require 'minitest/autorun'
require 'prism'
require 'tmpdir'

class OrmIndexStoreTest < Minitest::Test
  def setup
    @dir = Dir.mktmpdir('prism-index-store')
    @store = Prism::Orm::Store.new(File.join(@dir, 'test.pstore'))
    @store.create_table(:users, %w[id email age])
  end

  def teardown
    FileUtils.remove_entry(@dir)
  end

  def test_add_index_returns_a_default_name_and_lists_it
    name = @store.add_index(:users, :email)
    assert_equal 'index_users_on_email', name
    assert_equal [{ name: 'index_users_on_email', columns: ['email'], unique: false }], @store.indexes(:users)
  end

  def test_add_index_accepts_an_explicit_name
    name = @store.add_index(:users, :email, name: 'idx_email')
    assert_equal 'idx_email', name
  end

  def test_add_index_twice_with_the_same_name_raises
    @store.add_index(:users, :email)
    assert_raises(Prism::Orm::Store::IndexExists) { @store.add_index(:users, :email) }
  end

  def test_add_index_backfills_existing_rows
    @store.insert(:users, email: 'a@x.com', age: 20)
    @store.insert(:users, email: 'b@x.com', age: 30)
    @store.add_index(:users, :email)

    matches = @store.lookup_by_index(:users, { 'email' => 'a@x.com' })
    assert_equal ['a@x.com'], matches.map { |row| row['email'] }
  end

  def test_add_unique_index_over_existing_duplicates_raises_and_creates_nothing
    @store.insert(:users, email: 'dup@x.com', age: 20)
    @store.insert(:users, email: 'dup@x.com', age: 30)

    assert_raises(Prism::Orm::Store::UniqueConstraintViolation) do
      @store.add_index(:users, :email, unique: true)
    end
    assert_equal [], @store.indexes(:users)
  end

  def test_remove_index_by_name
    @store.add_index(:users, :email, name: 'idx_email')
    @store.remove_index(:users, 'idx_email')
    assert_equal [], @store.indexes(:users)
  end

  def test_remove_index_by_column_list
    @store.add_index(:users, :email)
    @store.remove_index(:users, :email)
    assert_equal [], @store.indexes(:users)
  end

  def test_remove_unknown_index_raises
    assert_raises(Prism::Orm::Store::UnknownIndex) { @store.remove_index(:users, :email) }
  end

  def test_lookup_by_index_returns_nil_without_a_covering_index
    @store.insert(:users, email: 'a@x.com', age: 20)
    assert_nil @store.lookup_by_index(:users, { 'email' => 'a@x.com' })
  end

  def test_lookup_by_index_returns_empty_array_for_no_match
    @store.add_index(:users, :email)
    @store.insert(:users, email: 'a@x.com', age: 20)
    assert_equal [], @store.lookup_by_index(:users, { 'email' => 'nobody@x.com' })
  end

  def test_composite_index_requires_every_column_present_in_the_lookup
    @store.add_index(:users, [:email, :age])
    @store.insert(:users, email: 'a@x.com', age: 20)

    assert_nil @store.lookup_by_index(:users, { 'email' => 'a@x.com' }),
               'a lookup missing one of the composite columns should not use this index'
    matches = @store.lookup_by_index(:users, { 'email' => 'a@x.com', 'age' => 20 })
    assert_equal 1, matches.size
  end

  def test_lookup_by_index_prefers_the_most_specific_covering_index
    @store.add_index(:users, :email)
    @store.add_index(:users, [:email, :age])
    @store.insert(:users, email: 'a@x.com', age: 20)
    @store.insert(:users, email: 'a@x.com', age: 99)

    matches = @store.lookup_by_index(:users, { 'email' => 'a@x.com', 'age' => 20 })
    assert_equal [20], matches.map { |row| row['age'] }
  end

  def test_unique_index_rejects_a_duplicate_insert
    @store.add_index(:users, :email, unique: true)
    @store.insert(:users, email: 'a@x.com', age: 20)

    assert_raises(Prism::Orm::Store::UniqueConstraintViolation) do
      @store.insert(:users, email: 'a@x.com', age: 30)
    end
    assert_equal 1, @store.count(:users), 'the rejected insert must not have partially applied'
  end

  def test_unique_index_rejects_an_update_that_collides_with_another_row
    @store.add_index(:users, :email, unique: true)
    id1 = @store.insert(:users, email: 'a@x.com', age: 20)
    id2 = @store.insert(:users, email: 'b@x.com', age: 30)

    assert_raises(Prism::Orm::Store::UniqueConstraintViolation) do
      @store.update(:users, id2, email: 'a@x.com')
    end
    assert_equal 'b@x.com', @store.find(:users, id2)['email'], 'the rejected update must not have partially applied'
    assert_equal 'a@x.com', @store.find(:users, id1)['email']
  end

