package main

import (
	"context"
	"fmt"
	"os"
	"strings"
)

// usage is the help text of the command.
const usage = `Usage: onechat [COMMAND]

Commands:
  backup FILE              archive the running daemon data
  restore FILE             restore into an empty data directory
  chat                     talk to the agent in this terminal (default)
  daemon                   run the agent, Telegram, and WhatsApp
  import [-n] [--agent NAME] ZIP...
                           import WhatsApp history (stop the daemon first)
    -n                     print the plan without model calls
    --agent NAME           import into an existing direct child (default: root)
  notify [--agent-id ID] --source SOURCE --id ID --text TEXT
                           send an external event (default: root)
  login                    log in to ChatGPT with a device code
  probe LOG COUNT [BUILDS] measure the compactor on a log, with real calls
  version                  show the build version
  help                     show this help

Chat needs a running daemon. ONECHAT_DIR sets the data directory.
In chat, /image PATH [caption] sends a JPEG, PNG, or WebP image up to 20 MB.
Quote PATH with single or double quotes when it contains spaces.
`

// version is set by the package build and stays dev for direct Go builds.
var version = "dev"

// parseCommand dispatches args with ctx and prints command output.
func parseCommand(ctx context.Context, args []string) error {
	switch {
	case len(args) == 1 && (args[0] == "help" || args[0] == "--help" || args[0] == "-h"):
		_, err := fmt.Print(usage)
		if err != nil {
			return fmt.Errorf("write command help: %w", err)
		}
	case len(args) == 1 && args[0] == "version":
		_, err := fmt.Println(version)
		if err != nil {
			return fmt.Errorf("write build version: %w", err)
		}
	case len(args) == 1 && args[0] == "login":
		err := chatgptLogin(ctx, os.Stdout)
		if err != nil {
			return fmt.Errorf("log in: %w", err)
		}

	// A signal is the normal stop of the daemon and the client, so their
	// result does not include ctx.Err().
	case len(args) == 1 && args[0] == "daemon":
		err := daemon(ctx, os.Stdout)
		if err != nil {
			return fmt.Errorf("run daemon: %w", err)
		}

		return nil
	case len(args) == 0 || len(args) == 1 && args[0] == "chat":
		err := terminal(ctx, os.Stdin, os.Stdout)
		if err != nil {
			return fmt.Errorf("run terminal: %w", err)
		}

		return nil
	case len(args) == 2 && args[0] == "backup":
		err := backup(ctx, args[1], os.Stdout)
		if err != nil {
			return fmt.Errorf("run backup: %w", err)
		}

		return nil
	case len(args) == 2 && args[0] == "restore":
		err := restore(ctx, args[1], os.Stdout)
		if err != nil {
			return fmt.Errorf("run restore: %w", err)
		}

		return nil
	case len(args) > 0 && args[0] == "notify":
		err := notify(ctx, args[1:], os.Stdout)
		if err != nil {
			return fmt.Errorf("submit external event: %w", err)
		}

		return nil
	case len(args) > 0 && args[0] == "import":
		err := whatsappImport(ctx, args[1:], os.Stdout)
		if err != nil {
			return fmt.Errorf("import WhatsApp history: %w", err)
		}

		return nil
	case len(args) > 0 && args[0] == "probe":
		err := probe(ctx, args[1:], os.Stdout)
		if err != nil {
			return fmt.Errorf("run probe: %w", err)
		}
	default:
		return fmt.Errorf("unknown command %q\n\n%s", strings.Join(args, " "), strings.TrimSuffix(usage, "\n"))
	}

	return ctx.Err()
}