From 7c1ab2f3cc200a526729fb16630d9142e491b047 Mon Sep 17 00:00:00 2001
From: Karchnu <karchnu@karchnu.fr>
Date: Sun, 25 Oct 2020 02:28:59 +0200
Subject: [PATCH] Baguette::Configuration.option_parser

---
 src/baguette-crystal-base.cr | 52 ++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/src/baguette-crystal-base.cr b/src/baguette-crystal-base.cr
index f115fc6..7d58c84 100644
--- a/src/baguette-crystal-base.cr
+++ b/src/baguette-crystal-base.cr
@@ -39,6 +39,58 @@ class Baguette::Configuration
 			end
 		end
 	end
+
+	# Read options from the CLI.
+	# We currently want to know:
+	# - the program verbosity
+	# - the configuration file to use
+	# - if the configuration files should be ignored
+	# - if this is just a simulation (used to print configuration then quit)
+	def self.option_parser
+		simulation = no_configuration = configuration_file = nil
+
+		help = false
+
+		OptionParser.parse do |parser|
+			parser.banner = "usage: #{PROGRAM_NAME} [-ns][-c configuration-file]"
+
+			parser.on "-s", "--simulation",
+				"Print configuration then quit." do
+				simulation = true
+			end
+
+			parser.on "-n", "--no-configuration",
+				"No configuration file should be read." do
+				no_configuration = true
+			end
+
+			parser.on "-v verbosity", "--verbosity level",
+				"Verbosity level. From 0 to 3. Default: 1" do |v|
+				Baguette::Context.verbosity = v.to_i
+			end
+
+			parser.on "-c file", "--configuration file",
+				"Configuration file." do |file|
+				configuration_file = file
+			end
+
+			parser.invalid_option do |arg|
+				# Do not print anything: we only check for configuration file stuff.
+			end
+
+			parser.on "-h", "--help", "Show this help" do
+				Baguette::Log.warning "for the first option parsing!"
+				puts parser
+				help = true
+			end
+		end
+
+		# Options are removed once read from the ARGV array, but we want to propagate
+		# this particular option to print the second set of options.
+		ARGV.push "-h" if help
+
+		return simulation, no_configuration, configuration_file
+	end
 end
 
 class Baguette::Log