receipt.go

// Copyright 2016 Factom Foundation
// Use of this source code is governed by the MIT
// license that can be found in the LICENSE file.

package factom

import (
	"encoding/json"
	"fmt"
)

// Receipt is the Merkel proof that a given Entry and its metadata (such as the
// Entry Block timestamp) have been written to the Factom Blockchain and
// possibly anchored into Bitcoin, Etherium, or other blockchains.
//
// The data from the reciept may be used to reconstruct the Merkel proof for the
// requested Entry thus cryptographically proving the Entry is represented by a
// known Factom Directory Block.
type Receipt struct {
	Entry struct {
		Raw       string `json:"raw,omitempty"`
		EntryHash string `json:"entryhash,omitempty"`
		Json      string `json:"json,omitempty"`
	} `json:"entry,omitempty"`
	MerkleBranch []struct {
		Left  string `json:"left,omitempty"`
		Right string `json:"right,omitempty"`
		Top   string `json:"top,omitempty"`
	} `json:"merklebranch,omitempty"`
	EntryBlockKeyMR        string `json:"entryblockkeymr,omitempty"`
	DirectoryBlockKeyMR    string `json:"directoryblockkeymr,omitempty"`
	BitcoinTransactionHash string `json:"bitcointransactionhash,omitempty"`
	BitcoinBlockHash       string `json:"bitcoinblockhash,omitempty"`
}

func (r *Receipt) String() string {
	var s string

	if r.Entry.Raw != "" {
		s += fmt.Sprintln("Raw:", r.Entry.Raw)
	}
	if r.Entry.EntryHash != "" {
		s += fmt.Sprintln("EntryHash:", r.Entry.EntryHash)
	}
	if r.Entry.Json != "" {
		s += fmt.Sprintln("JSON:", r.Entry.Json)
	}
	s += fmt.Sprintln("DirectoryBlockKeyMR:", r.DirectoryBlockKeyMR)
	s += fmt.Sprintln("EntryBlockKeyMR:", r.EntryBlockKeyMR)
	s += fmt.Sprintln("BitcoinTransactionHash:", r.BitcoinTransactionHash)
	s += fmt.Sprintln("BitcoinBlockHash:", r.BitcoinBlockHash)
	s += fmt.Sprintln("MerkelBranch [")
	for _, b := range r.MerkleBranch {
		s += fmt.Sprintln(" {")
		s += fmt.Sprintln("  left:", b.Left)
		s += fmt.Sprintln("  right:", b.Right)
		s += fmt.Sprintln("  top:", b.Top)
		s += fmt.Sprintln(" }")
	}
	s += fmt.Sprintln("]")

	return s
}

// GetReceipt requests a Receipt for a given Factom Entry.
func GetReceipt(hash string) (*Receipt, error) {
	type receiptResponse struct {
		Receipt *Receipt `json:"receipt"`
	}

	params := hashRequest{Hash: hash}
	req := NewJSON2Request("receipt", APICounter(), params)
	resp, err := factomdRequest(req)
	if err != nil {
		return nil, err
	}
	if resp.Error != nil {
		return nil, resp.Error
	}

	rec := new(receiptResponse)
	if err := json.Unmarshal(resp.JSONResult(), rec); err != nil {
		return nil, err
	}

	return rec.Receipt, nil
}