# frozen_string_literal: true

require "download_strategy"
require "cli/parser"
require "utils/github"
require "tmpdir"
require "bintray"

module Homebrew
  module_function

  def pr_pull_args
    Homebrew::CLI::Parser.new do
      usage_banner <<~EOS
        `pr-pull` [<options>] <pull_request> [<pull_request> ...]

        Download and publish bottles, and apply the bottle commit from a
        pull request with artifacts generated by GitHub Actions.
        Requires write access to the repository.
      EOS
      switch "--no-publish",
             description: "Download the bottles, apply the bottle commit and "\
                          "upload the bottles to Bintray, but don't publish them."
      switch "--no-upload",
             description: "Download the bottles and apply the bottle commit, "\
                          "but don't upload to Bintray."
      switch "-n", "--dry-run",
             description: "Print what would be done rather than doing it."
      switch "--clean",
             description: "Do not amend the commits from pull requests."
      switch "--branch-okay",
             description: "Do not warn if pulling to a branch besides master (useful for testing)."
      switch "--resolve",
             description: "When a patch fails to apply, leave in progress and allow user to resolve, "\
                          "instead of aborting."
      flag   "--workflow=",
             description: "Retrieve artifacts from the specified workflow (default: tests.yml)."
      flag   "--artifact=",
             description: "Download artifacts with the specified name (default: bottles)."
      flag   "--bintray-org=",
             description: "Upload to the specified Bintray organisation (default: homebrew)."
      flag   "--tap=",
             description: "Target tap repository (default: homebrew/core)."
      switch :verbose
      switch :debug
      min_named 1
    end
  end

  def setup_git_environment!
    # Passthrough Git environment variables
    ENV["GIT_COMMITTER_NAME"] = ENV["HOMEBREW_GIT_NAME"] if ENV["HOMEBREW_GIT_NAME"]
    ENV["GIT_COMMITTER_EMAIL"] = ENV["HOMEBREW_GIT_EMAIL"] if ENV["HOMEBREW_GIT_EMAIL"]

    # Depending on user configuration, git may try to invoke gpg.
    return unless Utils.popen_read("git config --get --bool commit.gpgsign").chomp == "true"

    begin
      gnupg = Formula["gnupg"]
    rescue FormulaUnavailableError
      nil
    else
      if gnupg.any_version_installed?
        path = PATH.new(ENV.fetch("PATH"))
        path.prepend(gnupg.installed_prefix/"bin")
        ENV["PATH"] = path
      end
    end
  end

  def signoff!(pr, path: ".")
    message = Utils.popen_read "git", "-C", path, "log", "-1", "--pretty=%B"
    subject = message.lines.first.strip

    # Skip the subject and separate lines that look like trailers (e.g. "Co-authored-by")
    # from lines that look like regular body text.
    trailers, body = message.lines.drop(1).partition { |s| s.match?(/^[a-z-]+-by:/i) }
    trailers = trailers.uniq.join.strip
    body = body.join.strip.gsub(/\n{3,}/, "\n\n")

    close_message = "Closes ##{pr}."
    body += "\n\n#{close_message}" unless body.include? close_message
    new_message = [subject, body, trailers].join("\n\n").strip

    if Homebrew.args.dry_run?
      puts "git commit --amend --signoff -m $message"
    else
      safe_system "git", "-C", path, "commit", "--amend", "--signoff", "--allow-empty", "-q", "-m", new_message
    end
  end

  def cherry_pick_pr!(pr, path: ".")
    if Homebrew.args.dry_run?
      puts <<~EOS
        git fetch --force origin +refs/pull/#{pr}/head
        git merge-base HEAD FETCH_HEAD
        git cherry-pick --ff --allow-empty $merge_base..FETCH_HEAD
      EOS
    else
      safe_system "git", "-C", path, "fetch", "--quiet", "--force", "origin", "+refs/pull/#{pr}/head"
      merge_base = Utils.popen_read("git", "-C", path, "merge-base", "HEAD", "FETCH_HEAD").strip
      commit_count = Utils.popen_read("git", "-C", path, "rev-list", "#{merge_base}..FETCH_HEAD").lines.count

      # git cherry-pick unfortunately has no quiet option
      ohai "Cherry-picking #{commit_count} commit#{"s" unless commit_count == 1} from ##{pr}"
      cherry_pick_args = "git", "-C", path, "cherry-pick", "--ff", "--allow-empty", "#{merge_base}..FETCH_HEAD"
      result = Homebrew.args.verbose? ? system(*cherry_pick_args) : quiet_system(*cherry_pick_args)

      unless result
        if Homebrew.args.resolve?
          odie "Cherry-pick failed: try to resolve it."
        else
          system "git", "-C", path, "cherry-pick", "--abort"
          odie "Cherry-pick failed!"
        end
      end
    end
  end

  def check_branch(path, ref)
    branch = Utils.popen_read("git", "-C", path, "symbolic-ref", "--short", "HEAD").strip

    return if branch == ref || args.clean? || args.branch_okay?

    opoo "Current branch is #{branch}: do you need to pull inside #{ref}?"
  end

  def formulae_need_bottles?(tap, original_commit)
    return if Homebrew.args.dry_run?

    if Homebrew::EnvConfig.disable_load_formula?
      opoo "Can't check if updated bottles are necessary as formula loading is disabled!"
      return
    end

