// Package walletmq defines RocketMQ payloads owned by wallet-service.
package walletmq

import (
	"encoding/json"
	"errors"
	"strings"
)

const (
	MessageTypeWalletOutboxEvent = "wallet_outbox_event"

	TagWalletOutboxEvent = "wallet_outbox_event"
)

// WalletOutboxMessage is the MQ representation of one committed wallet_outbox fact.
type WalletOutboxMessage struct {
	MessageType    string `json:"message_type"`
	AppCode        string `json:"app_code"`
	EventID        string `json:"event_id"`
	EventType      string `json:"event_type"`
	TransactionID  string `json:"transaction_id"`
	CommandID      string `json:"command_id"`
	UserID         int64  `json:"user_id"`
	AssetType      string `json:"asset_type"`
	AvailableDelta int64  `json:"available_delta"`
	FrozenDelta    int64  `json:"frozen_delta"`
	PayloadJSON    string `json:"payload_json"`
	OccurredAtMS   int64  `json:"occurred_at_ms"`
}

// EncodeWalletOutboxMessage serializes a wallet fact for fanout through RocketMQ.
func EncodeWalletOutboxMessage(message WalletOutboxMessage) ([]byte, error) {
	message.MessageType = MessageTypeWalletOutboxEvent
	if strings.TrimSpace(message.AppCode) == "" ||
		strings.TrimSpace(message.EventID) == "" ||
		strings.TrimSpace(message.EventType) == "" ||
		strings.TrimSpace(message.TransactionID) == "" ||
		strings.TrimSpace(message.CommandID) == "" ||
		message.OccurredAtMS <= 0 {
		return nil, errors.New("wallet outbox message is incomplete")
	}
	if strings.TrimSpace(message.PayloadJSON) == "" {
		message.PayloadJSON = "{}"
	}
	return json.Marshal(message)
}

// DecodeWalletOutboxMessage validates the MQ body and restores the wallet fact.
func DecodeWalletOutboxMessage(body []byte) (WalletOutboxMessage, error) {
	var message WalletOutboxMessage
	if err := json.Unmarshal(body, &message); err != nil {
		return WalletOutboxMessage{}, err
	}
	if message.MessageType != MessageTypeWalletOutboxEvent {
		return WalletOutboxMessage{}, errors.New("unexpected wallet outbox message_type")
	}
	if strings.TrimSpace(message.AppCode) == "" ||
		strings.TrimSpace(message.EventID) == "" ||
		strings.TrimSpace(message.EventType) == "" ||
		strings.TrimSpace(message.TransactionID) == "" ||
		strings.TrimSpace(message.CommandID) == "" ||
		message.OccurredAtMS <= 0 {
		return WalletOutboxMessage{}, errors.New("wallet outbox message is incomplete")
	}
	if strings.TrimSpace(message.PayloadJSON) == "" {
		message.PayloadJSON = "{}"
	}
	return message, nil
}