package cfg

import (
	"fmt"
	"os"

	"github.com/alecthomas/kong"
)

type AppSettings struct {
	ServerAddress string
	DataFile      string
	DataURL       string
}

var cliStruct struct {
	ServerAddress string `name:"listen-address" env:"GEOIP_LISTEN_ADDRESS" help:"Address to use for the metrics server" default:"${default_address}"`
	DataFile      string `name:"data-file" env:"GEOIP_DATA_FILE" help:"path to data file" default:"${default_file_path}"`
	DataURL       string `name:"data-url" env:"GEOIP_DATA_URL" help:"url to data file" default:"${default_file_url}"`
}

func Parse() *AppSettings {
	ctx := kong.Parse(
		&cliStruct,
		kong.Vars{
			"default_address":   ":8080",
			"default_file_path": "./data.csv",
			"default_file_url":  "https://data.neuber.io/data.csv",
		},
		kong.Name("country_geo_locations"),
		kong.Description("🚀 Start a simple web server for GeoIP data"),
		kong.UsageOnError(),
	)

	validateFlags(ctx)
	settings := &AppSettings{
		ServerAddress: cliStruct.ServerAddress,
		DataFile:      cliStruct.DataFile,
		DataURL:       cliStruct.DataURL,
	}
	return settings
}

func validateFlags(cliCtx *kong.Context) {
	var flagsValid = true
	var messages = []string{}
	if cliStruct.ServerAddress == "" {
		messages = append(messages, "error: invalid server address, must not be blank")
		flagsValid = false
	}
	if !flagsValid {
		cliCtx.PrintUsage(false)
		fmt.Println()
		for i := 0; i < len(messages); i++ {
			fmt.Println(messages[i])
		}
		os.Exit(1)
	}
}