class Tilt::Template

def basename(suffix='')
  File.basename(@file, suffix) if @file
end

def binary(string)
  original_encoding = string.encoding
  string.force_encoding(Encoding::BINARY)
  yield
ensure
  string.force_encoding(original_encoding)
end

def bind_compiled_method(method_source, offset, scope_class)
  path = compiled_path
  if path && scope_class.name
    path = path.dup
    if defined?(@compiled_path_counter)
      path << '-' << @compiled_path_counter.succ!
    else
      @compiled_path_counter = "0".dup
    end
    path << ".rb"
    # Wrap method source in a class block for the scope, so constant lookup works
    if freeze_string_literals?
      method_source_prefix = "# frozen-string-literal: true\n"
      method_source = method_source.sub(/\A# frozen-string-literal: true\n/, '')
    end
    method_source = "#{method_source_prefix}class #{scope_class.name}\n#{method_source}\nend"
    load_compiled_method(path, method_source)
  else
    if path
      warn "compiled_path (#{compiled_path.inspect}) ignored on template with anonymous scope_class (#{scope_class.inspect})"
    end
    eval_compiled_method(method_source, offset, scope_class)
  end
end

def compile_template_method(local_keys, scope_class=nil)
  source, offset = precompiled(local_keys)
  local_code = local_extraction(local_keys)
  method_name = "__tilt_#{Thread.current.object_id.abs}"
  method_source = String.new
  method_source.force_encoding(source.encoding)
  if freeze_string_literals?
    method_source << "# frozen-string-literal: true\n"
  end
  # Don't indent method source, to avoid indentation warnings when using compiled paths
  method_source << "::Tilt::TOPOBJECT.class_eval do\ndef #{method_name}(locals)\n#{local_code}\n"
  offset += method_source.count("\n")
  method_source << source
  method_source << "\nend;end;"
  bind_compiled_method(method_source, offset, scope_class)
  unbind_compiled_method(method_name)
end

def compiled_method(locals_keys, scope_class=nil)
  key = [scope_class, locals_keys].freeze
  LOCK.synchronize do
    if meth = @compiled_method[key]
      return meth
    end
  end
  meth = compile_template_method(locals_keys, scope_class)
  LOCK.synchronize do
    @compiled_method[key] = meth
  end
  meth
end

def compiled_path=(path)
  if path
    # Use expanded paths when loading, since that is helpful
    # for coverage.  Remove any .rb suffix, since that will
    # be added back later.
    path = File.expand_path(path.sub(/\.rb\z/i, ''))
  end
  @compiled_path = path
end

def default_mime_type
  metadata[:mime_type]
end

def default_mime_type=(value)
  metadata[:mime_type] = value
end

def eval_compiled_method(method_source, offset, scope_class)
  (scope_class || Object).class_eval(method_source, eval_file, line - offset)
end

def eval_file
  @file || '(__TEMPLATE__)'
end

def evaluate(scope, locals, &block)
  locals_keys = locals.keys
  locals_keys.sort!{|x, y| x.to_s <=> y.to_s}
  case scope
  when Object
    scope_class = Module === scope ? scope : scope.class
  else
    # :nocov:
    scope_class = USE_BIND_CALL ? CLASS_METHOD.bind_call(scope) : CLASS_METHOD.bind(scope).call
    # :nocov:
  end
  method = compiled_method(locals_keys, scope_class)
  if USE_BIND_CALL
    method.bind_call(scope, locals, &block)
  # :nocov:
  else
    method.bind(scope).call(locals, &block)
  # :nocov:
  end
end

def extract_encoding(script, &block)
  extract_magic_comment(script, &block) || script.encoding
end

def extract_magic_comment(script)
  if script.frozen?
    script = script.dup
    yield script
  end
  binary(script) do
    script[/\A[ \t]*\#.*coding\s*[=:]\s*([[:alnum:]\-_]+).*$/n, 1]
  end
end

