1 files changed, 222 insertions, 0 deletions
diff --git a/server/commands.go b/server/commands.go
index abb4e43..0b56aaf 100644
--- a/server/commands.go
+++ b/server/commands.go
@@ -1 +1,223 @@
 package server
+
+import (
+	"sort"
+	"strings"
+)
+
+type CommandSender interface {
+	OnCommandOutput(from *Server, output string)
+	OnCommandError(from *Server, err string)
+}
+type commandCtx struct {
+	server *Server
+	sender CommandSender
+	arg arguments
+	auth authLevel
+}
+type commandHandler func(commandCtx) (err string)
+
+func isCommand(message string) (isCmd bool, text string) {
+	text = message
+	if message[0] == '/' {
+		text = message[1:]
+		// an additional slash escapes the second //not command -> /not command
+		isCmd = len(text) != 0 && text[0] != '/'
+	}
+	return
+}
+
+func executeCommand(
+		s *Server, auth authLevel, from CommandSender, command string) {
+	ctx := commandCtx {
+		server: s,
+		sender: from,
+		arg: parseArgs(command),
+		auth: auth,
+	}
+	cmd, _ := ctx.arg.nextArg()
+	handler := commands[cmd]
+	var err string
+	if commandAuth[cmd] > auth {
+		err = "Permission denied"
+	} else if handler == nil {
+		err = "Unknown command: /" + cmd
+	} else {
+		err = handler(ctx)
+	}
+	if err != "" {
+		from.OnCommandError(s, err)
+	}
+}
+
+func usage(cmd string) string {
+	if help[cmd] != nil {
+		return "Usage: " + help[cmd][0]
+	} else {
+		return "Invalid usage"
+	}
+}
+
+var commands = map[string]commandHandler {
+	"op": func(ctx commandCtx) string {
+		name, ok := ctx.arg.nextArg()
+		if !ok {
+			return usage("op")
+		}
+		if !playerNameRegex.Match([]byte(name)) {
+			return "Unknown player."
+		}
+		ctx.server.changePlayerAuth(name, opAuth, func(ok bool) {
+			if ok {
+				ctx.sender.OnCommandOutput(ctx.server, "Opped.")
+			} else {
+				ctx.sender.OnCommandError(ctx.server, "Unknown player")
+			}
+		})
+		return ""
+	},
+	"deop": func(ctx commandCtx) string {
+		name, ok := ctx.arg.nextArg()
+		if !ok {
+			return usage("op")
+		}
+		ctx.server.changePlayerAuth(name, defaultAuth, func(ok bool) {
+			if ok {
+				ctx.sender.OnCommandOutput(ctx.server, "Deopped.")
+			} else {
+				ctx.sender.OnCommandError(ctx.server, "Unknown player")
+			}
+		})
+		return ""
+	},
+	"stop": func(ctx commandCtx) string {
+		ctx.server.Stop(nil)
+		return ""
+	},
+	"save": func(ctx commandCtx) string {
+		ctx.server.Save(nil)
+		return ""
+	},
+	"help": func(ctx commandCtx) string {
+		cmd, ok := ctx.arg.nextArg()
+		if !ok {
+			var usages []string
+			for cmd, helpMessages := range help {
+				if commandAuth[cmd] <= ctx.auth {
+					usages = append(usages, helpMessages[0])
+				}
+			}
+			sort.Strings(usages)
+			ctx.sender.OnCommandOutput(ctx.server, "Available commands:")
+			for _, usage := range usages {
+				ctx.sender.OnCommandOutput(ctx.server, "&7* &e" + usage)
+			}
+			return ""
+		}
+		if help[cmd] == nil {
+			return "Unknown command: /" + cmd
+		}
+		for n, line := range help[cmd] {
+			if n == 0 {
+				line = "Usage: " + line
+			} else {
+				line = "  " + line
+			}
+			ctx.sender.OnCommandOutput(ctx.server, line)
+		}
+		return ""
+	},
+}
+
+var commandAuth = map[string]authLevel {
+	"op": opAuth,
+	"deop": opAuth,
+	"save": opAuth,
+	"stop": opAuth,
+}
+
+var help = map[string][]string {
+	"op": []string {
+		"/op <player>",
+		"Grant operator status",
+	},
+	"deop": []string {
+		"/deop <player>",
+		"Revoke operator status",
+	},
+	"save": []string {
+		"/save",
+		"Save all levels",
+	},
+	"stop": []string {
+		"/stop",
+		"Stop the server",
+	},
+	"help": []string {
+		"/help [command]",
+	},
+}
+
+type arguments struct {
+	rd *strings.Reader
+}
+
+func parseArgs(command string) arguments {
+	return arguments {strings.NewReader(command)}
+}
+
+func (arg *arguments) nextArg() (string, bool) {
+	var out strings.Builder
+	for {
+		b, err := arg.rd.ReadByte()
+		if err != nil {
+			return "", false
+		}
+		if b != ' ' {
+			arg.rd.UnreadByte()
+			break
+		}
+	}
+	var splitChar byte = ' '
+	b, err := arg.rd.ReadByte()
+	if err != nil {
+		return "", false
+	}
+	if b == '"' {
+		splitChar = '"'
+	} else {
+		arg.rd.UnreadByte()
+	}
+	for {
+		b, err = arg.rd.ReadByte()
+		if err != nil {
+			if out.Len() > 0 {
+				break
+			}
+			return "", false
+		}
+		if b == splitChar {
+			break
+		}
+		if b == '\\' {
+			b, err = arg.rd.ReadByte()
+			if err != nil {
+				b = '\\'
+			}
+		}
+		out.WriteByte(b)
+	}
+	return out.String(), true
+}
+
+func (arg *arguments) allArgs() []string {
+	var (a string; ok bool; args []string)
+	for {
+		a, ok = arg.nextArg()
+		if !ok {
+			break
+		}
+		args = append(args, a)
+	}
+	return args
+}