require "pathname"
require "resource"
require "metafiles"
require "utils"

module DiskUsageExtension
  def disk_usage
    return @disk_usage if @disk_usage
    compute_disk_usage
    @disk_usage
  end

  def file_count
    return @file_count if @file_count
    compute_disk_usage
    @file_count
  end

  def abv
    out = ""
    compute_disk_usage
    out << "#{number_readable(@file_count)} files, " if @file_count > 1
    out << disk_usage_readable(@disk_usage).to_s
  end

  private

  def compute_disk_usage
    if directory?
      scanned_files = Set.new
      @file_count = 0
      @disk_usage = 0
      find do |f|
        if f.directory?
          @disk_usage += f.lstat.size
        else
          @file_count += 1 if f.basename.to_s != ".DS_Store"
          # use Pathname#lstat instead of Pathname#stat to get info of symlink itself.
          stat = f.lstat
          file_id = [stat.dev, stat.ino]
          # count hardlinks only once.
          unless scanned_files.include?(file_id)
            @disk_usage += stat.size
            scanned_files.add(file_id)
          end
        end
      end
    else
      @file_count = 1
      @disk_usage = lstat.size
    end
  end
end

# Homebrew extends Ruby's `Pathname` to make our code more readable.
# @see http://ruby-doc.org/stdlib-1.8.7/libdoc/pathname/rdoc/Pathname.html  Ruby's Pathname API
class Pathname
  include DiskUsageExtension

  # @private
  BOTTLE_EXTNAME_RX = /(\.[a-z0-9_]+\.bottle\.(\d+\.)?tar\.gz)$/

  # Moves a file from the original location to the {Pathname}'s.
  def install(*sources)
    sources.each do |src|
      case src
      when Resource
        src.stage(self)
      when Resource::Partial
        src.resource.stage { install(*src.files) }
      when Array
        if src.empty?
          opoo "tried to install empty array to #{self}"
          break
        end
        src.each { |s| install_p(s, File.basename(s)) }
      when Hash
        if src.empty?
          opoo "tried to install empty hash to #{self}"
          break
        end
        src.each { |s, new_basename| install_p(s, new_basename) }
      else
        install_p(src, File.basename(src))
      end
    end
  end

  def install_p(src, new_basename)
    raise Errno::ENOENT, src.to_s unless File.symlink?(src) || File.exist?(src)

    src = Pathname(src)
    dst = join(new_basename)
    dst = yield(src, dst) if block_given?
    return unless dst

    mkpath

    # Use FileUtils.mv over File.rename to handle filesystem boundaries. If src
    # is a symlink, and its target is moved first, FileUtils.mv will fail:
    #   https://bugs.ruby-lang.org/issues/7707
    # In that case, use the system "mv" command.
    if src.symlink?
      raise unless Kernel.system "mv", src, dst
    else
      FileUtils.mv src, dst
    end
  end
  private :install_p

  # Creates symlinks to sources in this folder.
  def install_symlink(*sources)
    sources.each do |src|
      case src
      when Array
        src.each { |s| install_symlink_p(s, File.basename(s)) }
      when Hash
        src.each { |s, new_basename| install_symlink_p(s, new_basename) }
      else
        install_symlink_p(src, File.basename(src))
      end
    end
  end

  def install_symlink_p(src, new_basename)
    src = Pathname(src).expand_path(self)
    dst = join(new_basename)
    mkpath
    FileUtils.ln_sf(src.relative_path_from(dst.parent), dst)
  end
  private :install_symlink_p

  if method_defined?(:write)
    # @private
    alias old_write write
  end

  # we assume this pathname object is a file obviously
  def write(content, *open_args)
    raise "Will not overwrite #{self}" if exist?
    dirname.mkpath
    open("w", *open_args) { |f| f.write(content) }
  end

  # Only appends to a file that is already created.
  def append_lines(content, *open_args)
    raise "Cannot append file that doesn't exist: #{self}" unless exist?
    open("a", *open_args) { |f| f.puts(content) }
  end

  def binwrite(contents, *open_args)
    open("wb", *open_args) { |f| f.write(contents) }
  end unless method_defined?(:binwrite)

  def binread(*open_args)
    open("rb", *open_args, &:read)
  end unless method_defined?(:binread)

  # NOTE always overwrites
  def atomic_write(content)
    require "tempfile"
    tf = Tempfile.new(basename.to_s, dirname)
    begin
      tf.binmode
      tf.write(content)

      begin
        old_stat = stat
      rescue Errno::ENOENT
        old_stat = default_stat
      end

      uid = Process.uid
      gid = Process.groups.delete(old_stat.gid) { Process.gid }

      begin
        tf.chown(uid, gid)
        tf.chmod(old_stat.mode)
      rescue Errno::EPERM
      end

