class Flay

def self.default_options
  {
    :diff    => false,
    :mass    => 16,
    :summary => false,
    :verbose => false,
    :number  => true,
    :timeout => 10,
    :liberal => false,
    :fuzzy   => false,
    :only    => nil,
    :filters => [],
  }
end

def self.load_plugins
  unless defined? @@plugins then
    @@plugins = []
    plugins = Gem.find_files("flay_*.rb").reject { |p| p =~ /flay_task/ }
    plugins.each do |plugin|
      plugin_name = File.basename(plugin, ".rb").sub(/^flay_/, "")
      next if @@plugins.include? plugin_name
      begin
        load plugin
        @@plugins << plugin_name
      rescue LoadError => e
        warn "error loading #{plugin.inspect}: #{e.message}. skipping..."
      end
    end
  end
  @@plugins
rescue => e
  warn "Error loading plugins: #{e}" if option[:verbose]
end

def self.parse_options args = ARGV
  options = self.default_options
  OptionParser.new do |opts|
    opts.banner  = "flay [options] files_or_dirs"
    opts.version = Flay::VERSION
    opts.separator ""
    opts.separator "Specific options:"
    opts.separator ""
    opts.on("-h", "--help", "Display this help.") do
      puts opts
      exit
    end
    opts.on("-f", "--fuzzy [DIFF]", Integer,
            "Detect fuzzy (copy & paste) duplication (default 1).") do |n|
      options[:fuzzy] = n || 1
    end
    opts.on("-l", "--liberal", "Use a more liberal detection method.") do
      options[:liberal] = true
    end
    opts.on("-m", "--mass MASS", Integer,
            "Sets mass threshold (default = #{options[:mass]})") do |m|
      options[:mass] = m.to_i
    end
    opts.on("-#", "Don't number output (helps with diffs)") do |m|
      options[:number] = false
    end
    opts.on("-v", "--verbose", "Verbose. Show progress processing files.") do
      options[:verbose] = true
    end
    opts.on("-o", "--only NODE", String, "Only show matches on NODE type.") do |s|
      options[:only] = s.to_sym
    end
    opts.on("-d", "--diff", "Diff Mode. Display N-Way diff for ruby.") do
      options[:diff] = true
    end
    opts.on("-s", "--summary", "Summarize. Show flay score per file only.") do
      options[:summary] = true
    end
    opts.on("-t", "--timeout TIME", Integer,
            "Set the timeout. (default = #{options[:timeout]})") do |t|
      options[:timeout] = t.to_i
    end
    extensions = ["rb"] + Flay.load_plugins
    opts.separator ""
    opts.separator "Known extensions: #{extensions.join(", ")}"
    extensions.each do |meth|
      msg = "options_#{meth}"
      send msg, opts, options if self.respond_to?(msg)
    end
    begin
      opts.parse! args
    rescue => e
      abort "#{e}\n\n#{opts}"
    end
  end
  options
end

def self.run args = ARGV
  extensions = ["rb"] + Flay.load_plugins
  glob = "**/*.{#{extensions.join ","}}"
  expander = PathExpander.new args, glob
  files = expander.filter_files expander.process, DEFAULT_IGNORE
  flay = Flay.new Flay.parse_options args
  flay.process(*files.sort)
  flay
end

def analyze filter = nil
  self.prune
  self.hashes.each do |hash,nodes|
    identical[hash] = nodes[1..-1].all? { |n| n == nodes.first }
  end
  update_masses
  sorted = masses.sort_by { |h,m|
    exp = hashes[h].first
    [-m,
     exp.file,
     exp.line,
     exp.sexp_type.to_s]
  }
  sorted.map { |hash, mass|
    nodes = hashes[hash]
    next unless nodes.first.first == filter if filter
    same  = identical[hash]
    node  = nodes.first
    n     = nodes.size
    bonus = "*#{n}" if same
    locs = nodes.sort_by { |x| [x.file, x.line] }.each_with_index.map { |x, i|
      extra = :fuzzy if x.modified?
      Location[x.file, x.line, extra]
    }
    Item[hash, node.sexp_type, bonus, mass, locs]
  }.compact
end

def collapse_and_label ary # :nodoc:
  ary[0].zip(*ary[1..-1]).map { |lines|
    if lines.uniq.size == 1 then
      "   #{lines.first}"
    else
      lines.reject { |l| l.empty? }.map { |l| "#{l.group}: #{l}" }
    end
  }
end

def filter_sexp exp
  exp.delete_if { |sexp|
    if Sexp === sexp then
      del = option[:filters].any? { |pattern| pattern.satisfy? sexp }
      del or (filter_sexp(sexp); false)
    end
  }
end

def initialize option = {}
  @option = Flay.default_options.merge option
  @hashes = Hash.new { |h,k| h[k] = [] }
  self.identical      = {}
  self.masses         = {}
  self.total          = 0
  self.mass_threshold = @option[:mass]
end

def n_way_diff *data
  comments = []
  codes    = []
  split_and_group(data).each do |subdata|
    n = subdata.find_index { |s| s !~ /^#/ }
    comment, code = subdata[0..n-1], subdata[n..-1]
    comment = [] if n == 0
    comments << comment
    codes    << code
  end
  comments = collapse_and_label pad_with_empty_strings comments
  codes    = collapse_and_label pad_with_empty_strings codes
  (comments + codes).flatten.join("\n")
end

def pad_with_empty_strings ary # :nodoc:
  max = ary.map { |s| s.size }.max
  ary.map { |a| a + ([""] * (max - a.size)) }
end

