1 files changed, 203 insertions, 0 deletions

diff --git a/src/bin/ngit/sub_commands/pull.rs b/src/bin/ngit/sub_commands/pull.rs
new file mode 100644
index 0000000..d79b7b1
--- /dev/null
+++ b/src/bin/ngit/sub_commands/pull.rs
@@ -0,0 +1,203 @@
+use anyhow::{bail, Context, Result};
+use ngit::git_events::is_event_proposal_root_for_branch;
+use nostr_sdk::PublicKey;
+
+use crate::{
+    client::{
+        fetching_with_report, get_all_proposal_patch_events_from_cache,
+        get_proposals_and_revisions_from_cache, get_repo_ref_from_cache, Client, Connect,
+    },
+    git::{str_to_sha1, Repo, RepoActions},
+    git_events::{get_commit_id_from_patch, get_most_recent_patch_with_ancestors, tag_value},
+    repo_ref::get_repo_coordinates,
+};
+
+#[allow(clippy::too_many_lines)]
+pub async fn launch() -> Result<()> {
+    let git_repo = Repo::discover().context("cannot find a git repository")?;
+    let git_repo_path = git_repo.get_path()?;
+
+    let (main_or_master_branch_name, _) = git_repo
+        .get_main_or_master_branch()
+        .context("no main or master branch")?;
+
+    let branch_name = git_repo
+        .get_checked_out_branch_name()
+        .context("cannot get checked out branch name")?;
+
+    if branch_name == main_or_master_branch_name {
+        bail!("checkout a branch associated with a proposal first")
+    }
+    let client = Client::default();
+
+    let repo_coordinates = get_repo_coordinates(&git_repo, &client).await?;
+    fetching_with_report(git_repo_path, &client, &repo_coordinates).await?;
+
+    let repo_ref = get_repo_ref_from_cache(git_repo_path, &repo_coordinates).await?;
+
+    let logged_in_public_key =
+        if let Ok(Some(npub)) = git_repo.get_git_config_item("nostr.npub", None) {
+            PublicKey::parse(npub).ok()
+        } else {
+            None
+        };
+
+    let proposal_root_event =
+        get_proposals_and_revisions_from_cache(git_repo_path, repo_ref.coordinates())
+            .await?
+            .iter()
+            .find(|e| {
+                is_event_proposal_root_for_branch(e, &branch_name, &logged_in_public_key)
+                    .unwrap_or(false)
+            })
+            .context("cannot find proposal that matches the current branch name")?
+            .clone();
+
+    let commit_events =
+        get_all_proposal_patch_events_from_cache(git_repo_path, &repo_ref, &proposal_root_event.id)
+            .await?;
+
+    let most_recent_proposal_patch_chain =
+        get_most_recent_patch_with_ancestors(commit_events.clone())
+            .context("cannot get most recent patch for proposal")?;
+
+    let local_branch_tip = git_repo.get_tip_of_branch(&branch_name)?;
+
+    let (main_branch_name, master_tip) = git_repo.get_main_or_master_branch()?;
+
+    let (local_ahead_of_main, local_beind_main) =
+        git_repo.get_commits_ahead_behind(&master_tip, &local_branch_tip)?;
+
+    let proposal_base_commit = str_to_sha1(&tag_value(
+        most_recent_proposal_patch_chain
+            .last()
+            .context("there should be at least one patch as we have already checked for this")?,
+        "parent-commit",
+    )?)
+    .context("cannot get valid parent commit id from patch")?;
+
+    let (_, proposal_behind_main) =
+        git_repo.get_commits_ahead_behind(&master_tip, &proposal_base_commit)?;
+
+    let proposal_tip =
+        str_to_sha1(
+            &get_commit_id_from_patch(most_recent_proposal_patch_chain.first().context(
+                "there should be at least one patch as we have already checked for this",
+            )?)
+            .context("cannot get valid commit_id from patch")?,
+        )
+        .context("cannot get valid commit_id from patch")?;
+
+    // if uptodate
+    if proposal_tip.eq(&local_branch_tip) {
+        println!("branch already up-to-date");
+    }
+    // if new appendments
+    else if most_recent_proposal_patch_chain.iter().any(|patch| {
+        get_commit_id_from_patch(patch)
+            .unwrap_or_default()
+            .eq(&local_branch_tip.to_string())
+    }) {
+        check_clean(&git_repo)?;
+        let applied = git_repo
+            .apply_patch_chain(&branch_name, most_recent_proposal_patch_chain)
+            .context("cannot apply patch chain")?;
+        println!("applied {} new commits", applied.len(),);
+    }
+    // if parent commit doesnt exist
+    else if !git_repo.does_commit_exist(&proposal_base_commit.to_string())? {
+        println!(
+            "a new version of the proposal has a prant commit that doesnt exist in your local repository."
