Support hierarchical loading of the config file

spec/ameba/cli/cmd_spec.cr

@@ -21,7 +21,7 @@ module Ameba::Cli
       %w(-c --config).each do |f|
         it "accepts #{f} flag" do
           c = Cli.parse_args [f, "config.yml"]
-          c.config.should eq "config.yml"
+          c.config.should eq Path["config.yml"]
         end
       end
 
@@ -82,12 +82,6 @@ module Ameba::Cli
         c.colors?.should be_true
       end
 
-      it "ignores --config if --gen-config flag passed" do
-        c = Cli.parse_args %w(--gen-config --config my_config.yml)
-        c.formatter.should eq :todo
-        c.config.should eq ""
-      end
-
       describe "-e/--explain" do
         it "configures file/line/column" do
           c = Cli.parse_args %w(--explain src/file.cr:3:5)
@@ -166,7 +160,7 @@ module Ameba::Cli
         c.globs.should be_nil
         c.only.should be_nil
         c.except.should be_nil
-        c.config.should eq Config::PATH
+        c.config.should be_nil
       end
     end
   end

spec/ameba/formatter/todo_formatter_spec.cr

@@ -45,7 +45,7 @@ module Ameba
           s = Source.new "a = 1", "source.cr"
           s.add_issue DummyRule.new, {1, 2}, "message"
           formatter.finished([s])
-          io.to_s.should contain "Created .ameba.yml"
+          io.to_s.should contain "Created #{Config::PATH}"
         end
       end
 

src/ameba/cli/cmd.cr

@@ -44,7 +44,7 @@ module Ameba::Cli
   end
 
   private class Opts
-    property config = Config::PATH
+    property config : Path?
     property formatter : Symbol | String | Nil
     property globs : Array(String)?
     property only : Array(String)?
@@ -76,7 +76,7 @@ module Ameba::Cli
 
       parser.on("-c", "--config PATH",
         "Specify a configuration file") do |path|
-        opts.config = path unless opts.config.empty?
+        opts.config = Path[path] unless path.empty?
       end
 
       parser.on("-f", "--format FORMATTER",
@@ -105,7 +105,6 @@ module Ameba::Cli
       parser.on("--gen-config",
         "Generate a configuration file acting as a TODO list") do
         opts.formatter = :todo
-        opts.config = ""
       end
 
       parser.on("--fail-level SEVERITY",

src/ameba/config.cr

@@ -24,7 +24,12 @@ class Ameba::Config
     json:     Formatter::JSONFormatter,
   }
 
-  PATH = ".ameba.yml"
+  DEFAULT_PATHS = {
+    "~/.ameba.yml",
+    "~/.config/ameba/config.yml",
+  }
+  FILENAME = ".ameba.yml"
+  PATH     = Path[Dir.current] / FILENAME
 
   DEFAULT_GLOBS = %w(
     **/*.cr
@@ -77,14 +82,33 @@ class Ameba::Config
   # ```
   # config = Ameba::Config.load
   # ```
-  def self.load(path = PATH, colors = true)
+  def self.load(path = nil, colors = true)
     Colorize.enabled = colors
-    content = File.exists?(path) ? File.read path : "{}"
+    content = read_config(path) || "{}"
     Config.new YAML.parse(content)
   rescue e
     raise "Config file is invalid: #{e.message}"
   end
 
+  protected def self.read_config(path) : String?
+    if path
+      return File.exists?(path) ? File.read(path) : nil
+    end
+    path = Path[PATH].expand(home: true)
+
+    search_paths = path
+      .parents
+      .map! { |search_path| search_path / FILENAME }
+
+    search_paths.reverse_each do |search_path|
+      return File.read(search_path) if File.exists?(search_path)
+    end
+
+    DEFAULT_PATHS.each do |default_path|
+      return File.read(default_path) if File.exists?(default_path)
+    end
+  end
+
   def self.formatter_names
     AVAILABLE_FORMATTERS.keys.join('|')
   end