parser/flag.go

package parser

import (
	"fmt"
	"strconv"
	"errors"
)

type ArgFlag struct {
	Name string
	Short string
	Long string
	Description string
	Type ArgType 
	Arg string
	Args []string
	OnMatch func () error
}

var flags = make(map[string]*ArgFlag)

func (f *ArgFlag) requireArg() bool {
	return f.Type != NoneType && f.Type != BoolType && f.Type != MatchType
}

func (f *ArgFlag) invalid() bool {
	return f.Name != ""
}

func (f *ArgFlag) Matches(identifier string) bool {
	if f.Name == identifier || f.Short == identifier || f.Long == identifier {
		return true
	}
	return false
}

func (f *ArgFlag) GetIndex() (int, error) {
	for i, arg := range f.Args {
		if arg == f.Short || arg == f.Long {
			return i, nil
		}
	}

	return 0, fmt.Errorf("ERROR : Flag(%s) not found in arguments", f.Name)
}

func (f *ArgFlag) GetValueInt() (int64, error) {
	if f.Type != IntType {
		return 0, fmt.Errorf("ERROR : Flag(%s) is not a IntType flag", f.symbol())
	}

	return strconv.ParseInt(f.Arg, 10, 64)
}

func (f *ArgFlag) GetValueString() (string, error) {
	if f.Type != StringType {
		return "", fmt.Errorf("ERROR : Flag(%s) is not a StringType flag", f.Name)
	}

	return f.Arg, nil
}

func (f *ArgFlag) symbol() string {
	index, err := f.GetIndex()
	if err != nil {
		return f.Name
	}

	return f.Args[index]
}

func (f *ArgFlag) GetValueFloat32() (float32, error) {
	if f.Type != Float32Type {
		return 0.0, fmt.Errorf("ERROR : Flag(%s) is not a Float32Type flag", f.symbol())
	}

	float, err := strconv.ParseFloat(f.Arg, 32)

	if err != nil {
		return 0.0, err
	}

	return float32(float), nil
}

func (f *ArgFlag) GetValueFloat64() (float64, error) {
	if f.Type != Float64Type {
		return 0.0, fmt.Errorf("ERROR : Flag(%s) is not a Float64Type flag", f.symbol())
	}
	return strconv.ParseFloat(f.Arg, 64)
}

func (f *ArgFlag) GetValueBool() (bool, error) {
	if f.Type != BoolType {
		return false, fmt.Errorf("ERROR : Flag(%s) is not a BoolType flag", f.symbol())
	}

	_, err := f.GetIndex()
	if err != nil {
		return false, nil
	} else {
		return true, nil
	}
}

type CheckFunc func(string) (bool,error)

func (f *ArgFlag) doCheck(arg string, check CheckFunc, error_string string) error {
		is_true, err := check(arg)
		if err != nil {
			return err
		}
		if ! is_true {
			return fmt.Errorf(error_string, f.symbol())
		}
		return nil
}

func (f *ArgFlag) CheckArg(args []string) error {
	// Just checking if the argument provided to this flag is a valid one based on the ArgType
	f.Args = args
	if f.Type == NoneType {
			return fmt.Errorf("ArgFlag(%s) : ERROR : Flag not configured with a type", f.symbol())
	}

	if len(args) < 2 {
		return fmt.Errorf("ArgFlag(%s) : ERROR : Not enough arguments", f.Name)
	}

	arg := args[1]

	switch f.Type {
	case StringType:
		is_flag, err := isFlag(arg)
		if err != nil {
			return err
		}
		if is_flag {
			return fmt.Errorf("Flag(%s) : ERROR : Argument is a flag", f.symbol())
		}
	case IntType:
		err := f.doCheck(arg, isInt, "Flag(%s) : ERROR : Argument is not a valid number")
		if err != nil {
			return err
		}
	case Float32Type, Float64Type:
		err := f.doCheck(arg, isFloat, "Flag(%s) : ERROR : Argument is not a valid float")
		if err != nil {
			return err
		}
	}

	f.Arg = arg

	return nil
}

func (f *ArgFlag) Check() error {
	if f.Name == "" {
		return errors.New("ERROR : Flag was not configured with Name")
	}
	if f.Type == NoneType {
		return fmt.Errorf("ArgFlag(%s) : ERROR : No type has been set", f.Name)
	}

	if f.Description == "" {
		return fmt.Errorf("ArgFlag(%s) : ERROR : No Description has been set", f.Name)
	}

	if f.Short == "" && f.Long == "" {
		return fmt.Errorf("ArgFlag(%s) : ERROR : No Short or Long flags were provided", f.Name)
	}

	return nil
}