? null : userHasSelect;

    expect(selectGranted).toBe(true);
  });
});

describe("Expected behavior per scenario", () => {
  test("Scenario 1: Superuser with postgres_ai.pg_statistic", () => {
    // to_regclass returns oid, has_table_privilege returns true
    const checkViewExists = true; // to_regclass('postgres_ai.pg_statistic') is not null
    const checkSelectPrivilege = true; // has_table_privilege returns true

    const missingOptional: string[] = [];
    if (!checkViewExists) {
      missingOptional.push("postgres_ai.pg_statistic view exists");
    }
    if (checkSelectPrivilege === false) {
      missingOptional.push("select on postgres_ai.pg_statistic");
    }

    expect(missingOptional).toHaveLength(0);
  });

  test("Scenario 2: pg_monitor, no postgres_ai schema access (before prepare-db)", () => {
    // to_regclass returns NULL because user lacks USAGE on postgres_ai schema
    const checkViewExists = false; // to_regclass('postgres_ai.pg_statistic') is null
    const checkSelectPrivilege = null; // skipped because view doesn't exist

    const missingOptional: string[] = [];
    if (!checkViewExists) {
      missingOptional.push("postgres_ai.pg_statistic view exists");
    }
    if (checkSelectPrivilege === false) {
      missingOptional.push("select on postgres_ai.pg_statistic");
    }

    // Should show warning about missing view but NOT crash
    expect(missingOptional).toEqual(["postgres_ai.pg_statistic view exists"]);
  });

  test("Scenario 3: No pg_monitor (before prepare-db)", () => {
    // to_regclass returns NULL because schema doesn't exist yet
    const checkViewExists = false; // to_regclass('postgres_ai.pg_statistic') is null
    const checkSelectPrivilege = null; // skipped

    const missingOptional: string[] = [];
    if (!checkViewExists) {
      missingOptional.push("postgres_ai.pg_statistic view exists");
    }
    if (checkSelectPrivilege === false) {
      missingOptional.push("select on postgres_ai.pg_statistic");
    }

    // Should show warning but NOT crash
    expect(missingOptional).toEqual(["postgres_ai.pg_statistic view exists"]);
  });

  test("Scenario 8: After prepare-db with schema grants", () => {
    // to_regclass returns oid, has_table_privilege returns true
    const checkViewExists = true; // to_regclass('postgres_ai.pg_statistic') is not null
    const checkSelectPrivilege = true; // has_table_privilege returns true

    const missingOptional: string[] = [];
    if (!checkViewExists) {
      missingOptional.push("postgres_ai.pg_statistic view exists");
    }
    if (checkSelectPrivilege === false) {
      missingOptional.push("select on postgres_ai.pg_statistic");
    }

    // Should be clean, no warnings
    expect(missingOptional).toHaveLength(0);
  });
});
