Refactor RPS/RPSLS

bot/rps.go

@@ -1,20 +1,14 @@
 package bot
 
 import (
-	"fmt"
 	"strings"
 
-	"git.kill0.net/chill9/beepboop/lib"
 	"git.kill0.net/chill9/beepboop/lib/rps"
 	"github.com/bwmarrin/discordgo"
 )
 
 func (b *Bot) RpsCommand() CommandFunc {
 	return func(args []string, m *discordgo.MessageCreate) error {
-		var (
-			bc, pc, be, pe string
-		)
-
 		if len(args) != 1 {
 			b.Session.ChannelMessageSend(
 				m.ChannelID, "help: `!rps (rock | paper | scissors)`",
@@ -22,23 +16,21 @@ func (b *Bot) RpsCommand() CommandFunc {
 			return nil
 		}
 
-		pc = strings.ToLower(args[0])
+		pc := strings.ToLower(args[0]) // player's choice
 
-		_, ok := rps.EmojiMapRps[pc] // player's choice
+		g := rps.NewGame(rps.RulesRps, rps.EmojiMapRps)
-		if !ok {
+
+		bc := g.Rand() // bot's choice
+
+		s, err := g.Play(bc, pc)
+		if _, ok := err.(rps.InvalidChoiceError); ok {
 			b.Session.ChannelMessageSend(
 				m.ChannelID, "help: `!rps (rock | paper | scissors)`",
 			)
-			return nil
 		}
 
-		bc = lib.MapRandKey(rps.EmojiMapRps) // bot's choice
+		b.Session.ChannelMessageSend(m.ChannelID, s)
-		pe = rps.EmojiMapRps[pc]             // player's emoji
-		be = rps.EmojiMapRps[bc]             // bot's emoji
 
-		b.Session.ChannelMessageSend(m.ChannelID, fmt.Sprintf(
-			"%s v %s: %s", pe, be, rps.Play(rps.RulesRps, bc, pc),
-		))
 		return nil
 	}
 }

bot/rpsls.go

@@ -1,44 +1,36 @@
 package bot
 
 import (
-	"fmt"
 	"strings"
 
-	"git.kill0.net/chill9/beepboop/lib"
 	"git.kill0.net/chill9/beepboop/lib/rps"
 	"github.com/bwmarrin/discordgo"
 )
 
 func (b *Bot) RpslsCommand() CommandFunc {
 	return func(args []string, m *discordgo.MessageCreate) error {
-		var (
-			bc, pc, be, pe string
-		)
-
 		if len(args) != 1 {
 			b.Session.ChannelMessageSend(
-				m.ChannelID, "help: `!rpsls (rock | paper | scissors | lizard | spock)`",
+				m.ChannelID, "help: `!rps (rock | paper | scissors | lizard | spock)`",
 			)
 			return nil
 		}
 
-		pc = strings.ToLower(args[0])
+		pc := strings.ToLower(args[0]) // player's choice
 
-		_, ok := rps.EmojiMapRpsls[pc] // player's choice
+		g := rps.NewGame(rps.RulesRpsls, rps.EmojiMapRpsls)
-		if !ok {
+
+		bc := g.Rand() // bot's choice
+
+		s, err := g.Play(bc, pc)
+		if _, ok := err.(rps.InvalidChoiceError); ok {
 			b.Session.ChannelMessageSend(
-				m.ChannelID, "help: `!rpsls (rock | paper | scissors | lizard | spock)`",
+				m.ChannelID, "help: `!rps (rock | paper | scissors | lizard | spock)`",
 			)
-			return nil
 		}
 
-		bc = lib.MapRandKey(rps.EmojiMapRpsls) // bot's choice
+		b.Session.ChannelMessageSend(m.ChannelID, s)
-		pe = rps.EmojiMapRpsls[pc]             // player's emoji
-		be = rps.EmojiMapRpsls[bc]             // bot's emoji
 
-		b.Session.ChannelMessageSend(m.ChannelID, fmt.Sprintf(
-			"%s v %s: %s", pe, be, rps.Play(rps.RulesRpsls, bc, pc),
-		))
 		return nil
 	}
 }

lib/rps/rps.go

@@ -2,6 +2,9 @@ package rps
 
 import (
 	"fmt"
+	"strings"
+
+	"git.kill0.net/chill9/beepboop/lib"
 )
 
 type (
@@ -11,6 +14,14 @@ type (
 	}
 )
 
+type InvalidChoiceError struct {
+	s string
+}
+
+func (e InvalidChoiceError) Error() string {
+	return fmt.Sprintf("%q is an invalid choice", e.s)
+}
+
 var (
 	RulesRps [][]string = [][]string{
 		{"rock", "scissors", "crushes"},
@@ -46,6 +57,51 @@ var (
 	}
 )
 
+func NewGame(rules [][]string, emojiMap map[string]string) *Game {
+	return &Game{rules: rules, emojiMap: emojiMap}
+}
+
+func (g *Game) Rand() string {
+	return lib.MapRandKey(g.emojiMap)
+}
+
+func (g *Game) Play(c1, c2 string) (string, error) {
+	var b strings.Builder
+
+	if !g.Valid(c1) {
+		return "", InvalidChoiceError{s: c1}
+	}
+	if !g.Valid(c2) {
+		return "", InvalidChoiceError{s: c2}
+	}
+
+	fmt.Fprintf(&b, "%s v %s: ", g.emojiMap[c1], g.emojiMap[c2])
+
+	for _, rule := range g.rules {
+		verb := rule[2]
+
+		if c1 == c2 {
+			fmt.Fprintf(&b, "draw")
+			return b.String(), nil
+		}
+
+		if c1 == rule[0] && c2 == rule[1] {
+			fmt.Fprintf(&b, "%s %s %s", c1, verb, c2)
+			return b.String(), nil
+		} else if c2 == rule[0] && c1 == rule[1] {
+			fmt.Fprintf(&b, "%s %s %s", c2, verb, c1)
+			return b.String(), nil
+		}
+	}
+
+	return b.String(), nil
+}
+
+func (g *Game) Valid(c string) bool {
+	_, ok := g.emojiMap[c]
+	return ok
+}
+
 func Play(rules [][]string, c1, c2 string) string {
 	for _, rule := range rules {
 		if c1 == c2 {