class Solargraph::ComplexType::UniqueType

def self.can_root_name?(name)
  # name is not lowercase

  !name.empty? && name != name.downcase
end

def self.parse name, substring = '', make_rooted: nil
  if name.start_with?(':::')
    raise ComplexTypeError, "Illegal prefix: #{name}"
  end
  if name.start_with?('::')
    name = name[2..-1]
    rooted = true
  elsif !can_root_name?(name)
    rooted = true
  else
    rooted = false
  end
  rooted = make_rooted unless make_rooted.nil?
  # @type [Array<ComplexType>]

  key_types = []
  # @type [Array<ComplexType>]

  subtypes = []
  parameters_type = nil
  unless substring.empty?
    subs = ComplexType.parse(substring[1..-2], partial: true)
    parameters_type = PARAMETERS_TYPE_BY_STARTING_TAG.fetch(substring[0])
    if parameters_type == :hash
      raise ComplexTypeError, "Bad hash type: name=#{name}, substring=#{substring}" unless !subs.is_a?(ComplexType) and subs.length == 2 and !subs[0].is_a?(UniqueType) and !subs[1].is_a?(UniqueType)
      # @todo should be able to resolve map; both types have it

      #   with same return type

      # @sg-ignore

      key_types.concat(subs[0].map { |u| ComplexType.new([u]) })
      # @sg-ignore

      subtypes.concat(subs[1].map { |u| ComplexType.new([u]) })
    else
      subtypes.concat subs
    end
  end
  new(name, key_types, subtypes, rooted: rooted, parameters_type: parameters_type)
end

def ==(other)
  eql?(other)
end

def all_rooted?
  return true if name == GENERIC_TAG_NAME
  rooted? && all_params.all?(&:rooted?)
end

def can_assign?(api_map, atype)
  logger.debug { "UniqueType#can_assign?(self=#{rooted_tags.inspect}, atype=#{atype.rooted_tags.inspect})" }
  downcasted_atype = atype.downcast_to_literal_if_possible
  out = downcasted_atype.all? do |autype|
    autype.name == name || api_map.super_and_sub?(name, autype.name)
  end
  logger.debug { "UniqueType#can_assign?(self=#{rooted_tags.inspect}, atype=#{atype.rooted_tags.inspect}) => #{out}" }
  out
end

def can_root_name?(name_to_check = name)
  self.class.can_root_name?(name_to_check)
end

def desc
  rooted_tags
end

def determine_non_literal_name
  # https://github.com/ruby/rbs/blob/master/docs/syntax.md

  #

  # _literal_ ::= _string-literal_

  #    | _symbol-literal_

  #    | _integer-literal_

  #    | `true`

  #    | `false`

  return name if name.empty?
  return 'NilClass' if name == 'nil'
  return 'Boolean' if ['true', 'false'].include?(name)
  return 'Symbol' if name[0] == ':'
  return 'String' if ['"', "'"].include?(name[0])
  return 'Integer' if name.match?(/^-?\d+$/)
  name
end

def downcast_to_literal_if_possible
  SINGLE_SUBTYPE.fetch(rooted_tag, self)
end

def eql?(other)
  self.class == other.class &&
    @name == other.name &&
    @key_types == other.key_types &&
    @subtypes == other.subtypes &&
    @rooted == other.rooted? &&
    @all_params == other.all_params &&
    @parameters_type == other.parameters_type
end

def equality_fields
@all_params, @subtypes, @key_types]

def force_rooted
  transform do |t|
    t.recreate(make_rooted: true)
  end
end

def generic?
  name == GENERIC_TAG_NAME || all_params.any?(&:generic?)
end

def hash
  [self.class, @name, @key_types, @sub_types, @rooted, @all_params, @parameters_type].hash
end

def implicit_union?
  # @todo use api_map to establish number of generics in type;

  #   if only one is allowed but multiple are passed in, treat

  #   those as implicit unions

  ['Hash', 'Array', 'Set', '_ToAry', 'Enumerable', '_Each'].include?(name) && parameters_type != :fixed
end

def initialize(name, key_types = [], subtypes = [], rooted:, parameters_type: nil)
  if parameters_type.nil?
    raise "You must supply parameters_type if you provide parameters" unless key_types.empty? && subtypes.empty?
  end
  raise "Please remove leading :: and set rooted instead - #{name.inspect}" if name.start_with?('::')
  @name = name
  @parameters_type = parameters_type
  if implicit_union?
    @key_types = key_types.uniq
    @subtypes = subtypes.uniq
  else
    @key_types = key_types
    @subtypes = subtypes
  end
  @rooted = rooted
  @all_params = []
  @all_params.concat @key_types
  @all_params.concat @subtypes
end

def items
  [self]
end

def literal?
  non_literal_name != name
end

def map &block
  [block.yield(self)]
end

def non_literal_name
  @non_literal_name ||= determine_non_literal_name
end

def parameters?
  !all_params.empty?
end

def parameters_as_rbs
  return '' unless parameters?
  return "[#{all_params.map(&:to_rbs).join(', ')}]" if key_types.empty?
  # handle, e.g., Hash[K, V] case

  key_types_str = rbs_union(key_types)
  subtypes_str = rbs_union(subtypes)
  "[#{key_types_str}, #{subtypes_str}]"
end

def qualify api_map, context = ''
  transform do |t|
    next t if t.name == GENERIC_TAG_NAME
    next t if t.duck_type? || t.void? || t.undefined?
    recon = (t.rooted? ? '' : context)
    fqns = api_map.qualify(t.name, recon)
    if fqns.nil?
      next UniqueType::BOOLEAN if t.tag == 'Boolean'
      next UniqueType::UNDEFINED
    end
    t.recreate(new_name: fqns, make_rooted: true)
  end
end

