#!/usr/bin/env ruby
# frozen_string_literal: true

require 'uri'
require 'net/http'
require 'openssl'
require 'rubygems/version'
require 'fspath'

CONFIG = {
  advancecomp: {
    url: 'https://github.com/amadvance/advancecomp/releases.atom',
    regexp: %r{<id>tag:github.com,2008:Repository/\d+/\D+?(\d+(?:\.\d+)*)</id>},
    info_url: 'http://www.advancemame.it/comp-history',
  },
  gifsicle: {
    url: 'https://www.lcdf.org/gifsicle/',
    regexp: /gifsicle-(\d+(?:\.\d+)*)\.tar\.gz/,
    info_url: 'https://www.lcdf.org/gifsicle/changes.html',
  },
  jhead: {
    url: 'https://www.sentex.ca/~mwandel/jhead/',
    regexp: /jhead-(\d+(?:\.\d+)*)/,
    info_url: 'https://www.sentex.ca/~mwandel/jhead/changes.txt',
  },
  jpegoptim: {
    url: 'https://github.com/tjko/jpegoptim/tags.atom',
    regexp: %r{<id>tag:github.com,2008:Repository/\d+/\D+?(\d+(?:\.\d+)*)</id>},
    info_url: 'https://github.com/tjko/jpegoptim/#readme',
  },
  jpegarchive: {
    url: 'https://github.com/danielgtaylor/jpeg-archive/releases.atom',
    regexp: %r{<id>tag:github.com,2008:Repository/\d+/\D+?(\d+(?:\.\d+)*)</id>},
    info_url: 'https://github.com/danielgtaylor/jpeg-archive/releases',
  },
  libjpeg: {
    url: 'https://www.ijg.org/files/',
    regexp: /jpegsrc.v(.*?).tar.gz/,
    info_url: 'https://jpegclub.org/reference/reference-sources/#:~:text=CHANGE%20LOG',
  },
  liblcms: {
    url: 'https://sourceforge.net/projects/lcms/rss?path=/lcms',
    regexp: %r{/lcms/(\d+(?:\.\d+)*)/},
    info_url: 'https://www.littlecms.com/blog/',
  },
  libmozjpeg: {
    url: 'https://github.com/mozilla/mozjpeg/releases.atom',
    regexp: %r{<id>tag:github.com,2008:Repository/\d+/\D+?(\d+(?:\.\d+)*)</id>},
    info_url: 'https://github.com/mozilla/mozjpeg/releases',
  },
  libpng: {
    url: 'https://sourceforge.net/projects/libpng/rss?path=/libpng16',
    regexp: %r{/libpng\d*/(\d+(?:\.\d+)*)/},
    info_url: 'https://github.com/glennrp/libpng/blob/libpng16/CHANGES#:~:text=Send%20comments/corrections/commendations%20to%20png%2Dmng%2Dimplement%20at%20lists.sf.net.',
  },
  libz: {
    url: 'https://sourceforge.net/projects/libpng/rss?path=/zlib',
    regexp: %r{/zlib/(\d+(?:\.\d+)*)/},
    info_url: 'https://github.com/glennrp/zlib/blob/master/ChangeLog',
  },
  optipng: {
    url: 'https://sourceforge.net/projects/optipng/rss',
    regexp: %r{/OptiPNG/optipng-(\d+(?:\.\d+)*)/},
    info_url: 'https://optipng.sourceforge.net/history.txt',
  },
  oxipng: {
    url: 'https://github.com/shssoichiro/oxipng/releases.atom',
    regexp: %r{<id>tag:github.com,2008:Repository/\d+/v(\d+(?:\.\d+)*)</id>},
    info_url: 'https://github.com/shssoichiro/oxipng/releases',
  },
  pngcrush: {
    url: 'https://sourceforge.net/projects/pmt/rss?path=/pngcrush',
    regexp: %r{/pngcrush/(\d+(?:\.\d+)*)/},
    info_url: 'https://pmt.sourceforge.io/pngcrush/ChangeLog.html',
  },
  pngout: {
    url: 'http://www.jonof.id.au/kenutils.html',
    regexp: %r{/files/kenutils/pngout-(\d{8})-linux.tar.gz},
    info_url: 'http://www.jonof.id.au/kenutils.html#:~:text=Revision%20history',
  },
  pngquant: {
    url: 'https://pngquant.org/releases.html',
    regexp: %r{<span itemprop='version'>(\d+(?:\.\d+)*)</span>},
  },
}.freeze

