require 'formula'
require 'utils'
require 'superenv'

module Homebrew extend self
  def audit
    formula_count = 0
    problem_count = 0

    ENV.setup_build_environment

    ff = if ARGV.named.empty?
      Formula
    else
      ARGV.formulae
    end

    ff.each do |f|
      fa = FormulaAuditor.new f
      fa.audit

      unless fa.problems.empty?
        puts "#{f.name}:"
        fa.problems.each { |p| puts " * #{p}" }
        puts
        formula_count += 1
        problem_count += fa.problems.size
      end
    end

    unless problem_count.zero?
      ofail "#{problem_count} problems in #{formula_count} formulae"
    end
  end
end

class Module
  def redefine_const(name, value)
    __send__(:remove_const, name) if const_defined?(name)
    const_set(name, value)
  end
end

# Formula extensions for auditing
class Formula
  def head_only?
    @head and @stable.nil?
  end

  def text
    @text ||= FormulaText.new(@path)
  end
end

class FormulaText
  def initialize path
    @text = path.open('r') { |f| f.read }
  end

  def without_patch
    @text.split("__END__")[0].strip()
  end

  def has_DATA?
    /\bDATA\b/ =~ @text
  end

  def has_END?
    /^__END__$/ =~ @text
  end

  def has_trailing_newline?
    /\Z\n/ =~ @text
  end
end

class FormulaAuditor
  attr_reader :f, :text, :problems

  BUILD_TIME_DEPS = %W[
    autoconf
    automake
    boost-build
    bsdmake
    cmake
    imake
    intltool
    libtool
    pkg-config
    scons
    smake
    swig
  ]

  def initialize f
    @f = f
    @problems = []
    @text = f.text.without_patch
    @specs = %w{stable devel head}.map { |s| f.send(s) }.compact

    # We need to do this in case the formula defines a patch that uses DATA.
    f.class.redefine_const :DATA, ""
  end

  def audit_file
    unless f.path.stat.mode.to_s(8) == "100644"
      problem "Incorrect file permissions: chmod 644 #{f.path}"
    end

    if f.text.has_DATA? and not f.text.has_END?
      problem "'DATA' was found, but no '__END__'"
    end

    if f.text.has_END? and not f.text.has_DATA?
      problem "'__END__' was found, but 'DATA' is not used"
    end

    unless f.text.has_trailing_newline?
      problem "File should end with a newline"
    end
  end

  def audit_deps
    # Don't depend_on aliases; use full name
    @@aliases ||= Formula.aliases
    f.deps.select { |d| @@aliases.include? d.name }.each do |d|
      problem "Dependency #{d} is an alias; use the canonical name."
    end

    # Check for things we don't like to depend on.
    # We allow non-Homebrew installs whenever possible.
    f.deps.each do |dep|
      begin
        dep_f = dep.to_formula
      rescue FormulaUnavailableError
        problem "Can't find dependency #{dep.name.inspect}."
      end

      dep.options.reject do |opt|
        dep_f.build.has_option?(opt.name)
      end.each do |opt|
        problem "Dependency #{dep} does not define option #{opt.name.inspect}"
      end

      case dep.name
      when *BUILD_TIME_DEPS
        # Build deps should be tagged
        problem <<-EOS.undent unless dep.tags.any? || f.name =~ /automake/ && dep.name == 'autoconf'
        #{dep} dependency should be "depends_on '#{dep}' => :build"
        EOS
      when "git", "ruby", "emacs", "mercurial"
        problem <<-EOS.undent
          Don't use #{dep} as a dependency. We allow non-Homebrew
          #{dep} installations.
          EOS
      when 'python', 'python2', 'python3'
        problem <<-EOS.undent
          Don't use #{dep} as a dependency (string).
             We have special `depends_on :python` (or :python2 or :python3 )
             that works with brewed and system Python and allows us to support
             bindings for 2.x and 3.x in parallel and much more.
          EOS
      when 'gfortran'
        problem "Use ENV.fortran during install instead of depends_on 'gfortran'"
      when 'open-mpi', 'mpich2'
        problem <<-EOS.undent
          There are multiple conflicting ways to install MPI. Use an MPIDependency:
            depends_on MPIDependency.new(<lang list>)
          Where <lang list> is a comma delimited list that can include:
            :cc, :cxx, :f90, :f77
          EOS
      end
    end
  end

  def audit_conflicts
    f.conflicts.each do |req|
      begin
        Formula.factory req.formula
      rescue FormulaUnavailableError
        problem "Can't find conflicting formula \"#{req.formula}\"."
      end
    end
  end

  def audit_urls
    unless f.homepage =~ %r[^https?://]
      problem "The homepage should start with http or https (url is #{f.homepage})."
    end

