package rtpconn

import (
	"crypto/rand"
	"fmt"
	"io"
	"math/big"
	"strings"
	"unicode/utf8"

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

const maxEightBallQuestionRunes = 500

var eightBallResponses = []string{
	"It is certain.",
	"It is decidedly so.",
	"Without a doubt.",
	"Yes, definitely.",
	"You may rely on it.",
	"As I see it, yes.",
	"Most likely.",
	"Outlook good.",
	"Yes.",
	"Signs point to yes.",
	"Reply hazy, try again.",
	"Ask again later.",
	"Better not tell you now.",
	"Cannot predict now.",
	"Concentrate and ask again.",
	"Don't count on it.",
	"My reply is no.",
	"My sources say no.",
	"Outlook not so good.",
	"Very doubtful.",
}

func normalizeEightBallQuestion(value any) (string, error) {
	question, ok := value.(string)
	if !ok {
		return "", hall.UserError("/8ball requires a question")
	}
	question = strings.Join(strings.Fields(question), " ")
	if question == "" {
		return "", hall.UserError("/8ball requires a question")
	}
	if utf8.RuneCountInString(question) > maxEightBallQuestionRunes {
		return "", hall.UserError(fmt.Sprintf(
			"Eight Ball questions may not exceed %d characters",
			maxEightBallQuestionRunes,
		))
	}
	return question, nil
}

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

func handleEightBall(c *webClient, g *hall.Hall, value any) error {
	if !member("message", c.Permissions()) {
		return c.error(hall.UserError("not authorised"))
	}
	question, err := normalizeEightBallQuestion(value)
	if err != nil {
		return c.error(err)
	}
	response, err := chooseEightBallResponse(rand.Reader)
	if err != nil {
		return c.error(err)
	}
	announcement := fmt.Sprintf(
		"%s asks: %s\nThe Eight Ball says: %s",
		c.Username(), question, response,
	)
	if err := broadcastServerChat(g, "Eight Ball", "eightball", announcement); err != nil {
		return c.error(err)
	}
	return nil
}