def rbs_name
  if name == 'undefined'
    'untyped'
  elsif literal?
    name
  else
    rooted_name
  end
end

def rbs_union(types)
  if types.length == 1
    types.first.to_rbs
  else
    "(#{types.map(&:to_rbs).join(' | ')})"
  end
end

def recreate(new_name: nil, make_rooted: nil, new_key_types: nil, new_subtypes: nil)
  raise "Please remove leading :: and set rooted instead - #{new_name}" if new_name&.start_with?('::')
  new_name ||= name
  new_key_types ||= @key_types
  new_subtypes ||= @subtypes
  make_rooted = @rooted if make_rooted.nil?
  UniqueType.new(new_name, new_key_types, new_subtypes, rooted: make_rooted, parameters_type: parameters_type)
end

def resolve_generics definitions, context_type
  return self if definitions.nil? || definitions.generics.empty?
  transform(name) do |t|
    if t.name == GENERIC_TAG_NAME
      idx = definitions.generics.index(t.subtypes.first&.name)
      next t if idx.nil?
      if context_type.parameters_type == :hash
        if idx == 0
          next ComplexType.new(context_type.key_types)
        elsif idx == 1
          next ComplexType.new(context_type.subtypes)
        else
          next ComplexType::UNDEFINED
        end
      elsif context_type.all?(&:implicit_union?)
        if idx == 0 && !context_type.all_params.empty?
          ComplexType.new(context_type.all_params)
        else
          ComplexType::UNDEFINED
        end
      else
        context_type.all_params[idx] || ComplexType::UNDEFINED
      end
    else
      t
    end
  end
end

def resolve_generics_from_context generics_to_resolve, context_type, resolved_generic_values: {}
  if name == ComplexType::GENERIC_TAG_NAME
    type_param = subtypes.first&.name
    return self unless generics_to_resolve.include? type_param
    unless context_type.nil? || !resolved_generic_values[type_param].nil?
      new_binding = true
      resolved_generic_values[type_param] = context_type
    end
    if new_binding
      resolved_generic_values.transform_values! do |complex_type|
        complex_type.resolve_generics_from_context(generics_to_resolve, nil, resolved_generic_values: resolved_generic_values)
      end
    end
    return resolved_generic_values[type_param] || self
  end
  # @todo typechecking should complain when the method being called has no @yieldparam tag

  new_key_types = resolve_param_generics_from_context(generics_to_resolve, context_type, resolved_generic_values, &:key_types)
  new_subtypes = resolve_param_generics_from_context(generics_to_resolve, context_type, resolved_generic_values, &:subtypes)
  recreate(new_key_types: new_key_types, new_subtypes: new_subtypes)
end

def resolve_param_generics_from_context(generics_to_resolve, context_type, resolved_generic_values)
  types = yield self
  types.each_with_index.flat_map do |ct, i|
    ct.items.flat_map do |ut|
      context_params = yield context_type if context_type
      if context_params && context_params[i]
        type_arg = context_params[i]
        type_arg.map do |new_unique_context_type|
          ut.resolve_generics_from_context generics_to_resolve, new_unique_context_type, resolved_generic_values: resolved_generic_values
        end
      else
        ut.resolve_generics_from_context generics_to_resolve, nil, resolved_generic_values: resolved_generic_values
      end
    end
  end
end

def rooted?
  !can_root_name? || @rooted
end

def rooted_tags
  rooted_tag
end

def self_to_type dst
  object_type_dst = dst.reduce_class_type
  transform do |t|
    next t if t.name != 'self'
    object_type_dst
  end
end

def selfy?
  @name == 'self' || @key_types.any?(&:selfy?) || @subtypes.any?(&:selfy?)
end

def simplify_literals
  transform do |t|
    next t unless t.literal?
    t.recreate(new_name: t.non_literal_name)
  end
end

def tags
  tag
end

def to_a
  [self]
end

def to_rbs
  if duck_type?
    'untyped'
  elsif name == 'Boolean'
    'bool'
  elsif name.downcase == 'nil'
    'nil'
  elsif name == GENERIC_TAG_NAME
    all_params.first.name
  elsif ['Class', 'Module'].include?(name)
    rbs_name
  elsif ['Tuple', 'Array'].include?(name) && fixed_parameters?
    # tuples don't have a name; they're just [foo, bar, baz].

    if substring == '()'
      # but there are no zero element tuples, so we go with an array

      if rooted?
        '::Array[]'
      else
        'Array[]'
      end
    else
      # already generated surrounded by []

      parameters_as_rbs
    end
  else
    "#{rbs_name}#{parameters_as_rbs}"
  end
end

def to_s
  tag
end

def transform(new_name = nil, &transform_type)
  raise "Please remove leading :: and set rooted with recreate() instead - #{new_name}" if new_name&.start_with?('::')
  if name == ComplexType::GENERIC_TAG_NAME
    # doesn't make sense to manipulate the name of the generic

    new_key_types = @key_types
    new_subtypes = @subtypes
  else
    new_key_types = @key_types.flat_map { |ct| ct.items.map { |ut| ut.transform(&transform_type) } }
    new_subtypes = @subtypes.flat_map { |ct| ct.items.map { |ut| ut.transform(&transform_type) } }
  end
  new_type = recreate(new_name: new_name || name, new_key_types: new_key_types, new_subtypes: new_subtypes, make_rooted: @rooted)
  yield new_type
end