require 'rubygems'
require 'rake'
require 'date'
require 'tempfile'

NODE_MODULES = File.join(File.dirname(__FILE__), 'node_modules')

#############################################################################
#
# Helper functions
#
#############################################################################

def release_branch
  ENV.fetch('RELEASE_BRANCH', 'master')
end

def date
   Time.now.strftime("%Y-%m-%d")
end

def name
  @name ||= Dir['*.gemspec'].first.split('.').first
end

def version
  line = File.read("lib/#{name}.rb")[/^\s*VERSION\s*=\s*.*/]
  line.match(/.*VERSION\s*=\s*['"](.*)['"]/)[1]
end

def latest_changes_file
  'LATEST_CHANGES.md'
end

def history_file
  'HISTORY.md'
end

# assumes x.y.z all digit version
def next_version
  # x.y.z
  v = version.split '.'
  # bump z
  v[-1] = v[-1].to_i + 1
  v.join '.'
end

def bump_version
  old_file = File.read("lib/#{name}.rb")
  old_version_line = old_file[/^\s*VERSION\s*=\s*.*/]
  new_version = next_version
  # replace first match of old version with new version
  old_file.sub!(old_version_line, "  VERSION = '#{new_version}'")

  File.write("lib/#{name}.rb", old_file)

  new_version
end

def gemspec_file
  "#{name}.gemspec"
end

def gem_file
  "#{name}-#{version}.gem"
end

def replace_header(head, header_name)
  head.sub!(/(\.#{header_name}\s*= ').*'/) { "#{$1}#{send(header_name)}'"}
end

def bundle_katex_fonts(assets_path)
  fonts_subpath = File.join('katex', 'dist', 'fonts')
  fonts_source = File.join(NODE_MODULES, fonts_subpath)
  fonts_target = File.join(assets_path, fonts_subpath)
  puts "\n  Copying KaTeX fonts from #{fonts_source} to #{fonts_target}..."
  `mkdir "#{fonts_target}"`
  `cp "#{fonts_source}"/*.woff2 "#{fonts_target}"/`
  puts "... Done."
end

#############################################################################
#
# Standard tasks
#
#############################################################################

task :default => :test

require 'rake/testtask'

namespace :test do
  Rake::TestTask.new('capybara') do |test|
    test.libs << 'lib' << 'test' << '.'
    test.pattern = 'test/integration/**/test_*.rb'
    test.verbose = true
    test.warning = false
  end
end

Rake::TestTask.new(:test) do |test|
  test.libs << 'lib' << 'test' << '.'
  test.test_files = FileList.new('test/**/test_*.rb') do |fl|
    fl.exclude('test/integration/**/test_*.rb')
  end
  test.verbose = true
  test.warning = false
end

desc "Generate RCov test coverage and open in your browser"
task :coverage do
  require 'rcov'
  sh "rm -fr coverage"
  sh "rcov test/test_*.rb"
  sh "open coverage/index.html"
end

desc "Open an irb session preloaded with this library"
task :console do
  sh "irb -rubygems -r ./lib/#{name}.rb"
end

#############################################################################
#
# Custom tasks (add your own tasks here)
#
#############################################################################

desc "Update version number and gemspec"
task :bump do
  puts "Updated version to #{bump_version}"
  # Execute does not invoke dependencies.
  # Manually invoke gemspec then validate.
  Rake::Task[:gemspec].execute
  Rake::Task[:validate].execute
end

#############################################################################
#
# Packaging tasks
#
#############################################################################

desc 'Create a release build and push to rubygems'
task :release => :build do
  branch = release_branch
  unless `git branch` =~ /^\* #{branch}$/
    puts "You must be on the #{branch} branch to release!"
    exit!
  end
  Rake::Task[:changelog].execute
  sh "git commit --allow-empty -a -m 'Release #{version}'"
  sh "git pull --rebase origin #{branch}"
  sh "git tag v#{version}"
  sh "git push origin #{branch}"
  sh "git push origin v#{version}"
  sh "gem push pkg/#{name}-#{version}.gem"
end

desc 'Publish to rubygems. Same as release'
task :publish => :release

desc 'Build gem'
task :build => :gemspec do
  sh "mkdir -p pkg"
  sh "gem build #{gemspec_file}"
  sh "mv #{gem_file} pkg"
end

desc "Build and install"
task :install => :build do
  sh "gem install --local --no-document pkg/#{name}-#{version}.gem"
end

desc 'Update gemspec'
task :gemspec => :validate do
  # read spec file and split out manifest section
  spec = File.read(gemspec_file)
  head, manifest, tail = spec.split("  # = MANIFEST =\n")

