#:  * `bump-formula-pr` [`--devel`] [`--dry-run` [`--write`]] [`--audit`|`--strict`] [`--mirror=`<URL>] [`--version=`<version>] [`--message=`<message>] (`--url=`<URL> `--sha256=`<sha-256>|`--tag=`<tag> `--revision=`<revision>) <formula>:
#:    Creates a pull request to update the formula with a new URL or a new tag.
#:
#:    If a <URL> is specified, the <sha-256> checksum of the new download must
#:    also be specified. A best effort to determine the <sha-256> and <formula>
#:    name will be made if either or both values are not supplied by the user.
#:
#:    If a <tag> is specified, the git commit <revision> corresponding to that
#:    tag must also be specified.
#:
#:    If `--devel` is passed, bump the development rather than stable version.
#:    The development spec must already exist.
#:
#:    If `--dry-run` is passed, print what would be done rather than doing it.
#:
#:    If `--write` is passed along with `--dry-run`, perform a not-so-dry run
#:    making the expected file modifications but not taking any git actions.
#:
#:    If `--audit` is passed, run `brew audit` before opening the PR.
#:
#:    If `--strict` is passed, run `brew audit --strict` before opening the PR.
#:
#:    If `--mirror=`<URL> is passed, use the value as a mirror URL.
#:
#:    If `--version=`<version> is passed, use the value to override the value
#:    parsed from the URL or tag. Note that `--version=0` can be used to delete
#:    an existing `version` override from a formula if it has become redundant.
#:
#:    If `--message=`<message> is passed, append <message> to the default PR
#:    message.
#:
#:    If `--no-browse` is passed, don't pass the `--browse` argument to `hub`
#:    which opens the pull request URL in a browser. Instead, output it to the
#:    command line.
#:
#:    If `--quiet` is passed, don't output replacement messages or warn about
#:    duplicate pull requests.
#:
#:    Note that this command cannot be used to transition a formula from a
#:    URL-and-sha256 style specification into a tag-and-revision style
#:    specification, nor vice versa. It must use whichever style specification
#:    the preexisting formula already uses.

require "formula"
require "cli_parser"

module Homebrew
  module_function

  def bump_formula_pr
    Homebrew::CLI::Parser.parse do
      switch    "--devel"
      switch    "-n", "--dry-run"
      switch    "--write"
      switch    "--audit"
      switch    "--strict"
      switch    "--no-browse"
      switch    :quiet
      switch    :force
      switch    :verbose
      switch    :debug

      flag      "--url="
      flag      "--revision="
      flag      "--tag=",         required_for: "--revision="
      flag      "--sha256=",      depends_on: "--url="
      flag      "--mirror="
      flag      "--version="
      flag      "--message="

      conflicts "--url", "--tag"
    end

    # As this command is simplifying user run commands then let's just use a
    # user path, too.
    ENV["PATH"] = ENV["HOMEBREW_PATH"]

    # Use the user's browser, too.
    ENV["BROWSER"] = ENV["HOMEBREW_BROWSER"]

    # Setup GitHub environment variables
    %w[GITHUB_USER GITHUB_PASSWORD GITHUB_TOKEN].each do |env|
      homebrew_env = ENV["HOMEBREW_#{env}"]
      next unless homebrew_env
      next if homebrew_env.empty?
      ENV[env] = homebrew_env
    end

    formula = ARGV.formulae.first

    if formula
      check_for_duplicate_pull_requests(formula)
      checked_for_duplicates = true
    end

    new_url = args.url
    if new_url && !formula
      # Split the new URL on / and find any formulae that have the same URL
      # except for the last component, but don't try to match any more than the
      # first five components since sometimes the last component isn't the only
      # one to change.
      new_url_split = new_url.split("/")
      maximum_url_components_to_match = 5
      components_to_match = [new_url_split.count - 1, maximum_url_components_to_match].min
      base_url = new_url_split.first(components_to_match).join("/")
      base_url = /#{Regexp.escape(base_url)}/
      is_devel = args.devel?
      guesses = []
      Formula.each do |f|
        if is_devel && f.devel && f.devel.url && f.devel.url.match(base_url)
          guesses << f
        elsif f.stable&.url && f.stable.url.match(base_url)
          guesses << f
        end
      end
      if guesses.count == 1
        formula = guesses.shift
      elsif guesses.count > 1
        odie "Couldn't guess formula for sure: could be one of these:\n#{guesses}"
      end
    end
    odie "No formula found!" unless formula

    check_for_duplicate_pull_requests(formula) unless checked_for_duplicates

    requested_spec, formula_spec = if args.devel?
      devel_message = " (devel)"
      [:devel, formula.devel]
    else
      [:stable, formula.stable]
    end
    odie "#{formula}: no #{requested_spec} specification found!" unless formula_spec

    hash_type, old_hash = if (checksum = formula_spec.checksum)
      [checksum.hash_type, checksum.hexdigest]
    end

