WIP: Command arguments

1 files changed, 53 insertions, 28 deletions

diff --git a/main.go b/main.go
index 0d89b06..67c0850 100644
--- a/main.go
+++ b/main.go
@@ -9,6 +9,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"errors"
+	"flag"
 	"fmt"
 	"html/template"
 	"image"
@@ -260,9 +261,9 @@ func parallelize(strings []string, callback parallelFunc) error {
 
 // cmdInit initializes a "gallery directory" that contains gallery.sqlite,
 // images, thumbs.
-func cmdInit(args []string) error {
+func cmdInit(fs *flag.FlagSet, args []string) error {
 	if len(args) != 1 {
-		return errors.New("usage: GD")
+		return errWrongUsage
 	}
 
 	if err := openDB(args[0]); err != nil {
@@ -1074,9 +1075,9 @@ func handleAPISearch(w http.ResponseWriter, r *http.Request) {
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 // cmdWeb runs a web UI against GD on ADDRESS.
-func cmdWeb(args []string) error {
+func cmdWeb(fs *flag.FlagSet, args []string) error {
 	if len(args) != 2 {
-		return errors.New("usage: GD ADDRESS")
+		return errWrongUsage
 	}
 	if err := openDB(args[0]); err != nil {
 		return err
@@ -1681,11 +1682,17 @@ func syncRun(ctx context.Context, tx *sql.Tx, roots []string) error {
 
 // cmdSync ensures the given (sub)roots are accurately reflected
 // in the database.
-func cmdSync(args []string) error {
-	if len(args) < 2 {
-		return errors.New("usage: GD ROOT...")
+func cmdSync(fs *flag.FlagSet, args []string) error {
+	// TODO: Convert the other commands as well.
+	fullpaths := fs.Bool("fullpaths", false, "don't basename the arguments")
+	if err := fs.Parse(args); err != nil {
+		return err
 	}
-	if err := openDB(args[0]); err != nil {
+	if fs.NArg() < 2 {
+		return errWrongUsage
+	}
+
+	if err := openDB(fs.Arg(0)); err != nil {
 		return err
 	}
 
@@ -1709,9 +1716,12 @@ func cmdSync(args []string) error {
 		return err
 	}
 
+	// TODO: Handle sensibly.
+	_ = fullpaths
+
 	// Normalize arguments.
 	// At least for now, turn all roots into absolute paths.
-	roots := args[1:]
+	roots := fs.Args()[1:]
 	for i := range roots {
 		roots[i], err = filepath.Abs(filepath.Clean(roots[i]))
 		if err != nil {
@@ -1739,9 +1749,9 @@ func cmdSync(args []string) error {
 
 // cmdRemove is for manual removal of subtrees from the database.
 // Beware that inputs are database, not filesystem paths.
-func cmdRemove(args []string) error {
+func cmdRemove(fs *flag.FlagSet, args []string) error {
 	if len(args) < 2 {
-		return errors.New("usage: GD PATH...")
+		return errWrongUsage
 	}
 	if err := openDB(args[0]); err != nil {
 		return err
@@ -1784,7 +1794,7 @@ func cmdRemove(args []string) error {
 
 // cmdTag mass imports tags from data passed on stdin as a TSV
 // of SHA1 TAG WEIGHT entries.
-func cmdTag(args []string) error {
+func cmdTag(fs *flag.FlagSet, args []string) error {
 	if len(args) < 2 || len(args) > 3 {
 		return errors.New("usage: GD SPACE [DESCRIPTION]")
 	}
@@ -1935,7 +1945,7 @@ func checkFiles(root, suffix string, hashes []string) (bool, []string, error) {
 }
 
 // cmdCheck carries out various database consistency checks.
-func cmdCheck(args []string) error {
+func cmdCheck(fs *flag.FlagSet, args []string) error {
 	if len(args) != 1 {
 		return errors.New("usage: GD")
 	}
@@ -2052,9 +2062,9 @@ func makeThumbnailFor(sha1 string) (message string, err error) {
 }
 
 // cmdThumbnail generates missing thumbnails, in parallel.
-func cmdThumbnail(args []string) error {
+func cmdThumbnail(fs *flag.FlagSet, args []string) error {
 	if len(args) < 1 {
-		return errors.New("usage: GD [SHA1...]")
+		return errWrongUsage
 	}
 	if err := openDB(args[0]); err != nil {
 		return err
@@ -2207,9 +2217,9 @@ func makeDhashFor(sha1 string) (message string, err error) {
 }
 
 // cmdDhash generates perceptual hash from thumbnails.
-func cmdDhash(args []string) error {
+func cmdDhash(fs *flag.FlagSet, args []string) error {
 	if len(args) < 1 {
-		return errors.New("usage: GD [SHA1...]")
+		return errWrongUsage
 	}
 	if err := openDB(args[0]); err != nil {
 		return err
@@ -2229,20 +2239,25 @@ func cmdDhash(args []string) error {
 
 // --- Main --------------------------------------------------------------------
 
+var errWrongUsage = errors.New("wrong usage")
+
 var commands = map[string]struct {
-	handler func(args []string) error
+	handler func(*flag.FlagSet, []string) error
+	usage   string
 }{
-	"init":      {cmdInit},
-	"web":       {cmdWeb},
-	"tag":       {cmdTag},
-	"sync":      {cmdSync},
-	"remove":    {cmdRemove},
-	"check":     {cmdCheck},
-	"thumbnail": {cmdThumbnail},
-	"dhash":     {cmdDhash},
+	"init":      {cmdInit, "GD"},
+	"web":       {cmdWeb, "GD ADDRESS"},
+	"tag":       {cmdTag, "GD SPACE [DESCRIPTION]"},
+	"sync":      {cmdSync, "GD ROOT..."},
+	"remove":    {cmdRemove, "GD PATH..."},
+	"check":     {cmdCheck, "GD"},
+	"thumbnail": {cmdThumbnail, "GD [SHA1...]"},
+	"dhash":     {cmdDhash, "GD [SHA1...]"},
 }
 
 func main() {
+	// TODO: Implement a global -h command.
+	// The flag package doesn't reorder, unlike GNU, so it's fine.
 	if len(os.Args) <= 2 {
 		log.Fatalln("Missing arguments")
 	}
@@ -2252,8 +2267,15 @@ func main() {
 		log.Fatalln("Unknown command: " + os.Args[1])
 	}
 
+	fs := flag.NewFlagSet(os.Args[1], flag.ExitOnError)
+	fs.Usage = func() {
+		fmt.Fprintf(fs.Output(),
+			"Usage: %s [OPTION...] %s...\n", fs.Name(), cmd.usage)
+		fs.PrintDefaults()
+	}
+
 	taskSemaphore = newSemaphore(runtime.NumCPU())
-	err := cmd.handler(os.Args[2:])
+	err := cmd.handler(fs, os.Args[2:])
 
 	// Note that the database object has a closing finalizer,
 	// we just additionally print any errors coming from there.
@@ -2263,7 +2285,10 @@ func main() {
 		}
 	}
 
-	if err != nil {
+	if errors.Is(err, errWrongUsage) {
+		fs.Usage()
+		os.Exit(2)
+	} else if err != nil {
 		log.Fatalln(err)
 	}
 }