require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"
  gem "rails"
  gem "sqlite3"
end

require "active_record/railtie"
require "minitest/autorun"
require "stringio"

ENV["DATABASE_URL"] = "sqlite3::memory:"

class TestApp < Rails::Application
  config.load_defaults Rails::VERSION::STRING.to_f
  config.eager_load = false
  config.logger = Logger.new(StringIO.new)
  config.secret_key_base = "secret_key_base"
end
Rails.application.initialize!

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")

class BugTest < ActiveSupport::TestCase
  # Both tables below are semantically identical to their single-line
  # equivalents, which Rails introspects correctly. Only the formatting differs.

  def test_generated_column_expression_survives_multiline_ddl
    connection = ActiveRecord::Base.connection

    connection.execute(<<~SQL)
      CREATE TABLE widgets (
        "id" INTEGER PRIMARY KEY AUTOINCREMENT,
        "price" integer,
        "qty" integer,
        "total" integer GENERATED ALWAYS AS (
          "price" * "qty"
        ) STORED
      )
    SQL

    column = connection.columns("widgets").find { |c| c.name == "total" }

    assert column.virtual?, "column is correctly detected as generated"

    # FAILS: the defining expression is silently dropped.
    assert_equal %{"price" * "qty"}, column.default_function
  end

  def test_collation_survives_multiline_ddl
    connection = ActiveRecord::Base.connection

    connection.execute(<<~SQL)
      CREATE TABLE people (
        "id" INTEGER PRIMARY KEY AUTOINCREMENT,
        "a" varchar COLLATE "NOCASE",
        "b" varchar COLLATE "RTRIM"
      )
    SQL

    columns = connection.columns("people").index_by(&:name)

    assert_equal "NOCASE", columns["a"].collation   # first collated column is fine
    assert_equal "RTRIM",  columns["b"].collation   # FAILS: silently nil
  end

  def test_schema_dump_does_not_silently_corrupt_schema
    connection = ActiveRecord::Base.connection

    connection.execute(<<~SQL)
      CREATE TABLE gadgets (
        "id" INTEGER PRIMARY KEY AUTOINCREMENT,
        "price" integer,
        "qty" integer,
        "total" integer GENERATED ALWAYS AS (
          "price" * "qty"
        ) STORED
      )
    SQL

    output = StringIO.new
    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection_pool, output)
    dump = output.string

    # FAILS: dump contains `as: nil`, which reloads as a permanently-NULL column.
    refute_includes dump, "as: nil"
  end
end

create_table "gadgets", force: :cascade do |t|
  t.integer "price"
  t.integer "qty"
  t.virtual "total", type: :integer, as: nil, stored: true   # <-- expression gone
end

create_table "people", force: :cascade do |t|
  t.string "a", collation: "NOCASE"
  t.string "b"                                                # <-- COLLATE RTRIM gone
end

.split(/,(?=\s(?:CONSTRAINT|"(?:#{Regexp.union(column_names).source})"))/i)

["\"id\" INTEGER PRIMARY KEY AUTOINCREMENT,\n  \"price\" integer,\n  \"qty\" integer,\n  \"total\" integer GENERATED ALWAYS AS (\n    \"price\" * \"qty\"\n  ) STORED"]

GENERATED_ALWAYS_AS_REGEX = /.*"(\w+)".+GENERATED ALWAYS AS \((.+)\) (?:STORED|VIRTUAL)/i

# 1. allow a newline + indentation between columns
.split(/,(?=\s+(?:CONSTRAINT|"(?:#{Regexp.union(column_names).source})"))/i)

# 2. allow the expression to span newlines
GENERATED_ALWAYS_AS_REGEX = /.*"(\w+)".+GENERATED ALWAYS AS \((.+)\) (?:STORED|VIRTUAL)/im