Add CLI parsing

3 files changed, 75 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 7ac047e..6c3a0b2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,3 +4,4 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+clap = { version = "4.5", features = ["derive"] }
diff --git a/src/cli.rs b/src/cli.rs
new file mode 100644
index 0000000..a223b8c
--- /dev/null
+++ b/src/cli.rs
@@ -0,0 +1,66 @@
+use clap::Parser;
+
+/// Minimal SafariBooks port (cookies only).
+#[derive(Parser, Debug, PartialEq)]
+#[command(version)]
+pub struct Args {
+    /// Book digits ID from the O'Reilly URL.
+    pub bookid: String,
+
+    /// Do not delete the log file on success.
+    #[arg(long = "preserve-log")]
+    pub preserve_log: bool,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Args;
+    use clap::{CommandFactory, Parser};
+
+    #[test]
+    fn parses_positional_bookid_only() {
+        // safaribooks-rs 9781491958698
+        let args = Args::try_parse_from(["safaribooks-rs", "9781491958698"]).unwrap();
+        assert_eq!(args.bookid, "9781491958698");
+        assert!(!args.preserve_log);
+    }
+
+    #[test]
+    fn parses_with_preserve_log_flag() {
+        // safaribooks-rs --preserve-log 9781491958698
+        let args =
+            Args::try_parse_from(["safaribooks-rs", "--preserve-log", "9781491958698"]).unwrap();
+        assert_eq!(args.bookid, "9781491958698");
+        assert!(args.preserve_log);
+    }
+
+    #[test]
+    fn error_when_missing_bookid() {
+        // safaribooks-rs --preserve-log
+        let err = Args::try_parse_from(["safaribooks-rs", "--preserve-log"]).unwrap_err();
+        let msg = err.to_string();
+        // clap’s message should indicate the missing required argument
+        assert!(msg.contains("<BOOKID>"));
+    }
+
+    #[test]
+    fn error_on_unknown_flag() {
+        // safaribooks-rs --kindle 9781491958698
+        let err =
+            Args::try_parse_from(["safaribooks-rs", "--kindle", "9781491958698"]).unwrap_err();
+        let msg = err.to_string().to_lowercase();
+        assert!(msg.contains("unexpected argument '--kindle' found"));
+    }
+
+    #[test]
+    fn help_and_version_are_available() {
+        // `--help` and `--version` are auto-provided by clap
+        let help = Args::command().render_help().to_string();
+        assert!(help.contains("Usage:"));
+        assert!(help.contains("<BOOKID>"));
+        assert!(help.contains("--preserve-log"));
+
+        let version = Args::command().render_version();
+        assert!(!version.trim().is_empty());
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..3b3e84d
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,8 @@
+mod cli;
+
+use clap::Parser;
+use cli::Args;
+
+fn main() {
+    let args = Args::parse();
+}