Add CLI to use in any repo (#1)

This opens up the tool to be used with any repo/project, rather than just rails.

## Usage

```shell
diffcrypt decrypt -k $(cat test/fixtures/master.key) test/fixtures/example.yml.enc > tmp/decrypted.yml
diffcrypt encrypt -k $(cat test/fixtures/master.key) test/fixtures/example.yml > tmp/encrypted.yml
```

Author: marcqualie

Diff for: CHANGELOG.md

@@ -7,6 +7,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 
+## [Unreleased]
+
+## Added
+
+- CLI: Use diffcrypt from command line of any project without requiring ruby integration
+- CLI: `diffcrypt encrypt` Directly encrypt any file and output the contents
+- CLI: `diffcrypt decrypt` Directly decrypt any file and output the contents
+
+
+
 ## [0.2.0] - 2020-06-28
 
 ### Added

Diff for: bin/diffcrypt

@@ -0,0 +1,8 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'thor'
+
+require_relative '../lib/diffcrypt/cli'
+
+Diffcrypt::CLI.start(ARGV)

Diff for: diffcrypt.gemspec

@@ -25,9 +25,10 @@ Gem::Specification.new do |spec|
   spec.files = Dir.chdir(File.expand_path(__dir__)) do
     `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
   end
-  spec.bindir = 'exe'
-  spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.bindir = 'bin'
+  spec.executables = %w[diffcrypt]
   spec.require_paths = ['lib']
 
   spec.add_runtime_dependency 'activesupport', '~> 6.0.0'
+  spec.add_runtime_dependency 'thor', '~> 1.0.1'
 end

Diff for: lib/diffcrypt/cli.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require_relative './encryptor'
+require_relative './version'
+
+module Diffcrypt
+  class CLI < Thor
+    desc 'decrypt <path>', 'Decrypt a file'
+    method_option :key, aliases: %i[k], required: true
+    def decrypt(path)
+      ensure_file_exists(path)
+      contents = File.read(path)
+      puts encryptor.decrypt(contents)
+    end
+
+    desc 'encrypt <path>', 'Encrypt a file'
+    method_option :key, aliases: %i[k], required: true
+    def encrypt(path)
+      ensure_file_exists(path)
+      contents = File.read(path)
+      puts encryptor.encrypt(contents)
+    end
+
+    desc 'version', 'Show client version'
+    def version
+      say Diffcrypt::VERSION
+    end
+
+    no_commands do
+      def key
+        options[:key]
+      end
+
+      def encryptor
+        @encryptor ||= Encryptor.new(key)
+      end
+
+      def ensure_file_exists(path)
+        abort('[ERROR] File does not exist') unless File.exist?(path)
+      end
+    end
+  end
+end

Diff for: lib/diffcrypt/encryptor.rb

@@ -8,6 +8,8 @@
 
 require 'active_support/message_encryptor'
 
+require_relative './version'
+
 module Diffcrypt
   class Encryptor
     CIPHER = 'aes-128-gcm'

Diff for: test/diffcrypt/cli_test.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+require 'thor'
+
+require_relative '../../lib/diffcrypt/cli'
+
+class Diffcrypt::CLITest < Minitest::Test
+  def test_it_extends_thor
+    assert Diffcrypt::CLI < Thor
+  end
+end