      File.rename(tf.path, self)
    ensure
      tf.close!
    end
  end

  def default_stat
    sentinel = parent.join(".brew.#{Process.pid}.#{rand(Time.now.to_i)}")
    sentinel.open("w") {}
    sentinel.stat
  ensure
    sentinel.unlink
  end
  private :default_stat

  # @private
  def cp_path_sub(pattern, replacement)
    raise "#{self} does not exist" unless exist?

    dst = sub(pattern, replacement)

    raise "#{self} is the same file as #{dst}" if self == dst

    if directory?
      dst.mkpath
    else
      dst.dirname.mkpath
      dst = yield(self, dst) if block_given?
      FileUtils.cp(self, dst)
    end
  end

  # @private
  alias extname_old extname

  # extended to support common double extensions
  def extname(path = to_s)
    bottle_ext = path[BOTTLE_EXTNAME_RX, 1]
    return bottle_ext if bottle_ext
    archive_ext = path[/(\.(tar|cpio|pax)\.(gz|bz2|lz|xz|Z))$/, 1]
    return archive_ext if archive_ext
    File.extname(path)
  end

  # for filetypes we support, basename without extension
  def stem
    File.basename((path = to_s), extname(path))
  end

  # I don't trust the children.length == 0 check particularly, not to mention
  # it is slow to enumerate the whole directory just to see if it is empty,
  # instead rely on good ol' libc and the filesystem
  # @private
  def rmdir_if_possible
    rmdir
    true
  rescue Errno::ENOTEMPTY
    if (ds_store = self+".DS_Store").exist? && children.length == 1
      ds_store.unlink
      retry
    else
      false
    end
  rescue Errno::EACCES, Errno::ENOENT
    false
  end

  # @private
  def version
    require "version"
    Version.parse(basename)
  end

  # @private
  def compression_type
    case extname
    when ".jar", ".war"
      # Don't treat jars or wars as compressed
      return
    when ".gz"
      # If the filename ends with .gz not preceded by .tar
      # then we want to gunzip but not tar
      return :gzip_only
    when ".bz2"
      return :bzip2_only
    when ".lha", ".lzh"
      return :lha
    end

    # Get enough of the file to detect common file types
    # POSIX tar magic has a 257 byte offset
    # magic numbers stolen from /usr/share/file/magic/
    case open("rb") { |f| f.read(262) }
    when /^PK\003\004/n         then :zip
    when /^\037\213/n           then :gzip
    when /^BZh/n                then :bzip2
    when /^\037\235/n           then :compress
    when /^.{257}ustar/n        then :tar
    when /^\xFD7zXZ\x00/n       then :xz
    when /^LZIP/n               then :lzip
    when /^Rar!/n               then :rar
    when /^7z\xBC\xAF\x27\x1C/n then :p7zip
    when /^xar!/n               then :xar
    when /^\xed\xab\xee\xdb/n   then :rpm
    else
      # This code so that bad-tarballs and zips produce good error messages
      # when they don't unarchive properly.
      case extname
      when ".tar.gz", ".tgz", ".tar.bz2", ".tbz" then :tar
      when ".zip" then :zip
      end
    end
  end

  # @private
  def text_executable?
    /^#!\s*\S+/ =~ open("r") { |f| f.read(1024) }
  end

  # @private
  def incremental_hash(klass)
    digest = klass.new
    if digest.respond_to?(:file)
      digest.file(self)
    else
      buf = ""
      open("rb") { |f| digest << buf while f.read(16384, buf) }
    end
    digest.hexdigest
  end

  def sha256
    require "digest/sha2"
    incremental_hash(Digest::SHA2)
  end

  def verify_checksum(expected)
    raise ChecksumMissingError if expected.nil? || expected.empty?
    actual = Checksum.new(expected.hash_type, send(expected.hash_type).downcase)
    raise ChecksumMismatchError.new(self, expected, actual) unless expected == actual
  end

  # FIXME: eliminate the places where we rely on this method
  alias to_str to_s unless method_defined?(:to_str)

  def cd
    Dir.chdir(self) { yield }
  end

  def subdirs
    children.select(&:directory?)
  end

  # @private
  def resolved_path
    symlink? ? dirname+readlink : self
  end

  # @private
  def resolved_path_exists?
    link = readlink
  rescue ArgumentError
    # The link target contains NUL bytes
    false
  else
    (dirname+link).exist?
  end

