golangdiff.go

package main

import (
	"fmt"
	"net"
	"strings"
	"time"

	"github.com/fatih/color"
	"github.com/google/go-cmp/cmp"
	"github.com/google/go-cmp/cmp/cmpopts"
)

type (
	Gateway struct {
		SSID      string
		IPAddress net.IP
		NetMask   net.IPMask
		Clients   []Client
	}
	Client struct {
		Hostname  string
		IPAddress net.IP
		LastSeen  time.Time
	}
)

// StructDiffReporter is a simple custom reporter that only records differences
// detected during comparison.
type StructDiffReporter struct {
	path  cmp.Path
	diffs []string
}

func (r *StructDiffReporter) PushStep(ps cmp.PathStep) {
	r.path = append(r.path, ps)
}

func (r *StructDiffReporter) Report(rs cmp.Result) {
	if !rs.Equal() {
		vx, vy := r.path.Last().Values()
		missing := fmt.Sprintf("- %+v", vx)
		found := fmt.Sprintf("+ %+v", vy)
		r.diffs = append(r.diffs, fmt.Sprintf("%#v\n\t%s\n\t%s\n", r.path, color.RedString(missing), color.GreenString(found)))
	}
}

func (r *StructDiffReporter) PopStep() {
	r.path = r.path[:len(r.path)-1]
}

func (r *StructDiffReporter) String() string {
	return strings.Join(r.diffs, "\n")
}

// StringDiffReporter is a simple custom reporter that only records differences
// detected during comparison.
type StringDiffReporter struct {
	path  cmp.Path
	diffs []string
}

func (r *StringDiffReporter) PushStep(ps cmp.PathStep) {
	r.path = append(r.path, ps)
}

func (r *StringDiffReporter) Report(rs cmp.Result) {
	if !rs.Equal() {
		vx, vy := r.path.Last().Values()
		missing := fmt.Sprintf("- %+v", vx)
		found := fmt.Sprintf("+ %+v", vy)
		r.diffs = append(r.diffs, fmt.Sprintf("%s\n%s\n", color.RedString(missing), color.GreenString(found)))
	}
}

func (r *StringDiffReporter) PopStep() {
	r.path = r.path[:len(r.path)-1]
}

func (r *StringDiffReporter) String() string {
	return strings.Join(r.diffs, "\n")
}

func main() {
  /**
  	// While the specified fields will be semantically ignored for the comparison,
	// the fields may be printed in the diff when displaying entire values
	// that are already determined to be different.
	if diff := cmp.Diff(want, got, cmpopts.IgnoreFields(Client{}, "IPAddress")); diff != "" {
		lines := strings.Split(diff, "\n")
		changes := ""
		for _, line := range lines {
			if strings.HasPrefix(line, "+") || strings.HasPrefix(line, "-") {
				changes += line + "\n"
			}
		}
		fmt.Println(changes)
		t.Errorf("MakeGatewayInfo() mismatch (-want +got):\n%s", diff)
	}
  **/
  
	got, want := MakeGatewayInfo()
	var r StructDiffReporter
	cmp.Equal(got, want, cmpopts.IgnoreFields(Gateway{}, "IPAddress"), cmpopts.IgnoreFields(Client{}, "IPAddress"), cmp.Reporter(&r))
	if r.String() != "" {
		fmt.Println(r.String())
		return
	}
	fmt.Println("Equal")
}

func MakeGatewayInfo() (x, y Gateway) {
	x = Gateway{
		SSID:      "CoffeeShopWiFi",
		IPAddress: net.IPv4(192, 168, 0, 1),
		NetMask:   net.IPv4Mask(255, 255, 0, 0),
		Clients: []Client{{
			Hostname:  "ristretto",
			IPAddress: net.IPv4(192, 168, 0, 116),
		}, {
			Hostname:  "aribica",
			IPAddress: net.IPv4(192, 168, 0, 104),
			LastSeen:  time.Date(2009, time.November, 10, 23, 6, 32, 0, time.UTC),
		}, {
			Hostname:  "macchiato",
			IPAddress: net.IPv4(192, 168, 0, 153),
			LastSeen:  time.Date(2009, time.November, 10, 23, 39, 43, 0, time.UTC),
		}, {
			Hostname:  "espresso",
			IPAddress: net.IPv4(192, 168, 0, 121),
		}, {
			Hostname:  "latte",
			IPAddress: net.IPv4(192, 168, 0, 219),
			// IPAddress: net.IPv4(192, 168, 0, 221),
			LastSeen: time.Date(2009, time.November, 10, 23, 0, 23, 0, time.UTC),
		},
		// {
		// 	Hostname:  "americano",
		// 	IPAddress: net.IPv4(192, 168, 0, 188),
		// 	LastSeen:  time.Date(2009, time.November, 10, 23, 3, 5, 0, time.UTC),
		// },
		},
	}
	y = Gateway{
		SSID:      "CoffeeShopWiFi",
		IPAddress: net.IPv4(192, 168, 0, 2),
		NetMask:   net.IPv4Mask(255, 255, 0, 0),
		Clients: []Client{{
			Hostname:  "ristretto",
			IPAddress: net.IPv4(192, 168, 0, 116),
		}, {
			Hostname:  "aribica",
			IPAddress: net.IPv4(192, 168, 0, 104),
			LastSeen:  time.Date(2009, time.November, 10, 23, 6, 32, 0, time.UTC),
		}, {
			Hostname:  "macchiato",
			IPAddress: net.IPv4(192, 168, 0, 153),
			LastSeen:  time.Date(2009, time.November, 10, 23, 39, 43, 0, time.UTC),
		}, {
			Hostname:  "espresso",
			IPAddress: net.IPv4(192, 168, 0, 121),
		}, {
			Hostname:  "latte",
			IPAddress: net.IPv4(192, 168, 0, 221),
			LastSeen:  time.Date(2009, time.November, 10, 23, 0, 23, 0, time.UTC),
		}},
	}
	return x, y
}