[#1332] cli/playground: Add help

Change-Id: I6160cfddf427b161619e4b96ceec8396b75c4d08
Signed-off-by: Alexander Chuprov <a.chuprov@yadro.com>

cmd/frostfs-cli/modules/container/policy_playground.go

@@ -5,7 +5,9 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"maps"
 	"os"
+	"slices"
 	"strings"
 
 	internalclient "git.frostfs.info/TrueCloudLab/frostfs-node/cmd/frostfs-cli/internal/client"
@@ -154,6 +156,23 @@ func (repl *policyPlaygroundREPL) handleEval(args []string) error {
 	return nil
 }
 
+func (repl *policyPlaygroundREPL) handleHelp(args []string) error {
+	if len(args) != 0 {
+		if _, ok := commands[args[0]]; !ok {
+			return fmt.Errorf("unknown command: %q", args[0])
+		}
+		fmt.Fprintln(repl.console, commands[args[0]].usage)
+		return nil
+	}
+
+	commandList := slices.Collect(maps.Keys(commands))
+	slices.Sort(commandList)
+	for _, command := range commandList {
+		fmt.Fprintf(repl.console, "%s: %s\n", command, commands[command].descriprion)
+	}
+	return nil
+}
+
 func (repl *policyPlaygroundREPL) netMap() netmap.NetMap {
 	var nm netmap.NetMap
 	var nodes []netmap.NodeInfo
@@ -164,15 +183,82 @@ func (repl *policyPlaygroundREPL) netMap() netmap.NetMap {
 	return nm
 }
 
-var policyPlaygroundCompleter = readline.NewPrefixCompleter(
-	readline.PcItem("list"),
-	readline.PcItem("ls"),
-	readline.PcItem("add"),
-	readline.PcItem("load"),
-	readline.PcItem("remove"),
-	readline.PcItem("rm"),
-	readline.PcItem("eval"),
-)
+type commandDescription struct {
+	descriprion string
+	usage       string
+}
+
+var commands = map[string]commandDescription{
+	"list": {
+		descriprion: "Display all nodes in the netmap",
+		usage: `Display all nodes in the netmap
+Example of usage:
+  list
+    1: id=03ff65b6ae79134a4dce9d0d39d3851e9bab4ee97abf86e81e1c5bbc50cd2826ae attrs={Continent:"Europe" Country:"Poland"}
+    2: id=02ac920cd7df0b61b289072e6b946e2da4e1a31b9ab1c621bb475e30fa4ab102c3 attrs={Continent:"Antarctica" Country:"Heard Island"}
+`,
+	},
+
+	"ls": {
+		descriprion: "Display all nodes in the netmap",
+		usage: `Display all nodes in the netmap
+Example of usage:
+  ls
+    1: id=03ff65b6ae79134a4dce9d0d39d3851e9bab4ee97abf86e81e1c5bbc50cd2826ae attrs={Continent:"Europe" Country:"Poland"}
+    2: id=02ac920cd7df0b61b289072e6b946e2da4e1a31b9ab1c621bb475e30fa4ab102c3 attrs={Continent:"Antarctica" Country:"Heard Island"}
+`,
+	},
+
+	"add": {
+		descriprion: "Add a new node: add <node-hash> attr=value",
+		usage: `Add a new node
+Example of usage:
+  add 03ff65b6ae79134a4dce9d0d39d3851e9bab4ee97abf86e81e1c5bbc50cd2826ae continent:Europe country:Poland`,
+	},
+
+	"load": {
+		descriprion: "Load netmap from file: load <path>",
+		usage: `Load netmap from file
+Example of usage:
+  load "netmap.json"
+File format (netmap.json):
+{
+  "03ff65b6ae79134a4dce9d0d39d3851e9bab4ee97abf86e81e1c5bbc50cd2826ae": {
+    "continent": "Europe",
+    "country": "Poland"
+  },
+  "02ac920cd7df0b61b289072e6b946e2da4e1a31b9ab1c621bb475e30fa4ab102c3": {
+    "continent": "Antarctica",
+    "country": "Heard Island"
+  }
+}`,
+	},
+
+	"remove": {
+		descriprion: "Remove a node: remove <node-hash>",
+		usage: `Remove a node
+Example of usage:
+  remove 03ff65b6ae79134a4dce9d0d39d3851e9bab4ee97abf86e81e1c5bbc50cd2826ae`,
+	},
+
+	"rm": {
+		descriprion: "Remove a node: rm <node-hash>",
+		usage: `Remove a node
+Example of usage:
+  rm 03ff65b6ae79134a4dce9d0d39d3851e9bab4ee97abf86e81e1c5bbc50cd2826ae`,
+	},
+
+	"eval": {
+		descriprion: "Evaluate a policy: eval <policy>",
+		usage: `Evaluate a policy
+Example of usage:
+  eval REP 2`,
+	},
+
+	"help": {
+		descriprion: "Show available commands",
+	},
+}
 
 func (repl *policyPlaygroundREPL) run() error {
 	if len(viper.GetString(commonflags.RPC)) > 0 {
@@ -199,12 +285,25 @@ func (repl *policyPlaygroundREPL) run() error {
 		"remove": repl.handleRemove,
 		"rm":     repl.handleRemove,
 		"eval":   repl.handleEval,
+		"help":   repl.handleHelp,
 	}
 
+	var cfgCompleter []readline.PrefixCompleterInterface
+	var helpSubItems []readline.PrefixCompleterInterface
+
+	for name := range commands {
+		if name != "help" {
+			cfgCompleter = append(cfgCompleter, readline.PcItem(name))
+			helpSubItems = append(helpSubItems, readline.PcItem(name))
+		}
+	}
+
+	cfgCompleter = append(cfgCompleter, readline.PcItem("help", helpSubItems...))
+	completer := readline.NewPrefixCompleter(cfgCompleter...)
 	rl, err := readline.NewEx(&readline.Config{
 		Prompt:          "> ",
 		InterruptPrompt: "^C",
-		AutoComplete:    policyPlaygroundCompleter,
+		AutoComplete:    completer,
 	})
 	if err != nil {
 		return fmt.Errorf("error initializing readline: %w", err)