require 'stringio'

# The Potlatch module provides helper functions for potlatch and its communication with the server
module Potlatch
  # The AMF class is a set of helper functions for encoding and decoding AMF.
  class AMF
    # Return two-byte integer
    def self.getint(s)
      s.getbyte * 256 + s.getbyte
    end

    # Return four-byte long
    def self.getlong(s)
      ((s.getbyte * 256 + s.getbyte) * 256 + s.getbyte) * 256 + s.getbyte
    end

    # Return string with two-byte length
    def self.getstring(s)
      len = s.getbyte * 256 + s.getbyte
      str = s.read(len)
      str.force_encoding("UTF-8") if str.respond_to?("force_encoding")
      str
    end

    # Return eight-byte double-precision float
    def self.getdouble(s)
      a = s.read(8).unpack('G')			# G big-endian, E little-endian
      a[0]
    end

    # Return numeric array
    def self.getarray(s)
      len = getlong(s)
      arr = []
      for i in (0..len - 1)
        arr[i] = getvalue(s)
      end
      arr
    end

    # Return object/hash
    def self.getobject(s)
      arr = {}
      while (key = getstring(s))
        if (key == '') then break end
        arr[key] = getvalue(s)
      end
      s.getbyte		# skip the 9 'end of object' value
      arr
    end

    # Parse and get value
    def self.getvalue(s)
      case s.getbyte
      when 0 then	return getdouble(s)			# number
      when 1 then	return s.getbyte			# boolean
      when 2 then	return getstring(s)			# string
      when 3 then	return getobject(s)			# object/hash
      when 5 then	return nil				# null
      when 6 then	return nil				# undefined
      when 8 then	s.read(4)				# mixedArray
                  return getobject(s)			#  |
      when 10 then  return getarray(s)			# array
      else;	return nil				# error
      end
    end

    # Envelope data into AMF writeable form
    def self.putdata(index, n)
      d = encodestring(index + "/onResult")
      d += encodestring("null")
      d += [-1].pack("N")
      d += encodevalue(n)
      d
    end

    # Pack variables as AMF
    def self.encodevalue(n)
      case n.class.to_s
      when 'Array'
        a = 10.chr + encodelong(n.length)
        n.each do |b|
          a += encodevalue(b)
        end
        a
      when 'Hash'
        a = 3.chr
        n.each do |k, v|
          a += encodestring(k.to_s) + encodevalue(v)
        end
        a + 0.chr + 0.chr + 9.chr
      when 'String'
        2.chr + encodestring(n)
      when 'Bignum', 'Fixnum', 'Float'
        0.chr + encodedouble(n)
      when 'NilClass'
        5.chr
    when 'TrueClass'
      0.chr + encodedouble(1)
    when 'FalseClass'
      0.chr + encodedouble(0)
    else
      Rails.logger.error("Unexpected Ruby type for AMF conversion: " + n.class.to_s)
      end
    end

    # Encode string with two-byte length
    def self.encodestring(n)
      n = n.dup.force_encoding("ASCII-8BIT") if n.respond_to?("force_encoding")
      a, b = n.size.divmod(256)
      a.chr + b.chr + n
    end

    # Encode number as eight-byte double precision float
    def self.encodedouble(n)
      [n].pack('G')
    end

    # Encode number as four-byte long
    def self.encodelong(n)
      [n].pack('N')
    end
  end

  # The Dispatcher class handles decoding a series of RPC calls
  # from the request, dispatching them, and encoding the response
  class Dispatcher
    def initialize(request, &_block)
      # Get stream for request data
      @request = StringIO.new(request + 0.chr)

      # Skip version indicator and client ID
      @request.read(2)

      # Skip headers
      AMF.getint(@request).times do     # Read number of headers and loop
        AMF.getstring(@request)         #  | skip name
        req.getbyte                     #  | skip boolean
        AMF.getvalue(@request)          #  | skip value
      end

      # Capture the dispatch routine
      @dispatch = Proc.new
    end

    def each(&_block)
      # Read number of message bodies
      bodies = AMF.getint(@request)

