package main

import (
	"flag"
	"fmt"
	"os"
)

// CLIArgs holds the arguments parsed from the command line, mirroring the
// argparse result in the legacy coconut-leaf.py.
type CLIArgs struct {
	// Config is the path to the configuration file (the legacy CONFIG_TOML).
	Config string
	// Init indicates whether to initialize the calendar system before running.
	Init bool
}

// ParseCLI parses the command-line arguments via the standard flag package and
// returns a *CLIArgs. When the required --config flag is missing, it prints the
// usage and exits with status 2 (matching argparse's exit code).
func ParseCLI() *CLIArgs {
	args := &CLIArgs{}

	// Custom usage output mirroring the legacy ArgumentParser description banner.
	flag.Usage = func() {
		out := flag.CommandLine.Output()
		fmt.Fprintln(out, "The server of light, self-host and multi-account calendar system.")
		fmt.Fprintln(out)
		fmt.Fprintf(out, "Usage of %s:\n", os.Args[0])
		flag.PrintDefaults()
	}

	// --config maps to the legacy -c/--config (required), --init to -i/--init.
	flag.StringVar(&args.Config, "config", "", "The configuration file `CONFIG_TOML` for coconut-leaf")
	flag.BoolVar(&args.Init, "init", false, "Set for initialize the calendar system")

	flag.Parse()

	// The standard flag package has no built-in "required", so validate manually.
	if args.Config == "" {
		fmt.Fprintln(os.Stderr, "error: the required flag --config is not provided")
		flag.Usage()
		os.Exit(2)
	}

	return args
}