package logging

import (
	"fmt"
	"os"
	"strconv"
	"time"

	"github.com/go-logr/logr"
	zaplib "go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"
)

const (
	LogLevelDebug = "debug"
	LogLevelInfo  = "info"
	LogLevelWarn  = "warn"
	LogLevelError = "error"
)

func NewLogger(logLevel string) logr.Logger {
	log := zap.New(func(o *zap.Options) {
		switch logLevel {
		case LogLevelDebug:
			o.Development = true
			lvl := zaplib.NewAtomicLevelAt(zaplib.DebugLevel) // maps to logr's V(1)
			o.Level = &lvl
		case LogLevelInfo:
			lvl := zaplib.NewAtomicLevelAt(zaplib.InfoLevel)
			o.Level = &lvl
		case LogLevelWarn:
			lvl := zaplib.NewAtomicLevelAt(zaplib.WarnLevel)
			o.Level = &lvl
		case LogLevelError:
			lvl := zaplib.NewAtomicLevelAt(zaplib.ErrorLevel)
			o.Level = &lvl
		default:
			// We use bitsize of 8 as zapcore.Level is a type alias to int8
			levelInt, err := strconv.ParseInt(logLevel, 10, 8)
			if err != nil {
				fmt.Fprintf(os.Stderr, "Failed to parse --log-level=%s: %v", logLevel, err)
				os.Exit(1)
			}

			// For example, --log-level=debug a.k.a --log-level=-1 maps to zaplib.DebugLevel, which is associated to logr's V(1)
			// --log-level=-2 maps the specific custom log level that is associated to logr's V(2).
			level := zapcore.Level(levelInt)
			atomicLevel := zaplib.NewAtomicLevelAt(level)
			o.Level = &atomicLevel
		}
		o.TimeEncoder = zapcore.TimeEncoderOfLayout(time.RFC3339)
	})

	return log
}