// Command discourse-go is a thin CLI over the client library: enough to
// drive and verify a Discourse instance by hand (categories, topics,
// posts, raw passthrough). Credentials arrive via environment only
// (DISCOURSE_URL / DISCOURSE_API_KEY / DISCOURSE_API_USERNAME, see
// env.example) — never as flags, so they never land in shell history or
// process listings.
package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"os/signal"
	"syscall"

	"git.knownelement.com/ukrrs/mopac-discourse-go"
)

const usage = `discourse-go — thin Discourse client CLI (config via env)

Usage:
  discourse-go whoami
  discourse-go categories list
  discourse-go categories create NAME [-color HEX] [-text-color HEX] [-perm GROUP=LEVEL]...
  discourse-go topics list [-category ID] [-slug SLUG] [-latest]
  discourse-go topics show ID
  discourse-go topics create -title TITLE -category ID [-file PATH | -raw TEXT]
  discourse-go posts create -topic ID [-file PATH | -raw TEXT]
  discourse-go posts update ID [-file PATH | -raw TEXT] [-reason TEXT]
  discourse-go raw METHOD PATH [-data JSON]

Environment (0600 env file, sourced before the call):
  DISCOURSE_URL            instance root, e.g. https://community.turnsys.com
  DISCOURSE_API_KEY        API key (never a flag, never logged)
  DISCOURSE_API_USERNAME   the user the key acts as (default: system)

Perm levels: 1 = reply/see, 2 = create posts, 3 = full.
raw PATH is everything after the instance root, e.g. /groups.json.
Exit codes: 0 ok · 1 usage/config · 2 API/transport error (message says
which class: forbidden/unauthorized/not-found/rate-limited/server/
unreachable/malformed).`

func main() {
	os.Exit(run(os.Args[1:]))
}

func run(args []string) int {
	if len(args) == 0 {
		fmt.Fprint(os.Stderr, usage)
		return 1
	}
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	client, err := discourse.NewFromEnv()
	if err != nil {
		fmt.Fprintf(os.Stderr, "discourse-go: %v\n", err)
		return 1
	}

	var out any
	switch args[0] {
	case "whoami":
		if len(args) != 1 {
			return usageErr()
		}
		out, err = client.CurrentUser(ctx)

	case "categories":
		out, err = runCategories(ctx, client, args[1:])
	case "topics":
		out, err = runTopics(ctx, client, args[1:])
	case "posts":
		out, err = runPosts(ctx, client, args[1:])
	case "raw":
		out, err = runRaw(ctx, client, args[1:])
	case "help", "-h", "--help":
		fmt.Print(usage)
		return 0
	default:
		fmt.Fprintf(os.Stderr, "discourse-go: unknown command %q\n\n%s", args[0], usage)
		return 1
	}
	if err != nil {
		fmt.Fprintf(os.Stderr, "discourse-go: %v\n", err)
		if errors.Is(err, discourse.ErrInvalidRequest) {
			return 1
		}
		return 2
	}
	if out == nil {
		return 0
	}
	enc := json.NewEncoder(os.Stdout)
	enc.SetIndent("", "  ")
	if err := enc.Encode(out); err != nil {
		fmt.Fprintf(os.Stderr, "discourse-go: encode output: %v\n", err)
		return 1
	}
	return 0
}

func usageErr() int {
	fmt.Fprint(os.Stderr, usage)
	return 1
}