#!/usr/bin/env ruby

require 'open-uri'
require 'open3'
require 'yaml'
require 'fileutils'
require 'set'
require 'json'

Dir.chdir(File.dirname(__dir__))

PACKAGES = YAML.load_stream(File.read('packages.yaml'))

BASE_URL = 'https://raw.githubusercontent.com/github/linguist/master'

DIRS = {
  default: %w(syntax indent doc compiler autoload ftplugin ctags after/syntax after/indent after/ftplugin),
  all: %w(syntax indent compiler autoload ftplugin after extras ctags doc),
  syntax: %w(syntax indent after/syntax after/indent)
}

def parallel(*procs)
  threads = procs.map { |p| Thread.new { method(p).call } }
  threads.map(&:join).map(&:value)
end

def read_strings(data, keys, print=false)
  if data.is_a?(Hash)
    data.flat_map do |key, val|
      read_strings(val, keys, keys.include?(key))
    end
  elsif data.is_a?(Array)
    data.flat_map { |d| read_strings(d, keys, print) }
  elsif data.is_a?(String)
    print ? [data] : []
  else
    []
  end
end

def transform_with(data, keys, transfrom=false, &block)
  if data.is_a?(Hash)
    Hash[data.map do |key, val|
      [key, transform_with(val, keys, keys.include?(key), &block)]
    end]
  elsif data.is_a?(Array)
    data.map { |d| transform_with(d, keys, transfrom, &block) }
  elsif data.is_a?(String)
    transfrom ? yield(data) : data
  else
    data
  end
end

def each_hash(data, &block)
  if data.is_a?(Hash)
    yield data
    data.each do |key, val|
      each_hash(val, &block)
    end
  elsif data.is_a?(Array)
    data.map { |d| each_hash(d, &block) }
  end
end

def patterns_to_vim_patterns(patterns)
  stdin, stdout, stderr = Open3.popen3('vim', '-V', '--clean', '/dev/stdin', '-es', '-c', "echo expand('%:p:h') | source #{__dir__}/scripts/eregex.vim", '-c', "for line in range(0, line('$')) | call setline(line, ExtendedRegex2VimRegex(getline(line))) | endfor", '-c', ':wq! /dev/stdout', chdir: __dir__)
  stdin.write(patterns.join("\n"))
  stdin.close
  stdout.readlines
end

def transform_patterns(data)
  patterns = read_strings(data, ["pattern", "patterns"])
  patterns_mapping = Hash[patterns.zip(patterns_to_vim_patterns(patterns))]
  transform_with(data, ["pattern", "patterns"]) { |a| patterns_mapping[a] }
end

def load_heuristics
  url = "#{BASE_URL}/lib/linguist/heuristics.yml"
  data = URI.open(url) { |io| YAML.load(io.read) }
  each_hash(data["disambiguations"]) do |h|
    if h.has_key?("named_pattern")
      h["pattern"] = data["named_patterns"].fetch(h["named_pattern"])
      h.delete("named_pattern")
    end
  end
  transform_patterns(data["disambiguations"])
end

def load_languages
  url = "#{BASE_URL}/lib/linguist/languages.yml"
  data = URI.open(url) { |io| YAML.load(io.read) }
end

def parse_remote(remote)
  match = remote.match(/(?<repo>[^@:]+)(?:@(?<branch>[^:]+))?(?::(?<path>.*))?/)
  [match[:repo], match[:branch] || "master", match[:path]]
end

def copy_file(package, src, dest)
  return unless [".vim", ".ctags", ".vital", ".txt"].include?(File.extname(src))
  FileUtils.mkdir_p(File.dirname(dest))
  name = package.fetch("name")

  open(src, "r") do |input|
    open(dest, "a+") do |output|
      if name == "jsx"
        output << "if !exists('g:polyglot_disabled') || !(index(g:polyglot_disabled, 'typescript') != -1 || index(g:polyglot_disabled, 'typescript') != -1 || index(g:polyglot_disabled, 'jsx') != -1)\n\n"
      else
        output << "if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, '#{name}') == -1\n\n"
      end
      IO.copy_stream(input, output)
      output << "\nendif\n"
    end
  end
end

def download
  FileUtils.rm_rf('tmp')

