#!/usr/bin/env bash
# pull-all-dirs - Pull git repositories in all subdirectories that are behind upstream
# Usage: pull-all-dirs [directory]

set -euo pipefail

target_dir="${1:-.}"

if [[ ! -d "$target_dir" ]]; then
    printf 'Error: Directory "%s" does not exist\n' "$target_dir" >&2
    exit 1
fi

cd "$target_dir"

updated_file="$(mktemp)"
trap 'rm -f "$updated_file"' EXIT

process_repo() {
    local dir=$1

    [[ -d "$dir/.git" ]] || return 0

    if ! git -C "$dir" remote update >/dev/null 2>&1; then
        printf 'Warning: could not update remotes for "%s"\n' "$dir" >&2
        return 1
    fi

    if git -C "$dir" status -uno | grep -q "Your branch is behind"; then
        printf 'Pulling updates for: %s\n' "$dir"
        if git -C "$dir" pull --ff-only; then
            printf '%s\n' "$dir" >>"$updated_file"
        else
            printf 'Error: failed to pull updates for "%s"\n' "$dir" >&2
            return 1
        fi
    fi
}

pids=()

for dir in */; do
    [[ -d "$dir" ]] || continue
    dir=${dir%/}
    process_repo "$dir" &
    pids+=("$!")
done

exit_status=0

for pid in "${pids[@]}"; do
    if ! wait "$pid"; then
        exit_status=1
    fi
done

if [[ ! -s "$updated_file" ]]; then
    echo "All repositories are up to date."
else
    echo "Updated repositories:"
    sort -u "$updated_file" | sed 's/^/  - /'
fi

exit "$exit_status"