feat(prs-create) find commits and create events

 - identify commits
 - create pull request event
 - create patch events

6 files changed, 900 insertions, 1 deletions

diff --git a/src/cli_interactor.rs b/src/cli_interactor.rs
index d7de087..cf6e3d0 100644
--- a/src/cli_interactor.rs
+++ b/src/cli_interactor.rs
@@ -1,5 +1,5 @@
 use anyhow::Result;
-use dialoguer::{theme::ColorfulTheme, Input, Password};
+use dialoguer::{theme::ColorfulTheme, Confirm, Input, Password};
 #[cfg(test)]
 use mockall::*;
 
@@ -12,6 +12,7 @@ pub struct Interactor {
 pub trait InteractorPrompt {
     fn input(&self, parms: PromptInputParms) -> Result<String>;
     fn password(&self, parms: PromptPasswordParms) -> Result<String>;
+    fn confirm(&self, params: PromptConfirmParms) -> Result<bool>;
 }
 impl InteractorPrompt for Interactor {
     fn input(&self, parms: PromptInputParms) -> Result<String> {
@@ -29,6 +30,13 @@ impl InteractorPrompt for Interactor {
         let pass: String = p.interact()?;
         Ok(pass)
     }
+    fn confirm(&self, params: PromptConfirmParms) -> Result<bool> {
+        let confirm: bool = Confirm::with_theme(&self.theme)
+            .with_prompt(params.prompt)
+            .default(params.default)
+            .interact()?;
+        Ok(confirm)
+    }
 }
 
 #[derive(Default)]
@@ -59,3 +67,20 @@ impl PromptPasswordParms {
         self
     }
 }
+
+#[derive(Default)]
+pub struct PromptConfirmParms {
+    pub prompt: String,
+    pub default: bool,
+}
+
+impl PromptConfirmParms {
+    pub fn with_prompt<S: Into<String>>(mut self, prompt: S) -> Self {
+        self.prompt = prompt.into();
+        self
+    }
+    pub fn with_default(mut self, default: bool) -> Self {
+        self.default = default;
+        self
+    }
+}
diff --git a/src/git.rs b/src/git.rs
new file mode 100644
index 0000000..ddbc646
--- /dev/null
+++ b/src/git.rs
@@ -0,0 +1,476 @@
+use std::env::current_dir;
+#[cfg(test)]
+use std::path::PathBuf;
+
+use anyhow::{bail, Context, Result};
+use git2::{Oid, Revwalk};
+use nostr::prelude::{sha1::Hash as Sha1Hash, Hash};
+
+pub struct Repo {
+    git_repo: git2::Repository,
+}
+
+impl Repo {
+    pub fn discover() -> Result<Self> {
+        Ok(Self {
+            git_repo: git2::Repository::discover(current_dir()?)?,
+        })
+    }
+    #[cfg(test)]
+    pub fn from_path(path: &PathBuf) -> Result<Self> {
+        Ok(Self {
+            git_repo: git2::Repository::open(path)?,
+        })
+    }
+}
+
+// pub type CommitId = [u8; 7];
+// pub type Sha1 = [u8; 20];
+
+pub trait RepoActions {
+    fn get_local_branch_names(&self) -> Result<Vec<String>>;
+    fn get_main_or_master_branch(&self) -> Result<(&str, Sha1Hash)>;
+    fn get_tip_of_local_branch(&self, branch_name: &str) -> Result<Sha1Hash>;
+    fn get_root_commit(&self, branch_name: &str) -> Result<Sha1Hash>;
+    fn get_head_commit(&self) -> Result<Sha1Hash>;
+    fn get_commit_parent(&self, commit: &Sha1Hash) -> Result<Sha1Hash>;
+    fn get_commits_ahead_behind(
+        &self,
+        base_commit: &Sha1Hash,
+        latest_commit: &Sha1Hash,
+    ) -> Result<(Vec<Sha1Hash>, Vec<Sha1Hash>)>;
+    fn make_patch_from_commit(&self, commit: &Sha1Hash) -> Result<String>;
+}
+
+impl RepoActions for Repo {
+    fn get_main_or_master_branch(&self) -> Result<(&str, Sha1Hash)> {
+        let main_branch_name = {
+            let local_branches = self
+                .get_local_branch_names()
+                .context("cannot find any local branches")?;
+            if local_branches.contains(&"main".to_string()) {
+                "main"
+            } else if local_branches.contains(&"master".to_string()) {
+                "master"
+            } else {
+                bail!("no main or master branch locally in this git repository to initiate from",)
+            }
