From e01aa11486d54a0e869f5bdfeb37160b21c20fd2 Mon Sep 17 00:00:00 2001
From: yinzhidong <echoyin@tom.com>
Date: Tue, 30 Apr 2024 17:54:36 +0800
Subject: [PATCH] feat: command - ping (#19)

---
 internal/command/command.go        |  2 +
 internal/command/conn/ping.go      | 41 ++++++++++++++
 internal/command/conn/ping_test.go | 89 ++++++++++++++++++++++++++++++
 3 files changed, 132 insertions(+)
 create mode 100644 internal/command/conn/ping.go
 create mode 100644 internal/command/conn/ping_test.go

diff --git a/internal/command/command.go b/internal/command/command.go
index bade24e..65d905c 100644
--- a/internal/command/command.go
+++ b/internal/command/command.go
@@ -49,6 +49,8 @@ func Parse(args [][]byte) (redis.Cmd, error) {
 	// connection
 	case "echo":
 		return conn.ParseEcho(b)
+	case "ping":
+		return conn.ParsePing(b)
 
 	// key
 	case "del":
diff --git a/internal/command/conn/ping.go b/internal/command/conn/ping.go
new file mode 100644
index 0000000..ac16556
--- /dev/null
+++ b/internal/command/conn/ping.go
@@ -0,0 +1,41 @@
+package conn
+
+import (
+	"strings"
+
+	"github.com/nalgeon/redka/internal/parser"
+	"github.com/nalgeon/redka/internal/redis"
+)
+
+const (
+	PONG = "PONG"
+)
+
+// Returns PONG if no argument is provided, otherwise return a copy of the argument as a bulk
+// https://redis.io/commands/ping
+type Ping struct {
+	redis.BaseCmd
+	Parts []string
+}
+
+
+func ParsePing(b redis.BaseCmd) (*Ping, error) {
+	cmd := &Ping{BaseCmd: b}
+	err := parser.New(
+		parser.Strings(&cmd.Parts),
+	).Required(0).Run(cmd.Args())
+	if err != nil {
+		return cmd, err
+	}
+	return cmd, nil
+}
+
+func (c *Ping) Run(w redis.Writer, _ redis.Redka) (any, error) {
+	if len(c.Parts) == 0 {
+		w.WriteAny(PONG)
+		return PONG, nil
+	}
+	out := strings.Join(c.Parts, " ")
+	w.WriteAny(out)
+	return out, nil
+}
diff --git a/internal/command/conn/ping_test.go b/internal/command/conn/ping_test.go
new file mode 100644
index 0000000..6074561
--- /dev/null
+++ b/internal/command/conn/ping_test.go
@@ -0,0 +1,89 @@
+package conn_test
+
+import (
+	"testing"
+
+	"github.com/nalgeon/redka/internal/command"
+	"github.com/nalgeon/redka/internal/command/conn"
+	"github.com/nalgeon/redka/internal/redis"
+	"github.com/nalgeon/redka/internal/testx"
+)
+
+func TestPingParse(t *testing.T) {
+	tests := []struct {
+		name string
+		args [][]byte
+		want []string
+		err  error
+	}{
+		{
+			name: "ping",
+			args: command.BuildArgs("ping"),
+			want: []string(nil),
+			err:  nil,
+		},
+		{
+			name: "ping hello",
+			args: command.BuildArgs("ping", "hello"),
+			want: []string{"hello"},
+			err:  nil,
+		},
+		{
+			name: "ping one two",
+			args: command.BuildArgs("ping", "one", "two"),
+			want: []string{"one", "two"},
+			err:  nil,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			cmd, err := command.Parse(test.args)
+			testx.AssertEqual(t, err, test.err)
+			if err == nil {
+				testx.AssertEqual(t, cmd.(*conn.Ping).Parts, test.want)
+			}
+		})
+	}
+}
+
+func TestPingExec(t *testing.T) {
+	db, red := getDB(t)
+	defer db.Close()
+
+	tests := []struct {
+		name string
+		cmd  *conn.Ping
+		res  any
+		out  string
+	}{
+		{
+			name: "ping",
+			cmd:  command.MustParse[*conn.Ping]("ping"),
+			res:  "PONG",
+			out:  "PONG",
+		},
+		{
+			name: "ping hello",
+			cmd:  command.MustParse[*conn.Ping]("ping hello"),
+			res:  "hello",
+			out:  "hello",
+		},
+		{
+			name: "ping one two",
+			cmd:  command.MustParse[*conn.Ping]("ping one two"),
+			res:  "one two",
+			out:  "one two",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			conn := redis.NewFakeConn()
+			res, err := test.cmd.Run(conn, red)
+			testx.AssertNoErr(t, err)
+			testx.AssertEqual(t, res, test.res)
+			testx.AssertEqual(t, conn.Out(), test.out)
+		})
+	}
+}