OPENAPI: these columns and such are actually int pointers, so we have…

… to dereference them

model/report.go

@@ -4,11 +4,64 @@
 package model
 
 import (
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
 	"github.com/pb33f/libopenapi/what-changed/model"
 	"github.com/pb33f/libopenapi/what-changed/reports"
 	"time"
 )
 
+type HashedChange struct {
+	*model.Change
+	ChangeHash string `json:"changeHash,omitempty"`
+}
+
+func (hc *HashedChange) MarshalJSON() ([]byte, error) {
+	changeJson, err := hc.Change.MarshalJSON()
+
+	if err != nil {
+		return nil, err
+	}
+
+	var data map[string]interface{}
+
+	err = json.Unmarshal(changeJson, &data)
+	if err != nil {
+		return nil, err
+	}
+
+	data["changeHash"] = hc.ChangeHash
+
+	return json.Marshal(data)
+}
+
+func getIntValue(pointer *int) int {
+	if pointer == nil {
+		return -1
+	}
+
+	return *pointer
+}
+
+func (hc *HashedChange) HashChange() {
+
+	context := hc.Context
+	contextString := fmt.Sprintf("%d-%d-%d-%d",
+		getIntValue(context.OriginalLine),
+		getIntValue(context.OriginalColumn),
+		getIntValue(context.NewLine),
+		getIntValue(context.NewColumn))
+
+	changeString := fmt.Sprintf("%d-%s-%s-%s-%s", hc.ChangeType, hc.Property, hc.Original, hc.New, contextString)
+
+	hasher := sha256.New()
+	hasher.Write([]byte(changeString))
+
+	hc.ChangeHash = base64.URLEncoding.EncodeToString(hasher.Sum(nil))
+}
+
 type Report struct {
 	ID        uint                        `gorm:"primaryKey" json:"-"`
 	Summary   map[string]*reports.Changed `gorm:"-" json:"reportSummary"`