+        };
+
+        let tip = self
+            .get_tip_of_local_branch(main_branch_name)
+            .context(format!(
+                "branch {main_branch_name} was listed as a local branch but cannot get its tip commit id",
+            ))?;
+
+        Ok((main_branch_name, tip))
+    }
+
+    fn get_local_branch_names(&self) -> Result<Vec<String>> {
+        let local_branches = self
+            .git_repo
+            .branches(Some(git2::BranchType::Local))
+            .context("getting GitRepo branches should not error even for a blank repository")?;
+
+        let mut branch_names = vec![];
+
+        for iter in local_branches {
+            let branch = iter?.0;
+            if let Some(name) = branch.name()? {
+                branch_names.push(name.to_string());
+            }
+        }
+        Ok(branch_names)
+    }
+
+    fn get_tip_of_local_branch(&self, branch_name: &str) -> Result<Sha1Hash> {
+        let branch = self
+            .git_repo
+            .find_branch(branch_name, git2::BranchType::Local)
+            .context(format!("cannot find branch {branch_name}"))?;
+        Ok(oid_to_sha1(&branch.into_reference().peel_to_commit()?.id()))
+    }
+
+    fn get_root_commit(&self, branch_name: &str) -> Result<Sha1Hash> {
+        let tip = self.get_tip_of_local_branch(branch_name)?;
+        let mut revwalk = self
+            .git_repo
+            .revwalk()
+            .context("revwalk should be created from git repo")?;
+        revwalk
+            .push(sha1_to_oid(&tip)?)
+            .context("revwalk should accept tip oid")?;
+        Ok(oid_to_sha1(
+            &revwalk
+                .last()
+                .context("revwalk from tip should be at least contain the tip oid")?
+                .context("revwalk iter from branch tip should not result in an error")?,
+        ))
+    }
+
+    fn get_head_commit(&self) -> Result<Sha1Hash> {
+        let head = self
+            .git_repo
+            .head()
+            .context("failed to get git repo head")?;
+        let oid = head.peel_to_commit()?.id();
+        Ok(oid_to_sha1(&oid))
+    }
+
+    fn get_commit_parent(&self, commit: &Sha1Hash) -> Result<Sha1Hash> {
+        let parent_oid = self
+            .git_repo
+            .find_commit(sha1_to_oid(commit)?)
+            .context(format!("could not find commit {commit}"))?
+            .parent_id(0)
+            .context(format!("could not find parent of commit {commit}"))?;
+        Ok(oid_to_sha1(&parent_oid))
+    }
+
+    fn make_patch_from_commit(&self, commit: &Sha1Hash) -> Result<String> {
+        let c = self
+            .git_repo
+            .find_commit(Oid::from_bytes(commit.as_byte_array()).context(format!(
+                "failed to convert commit_id format for {}",
+                &commit
+            ))?)
+            .context(format!("failed to find commit {}", &commit))?;
+        let patch = git2::Email::from_commit(&c, &mut git2::EmailCreateOptions::default())
+            .context(format!("failed to create patch from commit {}", &commit))?;
+
+        Ok(std::str::from_utf8(patch.as_slice())
+            .context("patch content could not be converted to a utf8 string")?
+            .to_owned())
+    }
+
+    fn get_commits_ahead_behind(
+        &self,
+        base_commit: &Sha1Hash,
+        latest_commit: &Sha1Hash,
+    ) -> Result<(Vec<Sha1Hash>, Vec<Sha1Hash>)> {
+        let mut ahead: Vec<Sha1Hash> = vec![];
+        let mut behind: Vec<Sha1Hash> = vec![];
+
+        let get_revwalk = |commit: &Sha1Hash| -> Result<Revwalk> {
+            let mut revwalk = self
+                .git_repo
+                .revwalk()
+                .context("revwalk should be created from git repo")?;
+            revwalk
+                .push(sha1_to_oid(commit)?)
