require 'pg'
require 'sequel'

require_relative 'connect'

def migrate
  db = DB
  db.create_table? :threads do
    primary_key :id
    String :title
    String :creator, index: true
    Integer :remote_id, index: true, unique: true
    String :last_post_creator
    DateTime :last_post_created_at
    DateTime :created_at, index: true
  end

  db.create_table? :posts do
    primary_key :id
    String :body
    String :creator, index: true
    Integer :remote_id, index: true, unique: true
    foreign_key :thread_id, :threads
    DateTime :created_at, index: true
    column :tsv, 'tsvector'
  end

  db.run('CREATE INDEX IF NOT EXISTS tsv_idx ON posts USING gin(tsv);')

  begin
    db.create_function(:update_last_post, <<-SQL, language: :plpgsql, returns: :trigger)
      BEGIN
        UPDATE threads
        SET
          last_post_created_at = NEW.created_at,
          last_post_creator = NEW.creator
        WHERE
          threads.id = NEW.thread_id;
        RETURN NEW;
      END
    SQL
  rescue Sequel::DatabaseError => e
    raise e unless e.wrapped_exception.is_a?(PG::DuplicateFunction)
  end

  begin
    db.create_function(:set_posts_tsv, <<-SQL, language: :plpgsql, returns: :trigger)
      BEGIN
        NEW.tsv = to_tsvector(new.body);
        RETURN NEW;
      END
    SQL
  rescue Sequel::DatabaseError => e
    raise e unless e.wrapped_exception.is_a?(PG::DuplicateFunction)
  end

  begin
    db.run(<<-SQL)
      CREATE TRIGGER update_last_post
      AFTER INSERT ON posts
      FOR EACH ROW
      EXECUTE PROCEDURE update_last_post();
    SQL
  rescue Sequel::DatabaseError => e
    raise e unless e.wrapped_exception.is_a?(PG::DuplicateObject)
  end

  begin
    db.run(<<-SQL)
      CREATE TRIGGER set_posts_tsv
      BEFORE INSERT OR UPDATE ON posts
      FOR EACH ROW
      EXECUTE PROCEDURE set_posts_tsv();
    SQL
  rescue Sequel::DatabaseError => e
    raise e unless e.wrapped_exception.is_a?(PG::DuplicateObject)
  end
end