etscrivner/rbsecp256k1

# frozen_string_literal: true

require 'mini_portile2'
require 'mkmf'
require 'zip'

# Enable the recovery module by default
WITH_RECOVERY = ENV.fetch('WITH_RECOVERY', '1') == '1'

# Recipe for downloading and building libsecp256k1 as part of installation
class Secp256k1Recipe < MiniPortile
  # Hard-coded URL for libsecp256k1 zipfile (Official release v0.2.0)
  LIBSECP256K1_ZIP_URL = 'https://github.com/bitcoin-core/secp256k1/archive/refs/tags/v0.2.0.zip'

  # Expected SHA-256 of the zipfile above (computed using sha256sum)
  LIBSECP256K1_SHA256 = '6ece280c0e6ea9d861051077c28a25b7f48800c43a4098a800b7d3b0c124e406'

  def initialize
    super('libsecp256k1', '0.2.0')
    @tarball = File.join(Dir.pwd, "/ports/archives/libsecp256k1.zip")
    @files = ["file://#{@tarball}"]
    self.configure_options += [
      "--with-pic=yes"
    ]

    # ECDH is enabled by default in release v0.2.0, but recovery still needs to
    # be enabled manually.
    configure_options << "--enable-module-recovery" if WITH_RECOVERY
  end

  def configure
    # Need to run autogen.sh before configure since it creates it
    if RUBY_PLATFORM =~ /mingw|mswin/
      # Windows doesn't recognize the shebang.
      execute('autogen', %w[sh ./autogen.sh])
    else
      execute('chmod', %w[chmod +x ./autogen.sh])
      execute('autogen', %w[./autogen.sh])
    end

    super
  end

  def download
    download_file_http(LIBSECP256K1_ZIP_URL, @tarball)
    verify_file(local_path: @tarball, sha256: LIBSECP256K1_SHA256)
  end

  def downloaded?
    File.exist?(@tarball)
  end

  def extract_zip_file(file, destination)
    FileUtils.mkdir_p(destination)

    Zip::File.open(file) do |zip_file|
      zip_file.each do |f|
        fpath = File.join(destination, f.name)
        zip_file.extract(f, fpath) unless File.exist?(fpath)
      end
    end
  end

  def extract
    files_hashs.each do |file|
      extract_zip_file(file[:local_path], tmp_path)
    end
  end
end

if with_config('system-library')
  # Require that libsecp256k1 be installed using `make install` or similar.
  message("checking for libsecp256k1\n")
  results = pkg_config('libsecp256k1')
  abort "missing libsecp256k1" unless results && results[1]
else
  # Build the libsecp256k1 dependency
  recipe = Secp256k1Recipe.new
  recipe.cook
  recipe.activate

  # Need to add paths to includes and libraries for library for build
  append_cflags(
    [
      "-I#{recipe.path}/include",
      "-fPIC",
      "-Wno-undef",
      "-Wall"
    ]
  )
  append_ldflags(
    [
      "-Wl,--no-as-needed"
    ]
  )
  # rubocop:disable Style/GlobalVars
  $LIBPATH = ["#{recipe.path}/lib"] | $LIBPATH
  # rubocop:enable Style/GlobalVars

  # Also need to make sure we add the library as part of the build
  have_library("secp256k1")
  have_library("gmp")
end

# Sanity check for the basic library
have_header('secp256k1.h')

# Check if we have the libsecp256k1 recoverable signature header.
have_header('secp256k1_recovery.h') if WITH_RECOVERY

# Check if we have EC Diffie-Hellman functionality
have_header('secp256k1_ecdh.h')

# Check if we have Schnorr signatures
have_header('secp256k1_schnorrsig.h')

# Check if we have extra keys module
have_header('secp256k1_extrakeys.h')

# See: https://guides.rubygems.org/gems-with-extensions/
create_makefile('rbsecp256k1/rbsecp256k1')