+                .context("revwalk should accept commit oid")?;
+            Ok(revwalk)
+        };
+
+        // scan through the base commit ancestory until a common ancestor is found
+        let most_recent_shared_commit = match get_revwalk(base_commit)
+            .context("failed to get revwalk for base_commit")?
+            .find(|base_res| {
+                let base_oid = base_res.as_ref().unwrap();
+
+                if get_revwalk(latest_commit)
+                    .unwrap()
+                    .any(|latest_res| base_oid.eq(latest_res.as_ref().unwrap()))
+                {
+                    true
+                } else {
+                    // add commits not found in latest ancestory to 'behind' vector
+                    behind.push(oid_to_sha1(base_oid));
+                    false
+                }
+            }) {
+            None => {
+                bail!(format!(
+                    "{} is not an ancestor of {}",
+                    latest_commit, base_commit
+                ));
+            }
+            Some(res) => res.context("revwalk failed to reveal commit")?,
+        };
+
+        // scan through the latest commits until shared commit is reached
+        get_revwalk(latest_commit)
+            .context("failed to get revwalk for latest_commit")?
+            .any(|latest_res| {
+                let latest_oid = latest_res.as_ref().unwrap();
+                if latest_oid.eq(&most_recent_shared_commit) {
+                    true
+                } else {
+                    // add commits not found in base to 'ahead' vector
+                    ahead.push(oid_to_sha1(latest_oid));
+                    false
+                }
+            });
+        Ok((ahead, behind))
+    }
+}
+
+fn oid_to_u8_20_bytes(oid: &Oid) -> [u8; 20] {
+    let b = oid.as_bytes();
+    [
+        b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7], b[8], b[9], b[10], b[11], b[12], b[13],
+        b[14], b[15], b[16], b[17], b[18], b[19],
+    ]
+}
+
+// fn oid_to_shorthand_string(oid: Oid) -> Result<String> {
+//     let binding = oid.to_string();
+//     let b = binding.as_bytes();
+//     String::from_utf8(vec![b[0], b[1], b[2], b[3], b[4], b[5], b[6]])
+//         .context("oid should always start with 7 u8 btyes of utf8")
+// }
+
+// fn oid_to_sha1_string(oid: Oid) -> Result<String> {
+//     let b = oid.as_bytes();
+//     String::from_utf8(vec![
+//         b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7], b[8], b[9], b[10],
+// b[11], b[12], b[13],         b[14], b[15], b[16], b[17], b[18], b[19],
+//     ])
+//     .context("oid should contain 20 u8 btyes of utf8")
+// }
+
+// git2 Oid object to Sha1Hash
+pub fn oid_to_sha1(oid: &Oid) -> Sha1Hash {
+    Sha1Hash::from_byte_array(oid_to_u8_20_bytes(oid))
+}
+
+/// `Sha1Hash` to git2 `Oid` object
+fn sha1_to_oid(hash: &Sha1Hash) -> Result<Oid> {
+    Oid::from_bytes(hash.as_byte_array()).context("Sha1Hash bytes failed to produce a valid Oid")
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::git::GitTestRepo;
+
+    use super::*;
+
+    mod make_patch_from_commit {
+        use super::*;
+        #[test]
+        fn simple_patch_matches_string() -> Result<()> {
+            let test_repo = GitTestRepo::default();
+            let oid = test_repo.populate()?;
+
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+
+            assert_eq!(
+                "\
+                From 431b84edc0d2fa118d63faa3c2db9c73d630a5ae Mon Sep 17 00:00:00 2001\n\
+                From: Joe Bloggs <joe.bloggs@pm.me>\n\
+                Date: Thu, 1 Jan 1970 00:00:00 +0000\n\
+                Subject: [PATCH] add t2.md\n\
+                \n\
+                ---\n \
+                t2.md | 1 +\n \
+                1 file changed, 1 insertion(+)\n \
+                create mode 100644 t2.md\n\
+                \n\
+                diff --git a/t2.md b/t2.md\n\
+                new file mode 100644\n\
+                index 0000000..a66525d\n\
+                --- /dev/null\n\
+                +++ b/t2.md\n\
+                @@ -0,0 +1 @@\n\
+                +some content1\n\\ \
+                No newline at end of file\n\
+                --\n\
+                libgit2 1.7.1\n\
+                \n\
+                ",
+                git_repo.make_patch_from_commit(&oid_to_sha1(&oid))?,
+            );
+            Ok(())
+        }
+    }
+
+    mod get_main_or_master_branch {
+
+        use super::*;
+        mod returns_main {