  PACKAGES.each_slice(20) do |batch|
    batch.map do |package|
      Thread.new do
        repo, branch, path = parse_remote(package.fetch("remote"))
        dir = "tmp/" + repo.split('/')[1]
        FileUtils.mkdir_p(dir)
        url = "https://codeload.github.com/#{repo}/tar.gz/#{branch}"
        `curl --silent -fL #{url} | tar -zx -C "#{dir}" --strip 1`
        progress
      end
    end.map(&:join)
  end
end

$i = 0
LYRICS = "Never gonna give you up.  Never gonna let you down.  " +
         "Never gonna run around and desert you.  " +
         "Never gonna make you cry.  Never gonna say goodbye.  " +
         "Never gonna tell a lie and hurt you."

$mutex = Mutex.new
def progress
  $mutex.synchronize do
    $stdout.write(LYRICS[$i] || ".")
    $i += 1
  end
end

def extract
  FileUtils.rm_rf(DIRS[:all])

  output = []
  PACKAGES.map do |package|
    repo, branch, path = parse_remote(package["remote"])
    dir = "tmp/" + repo.split('/')[1]
    subdirs = []
    dirs = DIRS.fetch(package.fetch("dirs", "default").to_sym)
    ignored_dirs = package.fetch("ignored_dirs", [])
    if ignored_dirs.size > 0
      dirs = dirs.reject { |d| ignored_dirs.any? { |id| d.start_with?(id) } }
    end
    dirs |= package.fetch("extra_dirs", [])
    for subdir in dirs
      subtree = "#{dir}/#{path ? path + "/" : ""}"
      subpath = "#{subtree}#{subdir}"
      if FileTest.directory?(subpath)
        Dir.glob("#{subdir}/**/*", base: subtree).each do |p|
          next unless File.file?("#{subtree}/#{p}")
          copy_file(package, "#{subtree}/#{p}", p)
        end

        subdirs << subdir.split("/").last
      elsif File.exist?(subpath)
        copy_file(package, subpath, subdir)
      end
    end

    output << "- [#{package["name"]}](https://github.com/#{repo}) (#{subdirs.uniq.join(", ")})"
    progress
  end

  readme = File.read('README.md')

  readme.gsub!(
    %r{(?<=<!--Package Count-->).*?(?=<!--/Package Count-->)},
    output.size.to_s
  )

  readme.gsub!(
    %r{(?<=<!--Language Packs-->).*?(?=<!--/Language Packs-->)}m,
    "\n" + output.sort.join("\n") + "\n"
  )

  File.write('README.md', readme)
end

def generate_ftdetect
  heuristics, languages = parallel(:load_heuristics, :load_languages)

  output = <<~EOS
    " don't spam the user when Vim is started in Vi compatibility mode
    let s:cpo_save = &cpo
    set cpo&vim

    if !exists('g:polyglot_disabled')
      let g:polyglot_disabled = []
    endif

    function! s:SetDefault(name, value)
      if !exists(a:name)
        let {a:name} = a:value
      endif
    endfunction

    call s:SetDefault('g:markdown_enable_spell_checking', 0)
    call s:SetDefault('g:markdown_enable_input_abbreviations', 0)
    call s:SetDefault('g:markdown_enable_mappings', 0)

    " Enable jsx syntax by default
    call s:SetDefault('g:jsx_ext_required', 0)

    " Make csv loading faster
    call s:SetDefault('g:csv_start', 1)
    call s:SetDefault('g:csv_end', 2)

    " Disable json concealing by default
    call s:SetDefault('g:vim_json_syntax_conceal', 0)

    call s:SetDefault('g:filetype_euphoria', 'elixir')

