From 730796a80d0eca520713c20971958e778ee06b67 Mon Sep 17 00:00:00 2001
From: bnewbold <bnewbold@robocracy.org>
Date: Sun, 12 Jun 2016 20:26:09 -0400
Subject: basic command line args

---
 Cargo.lock  |  6 ++++++
 Cargo.toml  |  1 +
 src/main.rs | 59 ++++++++++++++++++++++++++++++++++++++++++++++++-----------
 3 files changed, 55 insertions(+), 11 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a18a400..10b995f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,7 @@
 name = "exuberant-bovines"
 version = "0.1.0"
 dependencies = [
+ "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "glium 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "image 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -202,6 +203,11 @@ dependencies = [
  "winapi 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "getopts"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "gif"
 version = "0.8.0"
diff --git a/Cargo.toml b/Cargo.toml
index 0cf2e19..b04a2f6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,3 +10,4 @@ authors = ["bnewbold <bnewbold@robocracy.org>"]
 #glutin = { git = "https://github.com/bnewbold/glutin", branch = "feature-existing" }
 glium = "0.*"
 image = "0.*"
+getopts = "^0.2"
diff --git a/src/main.rs b/src/main.rs
index f393f9d..e07c972 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,10 +1,14 @@
 
 #[macro_use]
 extern crate glium; 
+
 extern crate image;
+extern crate getopts;
 
 use std::env;
 use std::u64;
+use std::process::exit;
+use getopts::Options;
 use glium::glutin::os::unix::WindowBuilderExt;
     
 mod util;
@@ -182,21 +186,54 @@ fn run(window_id: Option<u64>) {
 
 }
 
+fn print_usage(program: &str, opts: Options) {
+    let brief = format!("Usage: {} [options]", program);
+    print!("{}", opts.usage(&brief));
+}
+
 fn main() {
     let args: Vec<String> = env::args().collect();
-
-    let window_id: Option<u64> = {
-        if args.len() >= 2 {
-            let parsed = if (&args[1]).starts_with("0x") {
-                u64::from_str_radix(args[1].trim_left_matches('0').trim_left_matches('x'), 16)
-            } else {
-                args[1].parse::<u64>()
-            };
-            Some(parsed.expect("Failed to parse numerical arg"))
-        } else {
-            None
+    let program = args[0].clone();
+
+    // Turn, eg, "-root" into "--root"
+    let args = util::convert_xscreensaver_args(args);
+
+    let mut opts = Options::new();
+    opts.optflag("h", "help", "print this help menu");
+    opts.optflag("", "window", "run in a window (IGNORED)");
+    opts.optflag("", "root", "run in root window (IGNORED)");
+    opts.optopt("", "window-id", "X window id number", "NUM");
+
+    let matches = match opts.parse(&args[1..]) {
+        Ok(m) => { m }
+        Err(f) => {
+            print_usage(&program, opts);
+            println!("");
+            println!("{}", f.to_string());
+            exit(-1);
         }
     };
 
+    if matches.opt_present("help") {
+        print_usage(&program, opts);
+        exit(0);
+    }
+
+    // if no "--window-id", try environment variable (arg has priority though)
+    let window_id_string: Option<String> =
+        matches.opt_str("window-id")
+               .or(env::var("XSCREENSAVER_WINDOW").ok());
+
+    let window_id = window_id_string.map(|id| match util::dechex2u64(&id) {
+        Ok(y) => y,
+        Err(e) => {
+            println!("Couldn't parse numerical argument: {}", e);
+            exit(-1); },
+    });
+
+    if window_id.is_some() {
+        println!("Drawing on existing X window: 0x{:07X}", window_id.unwrap());
+    }
+
     run(window_id);
 }
-- 
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