package logging

import (
	"log/slog"
	"os"

	"github.com/go-kratos/kratos/contrib/otel/v3/tracing"
	kratoslog "github.com/go-kratos/kratos/v3/log"
	"go.uber.org/zap"
	"go.uber.org/zap/exp/zapslog"
	"go.uber.org/zap/zapcore"
)

// NewZapLogger adapts a Zap core to the slog logger used by Kratos v3.
// The file layout remains compatible with the administration log viewer.
func NewZapLogger(root, filename string, attrs ...any) (*slog.Logger, func()) {
	file := NewDailyWriter(root, filename)
	encoder := zap.NewProductionEncoderConfig()
	encoder.EncodeTime = zapcore.ISO8601TimeEncoder
	encoder.EncodeLevel = zapcore.LowercaseLevelEncoder
	core := zapcore.NewCore(
		zapcore.NewJSONEncoder(encoder),
		zapcore.NewMultiWriteSyncer(zapcore.AddSync(os.Stdout), zapcore.AddSync(file)),
		zap.NewAtomicLevelAt(zap.InfoLevel),
	)
	zapLogger := zap.New(core)
	handler := zapslog.NewHandler(zapLogger.Core(), zapslog.WithCaller(true), zapslog.AddStacktraceAt(slog.LevelError))
	logger := kratoslog.NewLogger(handler, kratoslog.WithExtractor(tracing.TraceAttrs)).With(attrs...)
	cleanup := func() {
		_ = zapLogger.Sync()
		_ = file.Close()
	}
	return logger, cleanup
}