  def test_unique_index_allows_updating_a_row_to_its_own_current_value
    @store.add_index(:users, :email, unique: true)
    id = @store.insert(:users, email: 'a@x.com', age: 20)
    @store.update(:users, id, age: 21)
    assert_equal 21, @store.find(:users, id)['age']
  end

  def test_index_tracks_updates_old_key_freed_new_key_claimed
    @store.add_index(:users, :email)
    id = @store.insert(:users, email: 'a@x.com', age: 20)
    @store.update(:users, id, email: 'b@x.com')

    assert_equal [], @store.lookup_by_index(:users, { 'email' => 'a@x.com' })
    assert_equal [id], @store.lookup_by_index(:users, { 'email' => 'b@x.com' }).map { |row| row['id'] }
  end

  def test_index_forgets_deleted_rows
    @store.add_index(:users, :email)
    id = @store.insert(:users, email: 'a@x.com', age: 20)
    @store.delete(:users, id)
    assert_equal [], @store.lookup_by_index(:users, { 'email' => 'a@x.com' })
  end

  def test_deleting_a_nonexistent_id_is_still_a_silent_no_op
    @store.add_index(:users, :email)
    @store.delete(:users, 999)
  end
end

# add_column/remove_column must keep any index that covers the affected
# column in sync - see the comments on Store#add_column/#remove_column for
# why a stale map here is a silent-wrong-results bug (Relation#rows trusts
# a non-nil #lookup_by_index result as definitive), not just a missed
# optimization.
class OrmIndexColumnMigrationTest < Minitest::Test
  def setup
    @dir = Dir.mktmpdir('prism-index-column-migration')
    @store = Prism::Orm::Store.new(File.join(@dir, 'test.pstore'))
    @store.create_table(:posts, %w[id title])
  end

  def teardown
    FileUtils.remove_entry(@dir)
  end

  def test_add_column_backfill_rebuilds_an_index_built_before_the_column_existed
    id1 = @store.insert(:posts, title: 'first')
    id2 = @store.insert(:posts, title: 'second')
    @store.add_index(:posts, :status)

    @store.add_column(:posts, :status, default: 'draft')

    matches = @store.lookup_by_index(:posts, { 'status' => 'draft' })
    refute_nil matches, 'the index should still cover the column after the backfill'
    assert_equal [id1, id2].sort, matches.map { |row| row['id'] }.sort
  end

  def test_add_column_backfill_drops_the_stale_nil_key_from_the_index
    @store.insert(:posts, title: 'first')
    @store.add_index(:posts, :status)

    @store.add_column(:posts, :status, default: 'draft')

    assert_equal [], @store.lookup_by_index(:posts, { 'status' => nil }),
                 'no row should still be indexed under the pre-backfill nil value'
  end

  def test_add_column_backfill_keeps_a_range_capable_index_usable
    id1 = @store.insert(:posts, title: 'first')
    id2 = @store.insert(:posts, title: 'second')
    @store.add_index(:posts, :priority)

    @store.add_column(:posts, :priority, default: 5)

    matches = @store.lookup_by_index_range(:posts, :priority, gte: 1)
    refute_nil matches
    assert_equal [id1, id2].sort, matches.map { |row| row['id'] }.sort
  end

  def test_remove_column_drops_a_single_column_index_covering_it
    @store.add_index(:posts, :status, name: 'idx_status')
    @store.remove_column(:posts, :status)

    assert_equal [], @store.indexes(:posts)
    assert_nil @store.lookup_by_index(:posts, { 'status' => 'draft' }),
               'a dropped column must never be reported as indexed again'
  end

  def test_remove_column_drops_a_composite_index_covering_it
    @store.add_column(:posts, :status, default: 'draft')
    @store.add_index(:posts, %i[title status])

    @store.remove_column(:posts, :title)

    assert_equal [], @store.indexes(:posts),
                 'a composite index cannot survive with one of its columns gone'
  end

  def test_remove_column_leaves_indexes_on_other_columns_untouched
    @store.add_column(:posts, :status, default: 'draft')
    @store.add_index(:posts, :title)
    @store.add_index(:posts, :status)

    @store.remove_column(:posts, :status)

    assert_equal ['index_posts_on_title'], @store.indexes(:posts).map { |index| index[:name] }
  end

  def test_remove_column_then_readding_it_starts_with_a_clean_index_free_slate
    id = @store.insert(:posts, title: 'first')
    @store.add_index(:posts, :status)
    @store.add_column(:posts, :status, default: 'draft')
    @store.remove_column(:posts, :status)