def process(*files) # TODO: rename from process - should act as SexpProcessor
  files.each do |file|
    warn "Processing #{file}" if option[:verbose]
    ext = File.extname(file).sub(/^\./, "")
    ext = "rb" if ext.nil? || ext.empty?
    msg = "process_#{ext}"
    unless respond_to? msg then
      warn "  Unknown file type: #{ext}, defaulting to ruby"
      msg = "process_rb"
    end
    begin
      sexp = begin
               send msg, file
             rescue => e
               warn "  #{e.message.strip}"
               warn "  skipping #{file}"
               nil
             end
      next unless sexp
      process_sexp sexp
    rescue SyntaxError => e
      warn "  skipping #{file}: #{e.message}"
    end
  end
end

def process_erb file
  erb = File.read file
  ruby = Erubi.new(erb).src
  begin
    RubyParser.new.process(ruby, file)
  rescue => e
    warn ruby if option[:verbose]
    raise e
  end
end

def process_fuzzy node, difference
  return unless node.has_code?
  avg_mass = node.mass / node.size
  return if node.size > MAX_NODE_SIZE or avg_mass > MAX_AVG_MASS
  tmpl, code = node.split_code
  tmpl.modified = true
  (code.size - 1).downto(code.size - difference) do |n|
    code.combination(n).each do |subcode|
      new_node = tmpl + subcode
      next unless new_node.any? { |sub| Sexp === sub }
      next if new_node.mass < self.mass_threshold
      # they're already structurally similar, don"t bother adding another
      next if self.hashes[new_node.structural_hash].any? { |sub|
        sub.file == new_node.file and sub.line == new_node.line
      }
      self.hashes[new_node.structural_hash] << new_node
    end
  end
end

def process_rb file
  begin
    RubyParser.new.process(File.binread(file), file, option[:timeout])
  rescue Timeout::Error
    warn "TIMEOUT parsing #{file}. Skipping."
  end
end

def process_sexp pt
  filter_sexp(pt).deep_each do |node|
    next :skip if node.none? { |sub| Sexp === sub }
    next :skip if node.mass < self.mass_threshold
    self.hashes[node.structural_hash] << node
    process_fuzzy node, option[:fuzzy] if option[:fuzzy]
  end
end

def prune
  # prune trees that aren't duped at all, or are too small
  self.hashes.delete_if { |_,nodes| nodes.size == 1 }
  self.hashes.delete_if { |_,nodes| nodes.all?(&:modified?) }
  if option[:liberal] then
    prune_liberally
  else
    prune_conservatively
  end
end

def prune_conservatively
  hashes_to_prune = {}
  # extract all subtree hashes from all nodes
  self.hashes.values.each do |nodes|
    nodes.first.all_structural_subhashes.each do |h|
      hashes_to_prune[h] = true
    end
  end
  # nuke subtrees so we show the biggest matching tree possible
  self.hashes.delete_if { |h,_| hashes_to_prune[h] }
end

def prune_liberally
  update_masses
  hashes_to_prune = Hash.new { |h,k| h[k] = [] }
  # record each subtree by subhash, but skip if subtree mass > parent mass
  self.hashes.values.each do |nodes|
    nodes.each do |node|
      tophash  = node.structural_hash
      topscore = self.masses[tophash]
      node.deep_each do |subnode|
        subhash  = subnode.structural_hash
        subscore = self.masses[subhash]
        next if subscore and subscore > topscore
        hashes_to_prune[subhash] << subnode
      end
    end
  end
  # nuke only individual items by object identity
  self.hashes.each do |h,v|
    v.delete_eql hashes_to_prune[h]
  end
  # nuke buckets we happened to fully empty
  self.hashes.delete_if { |k,v| v.size <= 1 }
end

def report io = $stdout
  only = option[:only]
  data = analyze only
  io.puts "Total score (lower is better) = #{self.total}"
  if option[:summary] then
    io.puts
    self.summary.sort_by { |f,v| [-v, f] }.each do |file, score|
      io.puts "%8.2f: %s" % [score, file]
    end
    return
  end
  data.each_with_index do |item, count|
    prefix = "%d) " % (count + 1) if option[:number]
    match = item.identical? ? "IDENTICAL" : "Similar"
    io.puts
    io.puts "%s%s code found in %p (mass%s = %d)" %
      [prefix, match, item.name, item.bonus, item.mass]
    item.locations.each_with_index do |loc, i|
      loc_prefix = "%s: " % (?A.ord + i).chr if option[:diff]
      extra = " (FUZZY)" if loc.fuzzy?
      io.puts "  %s%s:%d%s" % [loc_prefix, loc.file, loc.line, extra]
    end
    if option[:diff] then
      io.puts
      nodes = hashes[item.structural_hash]
      sources = nodes.map do |s|
        msg = "sexp_to_#{File.extname(s.file).sub(/./, "")}"
        self.respond_to?(msg) ? self.send(msg, s) : sexp_to_rb(s)
      end
      io.puts n_way_diff(*sources)
    end
  end
end

def sexp_to_rb sexp
  begin
    require "ruby2ruby"
  rescue LoadError
    return "ruby2ruby is required for diff"
  end
  @r2r ||= Ruby2Ruby.new
  @r2r.process sexp.deep_clone
end

def split_and_group ary # :nodoc:
  ary.each_with_index.map { |s, i|
    c = (?A.ord + i).chr
    s.scan(/^.*/).map { |s2|
      s2.group = c
      s2
    }
  }
end

def summary
  score = Hash.new 0
  masses.each do |hash, mass|
    sexps = hashes[hash]
    mass_per_file = mass.to_f / sexps.size
    sexps.each do |sexp|
      score[sexp.file] += mass_per_file
    end
  end
  score
end

def update_masses
  self.total = 0
  masses.clear
  self.hashes.each do |hash, nodes|
    masses[hash] = nodes.first.mass * nodes.size
    masses[hash] *= (nodes.size) if identical[hash]
    self.total += masses[hash]
  end
end