+            use super::*;
+            #[test]
+            fn when_it_exists() -> Result<()> {
+                let test_repo = GitTestRepo::new("main")?;
+                let main_oid = test_repo.populate()?;
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                let (name, commit_hash) = git_repo.get_main_or_master_branch()?;
+                assert_eq!(name, "main");
+                assert_eq!(commit_hash, oid_to_sha1(&main_oid));
+                Ok(())
+            }
+
+            #[test]
+            fn when_it_exists_and_other_branch_checkedout() -> Result<()> {
+                let test_repo = GitTestRepo::new("main")?;
+                let main_oid = test_repo.populate()?;
+                test_repo.create_branch("feature")?;
+                test_repo.checkout("feature")?;
+                std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+                let feature_oid = test_repo.stage_and_commit("add t3.md")?;
+
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                let (name, commit_hash) = git_repo.get_main_or_master_branch()?;
+                assert_eq!(name, "main");
+                assert_eq!(commit_hash, oid_to_sha1(&main_oid));
+                assert_ne!(commit_hash, oid_to_sha1(&feature_oid));
+                Ok(())
+            }
+
+            #[test]
+            fn when_exists_even_if_master_is_checkedout() -> Result<()> {
+                let test_repo = GitTestRepo::new("main")?;
+                let main_oid = test_repo.populate()?;
+                test_repo.create_branch("master")?;
+                test_repo.checkout("master")?;
+                std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+                let master_oid = test_repo.stage_and_commit("add t3.md")?;
+
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+                let (name, commit_hash) = git_repo.get_main_or_master_branch()?;
+                assert_eq!(name, "main");
+                assert_eq!(commit_hash, oid_to_sha1(&main_oid));
+                assert_ne!(commit_hash, oid_to_sha1(&master_oid));
+                Ok(())
+            }
+        }
+
+        #[test]
+        fn returns_master_if_exists_and_main_doesnt() -> Result<()> {
+            let test_repo = GitTestRepo::new("master")?;
+            let master_oid = test_repo.populate()?;
+            test_repo.create_branch("feature")?;
+            test_repo.checkout("feature")?;
+            std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+            let feature_oid = test_repo.stage_and_commit("add t3.md")?;
+
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+            let (name, commit_hash) = git_repo.get_main_or_master_branch()?;
+            assert_eq!(name, "master");
+            assert_eq!(commit_hash, oid_to_sha1(&master_oid));
+            assert_ne!(commit_hash, oid_to_sha1(&feature_oid));
+            Ok(())
+        }
+        #[test]
+        fn returns_error_if_no_main_or_master() -> Result<()> {
+            let test_repo = GitTestRepo::new("feature")?;
+            test_repo.populate()?;
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+            assert!(git_repo.get_main_or_master_branch().is_err());
+            Ok(())
+        }
+    }
+
+    mod get_commits_ahead_behind {
+        use super::*;
+        mod returns_main {
+            use super::*;
+
+            #[test]
+            fn when_on_same_commit_return_empty() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                let oid = test_repo.populate()?;
+                // create feature branch
+                test_repo.create_branch("feature")?;
+                test_repo.checkout("feature")?;
+
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+
+                let (ahead, behind) =
+                    git_repo.get_commits_ahead_behind(&oid_to_sha1(&oid), &oid_to_sha1(&oid))?;
+                assert_eq!(ahead, vec![]);
+                assert_eq!(behind, vec![]);
+                Ok(())
+            }
+
+            #[test]
+            fn when_2_commit_behind() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                test_repo.populate()?;
+                // create feature branch
+                test_repo.create_branch("feature")?;
+                let feature_oid = test_repo.checkout("feature")?;
+                // checkout main and add 2 commits
+                test_repo.checkout("main")?;
+                std::fs::write(test_repo.dir.join("t5.md"), "some content")?;
