Initial importv0.1.0

1 files changed, 54 insertions, 0 deletions

diff --git a/internal/bot/command.go b/internal/bot/command.go
new file mode 100644
index 0000000..9e13060
--- /dev/null
+++ b/internal/bot/command.go
@@ -0,0 +1,54 @@
+package bot
+
+import "strings"
+
+// Command is a parsed "/name@target argument" line.
+type Command struct {
+	// Name is the command without the leading slash, lowercased.
+	Name string
+
+	// Target is the bot username the command was addressed to, without the
+	// "@", or "" when the user did not address anyone.
+	Target string
+
+	// Argument is everything after the command, trimmed.
+	Argument string
+}
+
+// ParseCommand splits a message that starts with a slash.
+//
+// The "@username" suffix is not optional to handle. Telegram appends it
+// automatically whenever more than one bot is in a chat, so in exactly the busy
+// groups where the bot is most visible, every command arrives as
+// "/cep@thebotname 01001000". A bot that only matches the bare form looks broken
+// there.
+//
+// ok is false when the text is not a command at all.
+func ParseCommand(text string) (Command, bool) {
+	trimmed := strings.TrimSpace(text)
+	if !strings.HasPrefix(trimmed, "/") || len(trimmed) == 1 {
+		return Command{}, false
+	}
+
+	head, argument, _ := strings.Cut(trimmed[1:], " ")
+	name, target, _ := strings.Cut(head, "@")
+	if name == "" {
+		return Command{}, false
+	}
+
+	return Command{
+		Name:     strings.ToLower(name),
+		Target:   target,
+		Argument: strings.TrimSpace(argument),
+	}, true
+}
+
+// AddressedTo reports whether the command is for the bot with this username.
+//
+// An unaddressed command counts as addressed: in a private chat nobody types
+// the suffix, and in a group with a single bot Telegram does not add it either.
+// A command addressed to some other bot is not ours, and answering it would put
+// two replies under one message.
+func (c Command) AddressedTo(username string) bool {
+	return c.Target == "" || strings.EqualFold(c.Target, username)
+}