rom_url = 'https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Computers/Apple%20II/Apple%20IIc/ROM%20Images/Apple%20IIc%20ROM%2004%20-%20341-0445-B.bin'
source_rom = 'iic_rom4.bin'
source_rom_sha256 = '8ad5e6c4ed15d09b62183965b6c04762610d4b26510afc1896bdb4ecc55da883'
dest_rom = 'iic_rom4x.bin'
distzip = 'iic_rom4x.zip'
rom_base = 0xc000

source_files = Rake::FileList.new('*.s')

desc 'Default: clean and build it'
task :default => [:clean, :assemble, :build_rom] do
  sh "ls -l #{dest_rom}"
end

task :zip => [:clean, :assemble, :build_zip] do
  sh "ls -l #{dest_rom}"
end

desc 'Clean object files'
task :clean do
  sh "rm -f #{dest_rom}"
  sh "rm -f sf512_#{dest_rom}"
  sh "rm -f *.o"
  sh "rm -f *.lst"
  sh "rm -f *.b"
  sh "rm -f rom.sha256"
  sh "rm -f make_rom.sh"
  sh "rm -f #{distzip}"
end

desc 'Obtain ROM'
rule source_rom do
  require 'open-uri'
  
  puts "Downloading ROM..."
  
  File.open(source_rom, "wb") do |romfile|
    open(rom_url) do |wwwfile|
      romfile.write(wwwfile.read)
    end
  end
end

desc "Verify ROM Checksum"
task :checksum_rom => source_rom do
  require 'digest'

  sha256 = Digest::SHA256.file source_rom
  fail "ROM checksum failed" unless sha256.hexdigest == source_rom_sha256
  puts "Source ROM appears correct!"
end

desc "Assemble all source files"
task :assemble => source_files.ext('.b')

rule ".o" => ".s" do |t|
  sh "ca65 -l #{t.name}.lst #{t.source}"
end

rule ".b" => ".o" do |t|
  sh "ld65 -t none -o #{t.name} #{t.source}"
end

desc "Build ROM"
task :build_rom => [:assemble, :checksum_rom] do
  puts "Building ROM image..."
  obj_files = Rake::FileList.new('*.b')
  rom = File.read(source_rom)
  obj_files.each do |t|
    if t =~ /B(\h)_(\h{4})/
      bnum = $1.to_i(16)
      badd = $2.to_i(16)
      addr = bnum * 16384 + badd - rom_base
      fc = File.read(t)
      fl = fc.bytes.count
      puts "Loading #{t} into bank #{bnum} @ #{badd.to_s(16)}, file addr $#{addr.to_s(16)}, len $#{fl.to_s(16)} (#{fl})"
      nzc = 0
      fc.each_byte do |b|
        nzc += 1 if rom.getbyte(addr) != 0 && rom.getbyte(addr) != b
        rom.setbyte(addr, b)
        addr += 1
      end
      puts "\tNote: patched over #{nzc} nonzero bytes!" if nzc > 0
    else
      puts "I dont know where to load #{t}"
    end 
  end
  File.write(dest_rom, rom)
  puts "ROM image done: #{dest_rom}"
end

desc "Build SST27SF512 Image"
task :sf512 => [:build_rom] do
  sh "cat #{dest_rom} #{dest_rom} > sf512_#{dest_rom}"
end

desc "Build disributable ZIP"
task :build_zip => [:build_rom] do
  require 'digest'
  require 'date'
  
  sha256 = Digest::SHA256.file dest_rom
  shafile = <<EOF
#{source_rom_sha256}  #{source_rom}
#{sha256.hexdigest}  #{dest_rom}
EOF
  
  dd_cmds = []
  
  puts "Building distributable ZIP..."
  obj_files = Rake::FileList.new('*.b')
  obj_files.each do |t|
    if t =~ /B(\h)_(\h{4})/
      bnum = $1.to_i(16)
      badd = $2.to_i(16)
      addr = bnum * 16384 + badd - rom_base
      dd_cmds << "dd if=#{t} of=#{dest_rom} bs=1 seek=#{addr} conv=notrunc"
      sh "zip #{distzip} #{t}"
    end
  end
  
  puts "Creating maker script..."
  
  script = <<EOF
#!/bin/bash
set -e
BDATE="#{DateTime.now.to_s}"
ROM_URL="#{rom_url}"
echo ${BDATE}
if [ -e `which curl` ]; then
  curl -s "${ROM_URL}" > #{source_rom}
elif [ -e `which wget` ]; then
  wget -O #{source_rom} "${ROM_URL}"
else
  echo "Can't download source ROM image!"
fi
cp #{source_rom} #{dest_rom}
#{dd_cmds.join("\n")}
if [ -e `which shasum` ]; then
  shasum -a 256 -c rom.sha256
elif [ -e "sha256sum" ]; then
  sha256sum -c rom.sha256
else
  echo "Please check the .bin files against rom.sha256"
fi
echo "#{dest_rom} created!"
EOF

  File.write('rom.sha256', shafile)
  File.write('make_rom.sh', script)
  
  sh "zip #{distzip} rom.sha256 make_rom.sh"
end