package applog

import (
	"errors"
	"fmt"
	"log/slog"
	"os"
	"time"

	"gitea.auvem.com/go-toolkit/app"
	"github.com/lmittmann/tint"
	slogmulti "github.com/samber/slog-multi"
)

type moduleState struct {
	opts           AppLogOpts
	logfile        *os.File
	consoleHandler slog.Handler
}

func (s *moduleState) setup(m *app.Module) error {
	if s.opts.FileOutput == "" && s.opts.ConsoleOutput == nil {
		return fmt.Errorf("no logging output configured")
	}

	handlers := make([]slog.Handler, 0, 2)

	if s.opts.FileOutput != "" {
		f, err := os.OpenFile(s.opts.FileOutput, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
		if err != nil {
			return err
		}
		s.logfile = f

		fileLevel := s.opts.FileLevel
		if fileLevel == 0 && s.opts.ConsoleOutput == nil {
			fileLevel = slog.LevelInfo
		}
		handlers = append(handlers, slog.NewJSONHandler(f, &slog.HandlerOptions{Level: fileLevel}))
	}

	if s.opts.ConsoleOutput != nil {
		consoleLevel := s.opts.ConsoleLevel
		if consoleLevel == 0 {
			consoleLevel = slog.LevelInfo
		}
		s.consoleHandler = tint.NewHandler(s.opts.ConsoleOutput, &tint.Options{
			Level:      consoleLevel,
			TimeFormat: time.Kitchen,
		})
		handlers = append(handlers, s.consoleHandler)
	}

	logger := slog.New(slogmulti.Fanout(handlers...))
	m.Lifecycle().WithLogger(logger)

	if s.opts.SetDefault {
		slog.SetDefault(logger)
	}

	if !s.opts.DisableAnnouncement {
		logger.Info("Logger initialized", "module", ModuleName)
	}

	return nil
}

func (s *moduleState) teardown(lifecycle *app.Lifecycle) error {
	if lifecycle != nil {
		switch {
		case s.consoleHandler != nil:
			lifecycle.WithLogger(slog.New(s.consoleHandler))
		default:
			lifecycle.WithLogger(slog.New(slog.DiscardHandler))
		}
	}

	if s.logfile == nil {
		return nil
	}

	var err error
	if syncErr := s.logfile.Sync(); syncErr != nil {
		err = fmt.Errorf("flush log file: %w", syncErr)
	}
	if closeErr := s.logfile.Close(); closeErr != nil {
		err = errors.Join(err, fmt.Errorf("close log file: %w", closeErr))
	}
	s.logfile = nil
	return err
}