$:.unshift(File.dirname(__FILE__)) unless
	$:.include?(File.dirname(__FILE__)) || $:.include?(File.expand_path(File.dirname(__FILE__)))

$:.unshift(File.dirname(__FILE__+"\\..")) unless
	$:.include?(File.dirname(__FILE__+"\\..")) || $:.include?(File.expand_path(File.dirname(__FILE__+"\\..")))


require 'FileSystem'
class AppleCPM<FileSystem

def self.host_system
  Apple2
end  

def self.matching_score
  20
end

  RECORD_SIZE=128
  BLOCK_SIZE=1024
  BLOCKS_PER_EXTENT=16
  RECORDS_PER_BLOCK=BLOCK_SIZE/RECORD_SIZE
  RECORDS_PER_EXTENT=RECORDS_PER_BLOCK*BLOCKS_PER_EXTENT
  
 SECTORS_IN_BLOCK=[
    [0x00,0x06,0x0C,0x03],  #block 0
    [0x09,0x0F,0x0E,0x05],  #block 1
    [0x0B,0x02,0x08,0x07],  #block 2
    [0x0D,0x04,0x0A,0x01]  #block 3
  ]
  
  def self.get_block(file_system_image,block_no)
    track_no= ((block_no/4)+3)%file_system_image.track_count
    s=""
    SECTORS_IN_BLOCK[block_no%4].each {|sector_no| s+=file_system_image.get_sector(track_no,sector_no)}
    s
  end

  def self.set_block(file_system_image,block_no,contents)
    raise "invalid block #{block_no} - length was #{contents.length}" unless contents.length==BLOCK_SIZE
    track_no=(block_no/4)+3
    0.upto(3) do |i|
      sector_no=SECTORS_IN_BLOCK[block_no%4][i]
      file_system_image.set_sector(track_no,sector_no,contents[(i*256),256])
    end  
  end


  #look for a valid looking CPM directory on track 3.
  #go through each sector in order, for each sector, look at every 32nd byte, and see if it is a valid 'user number' (i.e. a number from 00..0F). Stop looking when you see an 'E5'.
  #if an invalid user number is found before an E5, then the disk is NOT a CPM disk
  is_valid_file_system_if lambda {
  is_valid=true
  found_0xE5_byte=false
  [0x0,0x6,0xC,0x3,0x9, 0xF,0xE,0x5].each do |sector_no|
    sector=file_system_image.get_sector(3,sector_no)
    if sector.nil? then
      is_valid=false
      break
    end
    [0x00,0x20,0x40,0x60,0x80,0xA0,0xC0,0xE0].each do |byte_number|        
      if (sector[byte_number]>0x0F && sector[byte_number]!=0xe5 && sector[byte_number]!=0x1F) then
        is_valid=false
        break
      end
      if (sector[byte_number]==0xe5) then
        found_0xE5_byte=true
      end
    end
  end
  is_valid && found_0xE5_byte
}

#CPM DIR looks like this:
#$00        User number, or E5h if it's a free entry 
#$01..0B   Filename + extension: 8+3 characters 
#$0C..0D  Extent number of this entry 
#$0E       ???
#$0F       Number of 128-byte records allocated in this extant
#$10..1F  Allocation map for this directory entry
def self.files(file_system_image)
  files=FileContainer.new
  catalog=get_block(file_system_image,0)+get_block(file_system_image,1)
  0.upto(63) do |dir_entry_no|
    dir_entry_start=dir_entry_no*0x20
    dir_entry=catalog[dir_entry_start..dir_entry_start+0x1F]      
    if (dir_entry[0]<0x10) then
      file_name=dir_entry[0x01..0x08].gsub(' ','')
      file_ext=dir_entry[0x09..0x0B].gsub(' ','')
      full_filename="#{file_name}.#{file_ext}"
      files<<NativeFileType.best_fit(file_system_image,full_filename,'',file_ext)
      if files[full_filename].nil? then
        files<<file 
      end
      s=""
      0x10.upto(0x1f) do |i|
        block=dir_entry[i]
        s+=get_block(file_system_image,block) unless block==0
      end        
      records_allocated=dir_entry[0x0F]
      files[full_filename].contents+=s[0,(records_allocated*128)]
    end
  end    
  files
end

def self.find_free_space(file_system_image)
  free_blocks=[]
  free_directory_entries=[]
  #first two blocks are where the catalog lives
  (2..((file_system_image.track_count-3)*4)-1).each {|block| free_blocks<<block}
  catalog=get_block(file_system_image,0)+get_block(file_system_image,1)
  0.upto(63) do |dir_entry_no|
    dir_entry_start=dir_entry_no*0x20
    dir_entry=catalog[dir_entry_start..dir_entry_start+0x1F]      
    if (dir_entry[0]<0x10) then
      0x10.upto(0x1f) do |i|
        block=dir_entry[i]
        free_blocks.delete(block)
      end        
    else
      free_directory_entries<<dir_entry_no      
    end
  end    
  [free_blocks,free_directory_entries]
end


