A plugins/decide.go

@@ -0,0 +1,91 @@
+package plugins
+
+import (
+	"fmt"
+	"math/rand"
+	"strconv"
+	"strings"
+
+	"gopkg.in/irc.v3"
+)
+
+type Decide struct{}
+
+func init() {
+	Register(Decide{})
+}
+
+func (Decide) Triggers() []string {
+	return []string{".decide", ".dice", ".roll"}
+}
+
+func (Decide) Execute(m *irc.Message) (string, error) {
+	params := strings.Split(m.Trailing(), " ")
+
+	trigger := params[0]
+	if trigger == ".decide" {
+		var terms []string
+		var currTerm strings.Builder
+		for _, word := range params[1:] {
+			if word == "" {
+				continue
+			}
+
+			if word == "or" && currTerm.Len() != 0 {
+				terms = append(terms, currTerm.String())
+				currTerm.Reset()
+			} else {
+				currTerm.WriteString(word)
+				currTerm.WriteByte(' ')
+			}
+		}
+		if currTerm.Len() > 0 {
+			terms = append(terms, currTerm.String())
+		}
+
+		if len(terms) < 1 {
+			return "usage: .decide proposition 1 [ or proposition 2 [ or proposition n ... ] ]", nil
+		} else if len(terms) < 2 {
+			return []string{"Yes.", "No."}[rand.Intn(2)], nil
+		} else {
+			return terms[rand.Intn(len(terms))], nil
+		}
+	} else if trigger == ".dice" || trigger == ".roll" {
+		if len(params) != 2 {
+			return "usage: .dice NNdXX - where NN is 1-36 and XX is 2-64", nil
+		}
+		dice := params[1]
+		if len(dice) > 5 {
+			return "Invalid dice specification: too big", nil
+		}
+
+		spec := strings.SplitN(dice, "d", 2)
+		if len(spec) != 2 {
+			return "Invalid dice specification: no separating 'd'", nil
+		}
+
+		numDie, err := strconv.Atoi(spec[0])
+		if err != nil || numDie < 1 || numDie > 36 {
+			return fmt.Sprintf("Invalid dice count: %s is not a number or is not between 1-36", spec[0]), nil
+		}
+		numDieFaces, err := strconv.Atoi(spec[1])
+		if err != nil || numDieFaces < 2 || numDieFaces > 64 {
+			return fmt.Sprintf("Invalid dice face count: %s is not a number or is not between 2-64", spec[0]), nil
+		}
+
+		var result strings.Builder
+		sum := 0
+		for i := 0; i < numDie; i++ {
+			r := rand.Intn(numDieFaces) + 1
+			sum += r
+			result.WriteString(strconv.Itoa(r))
+			result.WriteByte(' ')
+		}
+		result.WriteByte('=')
+		result.WriteByte(' ')
+		result.WriteString(strconv.Itoa(sum))
+		return result.String(), nil
+	}
+
+	panic("Unreachable!")
+}