+                let behind_1_oid = test_repo.stage_and_commit("add t5.md")?;
+                std::fs::write(test_repo.dir.join("t6.md"), "some content")?;
+                let behind_2_oid = test_repo.stage_and_commit("add t6.md")?;
+
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+
+                let (ahead, behind) = git_repo.get_commits_ahead_behind(
+                    &oid_to_sha1(&behind_2_oid),
+                    &oid_to_sha1(&feature_oid),
+                )?;
+                assert_eq!(ahead, vec![]);
+                assert_eq!(
+                    behind,
+                    vec![oid_to_sha1(&behind_2_oid), oid_to_sha1(&behind_1_oid),],
+                );
+                Ok(())
+            }
+
+            #[test]
+            fn when_2_commit_ahead() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                let main_oid = test_repo.populate()?;
+                // create feature branch and add 2 commits
+                test_repo.create_branch("feature")?;
+                test_repo.checkout("feature")?;
+                std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+                let ahead_1_oid = test_repo.stage_and_commit("add t3.md")?;
+                std::fs::write(test_repo.dir.join("t4.md"), "some content")?;
+                let ahead_2_oid = test_repo.stage_and_commit("add t4.md")?;
+
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+
+                let (ahead, behind) = git_repo.get_commits_ahead_behind(
+                    &oid_to_sha1(&main_oid),
+                    &oid_to_sha1(&ahead_2_oid),
+                )?;
+                assert_eq!(
+                    ahead,
+                    vec![oid_to_sha1(&ahead_2_oid), oid_to_sha1(&ahead_1_oid),],
+                );
+                assert_eq!(behind, vec![]);
+                Ok(())
+            }
+
+            #[test]
+            fn when_2_commit_ahead_and_2_commits_behind() -> Result<()> {
+                let test_repo = GitTestRepo::default();
+                test_repo.populate()?;
+                // create feature branch and add 2 commits
+                test_repo.create_branch("feature")?;
+                test_repo.checkout("feature")?;
+                std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+                let ahead_1_oid = test_repo.stage_and_commit("add t3.md")?;
+                std::fs::write(test_repo.dir.join("t4.md"), "some content")?;
+                let ahead_2_oid = test_repo.stage_and_commit("add t4.md")?;
+                // checkout main and add 2 commits
+                test_repo.checkout("main")?;
+                std::fs::write(test_repo.dir.join("t5.md"), "some content")?;
+                let behind_1_oid = test_repo.stage_and_commit("add t5.md")?;
+                std::fs::write(test_repo.dir.join("t6.md"), "some content")?;
+                let behind_2_oid = test_repo.stage_and_commit("add t6.md")?;
+
+                let git_repo = Repo::from_path(&test_repo.dir)?;
+
+                let (ahead, behind) = git_repo.get_commits_ahead_behind(
+                    &oid_to_sha1(&behind_2_oid),
+                    &oid_to_sha1(&ahead_2_oid),
+                )?;
+                assert_eq!(
+                    ahead,
+                    vec![oid_to_sha1(&ahead_2_oid), oid_to_sha1(&ahead_1_oid)],
+                );
+                assert_eq!(
+                    behind,
+                    vec![oid_to_sha1(&behind_2_oid), oid_to_sha1(&behind_1_oid)],
+                );
+                Ok(())
+            }
+        }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index e6eac32..5094c11 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,6 +6,7 @@ use clap::{Parser, Subcommand};
 
 mod cli_interactor;
 mod config;
+mod git;
 mod key_handling;
 mod login;
 mod sub_commands;
@@ -28,11 +29,14 @@ pub struct Cli {
 enum Commands {
     /// save encrypted nsec for future use
     Login(sub_commands::login::SubCommandArgs),
+    /// create and issue Prs
+    Prs(sub_commands::prs::SubCommandArgs),
 }
 
 fn main() -> Result<()> {
     let cli = Cli::parse();
     match &cli.command {
         Commands::Login(args) => sub_commands::login::launch(&cli, args),
+        Commands::Prs(args) => sub_commands::prs::launch(&cli, args),
     }
 }
diff --git a/src/sub_commands/mod.rs b/src/sub_commands/mod.rs
index 320cbbb..3c3da1d 100644
--- a/src/sub_commands/mod.rs
+++ b/src/sub_commands/mod.rs
@@ -1 +1,2 @@
 pub mod login;
