package main

import (
	"context"
	"encoding/json"
	"fmt"
)

// =============================================================================
// SMART CONTRACT IMPLEMENTATION - MODIFY THIS FILE
// =============================================================================

// Transaction represents the parsed transaction from the server.
// Customize this struct to match your transaction payload structure.
type Transaction struct {
	Version string            `json:"version"`
	Header  TransactionHeader `json:"header"`
	Payload map[string]any    `json:"payload"`
}

// TransactionHeader contains transaction metadata from Dragonchain.
type TransactionHeader struct {
	Tag       string `json:"tag"`
	DcId      string `json:"dc_id"`
	TxnId     string `json:"txn_id"`
	BlockId   string `json:"block_id"`
	TxnType   string `json:"txn_type"`
	Timestamp string `json:"timestamp"`
	Invoker   string `json:"invoker"`
}

// ProcessResult is the result returned from the Process function.
type ProcessResult struct {
	Data          map[string]any
	OutputToChain bool
	Error         error
}

// Process is the main function that handles incoming transactions.
// Implement your smart contract logic here.
//
// Parameters:
//   - ctx: Context for cancellation and timeouts
//   - txJSON: Raw transaction JSON string
//   - envVars: Environment variables passed from the server
//   - secrets: Secrets passed from the server (e.g., API keys, credentials)
//
// Returns:
//   - ProcessResult containing the result data, whether to output to chain, and any error
func Process(ctx context.Context, txJSON string, envVars, secrets map[string]string) ProcessResult {
	// Parse the transaction JSON
	var tx Transaction
	if err := json.Unmarshal([]byte(txJSON), &tx); err != nil {
		return ProcessResult{
			Error: fmt.Errorf("failed to parse transaction: %w", err),
		}
	}

	// ==========================================================================
	// TODO: Implement your smart contract logic here
	// ==========================================================================
	//
	// Example: Access transaction data
	// txnId := tx.Header.TxnId
	// txnType := tx.Header.TxnType
	// payload := tx.Payload
	//
	// Example: Access environment variables
	// scName := envVars["SMART_CONTRACT_NAME"]
	// dcID := envVars["DRAGONCHAIN_ID"]
	//
	// Example: Access secrets
	// apiKey := secrets["SC_SECRET_MY_API_KEY"]
	//
	// Example: Process based on payload action
	// action, _ := tx.Payload["action"].(string)
	// switch action {
	// case "create":
	//     // Handle create operation
	// case "update":
	//     // Handle update operation
	// default:
	//     return ProcessResult{Error: fmt.Errorf("unknown action: %s", action)}
	// }

	// Default implementation: echo back the transaction
	result := map[string]any{
		"status":         "processed",
		"transaction_id": tx.Header.TxnId,
		"txn_type":       tx.Header.TxnType,
		"payload":        tx.Payload,
		"message":        "Transaction processed successfully",
	}

	return ProcessResult{
		Data:          result,
		OutputToChain: true,
		Error:         nil,
	}
}