package main

/* 
	This simply parses the command line arguments using the default golang
	package called 'flag'. This can be used as a simple template to parse
	command line arguments in other programs.

	It puts everything in the 'config' package which I think is a good
	wrapper around the 'flags' package and doesn't need a whole mess of
	global variables
*/

import "log"
import "os"
import "flag"
import "fmt"
import "github.com/gookit/config"

var customUsage = func() {
	fmt.Fprintf(flag.CommandLine.Output(), "Usage of %s:\n", os.Args[0])
	flag.PrintDefaults()

	fmt.Println("")
	fmt.Println("EXAMPLES:")
	fmt.Println("")
	fmt.Println(os.Args[0] + " --width 1024 --height 768 --drift .1 --filename shaders/seascape.glsl")
	fmt.Println(os.Args[0] + " --width 640 --height 480 --filename shaders/planetfall.glsl")
	fmt.Println("")
}

func parseFlags() {
	var version       string
	var race          bool
	var filename      string
	var width         int
	var height        int
	var glDrift       float64

	flag.StringVar  (&version,       "version",       "v0.1",                     "Set compiled in version string")

	flag.StringVar  (&filename,      "filename",      "shaders/seascape.glsl",    "path to GLSL file")
	flag.IntVar     (&width,         "width",         1024,                       "Width of the OpenGL Window")
	flag.IntVar     (&height,        "height",        768,                        "Height of the OpenGL Window")

	flag.Float64Var (&glDrift,       "drift",         0.01,                       "Speed of the gradual camera drift")
	flag.BoolVar    (&race,          "race",          race,                       "Use race detector")

	// Set the output if something fails to stdout rather than stderr
	flag.CommandLine.SetOutput(os.Stdout)

	flag.Usage = customUsage
	flag.Parse()

	if flag.Parsed() {
		log.Println("flag.Parse() worked")
	} else {
		log.Println("flag.Parse() failed")
	}

	// keys := []string{"filename", "width", "height", "drift"}
	// keys := []string{"width", "height", "drift"}

//	keys := []string{"height"}
//	config.LoadFlags(keys)

	config.Set("width", width)
	config.Set("height", height)
	config.Set("glDrift", glDrift)
	config.Set("filename", filename)
}

func parseConfig() {
	config.WithOptions(config.ParseEnv)
	parseFlags()

	// config.LoadOSEnv([]string{"MAIL"})
	// config.LoadOSEnv([]string{"USER"})
	// config.LoadOSEnv([]string{"BUILDDEBUG"})
}