From 0c0c53f9df3b98a8042178fa9ee3d948c9825c3c Mon Sep 17 00:00:00 2001
From: gutmet <me.git@gutmet.org>
Date: Sat, 17 Oct 2020 20:15:50 +0200
Subject: [PATCH] check args usage before running a command

---
 drivel.go | 42 ++++++++++++++++++++----------------------
 1 file changed, 20 insertions(+), 22 deletions(-)

diff --git a/drivel.go b/drivel.go
index 5f169c5..1f0cee4 100644
--- a/drivel.go
+++ b/drivel.go
@@ -38,6 +38,14 @@ func optLogFatal(decorum string, err error) {
 	}
 }
 
+func checkUsage(args []string, argcMin int, argcMax int, help string) {
+	argc := len(args)
+	if (argcMin > -1 && argc < argcMin) || (argcMax > -1 && argc > argcMax) {
+		fmt.Fprintf(os.Stderr, "USAGE: %s %s\n", os.Args[0], help)
+		os.Exit(-1)
+	}
+}
+
 func get(url string) []byte {
 	return _send(url, nil, false)
 }
@@ -245,26 +253,21 @@ func PrintTweets(tweets []Status, userFilter hashset) {
 }
 
 func status(args []string) error {
+	checkUsage(args, 1, -1, "status STATUS [FILE1 FILE2 ...]")
 	tweets := updateStatus(args, "", "")
 	PrintTweets(tweets, nil)
 	return nil
 }
 
 func reply(args []string) error {
-	if len(args) < 2 {
-		fmt.Fprintln(os.Stderr, "Usage: drivel reply TWEET_ID MESSAGE [FILE1 FILE2 ...]")
-		os.Exit(-1)
-	}
+	checkUsage(args, 2, -1, "reply TWEET_ID MESSAGE [FILE1 FILE2 ...]")
 	tweets := updateStatus(args[1:], ObjectID(args[0]), "")
 	PrintTweets(tweets, nil)
 	return nil
 }
 
 func quote(args []string) error {
-	if len(args) < 2 {
-		fmt.Println(os.Stderr, "Usage: drivel quote TWEET_ID MESSAGE [FILE1 FILE2 ...]")
-		os.Exit(-1)
-	}
+	checkUsage(args, 2, -1, "quote TWEET_ID MESSAGE [FILE1 FILE2 ...]")
 	tweets := updateStatus(args[1:], "", ObjectID(args[0]))
 	PrintTweets(tweets, nil)
 	return nil
@@ -280,10 +283,7 @@ func _lookup(ids []string) []Status {
 }
 
 func lookup(args []string) error {
-	if len(args) < 1 {
-		fmt.Fprintln(os.Stderr, "USAGE: drivel lookup TWEET_ID1 [TWEET_ID2 TWEET_ID3 ...]")
-		os.Exit(-1)
-	}
+	checkUsage(args, 1, -1, "lookup TWEET_ID1 [TWEET_ID2 TWEET_ID3 ...]")
 	tweets := _lookup(args)
 	PrintTweets(tweets, nil)
 	return nil
@@ -299,18 +299,21 @@ func timeline(endpoint string) []Status {
 }
 
 func mentions(args []string) error {
+	checkUsage(args, 0, 0, "mentions")
 	tweets := timeline(MENTIONS_ENDPOINT)
 	PrintTweets(tweets, mentionsFilter)
 	return nil
 }
 
 func home(args []string) error {
+	checkUsage(args, 0, 0, "home")
 	tweets := timeline(HOME_ENDPOINT)
 	PrintTweets(tweets, homeFilter)
 	return nil
 }
 
 func userTimeline(flags userTimelineFlags, args []string) error {
+	checkUsage(args, 1, 1, "timeline USER")
 	tweets := timeline(TIMELINE_ENDPOINT + UserTimelineParameters(flags, args[0]))
 	PrintTweets(tweets, nil)
 	return nil
@@ -329,11 +332,8 @@ func userTimelineCommand() (goutil.CommandFlagsInit, goutil.CommandFunc) {
 }
 
 func retweet(args []string) error {
+	checkUsage(args, 1, 1, "retweet TWEET_ID")
 	log := func(err error) { optLogFatal("retweet", err) }
-	if len(args) != 1 {
-		fmt.Fprintln(os.Stderr, "USAGE: drivel retweet TWEET_ID")
-		os.Exit(-1)
-	}
 	id := args[0]
 	tweets := _lookup([]string{id})
 	if len(tweets) != 1 {
@@ -348,11 +348,8 @@ func retweet(args []string) error {
 }
 
 func like(args []string) error {
+	checkUsage(args, 1, 1, "like TWEET_ID")
 	log := func(err error) { optLogFatal("like", err) }
-	if len(args) != 1 {
-		fmt.Fprintln(os.Stderr, "USAGE: drivel like TWEET_ID")
-		os.Exit(-1)
-	}
 	body := send(LIKE_ENDPOINT, LikeRequest(args[0]))
 	var tweet Status
 	err := json.Unmarshal(body, &tweet)
@@ -414,7 +411,8 @@ func wipeTimeline(likes bool, keepDays int) {
 	}
 }
 
-func wipe(flags wipeFlags) error {
+func wipe(flags wipeFlags, args []string) error {
+	checkUsage(args, 0, 0, "wipe")
 	wipeTimeline(true, flags.keepDays)
 	wipeTimeline(false, flags.keepDays)
 	return nil
@@ -429,7 +427,7 @@ func wipeCommand() (goutil.CommandFlagsInit, goutil.CommandFunc) {
 	flagsInit := func(s *flag.FlagSet) {
 		s.IntVar(&f.keepDays, "keep-days", WIPE_KEEP_DAYS, "don't wipe the last N days")
 	}
-	return flagsInit, func([]string) error { return wipe(f) }
+	return flagsInit, func(args []string) error { return wipe(f, args) }
 }
 
 type hashset map[string]interface{}