class Vellum::PromptOutput

def self.error(member:)
  new(member: member, discriminant: "ERROR")
end

def self.from_json(json_object:)
  struct = JSON.parse(json_object, object_class: OpenStruct)
  member = case struct.type
           when "STRING"
             StringVariableValue.from_json(json_object: json_object)
           when "JSON"
             JsonVariableValue.from_json(json_object: json_object)
           when "ERROR"
             ErrorVariableValue.from_json(json_object: json_object)
           when "FUNCTION_CALL"
             FunctionCallVariableValue.from_json(json_object: json_object)
           else
             StringVariableValue.from_json(json_object: json_object)
           end
  new(member: member, discriminant: struct.type)
end

def self.function_call(member:)
  new(member: member, discriminant: "FUNCTION_CALL")
end

def self.json(member:)
  new(member: member, discriminant: "JSON")
end

def self.string(member:)
  new(member: member, discriminant: "STRING")
end

def self.validate_raw(obj:)
  case obj.type
  when "STRING"
    StringVariableValue.validate_raw(obj: obj)
  when "JSON"
    JsonVariableValue.validate_raw(obj: obj)
  when "ERROR"
    ErrorVariableValue.validate_raw(obj: obj)
  when "FUNCTION_CALL"
    FunctionCallVariableValue.validate_raw(obj: obj)
  else
    raise("Passed value matched no type within the union, validation failed.")
  end
end

def initialize(member:, discriminant:)
  # @type [Object]
  @member = member
  # @type [String]
  @discriminant = discriminant
end

def is_a?(obj)
  @member.is_a?(obj)
end

def to_json(*_args)
  case @discriminant
  when "STRING"
    { **@member.to_json, type: @discriminant }.to_json
  when "JSON"
    { **@member.to_json, type: @discriminant }.to_json
  when "ERROR"
    { **@member.to_json, type: @discriminant }.to_json
  when "FUNCTION_CALL"
    { **@member.to_json, type: @discriminant }.to_json
  else
    { "type": @discriminant, value: @member }.to_json
  end
  @member.to_json
end