    @store.add_column(:posts, :status, default: 'archived')

    assert_equal [], @store.indexes(:posts),
                 'removing the column must have dropped the earlier index for good'
    assert_equal 'archived', @store.find(:posts, id)['status']
  end
end

class OrmIndexRangeStoreTest < Minitest::Test
  def setup
    @dir = Dir.mktmpdir('prism-index-range-store')
    @store = Prism::Orm::Store.new(File.join(@dir, 'test.pstore'))
    @store.create_table(:users, %w[id email age])
  end

  def teardown
    FileUtils.remove_entry(@dir)
  end

  def test_single_column_index_is_range_capable_and_sorted
    @store.insert(:users, email: 'c@x.com', age: 30)
    @store.insert(:users, email: 'a@x.com', age: 10)
    @store.insert(:users, email: 'b@x.com', age: 20)
    @store.add_index(:users, :age)

    matches = @store.lookup_by_index_range(:users, :age, gte: 20)
    assert_equal [20, 30], matches.map { |row| row['age'] }.sort
  end

  def test_composite_index_is_never_range_capable
    @store.add_index(:users, [:email, :age])
    @store.insert(:users, email: 'a@x.com', age: 10)
    assert_nil @store.lookup_by_index_range(:users, :age, gte: 0)
  end

  def test_lookup_by_index_range_returns_nil_without_a_covering_index
    @store.insert(:users, email: 'a@x.com', age: 10)
    assert_nil @store.lookup_by_index_range(:users, :age, gte: 0)
  end

  def test_gte_is_inclusive
    @store.add_index(:users, :age)
    @store.insert(:users, email: 'a@x.com', age: 20)
    matches = @store.lookup_by_index_range(:users, :age, gte: 20)
    assert_equal 1, matches.size
  end

  def test_gt_is_exclusive
    @store.add_index(:users, :age)
    @store.insert(:users, email: 'a@x.com', age: 20)
    assert_equal [], @store.lookup_by_index_range(:users, :age, gt: 20)
  end

  def test_lte_is_inclusive
    @store.add_index(:users, :age)
    @store.insert(:users, email: 'a@x.com', age: 20)
    matches = @store.lookup_by_index_range(:users, :age, lte: 20)
    assert_equal 1, matches.size
  end

  def test_lt_is_exclusive
    @store.add_index(:users, :age)
    @store.insert(:users, email: 'a@x.com', age: 20)
    assert_equal [], @store.lookup_by_index_range(:users, :age, lt: 20)
  end

  def test_combined_lower_and_upper_bound
    @store.add_index(:users, :age)
    [5, 15, 25, 35, 45].each { |age| @store.insert(:users, email: "#{age}@x.com", age: age) }
    matches = @store.lookup_by_index_range(:users, :age, gte: 15, lte: 35)
    assert_equal [15, 25, 35], matches.map { |row| row['age'] }.sort
  end

  def test_nil_valued_rows_are_never_returned_by_a_range_lookup
    @store.add_index(:users, :age)
    @store.insert(:users, email: 'a@x.com', age: nil)
    @store.insert(:users, email: 'b@x.com', age: 10)
    matches = @store.lookup_by_index_range(:users, :age, gte: 0)
    assert_equal ['b@x.com'], matches.map { |row| row['email'] }
  end

  def test_index_backfilled_from_existing_rows_is_range_capable
    @store.insert(:users, email: 'a@x.com', age: 10)
    @store.insert(:users, email: 'b@x.com', age: 20)
    @store.add_index(:users, :age)
    matches = @store.lookup_by_index_range(:users, :age, gte: 15)
    assert_equal ['b@x.com'], matches.map { |row| row['email'] }
  end

  def test_range_lookup_tracks_updates
    @store.add_index(:users, :age)
    id = @store.insert(:users, email: 'a@x.com', age: 10)
    @store.update(:users, id, age: 99)

    assert_equal [id], @store.lookup_by_index_range(:users, :age, gte: 90).map { |r| r['id'] }
    assert_equal [], @store.lookup_by_index_range(:users, :age, gte: 5, lte: 10)
  end

  def test_range_lookup_forgets_deleted_rows
    @store.add_index(:users, :age)
    id = @store.insert(:users, email: 'a@x.com', age: 10)
    @store.delete(:users, id)
    assert_equal [], @store.lookup_by_index_range(:users, :age, gte: 0)
  end

  def test_reused_value_after_update_and_reinsert_still_resolves_correctly
    @store.add_index(:users, :age)
    a = @store.insert(:users, email: 'a@x.com', age: 10)
    @store.insert(:users, email: 'b@x.com', age: 10)
    @store.update(:users, a, age: 50)

    assert_equal ['b@x.com'], @store.lookup_by_index_range(:users, :age, gte: 0, lte: 20).map { |r| r['email'] }
    assert_equal ['a@x.com'], @store.lookup_by_index_range(:users, :age, gte: 40).map { |r| r['email'] }
  end
end

