Add brew font-casker command

cmd/font-casker.rb

@@ -0,0 +1,143 @@
+# frozen_string_literal: true
+
+require "cli/parser"
+require "open3"
+require "digest"
+
+module Homebrew
+  module_function
+
+  sig { returns(CLI::Parser) }
+  def font_casker_args
+    Homebrew::CLI::Parser.new do
+      usage_banner <<~EOS
+        `font-casker` <archive_path>
+
+        Generates cask stanzas from OTF/TTF files within <archive_path>.
+      EOS
+
+      named_args :archive_path, min: 1, max: 1
+
+      hide_from_man_page!
+    end
+  end
+
+  FONT_EXT_PATTERN = /.(otf|ttf)\Z/i
+
+  FONT_WEIGHTS = [
+    /black/i,
+    /bold/i,
+    /book/i,
+    /hairline/i,
+    /heavy/i,
+    /light/i,
+    /medium/i,
+    /normal/i,
+    /regular/i,
+    /roman/i,
+    /thin/i,
+    /ultra/i,
+  ].freeze
+
+  FONT_STYLES = [
+    /italic/i,
+    /oblique/i,
+    /roman/i,
+    /slanted/i,
+    /upright/i,
+  ].freeze
+
+  FONT_WIDTHS = [
+    /compressed/i,
+    /condensed/i,
+    /extended/i,
+    /narrow/i,
+    /wide/i,
+  ].freeze
+
+  def mce(enum)
+    enum.group_by(&:itself).values.max_by(&:size).first
+  end
+
+  def eval_bin_cmd(cmd, blob)
+    IO.popen(cmd, "r+b") do |io|
+      io.print(blob)
+      io.close_write
+      io.read
+    end
+  end
+
+  def font_paths(archive)
+    cmd = ["zipinfo", "-1", archive]
+
+    IO.popen(cmd, "r", &:read)
+      .chomp.split("\n")
+      .grep(FONT_EXT_PATTERN)
+      .reject { |x| x.start_with?("__MACOSX") }
+      .grep_v(%r{(?:\A|/)\._})
+      .sort
+  end
+
+  def font_blobs(archive, paths)
+    paths.map { |x| IO.popen(["unzip", "-p", archive, x], "rb", &:read) }
+  end
+
+  def stanzify(stanza_name, val = "")
+    if val.respond_to?(:map)
+      val.map { |x| "  #{stanza_name} \"#{x}\"" }.join("\n")
+    else
+      "  #{stanza_name} \"#{val}\""
+    end
+  end
+
+  def caskify(family, version, sha, paths)
+    output = ["FAMILY: #{family}"]
+    output << ""
+    output << "cask 'FIXME' do"
+    output << stanzify("version", version)
+    output << stanzify("sha256", sha)
+    output << ""
+    output << stanzify("url", "")
+    output << stanzify("name", "")
+    output << stanzify("homepage", "")
+    output << ""
+    output << stanzify("font", paths)
+    output << ""
+    output << "  # No zap stanza required"
+    output << "end"
+    output.join("\n")
+  end
+
+  def shasum(archive)
+    Digest::SHA256.file(archive)
+  end
+
+  def font_version(fontblobs)
+    cmd = ["otfinfo", "-v"]
+    versions = fontblobs.map { |x| eval_bin_cmd(cmd, x) }
+                        .map { |x| (m = /\A(?:Version\s+)?(\d[^\s,;]*)/i.match(x)) ? m[1] : x.delete("\n") }
+    mce(versions)
+  end
+
+  def font_family(fontblobs)
+    cmd = ["otfinfo", "-a"]
+    families = fontblobs.map { |x| eval_bin_cmd(cmd, x) }
+                        .map { |x| x.delete("\n") }
+    mce(families)
+  end
+
+  def font_casker
+    args = font_casker_args.parse
+    archive_path = args.named.first
+
+    paths = font_paths(archive_path)
+    blobs = font_blobs(archive_path, paths)
+
+    puts caskify(
+      font_family(blobs),
+      font_version(blobs),
+      shasum(archive_path),
+      paths,
+    )
+  end
+end