+pub mod prs;
diff --git a/src/sub_commands/prs/create.rs b/src/sub_commands/prs/create.rs
new file mode 100644
index 0000000..dd32c65
--- /dev/null
+++ b/src/sub_commands/prs/create.rs
@@ -0,0 +1,371 @@
+use anyhow::{bail, Context, Result};
+use nostr::{prelude::sha1::Hash as Sha1Hash, EventBuilder, Marker, Tag, TagKind};
+
+use crate::{
+    cli_interactor::{Interactor, InteractorPrompt, PromptConfirmParms, PromptInputParms},
+    git::{Repo, RepoActions},
+    login, Cli,
+};
+
+#[derive(Debug, clap::Args)]
+pub struct SubCommandArgs {
+    #[clap(short, long)]
+    /// title of pull request (defaults to first line of first commit)
+    title: Option<String>,
+    #[clap(short, long)]
+    /// optional description
+    description: Option<String>,
+    #[clap(long)]
+    /// branch to get changes from (defaults to head)
+    from_branch: Option<String>,
+    #[clap(long)]
+    /// destination branch (defaults to main or master)
+    to_branch: Option<String>,
+}
+
+pub fn launch(
+    cli_args: &Cli,
+    _pr_args: &super::SubCommandArgs,
+    args: &SubCommandArgs,
+) -> Result<()> {
+    let git_repo = Repo::discover().context("cannot find a git repository")?;
+
+    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 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!(
+                        "'{from_branch}' is {} commits behind '{to_branch}' and {} ahead. Consider rebasing before sending patches. Proceed anyway?",
+                        behind.len(),
+                        ahead.len(),
+                    )
+                )
+                .with_default(false)
+        ).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(),
+        );
+    }
+
+    let title = match &args.title {
+        Some(t) => t.clone(),
+        None => Interactor::default().input(PromptInputParms::default().with_prompt("title"))?,
+    };
+
+    let description = match &args.description {
+        Some(t) => t.clone(),
+        None => Interactor::default()
+            .input(PromptInputParms::default().with_prompt("description (Optional)"))?,
+    };
+
+    let root_commit = git_repo
+        .get_root_commit(to_branch.as_str())
+        .context("failed to get root commit of the repository")?;
+    // create PR event
+
+    let keys = login::launch(&cli_args.nsec, &cli_args.password)?;
+
+    let pr_event = EventBuilder::new(
+        nostr::event::Kind::Custom(318),
+        format!("{title}\r\n\r\n{description}"),
+        &[Tag::Hashtag(format!("r-{root_commit}"))],
+        // TODO: suggested branch name
+        // Tag::Generic(
+        //     TagKind::Custom("suggested-branch-name".to_string()),
+        //     vec![],
+        // ),
+        // TODO: add Repo event as root
+        // TODO: people tag maintainers
+        // TODO: add relay tags
+    )
+    .to_event(&keys)
+    .context("failed to create pr event")?;
+
+    let mut patch_events = vec![];
+    for commit in &ahead {
+        let commit_parent = git_repo
+            .get_commit_parent(commit)
+            .context("failed to create patch event")?;
+        patch_events.push(
+            EventBuilder::new(
+                nostr::event::Kind::Custom(317),
+                git_repo
+                    .make_patch_from_commit(commit)
+                    .context(format!("cannot make patch for commit {commit}"))?,
+                &[
+                    Tag::Hashtag(format!("r-{root_commit}")),
+                    Tag::Hashtag(commit.to_string()),
+                    Tag::Hashtag(commit_parent.to_string()),
+                    Tag::Event(
+                        pr_event.id,
+                        None, // TODO: add relay
+                        Some(Marker::Root),
+                    ),
+                    Tag::Generic(
+                        TagKind::Custom("commit".to_string()),
+                        vec![commit.to_string()],
+                    ),
+                    Tag::Generic(
+                        TagKind::Custom("parent-commit".to_string()),
+                        vec![commit_parent.to_string()],
+                    ),
+                    // TODO: add Repo event tags
+                    // TODO: people tag maintainers
+                    // TODO: add relay tags
+                ],
+            )
+            .to_event(&keys),
+        );
+    }
+
+    // TODO check if there is already a similarly named PR
+    // TODO connect to relays and post
+
+    Ok(())
+}
+
+// TODO
+// - find profile
