Refactor and enhance Colorize

- Refactor all codes.
  * Prefer to use enums instead of constants.
  * Separate `Object` and `Style`. `Style` represents a style on
  terminal purely, however `Object` has object content.
- Support 256 color and 32bit true color.
- Add TTY detection. If not, doesn't output escape sequence.

spec/std/colorize_spec.cr

@@ -2,6 +2,8 @@ require "spec"
 require "colorize"
 
 describe "colorize" do
+  Colorize.force = true
+
   it "colorizes without change" do
     "hello".colorize.to_s.should eq("hello")
   end
@@ -60,6 +62,7 @@ describe "colorize" do
 
   it "colorizes foreground with background" do
     "hello".colorize.blue.on_green.to_s.should eq("\e[34;42mhello\e[0m")
+    "hello".colorize(fore: :blue, back: :green).to_s.should eq("\e[34;42mhello\e[0m")
   end
 
   it "colorizes foreground with background with mode" do
@@ -71,6 +74,41 @@ describe "colorize" do
     "hello".colorize.fore(:red).to_s.should eq("\e[31mhello\e[0m")
   end
 
+  it "colorizes foreground with nil" do
+    "hello".colorize(nil).to_s.should eq("hello")
+    "hello".colorize.fore(nil).to_s.should eq("hello")
+  end
+
+  it "colorizes foreground with 256 color" do
+    "hello".colorize(Colorize::Color256.new 111).to_s.should eq("\e[38;5;111mhello\e[0m")
+    "hello".colorize.fore(Colorize::Color256.new 111).to_s.should eq("\e[38;5;111mhello\e[0m")
+  end
+
+  it "colorizes foreground with RGB" do
+    "hello".colorize(Colorize::ColorRGB.new 11, 22, 33).to_s.should eq("\e[38;2;11;22;33mhello\e[0m")
+    "hello".colorize.fore(Colorize::ColorRGB.new 11, 22, 33).to_s.should eq("\e[38;2;11;22;33mhello\e[0m")
+  end
+
+  it "colorizes background with symbol" do
+    "hello".colorize(back: :red).to_s.should eq("\e[41mhello\e[0m")
+    "hello".colorize.back(:red).to_s.should eq("\e[41mhello\e[0m")
+  end
+
+  it "colorizes background with nil" do
+    "hello".colorize(back: nil).to_s.should eq("hello")
+    "hello".colorize.back(nil).to_s.should eq("hello")
+  end
+
+  it "colorizes background with 256 color" do
+    "hello".colorize(back: Colorize::Color256.new 111).to_s.should eq("\e[48;5;111mhello\e[0m")
+    "hello".colorize.back(Colorize::Color256.new 111).to_s.should eq("\e[48;5;111mhello\e[0m")
+  end
+
+  it "colorizes background with RGB" do
+    "hello".colorize(back: Colorize::ColorRGB.new 11, 22, 33).to_s.should eq("\e[48;2;11;22;33mhello\e[0m")
+    "hello".colorize.back(Colorize::ColorRGB.new 11, 22, 33).to_s.should eq("\e[48;2;11;22;33mhello\e[0m")
+  end
+
   it "colorizes mode with symbol" do
     "hello".colorize.mode(:bold).to_s.should eq("\e[1mhello\e[0m")
   end
@@ -113,23 +151,23 @@ describe "colorize" do
     io.to_s.should eq("\e[31mhello\e[0m")
   end
 
-  it "colorizes with push and pop" do
+  it "colorizes with surround stack" do
     io = IO::Memory.new
-    with_color.red.push(io) do
+    with_color.red.surround(io) do
       io << "hello"
-      with_color.green.push(io) do
+      with_color.green.surround(io) do
         io << "world"
       end
       io << "bye"
     end
     io.to_s.should eq("\e[31mhello\e[0;32mworld\e[0;31mbye\e[0m")
   end
 
-  it "colorizes with push and pop resets" do
+  it "colorizes with surround stack resets" do
     io = IO::Memory.new
-    with_color.red.push(io) do
+    with_color.red.surround(io) do
       io << "hello"
-      with_color.green.bold.push(io) do
+      with_color.green.bold.surround(io) do
         io << "world"
       end
       io << "bye"
@@ -145,4 +183,32 @@ describe "colorize" do
   it "toggles off and on" do
     "hello".colorize.toggle(false).black.toggle(true).to_s.should eq("\e[30mhello\e[0m")
   end
+
+  Colorize.force = false
+
+  it "doesn't colorize no tty IO" do
+    "hello".colorize(fore: :red, back: :green, mode: :bold).to_s.should eq("hello")
+    "hello".colorize(fore: :red, back: :green, mode: :bold).inspect.should eq("\"hello\"")
+    io = IO::Memory.new
+    with_color(fore: :red, back: :green, mode: :bold).surround(io) do
+      io << "hello"
+    end
+    io.to_s.should eq("hello")
+  end
+
+  it "colorize no tty IO with force" do
+    io = IO::Memory.new
+    "hello".colorize(fore: :red, back: :green, mode: :bold).to_s(io, force: true)
+    io.to_s.should eq("\e[31;42;1mhello\e[0m")
+    io.clear
+
+    "hello".colorize(fore: :red, back: :green, mode: :bold).inspect(io, force: true)
+    io.to_s.should eq("\e[31;42;1m\"hello\"\e[0m")
+    io.clear
+
+    with_color(fore: :red, back: :green, mode: :bold).surround(io, force: true) do
+      io << "hello"
+    end
+    io.to_s.should eq("\e[31;42;1mhello\e[0m")
+  end
 end