class Phlex::SGML::State

# File lib/phlex/sgml/state.rb, line 4
def initialize(user_context: {}, output_buffer:, fragments:)
        @buffer = +""
        @capturing = false
        @user_context = user_context
        @fragments = fragments
        @fragment_depth = 0
        @cache_stack = []
        @halt_signal = nil
        @output_buffer = output_buffer
end

# File lib/phlex/sgml/state.rb, line 19
def around_render(component)
        stack = @stack

        if !@fragments || @halt_signal
                yield
        else
                catch do |signal|
                        @halt_signal = signal
                        yield
                end
        end
end

# File lib/phlex/sgml/state.rb, line 36
def begin_fragment(id)
        @fragment_depth += 1 if @fragments&.include?(id)

        if caching?
                current_byte_offset = 0                                              # Start tracking the byte offset of this fragment from the start of the cache buffer
                @cache_stack.reverse_each do |(cache_buffer, fragment_map)| # We'll iterate deepest to shallowest
                        current_byte_offset += cache_buffer.bytesize                                      # Add the length of the cache buffer to the current byte offset
                        fragment_map[id] = [current_byte_offset, nil, []]                   # Record the byte offset, length, and store a list of the nested fragments

                        fragment_map.each do |name, (_offset, length, nested_fragments)| # Iterate over the other fragments
                                next if name == id || length                                                                        # Skip if it's the current fragment, or if the fragment has already ended
                                nested_fragments << id                                              # Add the current fragment to the list of nested fragments
                        end
                end
        end
end

# File lib/phlex/sgml/state.rb, line 78
def caching(&)
        result = nil

        capture do
                @cache_stack.push([buffer, {}].freeze)
                yield
                result = @cache_stack.pop
        end

        result
end

# File lib/phlex/sgml/state.rb, line 90
def caching?
        @cache_stack.length > 0
end

# File lib/phlex/sgml/state.rb, line 94
def capture
        new_buffer = +""
        original_buffer = @buffer
        original_capturing = @capturing
        original_fragments = @fragments

        begin
                @buffer = new_buffer
                @capturing = true
                @fragments = nil
                yield
        ensure
                @buffer = original_buffer
                @capturing = original_capturing
                @fragments = original_fragments
        end

        new_buffer
end

# File lib/phlex/sgml/state.rb, line 53
def end_fragment(id)
        if caching?
                byte_length = nil
                @cache_stack.reverse_each do |(cache_buffer, fragment_map)|   # We'll iterate deepest to shallowest
                        byte_length ||= cache_buffer.bytesize - fragment_map[id][0] # The byte length is the difference between the current byte offset and the byte offset of the fragment
                        fragment_map[id][1] = byte_length                           # All cache contexts will use the same by
                end
        end

        return unless @fragments&.include?(id)

        @fragments.delete(id)
        @fragment_depth -= 1
        throw @halt_signal if @fragments.length == 0
end

# File lib/phlex/sgml/state.rb, line 114
def flush
        return if capturing

        buffer = @buffer
        @output_buffer << buffer.dup

        buffer.clear
        nil
end

# File lib/phlex/sgml/state.rb, line 69
def record_fragment(id, offset, length, nested_fragments)
        return unless caching?

        @cache_stack.reverse_each do |(cache_buffer, fragment_map)|
                offset += cache_buffer.bytesize
                fragment_map[id] = [offset, length, nested_fragments]
        end
end

# File lib/phlex/sgml/state.rb, line 32
def should_render?
        !@fragments || @fragment_depth > 0
end