+// - file relays
+// - find repo events
+// -
+
+/**
+ * returns `(from_branch,to_branch,ahead,behind)`
+ */
+fn identify_ahead_behind(
+    git_repo: &Repo,
+    from_branch: &Option<String>,
+    to_branch: &Option<String>,
+) -> Result<(String, String, Vec<Sha1Hash>, Vec<Sha1Hash>)> {
+    let (from_branch, from_tip) = match from_branch {
+        Some(name) => (
+            name.to_string(),
+            git_repo
+                .get_tip_of_local_branch(name)
+                .context(format!("cannot find from_branch '{name}'"))?,
+        ),
+        None => (
+            "head".to_string(),
+            git_repo
+                .get_head_commit()
+                .context("failed to get head commit")
+                .context(
+                    "checkout a commit or specify a from_branch. head does not reveal a commit",
+                )?,
+        ),
+    };
+
+    let (to_branch, to_tip) = match to_branch {
+        Some(name) => (
+            name.to_string(),
+            git_repo
+                .get_tip_of_local_branch(name)
+                .context(format!("cannot find to_branch '{name}'"))?,
+        ),
+        None => {
+            let (name, commit) = git_repo
+                .get_main_or_master_branch()
+                .context("a destination branch (to_branch) is not specified and the defaults (main or master) do not exist")?;
+            (name.to_string(), commit)
+        }
+    };
+
+    match git_repo.get_commits_ahead_behind(&to_tip, &from_tip) {
+        Err(e) => {
+            if e.to_string().contains("is not an ancestor of") {
+                return Err(e).context(format!(
+                    "'{from_branch}' is not branched from '{to_branch}'"
+                ));
+            }
+            Err(e).context(format!(
+                "failed to get commits ahead and behind from '{from_branch}' to '{to_branch}'"
+            ))
+        }
+        Ok((ahead, behind)) => Ok((from_branch, to_branch, ahead, behind)),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::git::GitTestRepo;
+
+    use super::*;
+    mod identify_ahead_behind {
+
+        use super::*;
+        use crate::git::oid_to_sha1;
+
+        #[test]
+        fn when_from_branch_doesnt_exist_return_error() -> Result<()> {
+            let test_repo = GitTestRepo::default();
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+
+            test_repo.populate()?;
+            let branch_name = "doesnt_exist";
+            assert_eq!(
+                identify_ahead_behind(&git_repo, &Some(branch_name.to_string()), &None)
+                    .unwrap_err()
+                    .to_string(),
+                format!("cannot find from_branch '{}'", &branch_name),
+            );
+            Ok(())
+        }
+
+        #[test]
+        fn when_to_branch_doesnt_exist_return_error() -> Result<()> {
+            let test_repo = GitTestRepo::default();
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+
+            test_repo.populate()?;
+            let branch_name = "doesnt_exist";
+            assert_eq!(
+                identify_ahead_behind(&git_repo, &None, &Some(branch_name.to_string()))
+                    .unwrap_err()
+                    .to_string(),
+                format!("cannot find to_branch '{}'", &branch_name),
+            );
+            Ok(())
+        }
+
+        #[test]
+        fn when_to_branch_is_none_and_no_main_or_master_branch_return_error() -> Result<()> {
+            let test_repo = GitTestRepo::new("notmain")?;
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+
+            test_repo.populate()?;
+
+            assert_eq!(
+                identify_ahead_behind(&git_repo, &None, &None)
+                    .unwrap_err()
+                    .to_string(),
+                "a destination branch (to_branch) is not specified and the defaults (main or master) do not exist",
+            );
+            Ok(())
+        }
+
+        #[test]
+        fn when_from_branch_is_none_return_as_head() -> Result<()> {
+            let test_repo = GitTestRepo::default();
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+
+            test_repo.populate()?;
+            // create feature branch with 1 commit ahead
+            test_repo.create_branch("feature")?;
+            test_repo.checkout("feature")?;
+            std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+            let head_oid = test_repo.stage_and_commit("add t3.md")?;
+
+            // make feature branch 1 commit behind
