comma/,

#!ruby --disable-gems

ENV['PATH'] = "@PATH_PREPEND@:" + ENV['PATH']
$NIX_INDEX_DB = "@NIX_INDEX_DB@"
$OVERLAY_PACKAGES = "@OVERLAY_PACKAGES@".split(':')

module Comma
  class << self
    def store_paths(argv, stdin)
      inputs = ARGV.empty? ? STDIN.readlines.map(&:chomp) : ARGV
      inputs.map! { |i| i =~ /^[a-z0-9]{32}-/ ? "/nix/store/#{i}" : i }
    end

    USAGE = <<~USAGE
      \1,h \4or \1, -h         \3: \4(show this help)\6

      \1,    \2<bin-name>    \3: \4(run a binary from whatever package it exists in)\6
      \1,i   \2<bin-name>    \3: \5nix-env -i \4(whichever package the binary exists in)\6

      \1,sl  \2<regex>       \3: \4(list nix-store entries matching regex)\6
      \1,sx  \2<store-path*> \3: \5nix-store --realise\6
      \1,sd  \2<store-path*> \3: \5nix show-derivation\6

      \1,qo  \2<store-path*> \3: \5nix-store --query --outputs\6
      \1,qd  \2<store-path*> \3: \5nix-store --query --deriver\6

      \1,q-  \2<store-path*> \3: \5nix-store --query --references\6
      \1,q-- \2<store-path*> \3: \5nix-store --query --requisites\6
      \1,q+  \2<store-path*> \3: \5nix-store --query --referers\6
      \1,q++ \2<store-path*> \3: \5nix-store --query --referers-closure\6

      \4Anything taking \2<store-path*>\4 can also be called like:
        \5echo \2<store-path*> \5| \1,q-
    USAGE

    COLORS = {
      1.chr => "\x1b[0;1;34m",
      2.chr => "\x1b[0;3;32m",
      3.chr => "\x1b[0;37m",
      4.chr => "\x1b[0;3;37m",
      5.chr => "\x1b[0;35m",
      6.chr => "\x1b[0m"
    }

    def usage(stream, color: stream.tty?)
      if color
        stream.puts(COLORS.reduce(USAGE) { |usage, (a, b)| usage.gsub(a, b) })
      else
        stream.puts(COLORS.reduce(USAGE) { |usage, (a, _)| usage.gsub(a, '') })
      end
    end

    def call(argv, stdin, stderr, execname)
      case execname

      when ',h'
        usage(stderr)
        exit(0)

      when ','
        if argv.empty? || argv.first == '-h' || argv.first == '--help'
          usage(stderr)
          exit(0)
        else
          comma(argv)
        end

      when ',i'
        comma_i(argv)

      when ',q'
        usage(stderr)
        exit(0)

      when ',sl'
        q_list(Regexp.new(argv.first || ''))
      when ',sd'
        exec('nix', 'show-derivation', *store_paths(argv, stdin))

      when ',qo'
        exec('nix-store', '--query', '--outputs', *store_paths(argv, stdin))
      when ',qd'
        exec('nix-store', '--query', '--deriver', *store_paths(argv, stdin))

      when ',q-'
        exec('nix-store', '--query', '--references', *store_paths(argv, stdin))
      when ',q--'
        exec('nix-store', '--query', '--requisites', *store_paths(argv, stdin))
      when ',q+'
        exec('nix-store', '--query', '--referers', *store_paths(argv, stdin))
      when ',q++'
        exec('nix-store', '--query', '--referers-closure', *store_paths(argv, stdin))

      when ',sx'
        exec('nix-store', '--realise', *store_paths(argv, stdin))

      else
        abort('invalid invocation')
      end
    end

    def q_list(pattern)
      Dir.entries('/nix/store').each do |entry|
        next if entry[0] == '.'
        puts(entry) if pattern.match?(entry)
      end
    end

    def comma(argv)
      match = comma_match(argv.first)
      exec('nix', 'run', "nixpkgs.#{match}", '-c', *argv)
      #   nix-env -iA "nixpkgs.${attr%%.*}"
    end

    def comma_i(argv)
      match = comma_match(argv.first)
      exec('nix-env', '-iA', "nixpkgs.#{match}")
    end

    def comma_match(str)
      return str if $OVERLAY_PACKAGES.include?(str)
      require('open3')
      out, err, stat = Open3.capture3(
        'nix-locate',
        '--db', $NIX_INDEX_DB,
        '--top-level',
        '--minimal',
        '--at-root',
        '--whole-name',
        "/bin/#{str}",
      )
      abort("no match: #{err}") unless stat.success?
      matches = out.lines.map { |m| m.chomp.sub(/\.out$/, '') }
      match = if matches.size > 1
        height = matches.size + 1
        out, stat = Open3.capture2(
          'fzf',
          '--height', height.to_s,
          '--layout', 'reverse',
          '--info', 'hidden',
          '--preview', "nix eval --raw '(import <nixpkgs> { }).{}.meta.description'",
          '--preview-window=right:99%:wrap',
          stdin_data: matches.join("\n"),
        )
        abort("fzf failed") unless stat.success?
        out.chomp
      else
        matches[0]
      end
      abort("no matches") if match.nil?
      match
    end

  end
end

Comma.call(ARGV, STDIN, STDERR, File.basename($PROGRAM_NAME))