    Utils.popen_read("git", "-C", tap.path, "diff-tree",
                     "-r", "--name-only", "--diff-filter=AM",
                     original_commit, "HEAD", "--", tap.formula_dir)
         .lines.each do |line|
      next unless line.end_with? ".rb\n"

      name = "#{tap.name}/#{File.basename(line.chomp, ".rb")}"
      begin
        f = Formula[name]
      rescue Exception # rubocop:disable Lint/RescueException
        # Make sure we catch syntax errors.
        next
      end
      return true if !f.bottle_unneeded? && !f.bottle_disabled?
    end
    nil
  end

  def download_artifact(url, dir, pr)
    token, username = GitHub.api_credentials
    case GitHub.api_credentials_type
    when :env_username_password, :keychain_username_password
      curl_args = ["--user", "#{username}:#{token}"]
    when :env_token
      curl_args = ["--header", "Authorization: token #{token}"]
    when :none
      raise Error, "Credentials must be set to access the Artifacts API"
    end

    # Download the artifact as a zip file and unpack it into `dir`. This is
    # preferred over system `curl` and `tar` as this leverages the Homebrew
    # cache to avoid repeated downloads of (possibly large) bottles.
    FileUtils.chdir dir do
      downloader = GitHubArtifactDownloadStrategy.new(url, "artifact", pr, curl_args: curl_args, secrets: [token])
      downloader.fetch
      downloader.stage
    end
  end

  def pr_pull
    pr_pull_args.parse

    bintray_user = ENV["HOMEBREW_BINTRAY_USER"]
    bintray_key = ENV["HOMEBREW_BINTRAY_KEY"]
    bintray_org = args.bintray_org || "homebrew"

    if bintray_user.blank? || bintray_key.blank?
      odie "Missing HOMEBREW_BINTRAY_USER or HOMEBREW_BINTRAY_KEY variables!" if !args.dry_run? && !args.no_upload?
    else
      bintray = Bintray.new(user: bintray_user, key: bintray_key, org: bintray_org)
    end

    workflow = args.workflow || "tests.yml"
    artifact = args.artifact || "bottles"
    tap = Tap.fetch(args.tap || CoreTap.instance.name)

    setup_git_environment!

    args.named.uniq.each do |arg|
      arg = "#{tap.default_remote}/pull/#{arg}" if arg.to_i.positive?
      url_match = arg.match HOMEBREW_PULL_OR_COMMIT_URL_REGEX
      _, user, repo, pr = *url_match
      odie "Not a GitHub pull request: #{arg}" unless pr

      check_branch tap.path, "master"

      ohai "Fetching #{tap} pull request ##{pr}"
      Dir.mktmpdir pr do |dir|
        cd dir do
          original_commit = Utils.popen_read("git", "-C", tap.path, "rev-parse", "HEAD").chomp
          cherry_pick_pr! pr, path: tap.path
          signoff! pr, path: tap.path unless args.clean?

          unless formulae_need_bottles? tap, original_commit
            ohai "Skipping artifacts for ##{pr} as the formulae don't need bottles"
            next
          end

          url = GitHub.get_artifact_url(user, repo, pr, workflow_id: workflow, artifact_name: artifact)
          download_artifact(url, dir, pr)

          json_files = Dir["*.json"]

          if Homebrew.args.dry_run?
            puts "brew bottle --merge --write #{json_files.join " "}"
          else
            quiet_system "#{HOMEBREW_PREFIX}/bin/brew", "bottle", "--merge", "--write", *json_files
          end

          next if args.no_upload?

          if Homebrew.args.dry_run?
            puts "Upload bottles described by these JSON files to Bintray:\n  #{json_files.join("\n  ")}"
          else
            bintray.upload_bottle_json json_files, publish_package: !args.no_publish?
          end

          bottles_hash = json_files.reduce({}) do |hash, json_file|
            hash.deep_merge(JSON.parse(IO.read(json_file)))
          end

          bottles_hash.each do |formula_name, _|
            formula = Formula[formula_name]
            stable_urls = [formula.stable.url] + formula.stable.mirrors
            stable_urls.grep(%r{^https://dl.bintray.com/homebrew/mirror/}) do |mirror_url|
              if Homebrew.args.dry_run?
                puts "Mirror formulae sources described by these JSON files to Bintray:\n  #{json_files.join("\n  ")}"
                next
              end

              next if bintray.stable_mirrored?(mirror_url)

              mirror_url = bintray.mirror_formula(formula)
              ohai "Mirrored #{formula.full_name} to #{mirror_url}!"
            end
          end
        end
      end
    end
  end
end

class GitHubArtifactDownloadStrategy < AbstractFileDownloadStrategy
  def fetch
    ohai "Downloading #{url}"
    if cached_location.exist?
      puts "Already downloaded: #{cached_location}"
    else
      begin
        curl "--location", "--create-dirs", "--output", temporary_path, url,
             *meta.fetch(:curl_args, []),
             secrets: meta.fetch(:secrets, [])
      rescue ErrorDuringExecution
        raise CurlDownloadStrategyError, url
      end
      ignore_interrupts do
        cached_location.dirname.mkpath
        temporary_path.rename(cached_location)
        symlink_location.dirname.mkpath
      end
    end
    FileUtils.ln_s cached_location.relative_path_from(symlink_location.dirname), symlink_location, force: true
  end

  private

  def resolved_basename
    "artifact.zip"
  end
end