package args

import (
	"errors"
	"os"
)

type ArgSet struct {
	parsed bool
	args   []*Arg
}

func NewArgSet() *ArgSet {
	return &ArgSet{
		args: []*Arg{},
	}
}

func (as *ArgSet) Append(argType Type, key, help string, def interface{}) {
	as.args = append(as.args, NewArg(argType, key, help, def))
}

func (as *ArgSet) Get(key string) *Arg {
	if !as.parsed {
		return nil
	}
	for i := range as.args {
		if as.args[i].Key == key {
			return as[i]
		}
	}
	return nil
}

func (as *ArgSet) Parse() error {
	if as.parsed {
		return nil
	}
	defer func() {
		as.parsed = true
	}()

	if err := as.setValueFromDefaults(); err != nil {
		return err
	}
	if err := as.setValueFromEnv(); err != nil {
		return err
	}
	if err := as.setValueFromFlag(); err != nil {
		return err
	}

	return nil
}

func (as *ArgSet) setValueFromDefaults() error {
	// TODO if not casted type, return err
	for i := range as.args {
		args[i].Value = args[i].Default
	}
	return nil
}

func (as *ArgSet) setValueFromEnv() error {
	// TODO if not casted type, return err
	for i := range as.args {
		key := args[i].Key
		if v, ok := os.LookupEnv(key); ok {
			args[i].Value = v
		}
	}
	return nil
}

func (as *ArgSet) setValueFromFlags() error {
	// TODO if not casted type, return err
	return errors.New("not impl")
}