2 files changed, 179 insertions, 25 deletions

diff --git a/src/git.rs b/src/git.rs
index 63bce20..d0eaf03 100644
--- a/src/git.rs
+++ b/src/git.rs
@@ -67,6 +67,7 @@ pub trait RepoActions {
         branch_name: &str,
         patch_and_ancestors: Vec<nostr::Event>,
     ) -> Result<Vec<nostr::Event>>;
+    fn parse_starting_commits(&self, starting_commits: &str) -> Result<Vec<Sha1Hash>>;
 }
 
 impl RepoActions for Repo {
@@ -407,6 +408,49 @@ impl RepoActions for Repo {
         }
         Ok(patches_to_apply)
     }
+
+    fn parse_starting_commits(&self, starting_commits: &str) -> Result<Vec<Sha1Hash>> {
+        let revspec = self
+            .git_repo
+            .revparse(starting_commits)
+            .context("specified value not in a valid format")?;
+        if revspec.mode().is_no_single() {
+            let (ahead, _) = self
+                .get_commits_ahead_behind(
+                    &oid_to_sha1(
+                        &revspec
+                            .from()
+                            .context("cannot get starting commit from specified value")?
+                            .id(),
+                    ),
+                    &self
+                        .get_head_commit()
+                        .context("cannot get head commit with gitlib2")?,
+                )
+                .context("specified commit is not an ancestor of current head")?;
+            Ok(ahead)
+        } else if revspec.mode().is_range() {
+            let (ahead, _) = self
+                .get_commits_ahead_behind(
+                    &oid_to_sha1(
+                        &revspec
+                            .from()
+                            .context("cannot get starting commit of range from specified value")?
+                            .id(),
+                    ),
+                    &oid_to_sha1(
+                        &revspec
+                            .to()
+                            .context("cannot get end of range commit from specified value")?
+                            .id(),
+                    ),
+                )
+                .context("specified commit is not an ancestor of current head")?;
+            Ok(ahead)
+        } else {
+            bail!("specified value not in a supported format")
+        }
+    }
 }
 
 fn oid_to_u8_20_bytes(oid: &Oid) -> [u8; 20] {
@@ -1753,4 +1797,99 @@ mod tests {
             }
         }
     }
+    mod parse_starting_commits {
+        use super::*;
+
+        mod head_1_returns_latest_commit {
+            use super::*;
+
+            #[test]
+            fn when_on_main_and_other_commits_are_more_recent_on_feature_branch() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                test_repo.populate_with_test_branch()?;
+                test_repo.checkout("main")?;
+
+                assert_eq!(
+                    git_repo.parse_starting_commits("HEAD~1")?,
+                    vec![str_to_sha1("431b84edc0d2fa118d63faa3c2db9c73d630a5ae")?],
+                );
+                Ok(())
+            }
+
+            #[test]
+            fn when_checked_out_branch_ahead_of_main() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                test_repo.populate_with_test_branch()?;
+
+                assert_eq!(
+                    git_repo.parse_starting_commits("HEAD~1")?,
+                    vec![str_to_sha1("82ff2bcc9aa94d1bd8faee723d4c8cc190d6061c")?],
+                );
+                Ok(())
+            }
+        }
+        mod head_2_returns_latest_2_commits_youngest_first {
+            use super::*;
+
+            #[test]
+            fn when_on_main_and_other_commits_are_more_recent_on_feature_branch() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                test_repo.populate_with_test_branch()?;
+                test_repo.checkout("main")?;
+
+                assert_eq!(
+                    git_repo.parse_starting_commits("HEAD~2")?,
+                    vec![
+                        str_to_sha1("431b84edc0d2fa118d63faa3c2db9c73d630a5ae")?,
+                        str_to_sha1("af474d8d271490e5c635aad337abdc050034b16a")?,
+                    ],
+                );
+                Ok(())
+            }
+        }
+        mod head_3_returns_latest_3_commits_youngest_first {
+            use super::*;
+
+            #[test]
+            fn when_checked_out_branch_ahead_of_main() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                test_repo.populate_with_test_branch()?;
+
+                assert_eq!(
+                    git_repo.parse_starting_commits("HEAD~3")?,
+                    vec![
+                        str_to_sha1("82ff2bcc9aa94d1bd8faee723d4c8cc190d6061c")?,
+                        str_to_sha1("a23e6b05aaeb7d1471b4a838b51f337d5644eeb0")?,
+                        str_to_sha1("7ab82116068982671a8111f27dc10599172334b2")?,
+                    ],
+                );
+                Ok(())
+            }
+        }
+        mod range_of_3_commits_not_in_branch_history_returns_3_commits_youngest_first {
+            use super::*;
+
+            #[test]
+            fn when_checked_out_branch_ahead_of_main() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                test_repo.populate_with_test_branch()?;
+                test_repo.checkout("main")?;
+
+                assert_eq!(
+                    git_repo.parse_starting_commits("af474d8..a23e6b0")?,
+                    vec![
+                        str_to_sha1("a23e6b05aaeb7d1471b4a838b51f337d5644eeb0")?,
+                        str_to_sha1("7ab82116068982671a8111f27dc10599172334b2")?,
+                        str_to_sha1("431b84edc0d2fa118d63faa3c2db9c73d630a5ae")?,
+                    ],
+                );
+                Ok(())
+            }
+        }
+    }
 }
diff --git a/src/sub_commands/send.rs b/src/sub_commands/send.rs
index 004d263..105f87a 100644
--- a/src/sub_commands/send.rs
+++ b/src/sub_commands/send.rs
@@ -21,8 +21,12 @@ use crate::{
 
