class Commands::ValidateSchema

def initialize
  @detect = false
  @fail_fast = false
  @extra_schemas = []
  @errors = []
  @messages = []
end

def initialize_store
  @store = JsonSchema::DocumentStore.new
  extra_schemas.each do |extra_schema|
    if !(extra_schema = parse(extra_schema))
      return false
    end
    @store.add_schema(extra_schema)
  end
  true
end

def map_schema_errors(file, errors)
  errors.map { |m| "#{file}#{m}" }
end

def parse(file)
  if !(schema_data = read_file(file))
    return nil
  end
  parser = JsonSchema::Parser.new
  if !(schema = parser.parse(schema_data))
    @errors = map_schema_errors(file, parser.errors)
    return nil
  end
  expander = JsonSchema::ReferenceExpander.new
  if !expander.expand(schema, store: @store)
    @errors = map_schema_errors(file, expander.errors)
    return nil
  end
  schema
end

def read_file(file)
  contents = File.read(file)
  # Perform an empty check because boath YAML and JSON's load will return
  # `nil` in the case of an empty file, which will otherwise produce
  # confusing results.
  if contents.empty?
    @errors = ["#{file}: File is empty."]
    nil
  else
    if File.extname(file) == ".yaml"
      YAML.load(contents)
    else
      JSON.load(contents)
    end
  end
rescue Errno::ENOENT
  @errors = ["#{file}: No such file or directory."]
  nil
rescue JSON::ParserError
  # Ruby's parsing exceptions aren't too helpful, just point user to
  # a better tool
  @errors = ["#{file}: Invalid JSON. Try to validate using `jsonlint`."]
  nil
rescue Psych::SyntaxError
  @errors = ["#{file}: Invalid YAML."]
  nil
end

def run(argv)
  return false if !initialize_store
  if !detect
    return false if !(schema_file = argv.shift)
    return false if !(schema = parse(schema_file))
  end
  # if there are no remaining files in arguments, also a problem
  return false if argv.count < 1
  argv.each do |data_file|
    if !(data = read_file(data_file))
      return false
    end
    if detect
      if !(schema_uri = data["$schema"])
        @errors = ["#{data_file}: No $schema tag for detection."]
        return false
      end
      if !(schema = @store.lookup_schema(schema_uri))
        @errors = ["#{data_file}: Unknown $schema, try specifying one with -s."]
        return false
      end
    end
    valid, errors = schema.validate(data, fail_fast: fail_fast)
    if valid
      @messages += ["#{data_file} is valid."]
    else
      @errors = map_schema_errors(data_file, errors)
    end
  end
  @errors.empty?
end