+            test_repo.checkout("main")?;
+            std::fs::write(test_repo.dir.join("t4.md"), "some content")?;
+            let main_oid = test_repo.stage_and_commit("add t4.md")?;
+            // checkout feature
+            test_repo.checkout("feature")?;
+
+            let (from_branch, to_branch, ahead, behind) =
+                identify_ahead_behind(&git_repo, &None, &None)?;
+
+            assert_eq!(from_branch, "head");
+            assert_eq!(ahead, vec![oid_to_sha1(&head_oid)]);
+            assert_eq!(to_branch, "main");
+            assert_eq!(behind, vec![oid_to_sha1(&main_oid)]);
+            Ok(())
+        }
+
+        #[test]
+        fn when_from_branch_is_not_head_return_as_from_branch() -> Result<()> {
+            let test_repo = GitTestRepo::default();
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+
+            test_repo.populate()?;
+            // create feature branch with 1 commit ahead
+            test_repo.create_branch("feature")?;
+            test_repo.checkout("feature")?;
+            std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+            let head_oid = test_repo.stage_and_commit("add t3.md")?;
+
+            // make feature branch 1 commit behind
+            test_repo.checkout("main")?;
+            std::fs::write(test_repo.dir.join("t4.md"), "some content")?;
+            let main_oid = test_repo.stage_and_commit("add t4.md")?;
+
+            let (from_branch, to_branch, ahead, behind) =
+                identify_ahead_behind(&git_repo, &Some("feature".to_string()), &None)?;
+
+            assert_eq!(from_branch, "feature");
+            assert_eq!(ahead, vec![oid_to_sha1(&head_oid)]);
+            assert_eq!(to_branch, "main");
+            assert_eq!(behind, vec![oid_to_sha1(&main_oid)]);
+            Ok(())
+        }
+
+        #[test]
+        fn when_to_branch_is_not_main_return_as_to_branch() -> Result<()> {
+            let test_repo = GitTestRepo::default();
+            let git_repo = Repo::from_path(&test_repo.dir)?;
+
+            test_repo.populate()?;
+            // create dev branch with 1 commit ahead
+            test_repo.create_branch("dev")?;
+            test_repo.checkout("dev")?;
+            std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+            let dev_oid_first = test_repo.stage_and_commit("add t3.md")?;
+
+            // create feature branch with 1 commit ahead of dev
+            test_repo.create_branch("feature")?;
+            test_repo.checkout("feature")?;
+            std::fs::write(test_repo.dir.join("t4.md"), "some content")?;
+            let feature_oid = test_repo.stage_and_commit("add t4.md")?;
+
+            // make feature branch 1 behind
+            test_repo.checkout("dev")?;
+            std::fs::write(test_repo.dir.join("t3.md"), "some content")?;
+            let dev_oid = test_repo.stage_and_commit("add t3.md")?;
+
+            let (from_branch, to_branch, ahead, behind) = identify_ahead_behind(
+                &git_repo,
+                &Some("feature".to_string()),
+                &Some("dev".to_string()),
+            )?;
+
+            assert_eq!(from_branch, "feature");
+            assert_eq!(ahead, vec![oid_to_sha1(&feature_oid)]);
+            assert_eq!(to_branch, "dev");
+            assert_eq!(behind, vec![oid_to_sha1(&dev_oid)]);
+
+            let (from_branch, to_branch, ahead, behind) =
+                identify_ahead_behind(&git_repo, &Some("feature".to_string()), &None)?;
+
+            assert_eq!(from_branch, "feature");
+            assert_eq!(
+                ahead,
+                vec![oid_to_sha1(&feature_oid), oid_to_sha1(&dev_oid_first)]
+            );
+            assert_eq!(to_branch, "main");
+            assert_eq!(behind, vec![]);
+
+            Ok(())
+        }
+    }
+}
diff --git a/src/sub_commands/prs/mod.rs b/src/sub_commands/prs/mod.rs
new file mode 100644
index 0000000..c316e73
--- /dev/null
+++ b/src/sub_commands/prs/mod.rs
@@ -0,0 +1,22 @@
+use anyhow::Result;
+use clap::Subcommand;
+
+use crate::Cli;
+pub mod create;
+
+#[derive(clap::Parser)]
+pub struct SubCommandArgs {
+    #[command(subcommand)]
+    pub prs_command: Commands,
+}
+
+#[derive(Debug, Subcommand)]
+pub enum Commands {
+    Create(create::SubCommandArgs),
+}
+
+pub fn launch(cli_args: &Cli, pr_args: &SubCommandArgs) -> Result<()> {
+    match &pr_args.prs_command {
+        Commands::Create(args) => create::launch(cli_args, pr_args, args),
+    }
+}