package config

import (
	"flag"
	"fmt"
	"os"
	"strconv"
	"strings"
	"time"
)

func getEnvKey(key string) string {
	return fmt.Sprintf("YTDL_WEB_%s", strings.ReplaceAll(strings.ToUpper(key), ".", "_"))
}

func String(key string, defaultValue string, usage string) func() string {
	flagValue := flag.String(key, defaultValue, usage)
	return func() string {
		if flagValue != nil && *flagValue != defaultValue {
			return *flagValue
		}

		envValue, ok := os.LookupEnv(getEnvKey(key))
		if ok {
			return envValue
		}

		return defaultValue
	}
}

func Int(key string, defaultValue int, usage string) func() int {
	flagValue := flag.Int(key, defaultValue, usage)
	return func() int {
		if flagValue != nil && *flagValue != defaultValue {
			return *flagValue
		}

		envValue, ok := os.LookupEnv(getEnvKey(key))
		if ok {
			value, err := strconv.Atoi(envValue)
			if err == nil {
				return value
			}
		}

		return defaultValue
	}
}

func Bool(key string, defaultValue bool, usage string) func() bool {
	flagValue := flag.Bool(key, defaultValue, usage)
	return func() bool {
		if flagValue != nil && *flagValue != defaultValue {
			return *flagValue
		}

		envValue, ok := os.LookupEnv(getEnvKey(key))
		if ok {
			value, err := strconv.ParseBool(envValue)
			if err == nil {
				return value
			}
		}

		return defaultValue
	}
}

func StringSlice(key string, defaultValue []string, usage string) func() []string {
	defaultString := strings.Join(defaultValue, ",")
	flagValue := flag.String(key, defaultString, usage)
	return func() []string {
		if flagValue != nil && *flagValue != defaultString {
			return strings.Split(*flagValue, ",")
		}

		envValue, ok := os.LookupEnv(getEnvKey(key))
		if ok {
			return strings.Split(envValue, ",")
		}

		return defaultValue
	}
}

func Duration(key string, defaultValue time.Duration, usage string) func() time.Duration {
	flagValue := flag.Duration(key, defaultValue, usage)
	return func() time.Duration {
		if flagValue != nil && *flagValue != defaultValue {
			return *flagValue
		}

		envValue, ok := os.LookupEnv(getEnvKey(key))
		if ok {
			value, err := time.ParseDuration(envValue)
			if err == nil {
				return value
			}
		}

		return defaultValue
	}
}