From 5d3efcc64fc9664e061b44659f85aeec03a56685 Mon Sep 17 00:00:00 2001
From: DJ O'Leary <dijitol@proton.me>
Date: Sun, 6 Sep 2026 23:53:43 +0200
Subject: feat(cli): add cli flags to call api

---
 main.go                     | 91 +++++++++++++++++++++++++++++++++++++++------
 src/cli/subcommand_group.go | 56 ++++++++++++++++++++++++++++
 2 files changed, 135 insertions(+), 12 deletions(-)
 create mode 100644 src/cli/subcommand_group.go

diff --git a/main.go b/main.go
index 313a57c..68e4adf 100644
--- a/main.go
+++ b/main.go
@@ -2,12 +2,15 @@ package main
 
 import (
 	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
 	"io"
-	"log"
 	"log/slog"
 	"os"
 
 	"codeberg.org/dijitol/trading_post/src/cardmarket"
+	"codeberg.org/dijitol/trading_post/src/cli"
 	"codeberg.org/dijitol/trading_post/src/config"
 	"codeberg.org/dijitol/trading_post/src/oauth"
 )
@@ -15,7 +18,8 @@ import (
 func main() {
 	conf, err := config.NewConfigFromEnv()
 	if err != nil {
-		log.Fatalln(err.Error())
+		fmt.Println(err.Error())
+		os.Exit(1)
 	}
 
 	if err := Run(
@@ -24,24 +28,92 @@ func main() {
 		os.Stdout,
 		os.Stderr,
 		conf,
+		os.Args,
 	); err != nil {
-		log.Fatalln(err.Error())
+		fmt.Println(err.Error())
+		os.Exit(1)
 	}
 }
 
 func Run(
 	ctx context.Context,
-	in io.Reader,
-	out, err io.Writer,
+	stdin io.Reader,
+	stdout, stderr io.Writer,
 	conf config.Config,
+	args []string,
 ) error {
+	flag.CommandLine.SetOutput(stderr)
+
+	_ = initLogger(ctx, stderr, conf)
+	client := initAPIClient(conf)
+
+	sg := cli.NewSubcommandGroup(stderr, flag.ContinueOnError)
+	sg.AddSubcommand(
+		"account",
+		"[account] outputs information about the owner of the credentials",
+		func(_ *flag.FlagSet) error {
+			account, err := client.GetAccountInformation(ctx)
+			if err != nil {
+				return err
+			}
+
+			out, err := json.Marshal(account)
+			if err != nil {
+				return err
+			}
+
+			fmt.Fprintln(stdout, string(out))
+
+			return nil
+		},
+	)
+	sg.AddSubcommand(
+		"games",
+		"[games] outputs all the games",
+		func(_ *flag.FlagSet) error {
+			games, err := client.GetGames(ctx)
+			if err != nil {
+				return err
+			}
+
+			out, err := json.Marshal(games)
+			if err != nil {
+				return err
+			}
+
+			fmt.Fprintln(stdout, string(out))
+
+			return nil
+		},
+	)
+
+	if len(args) < 2 { // 1st if program name, 2nd is subcommand
+		return fmt.Errorf("error: missing subcommand - usage: `trading_post [command]`\n%s", sg.Usage())
+	}
+
+	if err := sg.ExecSubcommand(args[1]); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func initLogger(
+	ctx context.Context,
+	stderr io.Writer,
+	conf config.Config,
+) *slog.Logger {
 	l := slog.New(
-		slog.NewJSONHandler(err, &slog.HandlerOptions{Level: conf.AppLogLevel}),
+		slog.NewJSONHandler(stderr, &slog.HandlerOptions{Level: conf.AppLogLevel}),
 	)
 	slog.SetDefault(l)
 
 	slog.DebugContext(ctx, conf.String())
 
+	return l
+}
+
+func initAPIClient(conf config.Config) *cardmarket.ApiClient {
 	oauthClient := oauth.NewClient(
 		oauth.Tokens{
 			Consumer: oauth.ConsumerToken{
@@ -60,10 +132,5 @@ func Run(
 		oauthClient,
 	)
 
-	_, accErr := client.GetAccountInformation(ctx)
-	if accErr != nil {
-		return accErr
-	}
-
-	return nil
+	return client
 }
diff --git a/src/cli/subcommand_group.go b/src/cli/subcommand_group.go
new file mode 100644
index 0000000..957e759
--- /dev/null
+++ b/src/cli/subcommand_group.go
@@ -0,0 +1,56 @@
+package cli
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"strings"
+)
+
+var ErrUnknownCommand = errors.New("error: unknown command")
+
+type SubcommandFunc = func(*flag.FlagSet) error
+
+type Subcommand struct {
+	FlagSet *flag.FlagSet
+	Usage   string
+	Func    SubcommandFunc
+}
+
+type SubcommandGroup struct {
+	subcommands   map[string]Subcommand
+	output        io.Writer
+	errorHandling flag.ErrorHandling
+}
+
+func NewSubcommandGroup(output io.Writer, errorHandling flag.ErrorHandling) SubcommandGroup {
+	return SubcommandGroup{subcommands: make(map[string]Subcommand), output: output, errorHandling: errorHandling}
+}
+
+func (sg *SubcommandGroup) AddSubcommand(name string, usage string, fn SubcommandFunc) {
+	fs := flag.NewFlagSet(name, sg.errorHandling)
+	fs.SetOutput(sg.output)
+	sg.subcommands[name] = Subcommand{
+		FlagSet: fs,
+		Usage:   usage,
+		Func:    fn,
+	}
+}
+
+func (sg SubcommandGroup) ExecSubcommand(name string) error {
+	cmd, ok := sg.subcommands[name]
+	if !ok {
+		return ErrUnknownCommand
+	}
+	return cmd.Func(cmd.FlagSet)
+}
+
+func (sg SubcommandGroup) Usage() string {
+	var b strings.Builder
+	b.WriteString("    subcommands:\n")
+	for _, cmd := range sg.subcommands {
+		fmt.Fprintf(&b, "        %s: %s\n", cmd.FlagSet.Name(), cmd.Usage)
+	}
+	return b.String()
+}
-- 
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