class ObjectFramework::Persistence::Query

# File lib/object_framework/persistence/query.rb, line 15
def self.identifier(name)
  raise ConfigurationError, "Invalid storage identifier: #{name.inspect}" unless /\A[a-zA-Z_][a-zA-Z0-9_]*\z/.match?(name.to_s)
  name.to_sym
end

# File lib/object_framework/persistence/query.rb, line 20
def initialize(table: nil, criteria: [], ordering: [], row_limit: nil, row_offset: 0)
  @table = self.class.identifier(table) if table
  @criteria, @ordering = criteria.freeze, ordering.freeze
  @row_limit, @row_offset = row_limit, row_offset
  freeze
end

# File lib/object_framework/persistence/query.rb, line 61
def apply(rows)
  selected = rows.select { |row| criteria.all? { |criterion| matches?(row, criterion) } }
  ordering = @ordering.any? { |field, _| field == :id } ? @ordering : @ordering + [[:id, :asc]]
  selected.sort! do |left, right|
    ordering.each do |field, direction|
      a, b = left[field], right[field]
      comparison = if a.nil? then b.nil? ? 0 : -1 elsif b.nil? then 1 else a <=> b end
      raise InvalidInput, "Incomparable query values" unless comparison
      break(direction == :desc ? -comparison : comparison) unless comparison.zero?
    end.then { |result| result.is_a?(Integer) ? result : 0 }
  end
  selected = selected.drop(row_offset)
  row_limit ? selected.take(row_limit) : selected
end

# File lib/object_framework/persistence/query.rb, line 38
def compare(field, operator, value)
  raise ConfigurationError, "Unsupported query operator" unless OPERATORS.include?(operator)
  raise ConfigurationError, "IN requires an array" if operator == :in && !value.is_a?(Array)
  criterion = Criterion.new(field: self.class.identifier(field), operator:, value: Values.detach(value))
  copy(criteria: criteria + [criterion])
end

# File lib/object_framework/persistence/query.rb, line 27
def for_table(table)
  copy(table:)
end

# File lib/object_framework/persistence/query.rb, line 52
def limit(count)
  copy(row_limit: nonnegative(count))
end

# File lib/object_framework/persistence/query.rb, line 57
def offset(count)
  copy(row_offset: nonnegative(count))
end

# File lib/object_framework/persistence/query.rb, line 46
def order(field, direction = :asc)
  raise ConfigurationError, "Invalid ordering direction" unless %i[asc desc].include?(direction)
  copy(ordering: ordering + [[self.class.identifier(field), direction].freeze])
end

# File lib/object_framework/persistence/query.rb, line 32
def where(**attributes)
  attributes.reduce(self) { |query, (field, value)| query.compare(field, :eq, value) }
end