package logger

import (
	"context"

	"git.dcentral.systems/toolz/goplt/pkg/logger"
	"go.opentelemetry.io/otel/trace"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

// Note: contextKey constants are defined in middleware.go to avoid duplication

// zapLogger implements the Logger interface using zap.
type zapLogger struct {
	zap *zap.Logger
}

// NewZapLogger creates a new zap-based logger.
// The format parameter determines the output format:
// - "json": JSON format (production)
// - "console": Human-readable format (development)
func NewZapLogger(level string, format string) (logger.Logger, error) {
	var zapConfig zap.Config
	var zapLevel zapcore.Level

	// Parse log level
	if err := zapLevel.UnmarshalText([]byte(level)); err != nil {
		zapLevel = zapcore.InfoLevel
	}

	// Configure based on format
	if format == "json" {
		zapConfig = zap.NewProductionConfig()
	} else {
		zapConfig = zap.NewDevelopmentConfig()
	}

	zapConfig.Level = zap.NewAtomicLevelAt(zapLevel)
	zapConfig.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder

	z, err := zapConfig.Build()
	if err != nil {
		return nil, err
	}

	return &zapLogger{zap: z}, nil
}

// Debug logs a message at debug level.
func (zl *zapLogger) Debug(msg string, fields ...logger.Field) {
	zl.zap.Debug(msg, convertFields(fields)...)
}

// Info logs a message at info level.
func (zl *zapLogger) Info(msg string, fields ...logger.Field) {
	zl.zap.Info(msg, convertFields(fields)...)
}

// Warn logs a message at warning level.
func (zl *zapLogger) Warn(msg string, fields ...logger.Field) {
	zl.zap.Warn(msg, convertFields(fields)...)
}

// Error logs a message at error level.
func (zl *zapLogger) Error(msg string, fields ...logger.Field) {
	zl.zap.Error(msg, convertFields(fields)...)
}

// With creates a child logger with the specified fields.
func (zl *zapLogger) With(fields ...logger.Field) logger.Logger {
	return &zapLogger{
		zap: zl.zap.With(convertFields(fields)...),
	}
}

// WithContext creates a child logger with fields extracted from context.
func (zl *zapLogger) WithContext(ctx context.Context) logger.Logger {
	fields := make([]logger.Field, 0)

	// Extract request ID from context
	if requestID, ok := ctx.Value(requestIDKey).(string); ok && requestID != "" {
		fields = append(fields, zap.String("request_id", requestID))
	}

	// Extract user ID from context
	if userID, ok := ctx.Value(userIDKey).(string); ok && userID != "" {
		fields = append(fields, zap.String("user_id", userID))
	}

	// Extract trace ID from OpenTelemetry context
	span := trace.SpanFromContext(ctx)
	if span.SpanContext().IsValid() {
		traceID := span.SpanContext().TraceID().String()
		spanID := span.SpanContext().SpanID().String()
		if traceID != "" {
			fields = append(fields, zap.String("trace_id", traceID))
		}
		if spanID != "" {
			fields = append(fields, zap.String("span_id", spanID))
		}
	}

	if len(fields) == 0 {
		return zl
	}

	return &zapLogger{
		zap: zl.zap.With(convertFields(fields)...),
	}
}

// convertFields converts logger.Field to zap.Field.
// Since Field is an alias for zap.Field, we can cast directly.
func convertFields(fields []logger.Field) []zap.Field {
	if len(fields) == 0 {
		return nil
	}

	zapFields := make([]zap.Field, 0, len(fields))
	for _, f := range fields {
		// Type assert to zap.Field
		if zf, ok := f.(zap.Field); ok {
			zapFields = append(zapFields, zf)
		} else {
			// Fallback: convert to Any field
			zapFields = append(zapFields, zap.Any("field", f))
		}
	}
	return zapFields
}

// RequestIDKey returns the context key for request ID.
// This is exported so modules can use it to set request IDs in context.
func RequestIDKey() ContextKey {
	return requestIDKey
}

// UserIDKey returns the context key for user ID.
// This is exported so modules can use it to set user IDs in context.
func UserIDKey() ContextKey {
	return userIDKey
}