  # @private
  def make_relative_symlink(src)
    dirname.mkpath
    File.symlink(src.relative_path_from(dirname), self)
  end

  def /(other)
    unless other.respond_to?(:to_str) || other.respond_to?(:to_path)
      opoo "Pathname#/ called on #{inspect} with #{other.inspect} as an argument"
      puts "This behavior is deprecated, please pass either a String or a Pathname"
    end
    self + other.to_s
  end unless method_defined?(:/)

  # @private
  def ensure_writable
    saved_perms = nil
    unless writable_real?
      saved_perms = stat.mode
      chmod 0644
    end
    yield
  ensure
    chmod saved_perms if saved_perms
  end

  # @private
  def install_info
    quiet_system "/usr/bin/install-info", "--quiet", to_s, "#{dirname}/dir"
  end

  # @private
  def uninstall_info
    quiet_system "/usr/bin/install-info", "--delete", "--quiet", to_s, "#{dirname}/dir"
  end

  # Writes an exec script in this folder for each target pathname
  def write_exec_script(*targets)
    targets.flatten!
    if targets.empty?
      opoo "tried to write exec scripts to #{self} for an empty list of targets"
      return
    end
    mkpath
    targets.each do |target|
      target = Pathname.new(target) # allow pathnames or strings
      (self+target.basename).write <<-EOS.undent
        #!/bin/bash
        exec "#{target}" "$@"
      EOS
    end
  end

  # Writes an exec script that sets environment variables
  def write_env_script(target, env)
    env_export = ""
    env.each { |key, value| env_export += "#{key}=\"#{value}\" " }
    dirname.mkpath
    write <<-EOS.undent
    #!/bin/bash
    #{env_export}exec "#{target}" "$@"
    EOS
  end

  # Writes a wrapper env script and moves all files to the dst
  def env_script_all_files(dst, env)
    dst.mkpath
    Pathname.glob("#{self}/*") do |file|
      next if file.directory?
      dst.install(file)
      new_file = dst+file.basename
      file.write_env_script(new_file, env)
    end
  end

  # Writes an exec script that invokes a java jar
  def write_jar_script(target_jar, script_name, java_opts = "")
    mkpath
    (self+script_name).write <<-EOS.undent
      #!/bin/bash
      exec java #{java_opts} -jar #{target_jar} "$@"
    EOS
  end

  def install_metafiles(from = Pathname.pwd)
    Pathname(from).children.each do |p|
      next if p.directory?
      next unless Metafiles.copy?(p.basename.to_s)
      # Some software symlinks these files (see help2man.rb)
      filename = p.resolved_path
      # Some software links metafiles together, so by the time we iterate to one of them
      # we may have already moved it. libxml2's COPYING and Copyright are affected by this.
      next unless filename.exist?
      filename.chmod 0644
      install(filename)
    end
  end

  # https://bugs.ruby-lang.org/issues/9915
  if RUBY_VERSION == "2.0.0"
    prepend Module.new {
      def inspect
        super.force_encoding(@path.encoding)
      end
    }
  end
end

# @private
module ObserverPathnameExtension
  class << self
    attr_accessor :n, :d

    def reset_counts!
      @n = @d = 0
      @put_verbose_trimmed_warning = false
    end

    def total
      n + d
    end

    def counts
      [n, d]
    end

    MAXIMUM_VERBOSE_OUTPUT = 100

    def verbose?
      return ARGV.verbose? unless ENV["TRAVIS"]
      return false unless ARGV.verbose?

      if total < MAXIMUM_VERBOSE_OUTPUT
        true
      else
        unless @put_verbose_trimmed_warning
          puts "Only the first #{MAXIMUM_VERBOSE_OUTPUT} operations were output."
          @put_verbose_trimmed_warning = true
        end
        false
      end
    end
  end

  def unlink
    super
    puts "rm #{self}" if ObserverPathnameExtension.verbose?
    ObserverPathnameExtension.n += 1
  end

  def mkpath
    super
    puts "mkdir -p #{self}" if ObserverPathnameExtension.verbose?
  end

  def rmdir
    super
    puts "rmdir #{self}" if ObserverPathnameExtension.verbose?
    ObserverPathnameExtension.d += 1
  end

  def make_relative_symlink(src)
    super
    puts "ln -s #{src.relative_path_from(dirname)} #{basename}" if ObserverPathnameExtension.verbose?
    ObserverPathnameExtension.n += 1
  end

  def install_info
    super
    puts "info #{self}" if ObserverPathnameExtension.verbose?
  end

  def uninstall_info
    super
    puts "uninfo #{self}" if ObserverPathnameExtension.verbose?
  end
end
