Basic implementation of CLI arguments

2 files changed, 62 insertions, 5 deletions

diff --git a/src/args.rs b/src/args.rs
new file mode 100644
index 0000000..6753664
--- /dev/null
+++ b/src/args.rs
@@ -0,0 +1,51 @@
+use std::env;
+
+pub struct Args {
+    pub directory: String,
+    pub n_sentences: u32,
+    pub unique: bool,
+}
+
+impl Args {
+    pub fn parse() -> Option<Args> {
+        let arg_vec: Vec<String> = env::args().collect();
+        let mut i = 1; //skip first arg (execution path)
+
+        let mut n_sentences = 1;
+        let mut unique = false;
+        let mut opt_directory: Option<String> = None;
+
+        while i < arg_vec.len() {
+            match arg_vec[i].as_str() {
+                "-n" | "--sentences" => {
+                    if i + 1 < arg_vec.len() {
+                        n_sentences = arg_vec[i+1].parse::<u32>().ok()?;
+                    } else {
+                        return None;
+                    }
+                    i += 2;
+                },
+                "--unique" => {
+                    unique = true;
+                    i += 1;
+                },
+                other => {
+                    opt_directory = match opt_directory {
+                        Some(_) => { return None; },
+                        None    => Some(other.to_string()),
+                    };
+                    i += 1;
+                },
+            }
+        }
+
+        let directory = opt_directory?;
+
+        Some(Args {
+            directory,
+            n_sentences,
+            unique,
+        })
+    }
+}
+
diff --git a/src/main.rs b/src/main.rs
index 4f299d4..82e568e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,11 +6,16 @@ use std::io;
 use std::path::PathBuf;
 use std::process;
 
+pub mod args;
+
+
 use rand::{thread_rng, seq::{SliceRandom, IteratorRandom}};
 use clap::Parser;
+use crate::args::Args;
 
 #[derive(Debug)]
 enum Error {
+    BadArguments,
     NoSentences,
     MultipleSentences,
     BadTemplate(String),
@@ -27,6 +32,8 @@ enum Error {
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
+            Error::BadArguments =>
+                write!(f, "error while parsing arguments"),
             Error::NoSentences =>
                 write!(f, "no sentences.txt file found"),
             Error::MultipleSentences =>
@@ -64,7 +71,7 @@ type ProgResult<T> = Result<T, Error>;
 #[derive(Parser, Debug)]
 #[command(name = "spout")]
 #[command(about = "Generates nonsense", long_about = None)]
-struct Args {
+struct OldArgs {
     /// Path to data directory
     directory: String,
 
@@ -326,7 +333,8 @@ fn crash(e: Error) -> ! {
     process::exit(1);
 }
 
-fn sub_main(args: Args) -> ProgResult<()> {
+fn sub_main() -> ProgResult<()> {
+    let args = Args::parse().ok_or(Error::BadArguments)?;
     let (mut sentences, mut categories) = read_files(&args.directory, args.unique)?;
 
     for _i in 0..args.n_sentences {
@@ -339,9 +347,7 @@ fn sub_main(args: Args) -> ProgResult<()> {
 }
 
 fn main() {
-    let args = Args::parse();
-
-    if let Err(e) = sub_main(args) {
+    if let Err(e) = sub_main() {
         crash(e)
     }
 }