# Covers Store#lookup_by_index_in - the IN-list lookup backing
# `where(column: [v1, v2, ...])`, most importantly `where(id: [...])`,
# which every belongs_to/has_one/has_many/has_many-through eager-load
# batches its preload query through (see Relation#preload_belongs_to and
# friends).
class OrmIndexInListStoreTest < Minitest::Test
  def setup
    @dir = Dir.mktmpdir('prism-index-in-store')
    @store = Prism::Orm::Store.new(File.join(@dir, 'test.pstore'))
    @store.create_table(:users, %w[id email age])
  end

  def teardown
    FileUtils.remove_entry(@dir)
  end

  def test_id_lookup_needs_no_add_index_call_at_all
    a = @store.insert(:users, email: 'a@x.com', age: 10)
    @store.insert(:users, email: 'b@x.com', age: 20)
    c = @store.insert(:users, email: 'c@x.com', age: 30)

    matches = @store.lookup_by_index_in(:users, :id, [a, c])
    assert_equal ['a@x.com', 'c@x.com'], matches.map { |row| row['email'] }.sort
  end

  def test_id_lookup_ignores_ids_that_do_not_exist
    a = @store.insert(:users, email: 'a@x.com', age: 10)
    matches = @store.lookup_by_index_in(:users, :id, [a, a + 1000])
    assert_equal [a], matches.map { |row| row['id'] }
  end

  def test_id_lookup_deduplicates_repeated_values
    a = @store.insert(:users, email: 'a@x.com', age: 10)
    matches = @store.lookup_by_index_in(:users, :id, [a, a, a])
    assert_equal 1, matches.size
  end

  def test_lookup_by_index_in_returns_nil_without_a_covering_index_on_a_non_id_column
    @store.insert(:users, email: 'a@x.com', age: 10)
    assert_nil @store.lookup_by_index_in(:users, :email, ['a@x.com'])
  end

  def test_lookup_by_index_in_uses_a_single_column_index_when_present
    @store.insert(:users, email: 'a@x.com', age: 10)
    @store.insert(:users, email: 'b@x.com', age: 20)
    @store.insert(:users, email: 'c@x.com', age: 30)
    @store.add_index(:users, :email)

    matches = @store.lookup_by_index_in(:users, :email, ['a@x.com', 'c@x.com'])
    assert_equal ['a@x.com', 'c@x.com'], matches.map { |row| row['email'] }.sort
  end

  def test_composite_index_cannot_answer_an_in_list_on_one_of_its_columns
    @store.add_index(:users, [:email, :age])
    @store.insert(:users, email: 'a@x.com', age: 10)
    assert_nil @store.lookup_by_index_in(:users, :email, ['a@x.com'])
  end

  def test_in_list_lookup_tracks_updates
    @store.add_index(:users, :email)
    id = @store.insert(:users, email: 'a@x.com', age: 10)
    @store.update(:users, id, email: 'new@x.com')

    assert_equal [], @store.lookup_by_index_in(:users, :email, ['a@x.com'])
    assert_equal [id], @store.lookup_by_index_in(:users, :email, ['new@x.com']).map { |r| r['id'] }
  end

  def test_in_list_lookup_forgets_deleted_rows
    @store.add_index(:users, :email)
    id = @store.insert(:users, email: 'a@x.com', age: 10)
    @store.delete(:users, id)
    assert_equal [], @store.lookup_by_index_in(:users, :email, ['a@x.com'])
    assert_equal [], @store.lookup_by_index_in(:users, :id, [id])
  end

  def test_an_empty_values_list_matches_nothing_without_touching_the_table
    @store.insert(:users, email: 'a@x.com', age: 10)
    assert_equal [], @store.lookup_by_index_in(:users, :id, [])
  end
end

# Counts full-table scans (Store#all) separately from index lookups
# (Store#lookup_by_index that actually found a covering index), the same
# shape as CountingStore/CountingThroughStore used by the eager-loading
# tests, so Relation's index usage can be proven rather than assumed.
class CountingIndexStore < Prism::Orm::Store
  attr_reader :scan_count

  attr_reader :range_hits

  attr_reader :in_hits

  attr_reader :eq_range_hits

  def initialize(*args)
    super
    @scan_count = 0
    @index_hits = 0
    @range_hits = 0
    @in_hits = 0
    @eq_range_hits = 0
  end

  def all(table)
    @scan_count += 1
    super
  end

  def lookup_by_index(table, equalities)
    result = super
    @index_hits += 1 unless result.nil?
    result
  end

  def lookup_by_index_range(table, column, operators)
    result = super
    @range_hits += 1 unless result.nil?
    result
  end

  def lookup_by_index_in(table, column, values)
    result = super
    @in_hits += 1 unless result.nil?
    result
  end

  def lookup_by_index_equality_range(table, equalities, column, operators)
    result = super
    @eq_range_hits += 1 unless result.nil?
    result
  end