2 files changed, 55 insertions, 2 deletions
diff --git a/src/2020/mod.rs b/src/2020/mod.rs
new file mode 100644
index 0000000..87c213b
--- /dev/null
+++ b/src/2020/mod.rs
@@ -0,0 +1,33 @@
+use anyhow::Context as _;
+use std::io::BufRead as _;
+
+pub fn run(day: u8, puzzle: u8) -> anyhow::Result<()> {
+    match (day, puzzle) {
+        (1, 1) => report_repair(),
+        _ => Err(anyhow::anyhow!("unknown puzzle {}-{}", day, puzzle)),
+    }
+}
+
+fn report_repair() -> anyhow::Result<()> {
+    let f = std::fs::File::open("data/1-1.txt")
+        .context("couldn't find data file")?;
+    let f = std::io::BufReader::new(f);
+    let ints: anyhow::Result<Vec<i32>> = f
+        .lines()
+        .map(|l| {
+            l.context("failed to read a line")?
+                .parse()
+                .context("failed to parse line into an integer")
+        })
+        .collect();
+    let ints = ints?;
+    for i in &ints {
+        for j in &ints {
+            if i + j == 2020 {
+                println!("{} + {} = {}", i, j, i * j);
+                return Ok(());
+            }
+        }
+    }
+    Err(anyhow::anyhow!("no numbers summing to 2020 found"))
+}
diff --git a/src/main.rs b/src/main.rs
index e7a11a9..b8677cb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,23 @@
-fn main() {
-    println!("Hello, world!");
+#[path = "2020/mod.rs"]
+mod year2020;
+
+#[derive(Debug, structopt::StructOpt)]
+#[structopt(about = "Advent of Code")]
+enum Opt {
+    #[structopt(name = "2020")]
+    Year2020 { day: u8, puzzle: u8 },
+}
+
+#[paw::main]
+fn main(opt: Opt) {
+    let res = match opt {
+        Opt::Year2020 { day, puzzle } => crate::year2020::run(day, puzzle),
+    };
+    match res {
+        Ok(()) => {}
+        Err(e) => {
+            eprintln!("{}", e);
+            std::process::exit(1);
+        }
+    }
 }