    if !exists('g:python_highlight_all')
      call s:SetDefault('g:python_highlight_builtins', 1)
      call s:SetDefault('g:python_highlight_builtin_objs', 1)
      call s:SetDefault('g:python_highlight_builtin_types', 1)
      call s:SetDefault('g:python_highlight_builtin_funcs', 1)
      call s:SetDefault('g:python_highlight_builtin_funcs_kwarg', 1)
      call s:SetDefault('g:python_highlight_exceptions', 1)
      call s:SetDefault('g:python_highlight_string_formatting', 1)
      call s:SetDefault('g:python_highlight_string_format', 1)
      call s:SetDefault('g:python_highlight_string_templates', 1)
      call s:SetDefault('g:python_highlight_indent_errors', 1)
      call s:SetDefault('g:python_highlight_space_errors', 1)
      call s:SetDefault('g:python_highlight_doctests', 1)
      call s:SetDefault('g:python_highlight_func_calls', 1)
      call s:SetDefault('g:python_highlight_class_vars', 1)
      call s:SetDefault('g:python_highlight_operators', 1)
      call s:SetDefault('g:python_highlight_file_headers_as_comments', 1)
      call s:SetDefault('g:python_slow_sync', 1)
    endif

  EOS

  ambiguous_extensions = PACKAGES.flat_map { |e| e["filetypes"] }.flat_map do |e|
    if e["linguist"]
      ((languages[e["linguist"]]["extensions"] || []).map { |e| e[1..-1] } | e.fetch("extra_extensions", [])) - e.fetch("ignored_extensions", [])
    else
      e.fetch("extensions", [])
    end
  end.group_by(&:itself).transform_values(&:count).select { |a, b| b > 1 }.keys.to_set

  expected_filetypes = detect_filetypes

  for package in PACKAGES
    name = package.fetch("name")
    output << if name == "jsx"
      "if !(index(g:polyglot_disabled, 'typescript') != -1 || index(g:polyglot_disabled, 'typescript') != -1 || index(g:polyglot_disabled, 'jsx') != -1)\n"
    else
      "if index(g:polyglot_disabled, '#{name}') == -1\n"
    end

    filetypes = package["filetypes"] or raise "Unknown filetype for: #{package["name"]}"

    for filetype in filetypes
      name = filetype.fetch("name")
      syntax = filetype["syntax"] ? " syntax=#{filetype["syntax"]}" : ""
      set_command = package.fetch("custom_set", "set ft=#{name}#{syntax}")

      linguist = filetype["linguist"] ? languages.fetch(filetype["linguist"]) : {}
      extensions = filetype["extensions"] || linguist.fetch("extensions", []).map { |e| e[1..] }
      extensions = (extensions | filetype.fetch("extra_extensions", [])) - filetype.fetch("ignored_extensions", [])

      filenames = filetype["filenames"] || linguist.fetch("filenames", [])
      filenames = (filenames | filetype.fetch("extra_filenames", [])) - filetype.fetch("ignored_filenames", [])

      if expected_filetypes[name] && !filetype["syntax"]
        for e in expected_filetypes.fetch(name)[:extensions] - extensions - expand_all(filetype.fetch("ignored_extensions", []))
          puts "Probable missing extension for #{name}: #{e}"
        end

        for e in expand_all(expected_filetypes.fetch(name)[:filenames]) - expand_all(filenames).flat_map { |e| [e, e.gsub(/^\./, '')] } - expand_all(filetype.fetch("ignored_filenames", [])) - ['*']
          puts "Probable missing filename for #{name}: #{e}"
        end
      end

      for extension in extensions.sort
        outer_filetype = filetype["outer_filetype"]
        if outer_filetype
          output << "  au BufNewFile *.*.#{extension} execute \"do BufNewFile filetypedetect \" . expand(\"<afile>:r\") | #{outer_filetype}\n"
          output << "  au BufReadPre *.*#{extension} execute \"do BufRead filetypedetect \" . expand(\"<afile>:r\") | #{outer_filetype}\n"
        end

        if ambiguous_extensions.include?(extension)
          output << "  au BufNewFile,BufRead *.#{extension} setf #{filetype["name"]}\n"
        else
          output << "  au BufNewFile,BufRead *.#{extension} #{set_command}\n"
        end
      end

      for filename in filenames.sort
        if filename[0] == "."
          filename = "{.,}" + filename[1..]
        end
        output << "  au BufNewFile,BufRead #{filename} #{set_command}\n"
      end
    end

    output << "endif\n\n"
  end

  output << <<~EOS
    " restore Vi compatibility settings
    let &cpo = s:cpo_save
    unlet s:cpo_save
  EOS
 
