package rtpconn

import (
	"crypto/rand"
	"fmt"
	"io"
	"math/big"
	"strings"

	"git.stormux.org/storm/skald/hall"
)

var coinSides = []string{"heads", "tails"}

func chooseCoinSide(reader io.Reader) (string, error) {
	index, err := rand.Int(reader, big.NewInt(int64(len(coinSides))))
	if err != nil {
		return "", err
	}
	return coinSides[index.Int64()], nil
}

func validateCoinRequest(value any) error {
	if value == nil {
		return nil
	}
	arguments, ok := value.(string)
	if !ok || strings.TrimSpace(arguments) != "" {
		return hall.UserError("/coin does not take any arguments")
	}
	return nil
}

func handleCoinFlip(c *webClient, g *hall.Hall, value any) error {
	if !member("message", c.Permissions()) {
		return c.error(hall.UserError("not authorised"))
	}
	if err := validateCoinRequest(value); err != nil {
		return c.error(err)
	}
	side, err := chooseCoinSide(rand.Reader)
	if err != nil {
		return c.error(err)
	}
	announcement := fmt.Sprintf("%s flips a coin: %s.", c.Username(), side)
	if err := broadcastServerChat(g, "Coin", "coin", announcement); err != nil {
		return c.error(err)
	}
	return nil
}