    new_hash = args[hash_type] if hash_type
    new_tag = args.tag
    new_revision = args.revision
    new_mirror = args.mirror
    forced_version = args.version
    new_url_hash = if new_url && new_hash
      true
    elsif new_tag && new_revision
      false
    elsif !hash_type
      odie "#{formula}: no --tag=/--revision= arguments specified!"
    elsif !new_url
      odie "#{formula}: no --url= argument specified!"
    else
      new_mirror ||= case new_url
      when requested_spec != :devel && %r{.*ftp.gnu.org/gnu.*}
        new_url.sub "ftp.gnu.org/gnu", "ftpmirror.gnu.org"
      when %r{.*mirrors.ocf.berkeley.edu/debian.*}
        new_url.sub "mirrors.ocf.berkeley.edu/debian", "mirrorservice.org/sites/ftp.debian.org/debian"
      end
      resource = Resource.new { @url = new_url }
      resource.download_strategy = DownloadStrategyDetector.detect_from_url(new_url)
      resource.owner = Resource.new(formula.name)
      resource.version = forced_version if forced_version
      odie "No --version= argument specified!" unless resource.version
      resource_path = resource.fetch
      tar_file_extensions = %w[.tar .tb2 .tbz .tbz2 .tgz .tlz .txz .tZ]
      if tar_file_extensions.any? { |extension| new_url.include? extension }
        gnu_tar_gtar_path = HOMEBREW_PREFIX/"opt/gnu-tar/bin/gtar"
        gnu_tar_gtar = gnu_tar_gtar_path if gnu_tar_gtar_path.executable?
        tar = which("gtar") || gnu_tar_gtar || which("tar")
        if Utils.popen_read(tar, "-tf", resource_path) =~ %r{/.*\.}
          new_hash = resource_path.sha256
        else
          odie "#{resource_path} is not a valid tar file!"
        end
      else
        new_hash = resource_path.sha256
      end
    end

    if args.dry_run?
      ohai "brew update"
    else
      safe_system "brew", "update"
    end

    old_formula_version = formula_version(formula, requested_spec)

    replacement_pairs = []
    if requested_spec == :stable && formula.revision.nonzero?
      replacement_pairs << [/^  revision \d+\n(\n(  head "))?/m, "\\2"]
    end

    replacement_pairs += formula_spec.mirrors.map do |mirror|
      [/ +mirror \"#{Regexp.escape(mirror)}\"\n/m, ""]
    end

    replacement_pairs += if new_url_hash
      [
        [/#{Regexp.escape(formula_spec.url)}/, new_url],
        [old_hash, new_hash],
      ]
    else
      [
        [formula_spec.specs[:tag], new_tag],
        [formula_spec.specs[:revision], new_revision],
      ]
    end

    backup_file = File.read(formula.path) unless args.dry_run?

    if new_mirror
      replacement_pairs << [/^( +)(url \"#{Regexp.escape(new_url)}\"\n)/m, "\\1\\2\\1mirror \"#{new_mirror}\"\n"]
    end

    if forced_version && forced_version != "0"
      if requested_spec == :stable
        if File.read(formula.path).include?("version \"#{old_formula_version}\"")
          replacement_pairs << [old_formula_version.to_s, forced_version]
        elsif new_mirror
          replacement_pairs << [/^( +)(mirror \"#{new_mirror}\"\n)/m, "\\1\\2\\1version \"#{forced_version}\"\n"]
        else
          replacement_pairs << [/^( +)(url \"#{new_url}\"\n)/m, "\\1\\2\\1version \"#{forced_version}\"\n"]
        end
      elsif requested_spec == :devel
        replacement_pairs << [/(  devel do.+?version \")#{old_formula_version}(\"\n.+?end\n)/m, "\\1#{forced_version}\\2"]
      end
    elsif forced_version && forced_version == "0"
      if requested_spec == :stable
        replacement_pairs << [/^  version \"[\w\.\-\+]+\"\n/m, ""]
      elsif requested_spec == :devel
        replacement_pairs << [/(  devel do.+?)^ +version \"[^\n]+\"\n(.+?end\n)/m, "\\1\\2"]
      end
    end
    new_contents = inreplace_pairs(formula.path, replacement_pairs)

    new_formula_version = formula_version(formula, requested_spec, new_contents)

    if new_formula_version < old_formula_version
      formula.path.atomic_write(backup_file) unless args.dry_run?
      odie <<~EOS
        You probably need to bump this formula manually since changing the
        version from #{old_formula_version} to #{new_formula_version} would be a downgrade.
      EOS
    elsif new_formula_version == old_formula_version
      formula.path.atomic_write(backup_file) unless args.dry_run?
      odie <<~EOS
        You probably need to bump this formula manually since the new version
        and old version are both #{new_formula_version}.
      EOS
    end

    if args.dry_run?
      if args.strict?
        ohai "brew audit --strict #{formula.path.basename}"
      elsif args.audit?
        ohai "brew audit #{formula.path.basename}"
      end
    else
      failed_audit = false
      if args.strict?
        system HOMEBREW_BREW_FILE, "audit", "--strict", formula.path
        failed_audit = !$CHILD_STATUS.success?
      elsif args.audit?
        system HOMEBREW_BREW_FILE, "audit", formula.path
        failed_audit = !$CHILD_STATUS.success?
      end
      if failed_audit
        formula.path.atomic_write(backup_file)
        odie "brew audit failed!"
      end
    end