    # Check for http:// GitHub homepage urls, https:// is preferred.
    # Note: only check homepages that are repo pages, not *.github.com hosts
    if f.homepage =~ %r[^http://github\.com/]
      problem "Use https:// URLs for homepages on GitHub (url is #{f.homepage})."
    end

    # Google Code homepages should end in a slash
    if f.homepage =~ %r[^https?://code\.google\.com/p/[^/]+[^/]$]
      problem "Google Code homepage should end with a slash (url is #{f.homepage})."
    end

    if f.homepage =~ %r[^http://.*\.github\.com/]
      problem "GitHub pages should use the github.io domain (url is #{f.homepage})"
    end

    urls = @specs.map(&:url)

    # Check GNU urls; doesn't apply to mirrors
    urls.grep(%r[^(?:https?|ftp)://(?!alpha).+/gnu/]) do |u|
      problem "\"ftpmirror.gnu.org\" is preferred for GNU software (url is #{u})."
    end

    # the rest of the checks apply to mirrors as well
    urls.concat(@specs.map(&:mirrors).flatten)

    # Check SourceForge urls
    urls.each do |p|
      # Is it a filedownload (instead of svnroot)
      next if p =~ %r[/svnroot/]
      next if p =~ %r[svn\.sourceforge]

      # Is it a sourceforge http(s) URL?
      next unless p =~ %r[^https?://.*\bsourceforge\.]

      if p =~ /(\?|&)use_mirror=/
        problem "Don't use #{$1}use_mirror in SourceForge urls (url is #{p})."
      end

      if p =~ /\/download$/
        problem "Don't use /download in SourceForge urls (url is #{p})."
      end

      if p =~ %r[^http://prdownloads\.]
        problem "Don't use prdownloads in SourceForge urls (url is #{p}).\n" +
                "\tSee: http://librelist.com/browser/homebrew/2011/1/12/prdownloads-is-bad/"
      end

      if p =~ %r[^http://\w+\.dl\.]
        problem "Don't use specific dl mirrors in SourceForge urls (url is #{p})."
      end
    end

    # Check for git:// GitHub repo urls, https:// is preferred.
    urls.grep(%r[^git://[^/]*github\.com/]) do |u|
      problem "Use https:// URLs for accessing GitHub repositories (url is #{u})."
    end

    # Check for http:// GitHub repo urls, https:// is preferred.
    urls.grep(%r[^http://github\.com/.*\.git$]) do |u|
      problem "Use https:// URLs for accessing GitHub repositories (url is #{u})."
    end

    # Use new-style archive downloads
    urls.select { |u| u =~ %r[https://.*/(?:tar|zip)ball/] and not u =~ %r[\.git$] }.each do |u|
      problem "Use /archive/ URLs for GitHub tarballs (url is #{u})."
    end

    if urls.any? { |u| u =~ /\.xz/ } && !f.deps.any? { |d| d.name == "xz" }
      problem "Missing a build-time dependency on 'xz'"
    end
  end

  def audit_specs
    problem "Head-only (no stable download)" if f.head_only?

    [:stable, :devel].each do |spec|
      s = f.send(spec)
      next if s.nil?

      if s.version.to_s.empty?
        problem "Invalid or missing #{spec} version"
      else
        version_text = s.version unless s.version.detected_from_url?
        version_url = Version.parse(s.url)
        if version_url.to_s == version_text.to_s && s.version.instance_of?(Version)
          problem "#{spec} version #{version_text} is redundant with version scanned from URL"
        end
      end

      cksum = s.checksum
      next if cksum.nil?

      len = case cksum.hash_type
        when :sha1 then 40
        when :sha256 then 64
        end

      if cksum.empty?
        problem "#{cksum.hash_type} is empty"
      else
        problem "#{cksum.hash_type} should be #{len} characters" unless cksum.hexdigest.length == len
        problem "#{cksum.hash_type} contains invalid characters" unless cksum.hexdigest =~ /^[a-fA-F0-9]+$/
        problem "#{cksum.hash_type} should be lowercase" unless cksum.hexdigest == cksum.hexdigest.downcase
      end
    end