  def self.add_file(file_system_image,native_filetype_class,full_filename,file_contents,file_type=nil,aux_code=nil)
    raise "#{native_filetype_class} not supported on Apple CPM file system" if  native_filetype_class.file_system_file_types[self].nil?
    partial_filename,file_type=CPMFile.split_filename(full_filename)
    full_filename ="#{partial_filename}.#{file_type}"
#    puts "#{full_filename},#{partial_filename},#{file_type}"
    delete_file(file_system_image,full_filename) unless file_system_image.files[full_filename].nil? #so we can overwrite the file if it already exists  
    free_blocks,free_directory_entries=find_free_space(file_system_image)
    total_record_count=(file_contents.length/RECORD_SIZE.to_f).ceil
    total_blocks_needed=(total_record_count/RECORDS_PER_BLOCK.to_f).ceil    
    total_extents_needed=(total_blocks_needed/BLOCKS_PER_EXTENT.to_f).ceil
#    puts "#{total_extents_needed} extents needed"
    raise "#{total_blocks_needed} free blocks required, only #{free_blocks.length} available" unless total_blocks_needed<=free_blocks.length
    raise "#{total_extents_needed} free directory entries required, only #{free_directory_entries.length} available" unless total_extents_needed<=free_directory_entries.length
    catalog=get_block(file_system_image,0)+get_block(file_system_image,1)
    padded_file_contents=file_contents+(0x1A.chr*BLOCK_SIZE)
    
    total_extents_needed.times do |extent_no|
      records_this_extent=(extent_no==(total_extents_needed-1) ? (total_record_count % RECORDS_PER_EXTENT):RECORDS_PER_EXTENT)
      blocks_this_extent=(records_this_extent/RECORDS_PER_BLOCK.to_f).ceil
      blocks_used=[0]*BLOCKS_PER_EXTENT
      first_record_this_extent=extent_no*RECORDS_PER_EXTENT
      contents_this_extent=padded_file_contents[(first_record_this_extent*RECORD_SIZE),blocks_this_extent*BLOCK_SIZE]
      
      blocks_this_extent.times do |block_no|
          this_block=free_blocks[block_no+(extent_no*BLOCKS_PER_EXTENT)]
          set_block(file_system_image,this_block,contents_this_extent[block_no*BLOCK_SIZE,BLOCK_SIZE])
          blocks_used[block_no]=this_block
      end
      dir_entry_no=free_directory_entries[extent_no]
      dir_entry_start=dir_entry_no*0x20
      dir_entry=[0,partial_filename,file_type,extent_no,0,0,records_this_extent,blocks_used].flatten.pack("CA8A3C4C16")
      catalog[dir_entry_start,0x20]=dir_entry
#      puts "dir entry # #{dir_entry_no}"
    end
    
    set_block(file_system_image,0,catalog[0,BLOCK_SIZE])
    set_block(file_system_image,1,catalog[BLOCK_SIZE,BLOCK_SIZE])
    
    native_file=files(file_system_image)[full_filename]
    raise "error: file should now be in catalog\n #{file_system_image.catalog}" if native_file.nil?
    return native_file
  end

  def self.delete_file(file_system_image,full_filename)
    catalog=get_block(file_system_image,0)+get_block(file_system_image,1)
    (partial_filename,file_ext)=CPMFile.split_filename(full_filename)
    0.upto(63) do |dir_entry_no|
      dir_entry_start=dir_entry_no*0x20
      dir_entry=catalog[dir_entry_start..dir_entry_start+0x1F]              
      if (partial_filename==dir_entry[0x01..0x08].gsub(' ','')) && (file_ext==dir_entry[0x09..0x0B].gsub(' ',''))      
        #we found a matching filename, so set the 'user number' field to a 'blank' entry
        catalog[dir_entry_start]=0xE5
      end
    end
    
    set_block(file_system_image,0,catalog[0,BLOCK_SIZE])
    set_block(file_system_image,1,catalog[BLOCK_SIZE,BLOCK_SIZE])
  end  

end

  
# == Author
# Jonno Downes (jonno@jamtronix.com)
#
# == Copyright
# Copyright (c) 2007 Jonno Downes (jonno@jamtronix.com)
#
#Permission is hereby granted, free of charge, to any person obtaining
#a copy of this software and associated documentation files (the
#"Software"), to deal in the Software without restriction, including
#without limitation the rights to use, copy, modify, merge, publish,
#distribute, sublicense, and/or sell copies of the Software, and to
#permit persons to whom the Software is furnished to do so, subject to
#the following conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.