#require 'pry'

require 'yaml'
require 'rake/clean'

CLEAN.include(['**/*.class','**/*.tmp','**/*.stx','**/*.libjava','**/*.chg'])
JAVA_TEST_FILES = FileList['tests/**/*.java']
JAVA_CLASS_FILES = []
TESTS = FileList['tests/*']
TESTS_DISABLED = [ "Threadring" , "Saxon" ]
# Threadring - ?
# SAXON        Segfaults due to a bug in JIT compiler. However, even bytecode
#              is quite fast (10 slower than JVM, not bad! :-)
        
STX_TEMPLATE = File.open("stx_template").read
LIBJAVA_TEMPLATE = File.open("libjava_template").read

task :default => [:all]

task :all => [:build, :run_tests]

task :build do
  TESTS.each do |test|
    Dir.chdir test do |path|
      test_name = test.gsub /^tests\//, ''
      build_java_test test_name
      build_stx_test test_name
      build_libjava_test test_name
    end
  end
end

task :run_tests do
  results = Hash.new
  TESTS.each do |test|
    disabled = false;
    TESTS_DISABLED.each do | e |
      if (test.include? e) 
        disabled = true
      end
    end
    if ! disabled
      test_name = test.gsub /^tests\//, ''
      puts "Running #{test_name}"      

      java_time = measure(test, :jvm)
      puts "#{java_time}"      

      stx_time = measure(test, :stx)      
      puts "#{stx_time}"      

      libjava_time = measure(test, :libjava)      
      puts "#{libjava_time}"      

      results[test_name] = {:java => java_time, :stx => stx_time, :libjava => libjava_time}
    end
  end
  results = Hash[results.sort]
  File.delete("perf_results")
  File.open("perf_results", "w") do |file| 
    values = [[ "Test", "JVM", "STX", "LIBJAVA" ]]
    results.each_pair do |key, value|
      values << [ key, results[key][:java], results[key][:stx], results[key][:libjava] ]
    end

    max_lengths = values[0].map { |val| val.length }
    values.each do |row|
      row.each_with_index do |elem, index|
        elem_size = elem.size
        max_lengths[index] = elem_size if elem_size > max_lengths[index]
      end
    end
    values.each do |val|
      format = max_lengths.map { |length| "%#{length}s" }.join(" " * 3)
      file.write(format % val)
      file.write("\n")
    end
  end
  p results
end

def build_java_test test_name
  if not File.exists? "#{test_name}.class"
    command = "javac #{classpath()} -d . ../../java/src/#{test_name}.java"
    puts command
    if ! system command
        raise Exception.new("Failed to compile #{test_name}.java")
    end
  end
end

def build_stx_test test_name
  full_test = STX_TEMPLATE
  File.open("#{test_name}.stx", "w") { |file| file.write full_test }
end

def build_libjava_test test_name
  if File.exists?("#{test_name}.libjava_test")
    test_content = File.open("#{test_name}.libjava_test").read
  else
    test_content = "(JAVA #{test_name}) main: (Array with: (Java as_String: Smalltalk commandLineArguments last))."
  end
  full_test = LIBJAVA_TEMPLATE.gsub /"TEST_GOES_HERE"/, test_content
  File.open("#{test_name}.libjava", "w") { |file| file.write full_test }
end

def test_params
  entries = Dir.entries "."
  if entries.include? "input"
    "< input"
  elsif entries.include? "params"
    `cat params`.chop()
  else 
    "1000"
  end
end

# Return a class path arguments to be passed to java/javac
# (including '-cp') or an empty string
def classpath()
  if (File.exist? "classpath") 
    f = File.open("classpath", "rb")                
    cp = "-cp #{f.read()}"      
    cp.gsub!("\n","")          
    f.close()
    return cp
  else
    return ''
  end
end


# Runs a given bench on given platform and return the time. 
# If bench fails (non-zero status value), raise an exception. 
def measure(test,platform)
   Dir.chdir test do |path|
       test_name = test.gsub /^tests\//, ''
       if (platform == :'jvm') 
          if (File.exist? "#{test_name}.class")
              command = "java #{classpath()} #{test_name} #{test_params()}" 
          else 
              return "N/A"
          end            
       elsif (platform == :'stx')
          if (File.exist? "#{test_name}.st")  
              command = "smalltalk -I --quick -f #{test_name}.stx #{test_params} 2>&1"
          else 
              return "N/A"
          end
       elsif (platform == :'libjava') 
          if (File.exist? "#{test_name}.class")          
              command = "smalltalk -I --quick -f #{test_name}.libjava #{test_params} 2>&1"
          else 
              return "N/A"
          end

       else 
          raise Exception.new("Unssuported platform: #{platform}")          
       end
       
       puts " running: #{command}"
       output = `#{command}`
       if ($? != 0) 
           puts output
           raise Exception.new("Command failed!")
       end
       execution_time = (output.scan /^EXECUTION TIME: \d*[\.\d]\d*$/).last()
       execution_time = execution_time.gsub /^EXECUTION TIME: /, ''
       return execution_time       
    end     
end