# Author::    Eric Crane  (mailto:eric.crane@mac.com)
# Copyright:: Copyright (c) 2019 Eric Crane.  All rights reserved.
#
# Helper class used to load a file and create objects in the heap.
#

module Gloo
  module Persist
    class FileLoader
      
      BEGIN_BLOCK = "BEGIN"
      END_BLOCK = "END"
      
      attr_reader :obj
      
      # Set up a file storage for an object.
      def initialize pn
        @pn = pn
        @tabs = 0
        @obj = nil
        @in_multiline = false
        @exiting_multiline = false
        @in_block = false
        @block_value = ""
				@debug = false
      end
            
      # 
      # Load the objects from the file.
      # 
      def load
        unless File.exists?( @pn )
          $log.error "File '#{@pn}' does not exist."
          return
        end
        @tabs = 0
        @parent_stack = []
        @parent = $engine.heap.root
        @parent_stack.push @parent
        f = File.open( @pn, "r" ) 
        f.each_line do |line|
          next if skip_line? line
          if line.strip.end_with? BEGIN_BLOCK
            @in_block = true
            @save_line = line
          elsif @in_block
            if line.strip == END_BLOCK
              @in_block = false
              determine_indent @save_line
              process_line @save_line
            else
              @block_value << line
            end
          else
            determine_indent line
            process_line line
          end
        end
      end
      
      # Is this line a comment or a blank line?
      # If so we'll skip it.
      def skip_line? line
        line = line.strip
        return true if line.empty?
        return true if line[0] == "#"
        return false
      end
      
      # Determine the relative indent level for the line.
      def determine_indent line
        tabs = tab_count( line )
        @indent = 0  # same level as prior line
        if tabs > @tabs  # indent
          # TODO:  What if indent is more than one more level?
          @tabs = tabs
          @indent = 1
        elsif tabs < @tabs  # outdent
          while tabs < @tabs
            @tabs -= 1
            @indent -= 1
          end
        end
				puts "tabs: #{@tabs}, indent: #{@indent}, line: #{line}" if @debug
      end

      # Process one line and add objects.
      def process_line line
        # reset multiline unless we're actually indented
        if @in_multiline && @multi_indent > @indent
					puts "Done multiline mi: #{@multi_indent}, i: #{@indent}" if @debug
          @in_multiline = false
          @exiting_multiline = true
        end
        
        if @in_multiline
          @last.add_line line
        else
          process_obj_line line
        end
      end
      
      # Process one line and add objects.
      def process_obj_line line
        if @exiting_multiline
          @exiting_multiline = false
        elsif @indent > 0
          @parent = @last
          @parent_stack.push @parent
        elsif @indent < 0
          @indent.abs.times do
            @parent_stack.pop
            @parent = @parent_stack.last
          end
        end
        
        name, type, value = split_line( line )
        unless @block_value == ""
          value = @block_value
          @block_value = ""
        end
        @last = $engine.factory.create( name, type, value, @parent )
        if @last && @last.has_multiline_value?
          @multi_indent = 0
          @in_multiline = true
					puts "*** Start multiline. multi_indent: #{@multi_indent}" if @debug
        end
        
        @obj = @last if @obj.nil?
      end
      
      # Get the number of leading tabs.
      def tab_count line
        i = 0
        while line[i] == "\t"
          i += 1
        end
        return i
      end
      
      # Split the line into 3 parts.
      def split_line line
				puts "splitting line: #{line}" if @debug
        line = line[ @tabs..-1]
				line = line[0..-2] if line[-1] == "\n"
        i = line.index( ' ' )
        name = line[0..i-1]
        
        line = line[i+1..-1]
        i = line.index( ' ' )
        type = line[0..(i ? i-1 : -1)]
        type = type[1..-1] if type[0] == '['
        type = type[0..-2] if type[-1] == ']'
        
				if i
	        value = line[i+1..-1]
					if value[0..1] == ': '
						value = value[2..-1] 
					elsif value[0] == ':'
	        	value = value[1..-1] 
					end
				else
					value = nil
				end
				# puts "'#{value}'".yellow
        return name, type, value
      end
      
    end
  end
end