  # replace name and version
  replace_header(head, :name)
  replace_header(head, :version)

  # determine file list from git ls-files
  files = `git ls-files`.
    split("\n").
    sort.
    reject { |file| file =~ /^\./ }.
    reject { |file| file =~ /^(rdoc|pkg|test|Home\.md|\.gitattributes)/ }.
    map { |file| "    #{file}" }.
    join("\n")

  # piece file back together and write
  manifest = "  s.files = %w[\n#{files}\n  ]\n"
  spec = [head, manifest, tail].join("  # = MANIFEST =\n")
  File.open(gemspec_file, 'w') { |io| io.write(spec) }
  puts "Updated #{gemspec_file}"
end

desc 'Validate lib files and version file'
task :validate do
  libfiles = Dir['lib/*'] - ["lib/#{name}.rb", "lib/#{name}"]
  unless libfiles.empty?
    puts "Directory `lib` should only contain a `#{name}.rb` file and `#{name}` dir."
    exit!
  end
  unless Dir['VERSION*'].empty?
    puts "A `VERSION` file at root level violates Gem best practices."
    exit!
  end
end

desc 'Build changelog'
task :changelog do
  [latest_changes_file, history_file].each do |f|
    unless File.exist?(f)
      puts "#{f} does not exist but is required to build a new release."
      exit!
    end
  end

  latest_changes = File.open(latest_changes_file)
  version_pattern = "# #{version}"

  if !`grep "#{version_pattern}" #{history_file}`.empty?
    puts "#{version} is already described in #{history_file}"
    exit!
  end

  begin
    unless latest_changes.readline.chomp! =~ %r{#{version_pattern}}
      puts "#{latest_changes_file} should begin with '#{version_pattern}'"
      exit!
    end
  rescue EOFError
    puts "#{latest_changes_file} is empty!"
    exit!
  end

  body = latest_changes.read
  body.scan(/\s*#\s+\d\.\d.*/) do |match|
    puts "#{latest_changes_file} may not contain multiple markdown headers!"
    exit!
  end

  temp = Tempfile.new
  temp.puts("#{version_pattern} / #{date}\n#{body}\n")
  temp.close
  `cat #{history_file} >> #{temp.path}`
  `cat #{temp.path} > #{history_file}`
end

desc 'Precompile assets'
task :precompile do
  # Attempt to install JavaScript dependencies managed by Yarn via the
  # `package.json` file in Gollum's project root. If it fails, raise an error
  # and exit the task early.
  puts "\n  Installing `yarn`-managed JavaScript dependencies...  \n\n"
  system "yarn install"
    unless $?.success?
    raise "This task tried to run `yarn install` to get up-to-date "          \
      "JavaScript dependencies before precompilation. But it failed. Please " \
      "run `yarn install` manually from your shell and resolve any issues. "  \
      "It's possible that you just need to install `yarn` on your system."
  end

  require 'terser'
  module Precious
    module Assets
      JS_COMPRESSOR = ::Terser.new
    end
  end

  require './lib/gollum/app.rb'

  # Next, configure the Sprockets asset pipeline and precompile production-
  # ready assets.
  Precious::App.set(:environment, :production)

  env = Precious::Assets.sprockets
  path = ENV.fetch 'GOLLUM_ASSETS_PATH',
    File.join(File.dirname(__FILE__), 'lib/gollum/public/assets')
  manifest = Sprockets::Manifest.new(env, path)

  Sprockets::Helpers.configure do |config|
    config.environment = env
    config.prefix      = Precious::Assets::ASSET_URL
    config.digest      = true
    config.public_path = path
    config.manifest    = manifest
  end

  manifest.clobber
  puts "\n  Precompiling assets to #{path}...  \n\n"
  manifest.compile(Precious::Assets::MANIFEST)
  bundle_katex_fonts(path)
end