v0.0.1-alpha funcs

1 files changed, 95 insertions, 0 deletions

diff --git a/src/funcs/apply_patches.rs b/src/funcs/apply_patches.rs
new file mode 100644
index 0000000..7d3147e
--- /dev/null
+++ b/src/funcs/apply_patches.rs
@@ -0,0 +1,95 @@
+use std::{path::PathBuf, process::Command, fs::{self, File}, io::Write};
+
+use git2::Repository;
+use nostr::Event;
+
+use crate::{utils::save_event, ngit_tag::{tag_extract_value, tag_is_commit}};
+
+
+pub fn apply_patches(
+    git_repo: &Repository,
+    repo_dir_path: &PathBuf,
+    patches_correctly_ordered:&mut Vec<Event>,
+
+) {
+    // check git is installed
+    match Command::new("git").output() {
+        Ok(_o) => (),
+        Err(_e) => {
+            panic!("git isn't installed :( Install git and then you can use ngit :)");
+        }
+    }
+    let ngit_path = repo_dir_path.join(".ngit");
+
+    println!("{} commits to apply",patches_correctly_ordered.len());
+    fs::create_dir(ngit_path.join("patches/mbox"))
+        .expect("patches/mbox to be created by create_dir");
+    for (i, event) in patches_correctly_ordered.iter().enumerate() {
+        save_event(
+            ngit_path.join(format!(
+                "patches/{}.json",
+                tag_extract_value(
+                    &event.tags.iter().find(|t| tag_is_commit(t))
+                        .expect("each patch contains commit tag")
+                )
+            )),
+            &event,
+        )
+            .expect("patch to be saved with [commit_id].json using save_event");
+        // extract mbox patch and save to file for 'git am' to recieve
+        let patch_path = format!("patches/mbox/{:0>5}.patch",i);
+        let mut f = File::create(ngit_path.join(&patch_path))
+            .expect("patch file can be created at patch_path location");
+        f.write_all(&event.content.as_bytes())
+            .expect("can use write_all to write event content to patch file");
+        // gitoxide or libgit2 do not support applying patches whilst maintaining the commit ids so we fall back to indirectly using git
+        // it turns out that git am doesnt retain commit ids. for now we will modify the committer author and timestamp to correct the commit id.
+        match Command::new("git")
+        .current_dir(&repo_dir_path)
+        .args([
+            "am",
+            ngit_path.join(&patch_path).to_string_lossy().to_string().as_str(),
+        ])
+        .output() {
+            Ok(_o) => {
+                let mut revwalk = git_repo.revwalk()
+                    .expect("revwalk not to error");
+                revwalk.push_head()
+                    .expect("revwalk.push_head not to error");
+                
+                for (i, oid) in revwalk.enumerate() {
+                    if i == 0 {
+                        let old_commit = git_repo.find_commit(
+                            oid
+                                .expect("oid of newly added commit")
+                        )
+                            .expect("commit from newly added commit oid");
+                        // create commit using amend with relects the original commit id (assumes committer should be identical to author
+                        // TODO: in git push add a tag if the committer information is different to author. Then here use that info instead.
+                        let updated_commit_oid = old_commit.amend(
+                            None,
+                            None,
+                            Some(&old_commit.author()),
+                            None,
+                            None,
+                            None,
+                        )
+                            .expect("ammend commit to produce new oid");
+                        // replace the commit with the wrong oid with the newly created one with the correct oid
+                        git_repo.head()
+                            .expect("to return head of git_repo")
+                            .set_target(
+                                updated_commit_oid,
+                                "ref commit with fix committer details",
+                            )
+                                .expect("branch to be updated with fixed commt");
+                    }
+                };
+            },
+            Err(_e) => { panic!(":( git error: {:#?}",_e); },
+        }
+    }
+    // clear up by removing mbox directory
+    fs::remove_dir_all(ngit_path.join("patches/mbox"))
+        .expect("patches/mbox to be removed recursively now we are done with it");
+}