  # filetypes = detect_filetypes
  #
  # for filetype in filetypes
  #   
  # end

  File.write('ftdetect/polyglot.vim', output)
end

def generate_tests
  output = <<~EOS
    function! TestFiletype(filetype)
      try
        enew
        exec 'set ft=' . a:filetype
      catch
        echo 'Error loading filetype ' . a:filetype  . ':'
        echo v:exception
        echo v:throwpoint
        exec ':cq!'
      endtry
    endfunction

  EOS

  for package in PACKAGES
    for filetype in package.fetch("filetypes", [])
      output << "call TestFiletype('#{filetype["name"]}')\n"
    end
  end

  File.write('scripts/test_filetypes.vim', output)


end

def brace_expansion(s)
  r=1                                       # Dummy value to forward-declare the parse function `r`
  t=->x{                                    # Function to parse a bracket block
    x=x[0].gsub(/^{(.*)}$/){$1}             # Remove outer brackets if both are present
                                            # x[0] is required because of quirks in the `scan` function
    x=x.scan(/(({(\g<1>|,)*}|[^,{}]|(?<=,|^)(?=,|$))+)/)
                                            # Regex black magic: collect elements of outer bracket
    x.map{|i|i=i[0];i[?{]?r[i]:i}.flatten   # For each element with brackets, run parse function
  }
  r=->x{                                    # Function to parse bracket expansions a{b,c}{d,e}
    i=x.scan(/({(\g<1>)*}|[^{} ]+)/)        # Regex black magic: scan for adjacent sets of brackets
    i=i.map(&t)                             # Map all elements against the bracket parser function `t`
    i.shift.product(*i).map &:join          # Combine the adjacent sets with cartesian product and join them together
  }
  s.split.map(&r).flatten
end

def square_expansion(s)
  return [s] unless s.include?('[')
  s.scan(/(\[[^\]]+\]|[^\[]+)/).map { |x| x[0] }
    .map { |x| x[0] == "[" ? x[1..-2].split("") : [x] }
    .reduce(&:product).map(&:flatten).map(&:join)
end

def comma_expanson(s)
  s.scan(/{[^{]+}|[^{]+/).map { |a| a[0] == "{" ? a : a.split(",", -1) }.reduce([]) do |a, b|
    a.size > 0 ?
      (b.is_a?(String) ?
         a[0..-2] + [a[-1] + b] :
         a[0..-2] + [a[-1] + b[0]] + b[1..-1]) :
      [b].flatten
  end
end

def expand_all(pattern)
  if pattern.is_a?(Array)
    return pattern.flat_map { |p| expand_all(p) }
  end

  comma_expanson(pattern).flat_map do |e|
    brace_expansion(e).flat_map do |e2|
      square_expansion(e2)
    end
  end
end

def detect_filetypes
  filetypes = Dir['tmp/*/ftdetect/*.vim'].flat_map do |file|
    contents = File.read(file).gsub(/^\s*au(tocmd)?!?\s*$/, '')
    results = contents.scan(/^\s*(?:au!|au|au[^g][^ ]*) +(?:\S+)\s+(\S+)[\s\\]+([^\n]+)/)
    results = results.map do |a, b|
      [
        a,
        b.gsub(/call (?:s:setf|s:StarSetf)\('([^']+)'\)/i, 'setf \1')
          .gsub(/set(?:local)?\s+(?:ft|filetype)=(\S+)/, 'setf \1')
        .gsub(/setf\S*/, 'setf')
        .gsub(/.*setf\s+(\S+).*/, 'setf \1')
      ]
    end.select { |a, b| b.match(/setf \S+/) }.map { |a, b| [a, b.split(" ")[1]] }
    results
  end

  Hash[filetypes.flat_map do |ext, filetype|
    expand_all(ext).map { |e| [filetype, e] }
  end.group_by { |a, b| a }.map { |a, b| [a, b.map { |c, d| d }] }.map { |a, b|
    [a, {
      extensions: b.select { |x| x.match(/^\*\.[^\/]+$/) }.map { |a| a.strip[2..] },
      filenames: b.select { |x| !x.match(/^\*\.[^\/]+$/) }
    }]
  }]
end

download
extract
generate_ftdetect
generate_tests
puts(" Bye! Have a wonderful time!")
FileUtils.rm_rf("tmp")