prune_squashed.fish

#!/usr/bin/env fish

### Finds and optionally deletes all local branches that have been squashed-merged on remote

# Fetch latest from remote to ensure up-to-date references
git fetch --prune

# Get the list of local branches excluding the current one
set local_branches (git branch --format="%(refname:short)")

# Initialize an empty list to store branches to delete
set branches_to_delete

# Define protected branches
set protected_branches "ci" "uat" "staging" "prod" "master"

# Loop through each local branch
for branch in $local_branches
    # Skip the current branch and protected branches
    if [ $branch = (git rev-parse --abbrev-ref HEAD) ]
        continue
    end
    
    # Check if branch is protected
    if contains $branch $protected_branches
        continue
    end

    # Check if the branch has been squash-merged on the remote main branch
    # For squash-merged branches, we need to:
    # 1. Find the merge base between the branch and main
    # 2. Create a temporary commit with the branch's tree and merge base as parent
    # 3. Use git cherry to see if this content is already in main
    set merge_base (git merge-base origin/main $branch)
    set temp_commit (git commit-tree (git rev-parse $branch^{tree}) -p $merge_base -m _)
    set cherry_result (git cherry origin/main $temp_commit)
    
    # If cherry result starts with "-", the changes are already in main
    if string match -q -- "-*" $cherry_result
        set branches_to_delete $branches_to_delete $branch
    end
end

# If no branches were found, notify and exit
if test (count $branches_to_delete) -eq 0
    echo "No local branches found that were squash-merged on remote."
    exit 0
end

# Show all branches that will be deleted
echo "The following branches appear to be squash-merged on remote:"
for branch in $branches_to_delete
    echo "  - $branch"
end

# Prompt once for all branches
echo "Do you want to delete all these branches? (y/N)"
read -l confirm
if [ $confirm = "y" ]
    for branch in $branches_to_delete
        git branch -D $branch
    end
else
    echo "Operation cancelled. No branches were deleted."
end