    # Check for :using that is already detected from the url
    @specs.each do |s|
      next if s.using.nil?

      url_strategy = DownloadStrategyDetector.detect(s.url)
      using_strategy = DownloadStrategyDetector.detect('', s.using)

      problem "redundant :using specification in url or head" if url_strategy == using_strategy
    end
  end

  def audit_patches
    Patches.new(f.patches).select(&:external?).each do |p|
      case p.url
      when %r[raw\.github\.com], %r[gist\.github\.com/raw]
        unless p.url =~ /[a-fA-F0-9]{40}/
          problem "GitHub/Gist patches should specify a revision:\n#{p.url}"
        end
      when %r[macports/trunk]
        problem "MacPorts patches should specify a revision instead of trunk:\n#{p.url}"
      end
    end
  end

  def audit_text
    if text =~ /<(Formula|AmazonWebServicesFormula|ScriptFileFormula|GithubGistFormula)/
      problem "Use a space in class inheritance: class Foo < #{$1}"
    end

    # Commented-out cmake support from default template
    if (text =~ /# system "cmake/)
      problem "Commented cmake call found"
    end

    # FileUtils is included in Formula
    if text =~ /FileUtils\.(\w+)/
      problem "Don't need 'FileUtils.' before #{$1}."
    end

    # Check for long inreplace block vars
    if text =~ /inreplace .* do \|(.{2,})\|/
      problem "\"inreplace <filenames> do |s|\" is preferred over \"|#{$1}|\"."
    end

    # Check for string interpolation of single values.
    if text =~ /(system|inreplace|gsub!|change_make_var!).*[ ,]"#\{([\w.]+)\}"/
      problem "Don't need to interpolate \"#{$2}\" with #{$1}"
    end

    # Check for string concatenation; prefer interpolation
    if text =~ /(#\{\w+\s*\+\s*['"][^}]+\})/
      problem "Try not to concatenate paths in string interpolation:\n   #{$1}"
    end

    # Prefer formula path shortcuts in Pathname+
    if text =~ %r{\(\s*(prefix\s*\+\s*(['"])(bin|include|libexec|lib|sbin|share)[/'"])}
      problem "\"(#{$1}...#{$2})\" should be \"(#{$3}+...)\""
    end

    if text =~ %r[((man)\s*\+\s*(['"])(man[1-8])(['"]))]
      problem "\"#{$1}\" should be \"#{$4}\""
    end

    # Prefer formula path shortcuts in strings
    if text =~ %r[(\#\{prefix\}/(bin|include|libexec|lib|sbin|share))]
      problem "\"#{$1}\" should be \"\#{#{$2}}\""
    end

    if text =~ %r[((\#\{prefix\}/share/man/|\#\{man\}/)(man[1-8]))]
      problem "\"#{$1}\" should be \"\#{#{$3}}\""
    end

    if text =~ %r[((\#\{share\}/(man)))[/'"]]
      problem "\"#{$1}\" should be \"\#{#{$3}}\""
    end

    if text =~ %r[(\#\{prefix\}/share/(info|man))]
      problem "\"#{$1}\" should be \"\#{#{$2}}\""
    end

    # Commented-out depends_on
    if text =~ /#\s*depends_on\s+(.+)\s*$/
      problem "Commented-out dep #{$1}"
    end

    # No trailing whitespace, please
    if text =~ /[\t ]+$/
      problem "Trailing whitespace was found"
    end

    if text =~ /if\s+ARGV\.include\?\s+'--(HEAD|devel)'/
      problem "Use \"if ARGV.build_#{$1.downcase}?\" instead"
    end

    if text =~ /make && make/
      problem "Use separate make calls"
    end

    if text =~ /^[ ]*\t/
      problem "Use spaces instead of tabs for indentation"
    end

    # xcodebuild should specify SYMROOT
    if text =~ /system\s+['"]xcodebuild/ and not text =~ /SYMROOT=/
      problem "xcodebuild should be passed an explicit \"SYMROOT\""
    end

    if text =~ /ENV\.x11/
      problem "Use \"depends_on :x11\" instead of \"ENV.x11\""
    end

