Closes #3; Add help info text

Author: pwalig

src/HelpMessage.zig

@@ -0,0 +1,22 @@
+const std = @import("std");
+
+const helpMessage =
+    "Usage:\n" ++
+    "(1) {s} <host> <port> [runModeOptions]\n" ++
+    "(2) {s} [infoOptions]\n" ++
+    "\n" ++
+    "Arguments:\n" ++
+    "\t<host>\t\t IPv4 address of the server\n" ++
+    "\t<port>\t\t Port number of the server\n" ++
+    "\n" ++
+    "[runModeOptions]:\n" ++
+    "\tfor now there are no runModeOptions\n" ++
+    "\n" ++
+    "[infoOptions]:\n" ++
+    "\t-h, --help\tPrint this help and exit\n" ++
+    "\t-v, --version\tPrint version number and exit\n" ++
+    "\n";
+
+pub fn printHelpMessage(programName: []const u8) !void {
+    try std.io.getStdOut().writer().print(helpMessage, .{ programName, programName });
+}

src/main.zig

@@ -3,6 +3,7 @@ const net = std.net;
 const print = std.debug.print;
 
 const Client = @import("client.zig").Client;
+const HelpMessage = @import("HelpMessage.zig");
 
 const version = "1.0.0";
 
@@ -17,20 +18,40 @@ pub fn main() !void {
     const program_name = args.next() orelse "mini-RTS-zig-bot";
 
     const host_value = args.next() orelse {
-        print("no host name or ip address provided\nusage {s} <host> <port>\n", .{program_name});
+        try std.io.getStdOut().writer().print("no host provided\n", .{});
+        try HelpMessage.printHelpMessage(program_name);
         return;
     };
 
-    if (std.mem.eql(u8, host_value, "--version") or std.mem.eql(u8, host_value, "-v")) {
-        try std.io.getStdOut().writer().print("{s}\n", .{version});
+    if (std.mem.eql(u8, host_value, "-v") or std.mem.eql(u8, host_value, "--version")) {
+        if (args.next()) |option| {
+            try std.io.getStdOut().writer().print("unnecessary additional option: {s}\n", .{option});
+            try HelpMessage.printHelpMessage(program_name);
+        } else try std.io.getStdOut().writer().print("{s}\n", .{version});
+        return;
+    } else if (std.mem.eql(u8, host_value, "-h") or std.mem.eql(u8, host_value, "--help")) {
+        if (args.next()) |option| try std.io.getStdOut().writer().print("unnecessary additional option: {s}\n", .{option});
+        try HelpMessage.printHelpMessage(program_name);
         return;
     }
 
     const port_value = args.next() orelse {
-        print("no port provided\nusage {s} <host> <port>\n", .{program_name});
+        try std.io.getStdOut().writer().print("no port provided\n", .{});
+        try HelpMessage.printHelpMessage(program_name);
+        return;
+    };
+
+    if (args.next()) |option| {
+        try std.io.getStdOut().writer().print("unnecessary additional option: {s}\nrunModeOptions are not supported\n", .{option});
+        try HelpMessage.printHelpMessage(program_name);
+        return;
+    }
+
+    const port = std.fmt.parseInt(u16, port_value, 10) catch {
+        try std.io.getStdOut().writer().print("invalid port number {s}\n", .{port_value});
+        try HelpMessage.printHelpMessage(program_name);
         return;
     };
-    const port = try std.fmt.parseInt(u16, port_value, 10);
 
     var cli = try Client.init(host_value, port, null);
     defer cli.deinit();