// © 2013 the CatBase Authors under the WTFPL. See AUTHORS for the list of authors.

package dice

import (
	"github.com/velour/catbase/bot"
	"github.com/velour/catbase/bot/msg"
)

import (
	"fmt"
	"math/rand"
)

// This is a dice plugin to serve as an example and quick copy/paste for new plugins.

type DicePlugin struct {
	Bot bot.Bot
}

// NewDicePlugin creates a new DicePlugin with the Plugin interface
func New(b bot.Bot) *DicePlugin {
	dp := &DicePlugin{
		Bot: b,
	}
	b.Register(dp, bot.Message, dp.message)
	b.Register(dp, bot.Help, dp.help)
	return dp
}

func rollDie(sides int) int {
	return rand.Intn(sides) + 1
}

// Message responds to the bot hook on recieving messages.
// This function returns true if the plugin responds in a meaningful way to the users message.
// Otherwise, the function returns false and the bot continues execution of other plugins.
func (p *DicePlugin) message(kind bot.Kind, message msg.Message, args ...interface{}) bool {
	if !message.Command {
		return false
	}

	channel := message.Channel
	nDice := 0
	sides := 0

	if n, err := fmt.Sscanf(message.Body, "%dd%d", &nDice, &sides); n != 2 || err != nil {
		return false
	}

	if sides < 2 || nDice < 1 || nDice > 20 {
		p.Bot.Send(bot.Message, channel, "You're a dick.")
		return true
	}

	rolls := fmt.Sprintf("%s, you rolled: ", message.User.Name)

	for i := 0; i < nDice; i++ {
		rolls = fmt.Sprintf("%s %d", rolls, rollDie(sides))
		if i != nDice-1 {
			rolls = fmt.Sprintf("%s,", rolls)
		} else {
			rolls = fmt.Sprintf("%s.", rolls)
		}
	}

	p.Bot.Send(bot.Message, channel, rolls)
	return true

}

// Help responds to help requests. Every plugin must implement a help function.
func (p *DicePlugin) help(kind bot.Kind, message msg.Message, args ...interface{}) bool {
	p.Bot.Send(bot.Message, message.Channel, "Roll dice using notation XdY. Try \"3d20\".")
	return true
}