    formula.path.parent.cd do
      branch = "#{formula.name}-#{new_formula_version}"
      git_dir = Utils.popen_read("git rev-parse --git-dir").chomp
      shallow = !git_dir.empty? && File.exist?("#{git_dir}/shallow")

      if args.dry_run?
        ohai "fork repository with GitHub API"
        ohai "git fetch --unshallow origin" if shallow
        ohai "git checkout --no-track -b #{branch} origin/master"
        ohai "git commit --no-edit --verbose --message='#{formula.name} #{new_formula_version}#{devel_message}' -- #{formula.path}"
        ohai "git push --set-upstream $HUB_REMOTE #{branch}:#{branch}"
        ohai "create pull request with GitHub API"
        ohai "git checkout -"
      else

        begin
          response = GitHub.create_fork(formula.tap.full_name)
          # GitHub API responds immediately but fork takes a few seconds to be ready.
          sleep 3
        rescue *GitHub.api_errors => e
          formula.path.atomic_write(backup_file) unless args.dry_run?
          odie "Unable to fork: #{e.message}!"
        end

        remote_url = response.fetch("clone_url")
        username = response.fetch("owner").fetch("login")

        safe_system "git", "fetch", "--unshallow", "origin" if shallow
        safe_system "git", "checkout", "--no-track", "-b", branch, "origin/master"
        safe_system "git", "commit", "--no-edit", "--verbose",
          "--message=#{formula.name} #{new_formula_version}#{devel_message}",
          "--", formula.path
        safe_system "git", "push", "--set-upstream", remote_url, "#{branch}:#{branch}"
        safe_system "git", "checkout", "--quiet", "-"
        pr_message = <<~EOS
          Created with `brew bump-formula-pr`.
        EOS
        user_message = args.message
        if user_message
          pr_message += "\n" + <<~EOS
            ---

            #{user_message}
          EOS
        end
        pr_title = "#{formula.name} #{new_formula_version}#{devel_message}"

        begin
          url = GitHub.create_pull_request(formula.tap.full_name, pr_title,
                                           "#{username}:#{branch}", "master", pr_message)["html_url"]
          if args.no_browse?
            puts url
          else
            exec_browser url
          end
        rescue *GitHub.api_errors => e
          odie "Unable to open pull request: #{e.message}!"
        end
      end
    end
  end

  def inreplace_pairs(path, replacement_pairs)
    if args.dry_run?
      contents = path.open("r") { |f| Formulary.ensure_utf8_encoding(f).read }
      contents.extend(StringInreplaceExtension)
      replacement_pairs.each do |old, new|
        unless Homebrew.args.quiet?
          ohai "replace #{old.inspect} with #{new.inspect}"
        end
        unless old
          raise "No old value for new value #{new}! Did you pass the wrong arguments?"
        end
        contents.gsub!(old, new)
      end
      unless contents.errors.empty?
        raise Utils::InreplaceError, path => contents.errors
      end
      path.atomic_write(contents) if args.write?
      contents
    else
      Utils::Inreplace.inreplace(path) do |s|
        replacement_pairs.each do |old, new|
          unless Homebrew.args.quiet?
            ohai "replace #{old.inspect} with #{new.inspect}"
          end
          unless old
            raise "No old value for new value #{new}! Did you pass the wrong arguments?"
          end
          s.gsub!(old, new)
        end
      end
      path.open("r") { |f| Formulary.ensure_utf8_encoding(f).read }
    end
  end

  def formula_version(formula, spec, contents = nil)
    name = formula.name
    path = formula.path
    if contents
      Formulary.from_contents(name, path, contents, spec).version
    else
      Formulary::FormulaLoader.new(name, path).get_formula(spec).version
    end
  end

  def fetch_pull_requests(formula)
    GitHub.issues_for_formula(formula.name, tap: formula.tap).select do |pr|
      pr["html_url"].include?("/pull/") &&
        /(^|\s)#{Regexp.quote(formula.name)}(:|\s|$)/i =~ pr["title"]
    end
  rescue GitHub::RateLimitExceededError => e
    opoo e.message
    []
  end

  def check_for_duplicate_pull_requests(formula)
    pull_requests = fetch_pull_requests(formula)
    return unless pull_requests
    return if pull_requests.empty?
    duplicates_message = <<~EOS
      These open pull requests may be duplicates:
      #{pull_requests.map { |pr| "#{pr["title"]} #{pr["html_url"]}" }.join("\n")}
    EOS
    error_message = "Duplicate PRs should not be opened. Use --force to override this error."
    if Homebrew.args.force? && !Homebrew.args.quiet?
      opoo duplicates_message
    elsif !Homebrew.args.force? && Homebrew.args.quiet?
      odie error_message
    elsif !Homebrew.args.force?
      odie <<~EOS
        #{duplicates_message.chomp}
        #{error_message}
      EOS
    end
  end
end