def freeze_string_literals?
  false
end

def initialize(file=nil, line=nil, options=nil)
  @file, @line, @options = nil, 1, nil
  process_arg(options)
  process_arg(line)
  process_arg(file)
  raise ArgumentError, "file or block required" unless @file || block_given?
  @options ||= {}
  set_compiled_method_cache
  # Force the encoding of the input data
  @default_encoding = @options.delete :default_encoding
  # Skip encoding detection from magic comments and forcing that encoding
  # for compiled templates
  @skip_compiled_encoding_detection = @options.delete :skip_compiled_encoding_detection
  # load template data and prepare (uses binread to avoid encoding issues)
  @data = block_given? ? yield(self) : read_template_file
  if @data.respond_to?(:force_encoding)
    if default_encoding
      @data = @data.dup if @data.frozen?
      @data.force_encoding(default_encoding)
    end
    if !@data.valid_encoding?
      raise Encoding::InvalidByteSequenceError, "#{eval_file} is not valid #{@data.encoding}"
    end
  end
  prepare
end

def load_compiled_method(path, method_source)
  File.binwrite(path, method_source)
  # Use load and not require, so unbind_compiled_method does not
  # break if the same path is used more than once.
  load path
end

def local_extraction(local_keys)
  assignments = local_keys.map do |k|
    if k.to_s =~ /\A[a-z_][a-zA-Z_0-9]*\z/
      "#{k} = locals[#{k.inspect}]"
    else
      raise "invalid locals key: #{k.inspect} (keys must be variable names)"
    end
  end
  s = "locals = locals[:locals]"
  if assignments.delete(s)
    # If there is a locals key itself named `locals`, delete it from the ordered keys so we can
    # assign it last. This is important because the assignment of all other locals depends on the
    # `locals` local variable still matching the `locals` method argument given to the method
    # created in `#compile_template_method`.
    assignments << s
  end
  assignments.join("\n")
end

def metadata
  @metadata ||= {}
end

def metadata
  if respond_to?(:allows_script?)
    self.class.metadata.merge(:allows_script => allows_script?)
  else
    self.class.metadata
  end
end

def name
  if bname = basename
    bname.split('.', 2).first
  end
end

def precompiled(local_keys)
  preamble = precompiled_preamble(local_keys)
  template = precompiled_template(local_keys)
  postamble = precompiled_postamble(local_keys)
  source = String.new
  unless skip_compiled_encoding_detection?
    # Ensure that our generated source code has the same encoding as the
    # the source code generated by the template engine.
    template_encoding = extract_encoding(template){|t| template = t}
    if template.encoding != template_encoding
      # template should never be frozen here. If it was frozen originally,
      # then extract_encoding should yield a dup.
      template.force_encoding(template_encoding)
    end
  end
  source.force_encoding(template.encoding)
  source << preamble << "\n" << template << "\n" << postamble
  [source, preamble.count("\n")+1]
end

def precompiled_postamble(local_keys)
  ''
end

def precompiled_preamble(local_keys)
  ''
end

def precompiled_template(local_keys)
  raise NotImplementedError
end

def prepare
end

def process_arg(arg)
  if arg
    case
    when arg.respond_to?(:to_str)  ; @file = arg.to_str
    when arg.respond_to?(:to_int)  ; @line = arg.to_int
    when arg.respond_to?(:to_hash) ; @options = arg.to_hash.dup
    when arg.respond_to?(:path)    ; @file = arg.path
    when arg.respond_to?(:to_path) ; @file = arg.to_path
    else raise TypeError, "Can't load the template file. Pass a string with a path " +
      "or an object that responds to 'to_str', 'path' or 'to_path'"
    end
  end
end

def read_template_file
  data = File.binread(file)
  # Set it to the default external (without verifying)
  # :nocov:
  data.force_encoding(Encoding.default_external) if Encoding.default_external
  # :nocov:
  data
end

def render(scope=nil, locals=nil, &block)
  evaluate(scope || Object.new, locals || EMPTY_HASH, &block)
end

def set_compiled_method_cache
  @compiled_method = {}
end

def skip_compiled_encoding_detection?
  @skip_compiled_encoding_detection
end

def unbind_compiled_method(method_name)
  method = TOPOBJECT.instance_method(method_name)
  TOPOBJECT.class_eval { remove_method(method_name) }
  method
end