Added logic for performant update.

Gemfile.lock

@@ -2,10 +2,11 @@ PATH
   remote: .
   specs:
     elm_install (0.1.0)
-      colorize (~> 0.8.1)
       commander (~> 4.4, >= 4.4.2)
       git (~> 1.3)
       git_clone_url (~> 2.0)
+      hashdiff (~> 0.3.1)
+      smart_colored (~> 1.1, >= 1.1.1)
       solve (~> 3.1)
 
 GEM
@@ -22,7 +23,6 @@ GEM
       virtus (~> 1.0)
     coercible (1.0.0)
       descendants_tracker (~> 0.0.1)
-    colorize (0.8.1)
     commander (4.4.2)
       highline (~> 1.7.2)
     descendants_tracker (0.0.4)
@@ -42,6 +42,7 @@ GEM
     git (1.3.0)
     git_clone_url (2.0.0)
       uri-ssh_git (>= 2.0)
+    hashdiff (0.3.1)
     highline (1.7.8)
     ice_nine (0.11.2)
     launchy (2.4.3)
@@ -90,6 +91,7 @@ GEM
       virtus (~> 1.0)
     semverse (2.0.0)
     sexp_processor (4.7.0)
+    smart_colored (1.1.1)
     solve (3.1.0)
       molinillo (>= 0.5)
       semverse (>= 1.1, < 3.0)

elm_install.gemspec

@@ -22,7 +22,8 @@ Gem::Specification.new do |s|
   s.add_dependency 'git_clone_url', '~> 2.0'
   s.add_dependency 'solve', '~> 3.1'
   s.add_dependency 'commander', '~> 4.4', '>= 4.4.2'
-  s.add_dependency 'colorize', '~> 0.8.1'
+  s.add_dependency 'smart_colored', '~> 1.1', '>= 1.1.1'
+  s.add_dependency 'hashdiff', '~> 0.3.1'
 
   s.extra_rdoc_files = ['Readme.md']
 end

lib/elm_install.rb

@@ -1,7 +1,8 @@
+require 'smart_colored/extend'
 require 'git_clone_url'
 require 'forwardable'
 require 'fileutils'
-require 'colorize'
+require 'hashdiff'
 require 'solve'
 require 'json'
 require 'git'

lib/elm_install/cache.rb

@@ -15,24 +15,28 @@ class Cache
     # Initializes a new cache with the given options.
     def initialize(options = {})
       @options = options
+      @ref_cache = {}
       @cache = {}
       load
     end
 
     # Saves the cache into the json file.
     def save
+      File.binwrite(ref_file, JSON.pretty_generate(@ref_cache))
       File.binwrite(file, JSON.pretty_generate(@cache))
     end
 
-    def clear
-      @cache = {}
-    end
-
     # Loads a cache from the json file.
     def load
+      @ref_cache = JSON.parse(File.read(ref_file))
       @cache = JSON.parse(File.read(file))
     rescue
-      clear
+      @ref_cache = {}
+      @cache = {}
+    end
+
+    def clear
+      @ref_cache = {}
     end
 
     # Returns the directory where the cache is stored.
@@ -42,7 +46,7 @@ def directory
 
     # Returns if there is a package in the cache (with at least one version).
     def package?(package)
-      @cache.key?(package)
+      @ref_cache.key?(package) && @cache.key?(package)
     end
 
     # Adds a new dependency to the cache for a given package & version
@@ -75,21 +79,38 @@ def repository(path)
       if Dir.exist?(repo_path)
         repo = Git.open(repo_path)
         repo.reset_hard
-        unless package?(path)
-          Utils.log_with_dot "
-            Package: #{path} maybe not be up to date fetching changes...
-          ".strip
-          repo.fetch
+
+        unless @ref_cache[path]
+          refs = refs_for(repo_path)
+
+          if HashDiff.diff(@ref_cache[path], refs).empty?
+            Utils.log_with_arrow "Package: #{path.bold} is outdated fetching changes..."
+            repo.fetch
+          end
+
+          @ref_cache[path] = refs
         end
+
         repo
       else
-        Utils.log_with_dot "Package: #{path} not found in cache, cloning..."
-        Git.clone(path, repo_path)
+        Utils.log_with_arrow "Package: #{path.bold} not found in cache, cloning..."
+        repo = Git.clone(path, repo_path)
+        @ref_cache[path] = refs_for(repo_path)
+        repo
       end
     end
 
     private
 
+    def refs_for(repo_path)
+      refs = Git.ls_remote(repo_path)
+      refs.delete('head')
+    end
+
+    def ref_file
+      File.join(directory, 'ref-cache.json')
+    end
+
     # Returns the path to the json file.
     def file
       File.join(directory, 'cache.json')

lib/elm_install/installer.rb

@@ -24,19 +24,32 @@ def install
       begin
         populate_elm_stuff
       rescue
+        puts ' ▶ Could not find a solution in local cache, refreshing packages...'
+
         @cache.clear
         resolver.add_constraints dependencies
-        populate_elm_stuff
+
+        begin
+          populate_elm_stuff
+        rescue Solve::Errors::NoSolutionError => e
+          puts 'Could not find a solution:'
+          puts indent(e.to_s)
+        end
       end
+    end
 
-      puts 'Saving index cache...'
-      @cache.save
+    private
 
-      puts 'Packages configured successfully!'
+    def indent(str)
+      str.split("\n").map { |s| "  #{s}" }.join("\n")
     end
 
-    private
+    def end_sucessfully
+      puts 'Saving package cache...'
+      @cache.save
 
+      puts 'Packages configured successfully!'
+    end
     # Populates the `elm-stuff` directory with the packages from
     # the solution.
     def populate_elm_stuff
@@ -45,6 +58,7 @@ def populate_elm_stuff
       end
 
       write_exact_dependencies
+      end_sucessfully
     end
 
     # Resolves and copies a package and it's version to `elm-stuff/packages`
@@ -60,7 +74,7 @@ def resolve_package(package, version)
       @cache.repository(package).checkout(ref)
 
       version_str = ref == version ? ref : "#{ref}(#{version})"
-      Utils.log_with_dot "#{package_name} - #{version_str}"
+      Utils.log_with_dot "#{package_name.bold} - #{version_str.bold}"
 
       return if Dir.exist?(package_path)
 

lib/elm_install/utils.rb

@@ -23,6 +23,10 @@ def log_with_dot(message)
       puts '  ● '.green + message
     end
 
+    def log_with_arrow(message)
+      puts "  ▶ #{message}"
+    end
+
     def package_version_path(package, version)
       package_name = GitCloneUrl.parse(package).path
       [package_name, File.join('elm-stuff', 'packages', package_name, version)]