// Copyright 2023 wanderer <a_mirre at utb dot cz>
// SPDX-License-Identifier: AGPL-3.0-only

package slogging

import (
	"fmt"
	"os"

	"golang.org/x/exp/slog"
)

type Slogger struct {
	*slog.Logger
}

const (
	LevelInfo int = iota
	LevelDebug
	LevelWarn
	LevelError
)

var (
	logger      *Slogger
	opts        *slog.HandlerOptions
	initialised = false
)

func Opts() *slog.HandlerOptions {
	return opts
}

func Logger() *Slogger {
	return logger
}

func Init(jsonHandler bool) *Slogger {
	opts = &slog.HandlerOptions{
		Level: slog.LevelInfo,
	}

	if jsonHandler {
		logger = &Slogger{slog.New(slog.NewJSONHandler(os.Stderr, opts))}
	} else {
		logger = &Slogger{slog.New(slog.NewTextHandler(os.Stderr, opts))}
	}

	slog.SetDefault(logger.Logger)

	if initialised {
		logger.Info("slog logger reinitialised")
	} else {
		initialised = true
		logger.Info("slog logger initialised")
	}

	return logger
}

// SetLevel allows setting log level and returns the pointer to the re-created
// logger.
func SetLevel(level int) *Slogger {
	switch level {
	case LevelInfo:
		opts.Level = slog.LevelInfo

	case LevelDebug:
		opts.Level = slog.LevelDebug

	case LevelWarn:
		opts.Level = slog.LevelWarn

	case LevelError:
		opts.Level = slog.LevelError

	default:
		logger.Infof("unknown level '%d', resetting to level INFO", level)

		opts.Level = slog.LevelInfo
	}

	if _, ok := logger.Handler().(*slog.JSONHandler); ok {
		logger = &Slogger{slog.New(slog.NewJSONHandler(os.Stderr, opts))}
	} else {
		logger = &Slogger{slog.New(slog.NewTextHandler(os.Stderr, opts))}
	}

	slog.SetDefault(logger.Logger)

	return logger
}

func (l *Slogger) Debugf(msg string, args ...any) {
	l.Debug(fmt.Sprintf(msg, args...))
}

func (l *Slogger) Infof(msg string, args ...any) {
	l.Info(fmt.Sprintf(msg, args...))
}

func (l *Slogger) Warnf(msg string, args ...any) {
	l.Warn(fmt.Sprintf(msg, args...))
}

func (l *Slogger) Errorf(msg string, args ...any) {
	l.Error(fmt.Sprintf(msg, args...))
}