require 'rails_helper'
require 'column_dropper'

RSpec.describe ColumnDropper do

  def has_column?(table, column)
    Topic.exec_sql("SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
                    WHERE
                      table_schema = 'public' AND
                      table_name = :table AND
                      column_name = :column
                   ",
                      table: table, column: column
                  ).to_a.length == 1
  end

  it "can correctly drop columns after correct delay" do
    Topic.exec_sql "ALTER TABLE topics ADD COLUMN junk int"
    name = Topic
            .exec_sql("SELECT name FROM schema_migration_details LIMIT 1")
            .getvalue(0,0)

    Topic.exec_sql("UPDATE schema_migration_details SET created_at = :created_at WHERE name = :name",
                  name: name, created_at: 15.minutes.ago)

    dropped_proc_called = false

    ColumnDropper.drop(
      table: 'topics',
      after_migration: name,
      columns: ['junk'],
      delay: 20.minutes,
      on_drop: ->(){dropped_proc_called = true}
    )

    expect(has_column?('topics', 'junk')).to eq(true)
    expect(dropped_proc_called).to eq(false)

    ColumnDropper.drop(
      table: 'topics',
      after_migration: name,
      columns: ['junk'],
      delay: 10.minutes,
      on_drop: ->(){dropped_proc_called = true}
    )

    expect(has_column?('topics', 'junk')).to eq(false)
    expect(dropped_proc_called).to eq(true)

  end

  # describe '.mark_readonly' do
  #   let(:table_name) { "table_with_readonly_column" }
  #
  #   before do
  #     ActiveRecord::Base.exec_sql <<~SQL
  #     CREATE TABLE #{table_name} (topic_id INTEGER, email TEXT);
  #
  #     INSERT INTO #{table_name} (topic_id, email)
  #     VALUES (1, 'something@email.com');
  #     SQL
  #
  #     described_class.mark_readonly(table_name, 'email')
  #   end
  #
  #   after do
  #     ActiveRecord::Base.exec_sql <<~SQL
  #     DROP TABLE IF EXISTS #{table_name};
  #     DROP TRIGGER IF EXISTS #{table_name}_email_readonly ON #{table_name};
  #     SQL
  #   end
  #
  #   it 'should prevent updates to the readonly column' do
  #     expect do
  #       ActiveRecord::Base.exec_sql <<~SQL
  #       UPDATE #{table_name}
  #       SET email = 'testing@email.com'
  #       WHERE topic_id = 1;
  #       SQL
  #     end.to raise_error(
  #       PG::RaiseException,
  #       /Discourse: email in #{table_name} is readonly/
  #     )
  #
  #     ActiveRecord::Base.exec_sql("ROLLBACK")
  #   end
  #
  #   it 'should allow updates to the other columns' do
  #     ActiveRecord::Base.exec_sql <<~SQL
  #     UPDATE #{table_name}
  #     SET topic_id = 2
  #     WHERE topic_id = 1
  #     SQL
  #
  #     expect(
  #       ActiveRecord::Base.exec_sql("SELECT * FROM #{table_name};").values
  #     ).to include(["2", "something@email.com"])
  #   end
  #
  #   it 'should prevent insertions to the readonly column' do
  #     expect do
  #       ActiveRecord::Base.exec_sql <<~SQL
  #       INSERT INTO #{table_name} (topic_id, email)
  #       VALUES (2, 'something@email.com');
  #       SQL
  #     end.to raise_error(
  #       PG::RaiseException,
  #       /Discourse: email in table_with_readonly_column is readonly/
  #     )
  #
  #     ActiveRecord::Base.exec_sql("ROLLBACK")
  #   end
  #
  #   it 'should allow insertions to the other columns' do
  #     ActiveRecord::Base.exec_sql <<~SQL
  #     INSERT INTO #{table_name} (topic_id)
  #     VALUES (2);
  #     SQL
  #
  #     expect(
  #       ActiveRecord::Base.exec_sql("SELECT * FROM #{table_name} WHERE topic_id = 2;").values
  #     ).to include(["2", nil])
  #   end
  # end
end