discourse/migrations/lib/database/schema/global_config.rb

# frozen_string_literal: true

module Migrations::Database::Schema
  class GlobalConfig
    attr_reader :excluded_column_names, :modified_columns

    def initialize(schema_config)
      @schema_config = schema_config
      @excluded_table_names = load_globally_excluded_table_names.freeze
      @excluded_column_names = load_globally_excluded_column_names.freeze
      @modified_columns = load_globally_modified_columns.freeze
    end

    def excluded_table_name?(table_name)
      @excluded_table_names.include?(table_name)
    end

    def modified_name(column_name)
      if (modified_column = find_modified_column(column_name))
        modified_column[:rename_to]
      end
    end

    def modified_datatype(column_name)
      if (modified_column = find_modified_column(column_name))
        modified_column[:datatype]
      end
    end

    private

    def find_modified_column(column_name)
      @modified_columns.find { |column| column[:name] == column_name } ||
        @modified_columns.find { |column| column[:name_regex]&.match?(column_name) }
    end

    def load_globally_excluded_table_names
      table_names = @schema_config.dig(:global, :tables, :exclude)
      table_names.presence&.to_set || Set.new
    end

    def load_globally_excluded_column_names
      column_names = @schema_config.dig(:global, :columns, :exclude)
      column_names.presence || []
    end

    def load_globally_modified_columns
      modified_columns = @schema_config.dig(:global, :columns, :modify)
      return {} if modified_columns.blank?

      modified_columns.map do |column|
        if column[:name_regex]
          column[:name_regex_original] = column[:name_regex]
          column[:name_regex] = Regexp.new(column[:name_regex])
        end
        column[:datatype] = column[:datatype]&.to_sym
        column
      end
    end
  end
end