Allow for chain to be encoded

.travis.yml

@@ -1,6 +1,7 @@
 language: go
 sudo: false
 go:
+  - 1.11
   - tip
 before_install:
   - go get github.com/mattn/goveralls

README.md

@@ -5,8 +5,6 @@
 
 Port of my Blockchain-PHP library to a Golang. The speed is roughly 90% faster.
 
-*Note: Not yet completed.*
-
 ## Usage
 
 ```go
@@ -17,6 +15,8 @@ import (
   "fmt"
 )
 
+// See tests for more examples...
+
 // New chain.
 c := new(gc.Chain)
 
@@ -30,7 +30,23 @@ blk1.GenerateHash(true)
 blk2.Mine()
 blk2.GenerateHash(true)
 
-fmt.Println("Chain is valid?", c.IsValid()); // See tests for more examples
+fmt.Println("Block valid?", blk.IsValid())
+fmt.Println("Block valid?", blk2.IsValid())
+fmt.Println("Same block?", c.IsSameBlock(blk, blk))
+fmt.Println("Chain is valid?", c.IsValid())
+
+// Block to JSON
+j := blk1.Encode()
+fmt.Println(string(j)) // example: {"previous_hash": ..., "hash": ..., "index": ..., "nonce": ..., "timestamp": ..., "difficulty": ..., "data": ...}
+
+// Chain to JSON
+cj := c.Encode()
+fmt.Println(string(j)) // example: {"blocks":[{"previous_hash": ..., "hash": ..., "index": ..., "nonce": ..., "timestamp": ..., "difficulty": ..., "data": ...}, {...}]}
+
+// Get first, last, previous blocks
+fb, _ := c.FirstBlock() // equals blk1, if no first block, error will be second return
+lb, _ := c.LastBlock() // equals blk2, if no last block, error will be second return
+pb, _ := c.PreviousBlock(1) // by index, 1 - 1 = 0, so this will equal blk1, if no previous block, error will be second return
 ```
 
 ## Testing

chain.go

@@ -2,13 +2,21 @@ package gochain
 
 import (
 	"bytes"
+	"encoding/json"
 	"errors"
 	"time"
 )
 
 // Reprecents a block chain.
 type Chain struct {
-	Blocks []*Block
+	Blocks []*Block `json:"blocks"`
+}
+
+// Encodes the struct to JSON format.
+func (c Chain) Encode() (j []byte) {
+	j, _ = json.Marshal(c)
+
+	return
 }
 
 // Return the chain length.

chain_test.go

@@ -3,6 +3,7 @@ package gochain
 import (
 	"reflect"
 	"testing"
+	"time"
 )
 
 // Test chain has a length.
@@ -195,3 +196,21 @@ func TestInValidChain(t *testing.T) {
 		t.Errorf("Expected chain to invalid but result was valid")
 	}
 }
+
+// Test chain ability to encode its struct to JSON data.
+func TestChainEncode(t *testing.T) {
+	// New chain.
+	c := new(Chain)
+
+	// Add a block manually
+	blk := createBlock()
+	c.AddBlock(blk)
+
+	// Actual and expected.
+	a := string(c.Encode())
+	e := "{\"blocks\":[{\"previous_hash\":null,\"hash\":null,\"index\":1,\"nonce\":0,\"difficulty\":1,\"data\":\"Hello World\",\"timestamp\":\"" + blk.Timestamp.Format(time.RFC3339Nano) + "\"}]}"
+
+	if a != e {
+		t.Errorf("Expected encode of %s but got %s", a, e)
+	}
+}