package fog

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

var levels = map[string]int8{
	"info":  0,
	"debug": 1,
	"error": -1, // -1 signals via options to only log errors
}

var flagOpts options

func BindFlags(_ *flag.FlagSet) {
	var lvl lvlFlag
	lvl.setFunc = func(v int8) {
		flagOpts.lvl = v
	}
}

type lvlFlag struct {
	setFunc func(int8)
	value   string
}

// assert that our log level flag implements interface for binding to a command
// line flag
var _ flag.Value = &lvlFlag{}

// Set checks if the flag value matches one of the string representations for a
// logging level. If it is, it returns the corresponding int from the levels map.
// Otherwise the value is converted into an integer. Passing an integer value
// greater than 1 will allow you to use logging levels above debug, even though
// that is the most verbose log level in GCP.
func (f *lvlFlag) Set(v string) error {
	f.value = v

	lvl, ok := levels[strings.ToLower(v)]
	if ok {
		f.setFunc(lvl)
		return nil
	}

	intLvl, err := strconv.Atoi(v)
	if err != nil || intLvl < 0 {
		return fmt.Errorf("invalid log level '%s': %w", v, err)
	}
	f.setFunc(int8(toZapLevel(intLvl)))

	return nil
}

func (f *lvlFlag) String() string {
	return f.value
}