 #[derive(Debug, clap::Args)]
 pub struct SubCommandArgs {
-    #[clap(short, long)]
+    #[arg(default_value = "")]
+    /// starting commit (commits since in current branch) or commit range, like
+    /// in `git format-patch`
+    starting_commit: String,
     /// optional cover letter title
+    #[clap(short, long)]
     title: Option<String>,
     #[clap(short, long)]
     /// optional cover letter description
@@ -42,22 +46,24 @@ pub struct SubCommandArgs {
 pub async fn launch(cli_args: &Cli, args: &SubCommandArgs) -> Result<()> {
     let git_repo = Repo::discover().context("cannot find a git repository")?;
 
-    let (from_branch, to_branch, mut ahead, behind) =
-        identify_ahead_behind(&git_repo, &args.from_branch, &args.to_branch)?;
+    let mut commits: Vec<Sha1Hash> = {
+        if args.starting_commit.is_empty() {
+            let (from_branch, to_branch, ahead, behind) =
+                identify_ahead_behind(&git_repo, &args.from_branch, &args.to_branch)?;
 
-    if ahead.is_empty() {
-        bail!(format!(
-            "'{from_branch}' is 0 commits ahead of '{to_branch}' so no patches were created"
-        ));
-    }
+            if ahead.is_empty() {
+                bail!(format!(
+                    "'{from_branch}' is 0 commits ahead of '{to_branch}' so no patches were created"
+                ));
+            }
 
-    if behind.is_empty() {
-        println!(
-            "creating patch for {} commits from '{from_branch}' that can be merged into '{to_branch}'",
-            ahead.len(),
-        );
-    } else {
-        if !Interactor::default().confirm(
+            if behind.is_empty() {
+                println!(
+                    "creating patch for {} commits from '{from_branch}' that can be merged into '{to_branch}'",
+                    ahead.len(),
+                );
+            } else {
+                if !Interactor::default().confirm(
             PromptConfirmParms::default()
                 .with_prompt(
                     format!(
@@ -70,14 +76,23 @@ pub async fn launch(cli_args: &Cli, args: &SubCommandArgs) -> Result<()> {
         ).context("failed to get confirmation response from interactor confirm")? {
             bail!("aborting so branch can be rebased");
         }
-        println!(
-            "creating patch for {} commit{} from '{from_branch}' that {} {} behind '{to_branch}'",
-            ahead.len(),
-            if ahead.len() > 1 { "s" } else { "" },
-            if ahead.len() > 1 { "are" } else { "is" },
-            behind.len(),
-        );
-    }
+                println!(
+                    "creating patch for {} commit{} from '{from_branch}' that {} {} behind '{to_branch}'",
+                    ahead.len(),
+                    if ahead.len() > 1 { "s" } else { "" },
+                    if ahead.len() > 1 { "are" } else { "is" },
+                    behind.len(),
+                );
+            }
+            ahead
+        } else {
+            let ahead = git_repo
+                .parse_starting_commits(&args.starting_commit)
+                .context("cannot parse specified starting commit or range")?;
+            println!("creating patch for {} commits", ahead.len(),);
+            ahead
+        }
+    };
 
     let title = if args.no_cover_letter {
         None
@@ -138,12 +153,12 @@ pub async fn launch(cli_args: &Cli, args: &SubCommandArgs) -> Result<()> {
     .await?;
 
     // oldest first
-    ahead.reverse();
+    commits.reverse();
 
     let events = generate_cover_letter_and_patch_events(
         cover_letter_title_description.clone(),
         &git_repo,
-        &ahead,
+        &commits,
         &keys,
         &repo_ref,
     )?;