      # Output response header
      a, b = bodies.divmod(256)
      yield 0.chr + 0.chr + 0.chr + 0.chr + a.chr + b.chr

      # Process the bodies
      bodies.times do                     # Read each body
        name = AMF.getstring(@request)    #  | get message name
        index = AMF.getstring(@request)   #  | get index in response sequence
        AMF.getlong(@request)             #  | get total size in bytes
        args = AMF.getvalue(@request)     #  | get response (probably an array)

        result = @dispatch.call(name, *args)

        yield AMF.putdata(index, result)
      end
    end
  end

  # The Potlatch class is a helper for Potlatch
  class Potlatch
    # ----- getpresets
    #		  in:   none
    #		  does: reads tag preset menus, colours, and autocomplete config files
    #	      out:  [0] presets, [1] presetmenus, [2] presetnames,
    #				[3] colours, [4] casing, [5] areas, [6] autotags
    #				(all hashes)
    def self.get_presets
      Rails.logger.info("  Message: getpresets")

      # Read preset menus
      presets = {}
      presetmenus = {}; presetmenus['point'] = []; presetmenus['way'] = []; presetmenus['POI'] = []
      presetnames = {}; presetnames['point'] = {}; presetnames['way'] = {}; presetnames['POI'] = {}
      presettype = ''
      presetcategory = ''
      #	StringIO.open(txt) do |file|
      File.open("#{Rails.root}/config/potlatch/presets.txt") do |file|
        file.each_line do|line|
          t = line.chomp
          if t =~ /(\w+)\/(\w+)/
            presettype = $1
            presetcategory = $2
            presetmenus[presettype].push(presetcategory)
            presetnames[presettype][presetcategory] = ["(no preset)"]
          elsif t =~ /^([\w\s]+):\s?(.+)$/
            pre = $1; kv = $2
            presetnames[presettype][presetcategory].push(pre)
            presets[pre] = {}
            kv.split(',').each do|a|
              if a =~ /^(.+)=(.*)$/ then presets[pre][$1] = $2 end
            end
          end
        end
      end

      # Read colours/styling
      colours = {}; casing = {}; areas = {}
      File.open("#{Rails.root}/config/potlatch/colours.txt") do |file|
        file.each_line do|line|
          t = line.chomp
          if t =~ /(\w+)\s+([^\s]+)\s+([^\s]+)\s+([^\s]+)/
            tag = $1
            if ($2 != '-') then colours[tag] = $2.hex end
            if ($3 != '-') then casing[tag] = $3.hex end
            if ($4 != '-') then areas[tag] = $4.hex end
          end
        end
      end

      # Read relations colours/styling
      relcolours = {}; relalphas = {}; relwidths = {}
      File.open("#{Rails.root}/config/potlatch/relation_colours.txt") do |file|
        file.each_line do|line|
          t = line.chomp
          if t =~ /(\w+)\s+([^\s]+)\s+([^\s]+)\s+([^\s]+)/
            tag = $1
            if ($2 != '-') then relcolours[tag] = $2.hex end
            if ($3 != '-') then relalphas[tag] = $3.to_i end
            if ($4 != '-') then relwidths[tag] = $4.to_i end
          end
        end
      end

      # Read POI presets
      icon_list = []; icon_tags = {}
      File.open("#{Rails.root}/config/potlatch/icon_presets.txt") do |file|
        file.each_line do|line|
          (icon, tags) = line.chomp.split("\t")
          icon_list.push(icon)
          icon_tags[icon] = Hash[*tags.scan(/([^;=]+)=([^;=]+)/).flatten]
        end
      end
      icon_list.reverse!

      # Read auto-complete
      autotags = {}; autotags['point'] = {}; autotags['way'] = {}; autotags['POI'] = {}
      File.open("#{Rails.root}/config/potlatch/autocomplete.txt") do |file|
        file.each_line do|line|
          t = line.chomp
          if t =~ /^([\w:]+)\/(\w+)\s+(.+)$/
            tag = $1; type = $2; values = $3
            if values == '-'
              autotags[type][tag] = []
            else
              autotags[type][tag] = values.split(',').sort.reverse
            end
          end
        end
      end

      [presets, presetmenus, presetnames, colours, casing, areas, autotags, relcolours, relalphas, relwidths, icon_list, {}, icon_tags]
    end
  end
end