Make demo use JSON, include compile time, sha256 hash, arg option

demo/src/main.rs

@@ -1,5 +1,34 @@
-static LONG_STRING: &'static str = include_str!(concat!(env!("OUT_DIR"), "/long_string.txt"));
+use serde::{Deserialize, Serialize};
+use sha2::Digest;
+
+// Shared between build.rs and main.rs
+#[derive(Serialize, Deserialize, Debug)]
+struct KeyData<'a> {
+    value: &'a str,
+    value_hash: String,
+    compile_time: String,
+}
+
+static KEY: &'static str = include_str!(concat!(env!("OUT_DIR"), "/key.json"));
 
 fn main() {
-    println!("This package was compiled at {}", LONG_STRING);
+    let key_data: KeyData = serde_json::from_str(KEY).unwrap();
+
+    // Print the key data
+    let args: Vec<String> = std::env::args().collect();
+    if args.contains(&"--help".to_string()) {
+        println!("Usage: {} [--json] [--help]", args[0]);
+        println!("--json: Print the key data as JSON");
+        println!("--help: Print this help message");
+        return;
+    } else if args.contains(&"--json".to_string()) {
+        println!("{}", serde_json::to_string_pretty(&key_data).unwrap());
+        return;
+    }
+
+    // Check the hash of the value
+    let value_hash = sha2::Sha256::digest(key_data.value.as_bytes());
+    let hash_match = hex::encode(value_hash) == key_data.value_hash;
+
+    println!("Hash match: {}", hash_match);
 }