    # Avoid hard-coding compilers
    if text =~ %r{(system|ENV\[.+\]\s?=)\s?['"](/usr/bin/)?(gcc|llvm-gcc|clang)['" ]}
      problem "Use \"\#{ENV.cc}\" instead of hard-coding \"#{$3}\""
    end

    if text =~ %r{(system|ENV\[.+\]\s?=)\s?['"](/usr/bin/)?((g|llvm-g|clang)\+\+)['" ]}
      problem "Use \"\#{ENV.cxx}\" instead of hard-coding \"#{$3}\""
    end

    if text =~ /system\s+['"](env|export)/
      problem "Use ENV instead of invoking '#{$1}' to modify the environment"
    end

    if text =~ /version == ['"]HEAD['"]/
      problem "Use 'build.head?' instead of inspecting 'version'"
    end

    if text =~ /build\.include\?\s+['"]\-\-(.*)['"]/
      problem "Reference '#{$1}' without dashes"
    end

    if text =~ /build\.with\?\s+['"]-?-?with-(.*)['"]/
      problem "No double 'with': Use `build.with? '#{$1}'` to check for \"--with-#{$1}\""
    end

    if text =~ /build\.without\?\s+['"]-?-?without-(.*)['"]/
      problem "No double 'without': Use `build.without? '#{$1}'` to check for \"--without-#{$1}\""
    end

    if text =~ /ARGV\.(?!(debug\?|verbose\?|find[\(\s]))/
      problem "Use build instead of ARGV to check options"
    end

    if text =~ /def options/
      problem "Use new-style option definitions"
    end

    if text =~ /MACOS_VERSION/
      problem "Use MacOS.version instead of MACOS_VERSION"
    end

    cats = %w{leopard snow_leopard lion mountain_lion}.join("|")
    if text =~ /MacOS\.(?:#{cats})\?/
      problem "\"#{$&}\" is deprecated, use a comparison to MacOS.version instead"
    end

    if text =~ /skip_clean\s+:all/
      problem "`skip_clean :all` is deprecated; brew no longer strips symbols"
    end

    if text =~ /depends_on [A-Z][\w:]+\.new$/
      problem "`depends_on` can take requirement classes instead of instances"
    end

    if text =~ /^def (\w+).*$/
      problem "Define method #{$1.inspect} in the class body, not at the top-level"
    end
  end

  def audit_python
    if text =~ /system\(?\s*['"]python/
      # Todo: In `def test` it is okay to do it this way. It's even recommended!
      problem "Instead of `system 'python', ...`, call `system python, ...`."
    end

    if text =~ /system\(?\s*python\.binary/
      problem "Instead of `system python.binary, ...`, call `system python, ...`."
    end

    if text =~ /(def\s*)?which_python/
      problem "Replace `which_python` by `python.xy`, which returns e.g. 'python2.7'."
    end

    if text =~ /which\(?["']python/
      problem "Don't locate python with `which 'python'`, use `python.binary` instead"
    end

    if f.requirements.any?{ |r| r.kind_of?(PythonInstalled) }
      # Don't check this for all formulae, because some are allowed to set the
      # PYTHONPATH. E.g. python.rb itself needs to set it.
      if text =~ /ENV\.append.*PYTHONPATH/ || text =~ /ENV\[['"]PYTHONPATH['"]\]\s*=[^=]/
        problem "Don't set the PYTHONPATH, instead declare `depends_on :python`."
      end
    end

    if text =~ /(\s*)def\s+caveats((.*\n)*?)(\1end)/ || /(\s*)def\s+caveats;(.*?)end/
      caveats_body = $2
        if caveats_body =~ /(python[23]?)\.(.*\w)/
          # So if in the body of caveats there is a `python.whatever` called,
          # check that there is a guard like `if python` or similiar:
          python = $1
          method = $2
          unless caveats_body =~ /(if python[23]?)|(if build\.with\?\s?\(?['"]python)|(unless build.without\?\s?\(?['"]python)/
          problem "Please guard `#{python}.#{method}` like so `#{python}.#{method} if #{python}`"
        end
      end
    end

    # Todo:
    # The python do ... end block is possibly executed twice. Once for
    # python 2.x and once for 3.x. So if a `system 'make'` is called, a
    # `system 'make clean'` should also be called at the end of the block.

  end

  def audit
    audit_file
    audit_specs
    audit_urls
    audit_deps
    audit_conflicts
    audit_patches
    audit_text
    audit_python
  end

  private

  def problem p
    @problems << p
  end
end