+        );
+        println!("your '{main_branch_name}' branch may not be up-to-date.");
+        println!("manually run `git pull` on '{main_branch_name}' and try again");
+    }
+    // if new revision and no local changes (tip of local in proposal history)
+    else if commit_events.iter().any(|patch| {
+        get_commit_id_from_patch(patch)
+            .unwrap_or_default()
+            .eq(&local_branch_tip.to_string())
+    }) {
+        check_clean(&git_repo)?;
+
+        git_repo.create_branch_at_commit(&branch_name, &proposal_base_commit.to_string())?;
+        let applied = git_repo
+            .apply_patch_chain(&branch_name, most_recent_proposal_patch_chain)
+            .context("cannot apply patch chain")?;
+
+        println!(
+            "pulled new version of proposal ({} ahead {} behind '{main_branch_name}'), replacing old version ({} ahead {} behind '{main_branch_name}')",
+            applied.len(),
+            proposal_behind_main.len(),
+            local_ahead_of_main.len(),
+            local_beind_main.len(),
+        );
+    }
+    // if tip of proposal in branch in history (local appendments made to up-to-date
+    // proposal)
+    else if git_repo.ancestor_of(&local_branch_tip, &proposal_tip)? {
+        let (local_ahead_of_proposal, _) = git_repo
+            .get_commits_ahead_behind(&proposal_tip, &local_branch_tip)
+            .context("cannot get commits ahead behind for propsal_top and local_branch_tip")?;
+        println!(
+            "local proposal branch exists with {} unpublished commits on top of the most up-to-date version of the proposal",
+            local_ahead_of_proposal.len()
+        );
+    } else {
+        println!("you have an amended/rebase version the proposal that is unpublished");
+        // user probably has a unpublished amended or rebase version of the latest
+        // proposal version
+        // if tip of proposal commits exist (were once part of branch but have been
+        // amended and git clean up job hasn't removed them)
+        if git_repo.does_commit_exist(&proposal_tip.to_string())? {
+            println!(
+                "you have previously applied the latest version of the proposal ({} ahead {} behind '{main_branch_name}') but your local proposal branch has amended or rebased it ({} ahead {} behind '{main_branch_name}')",
+                most_recent_proposal_patch_chain.len(),
+                proposal_behind_main.len(),
+                local_ahead_of_main.len(),
+                local_beind_main.len(),
+            );
+        }
+        // user probably has a unpublished amended or rebase version of an older
+        // proposal version
+        else {
+            println!(
+                "your local proposal branch ({} ahead {} behind '{main_branch_name}') has conflicting changes with the latest published proposal ({} ahead {} behind '{main_branch_name}')",
+                local_ahead_of_main.len(),
+                local_beind_main.len(),
+                most_recent_proposal_patch_chain.len(),
+                proposal_behind_main.len(),
+            );
+
+            println!(
+                "its likely that you have rebased / amended an old proposal version because git has no record of the latest proposal commit."
+            );
+            println!(
+                "it is possible that you have been working off the latest version and git has delete this commit as part of a clean up"
+            );
+        }
+        println!("to view the latest proposal but retain your changes:");
+        println!("  1) create a new branch off the tip commit of this one to store your changes");
+        println!("  2) run `ngit list` and checkout the latest published version of this proposal");
+
+        println!("if you are confident in your changes consider running `ngit push --force`");
+
+        // TODO: this copy could be refined further based on this:
+        //  - amended commits in the proposal
+        //     - if local_base eq proposal base
+        //  - amended an older version of proposal
+        //     - if local_base is behind proposal_base
+        //  - rebased the proposal
+        //     - if local_base is ahead of proposal_base
+    }
+    Ok(())
+}
+
+fn check_clean(git_repo: &Repo) -> Result<()> {
+    if git_repo.has_outstanding_changes()? {
+        bail!(
+            "cannot pull proposal branch when repository is not clean. discard or stash (un)staged changes and try again."
+        );
+    }
+    Ok(())
+}