# Fetch and compare latest tool/library versions
class Livecheck
  # Commands
  class Cli
    VERSION_REGEXP = /^([A-Z]+)_VER *:= *(.*)$/.freeze

    def initialize(args)
      @update = args.delete('--update')
      abort '--update is the only supported option' unless args.empty?
    end

    def run
      dump_changes

      return unless livechecks.any?(&:changed?)

      exit 1 unless @update

      update_changelog
      update_makefile
    rescue StandardError => e
      warn e
      exit 2
    end

  private

    def dump_changes
      livechecks.each do |lc|
        next unless lc.changed?

        puts "#{lc.name_n_latest_version} (current: #{lc.current_version}) #{lc.info_url}"
      end
    end

    def update_changelog
      changelog = FSPath('CHANGELOG.markdown')
      lines = changelog.readlines
      lines.insert(4, "\n") if lines[4] =~ /^## /
      lines.insert(4, changelog_entry)
      write(changelog, lines.join(''))
    end

    def update_makefile
      content = makefile.read.gsub(VERSION_REGEXP) do
        livecheck = livechecks_by_name[Regexp.last_match[1].downcase]
        "#{livecheck.name.upcase}_VER := #{livecheck.latest_version}"
      end
      write(makefile, content)
    end

    def makefile
      FSPath('Makefile')
    end

    def livechecks
      @livechecks ||= makefile.read.scan(VERSION_REGEXP).map do |name, version|
        Livecheck.new(name.downcase, version)
      end
    end

    def livechecks_by_name
      @livechecks_by_name ||= Hash[livechecks.map{ |lc| [lc.name, lc] }]
    end

    def changelog_entry
      github_user = `git config github.user`.strip
      changed = livechecks.select(&:changed?)
      "* #{to_sentence(changed.map(&:name_n_latest_version))} [@#{github_user}](https://github.com/#{github_user})\n"
    end

    def to_sentence(array)
      case array.length
      when 0 then ''
      when 1 then array[0].to_s
      else "#{array[0...-1].join(', ')} and #{array[-1]}"
      end
    end

    def write(path, data)
      path.temp_file(path.dirname) do |io|
        io.write data
        mode = path.exist? ? path.stat.mode : (~File.umask & 0o777)
        io.path.rename(path)
        path.chmod(mode)
      end
      warn "Wrote #{path}"
    end
  end

  # Compare versions including libjpeg ones (9b <=> 9)
  class Version
    include Comparable

    attr_reader :string, :parsed
    alias_method :to_s, :string

    def initialize(string)
      @string = string
      @parsed = begin
        Gem::Version.new(string)
      rescue ArgumentError
        nil
      end
    end

    def <=>(other)
      if parsed && other.parsed
        parsed <=> other.parsed
      else
        string <=> other.string
      end
    end
  end

  attr_reader :name, :current_version

  def initialize(name, current_version)
    @name = name
    @current_version = Version.new(current_version)
    @fetcher = Thread.new{ fetch_versions.last }
  end

  def latest_version
    @fetcher.value
  end

  def changed?
    latest_version != current_version
  end

  def name_n_latest_version
    "#{name} #{latest_version}"
  end

  def info_url
    config[:info_url]
  end

private

  def config
    CONFIG[name.to_sym] || fail(ArgumentError, "Livecheck for #{name} not defined")
  end

  def get(url)
    uri = URI(url)
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = (uri.scheme == 'https')
    http.request_get(uri.request_uri).body
  end

  def fetch_versions
    body = get(config[:url])

    version_regex = config[:regexp]

    versions = body.scan(version_regex).map{ |match| Version.new(*match) }.sort
    fail "No versions found for #{name} in body:\n#{body}" if versions.empty?

    versions
  end
end

Livecheck::Cli.new(ARGV).run