#!/usr/bin/env bash

merge-git-remote() {
    local git_folders
    git_folders=$(ls-git-folder .)
    for git_folder in $git_folders; do
        git_folder="${git_folder#./}"
        if ! git config -f .gitmodules --get-regexp "merge\.$git_folder\." &>/dev/null; then
            continue
        fi
        echo "=== Processing submodule: $git_folder ==="

        # Add explicit remotes from [remotes] section
        while IFS= read -r line; do
            local key value remote_name
            key=$(echo "$line" | awk '{print $1}')
            value=$(echo "$line" | awk '{print $2}')
            remote_name="${key##remotes.$git_folder.}"
            echo "  Adding remote '$remote_name' -> $value"
            git -C "$git_folder" remote add "$remote_name" "$value" 2>/dev/null || \
                git -C "$git_folder" remote set-url "$remote_name" "$value"
            git -C "$git_folder" fetch -q "$remote_name"
        done < <(git config -f .gitmodules --get-regexp "remotes\.$git_folder\." 2>/dev/null)

        local pinned_commit
        pinned_commit=$(git config -f .gitmodules submodule."$git_folder".commit 2>/dev/null)
        if [[ -n "$pinned_commit" ]]; then
            git -C "$git_folder" checkout -q -B merged "$pinned_commit"
        else
            git -C "$git_folder" checkout -q -B merged HEAD
        fi

        # Fetch origin once upfront for any origin merge refs
        if git config -f .gitmodules --get-regexp "merge\.$git_folder\.origin" &>/dev/null; then
            git -C "$git_folder" fetch -q origin
        fi

        while IFS= read -r line; do
            local key merge_ref remote_name tmp_ref
            key=$(echo "$line" | awk '{print $1}')
            merge_ref=$(echo "$line" | awk '{print $2}')
            remote_name="${key##merge.$git_folder.}"
            echo "  Merging $remote_name/$merge_ref"
            tmp_ref="refs/merge-tmp/${remote_name}-$(echo "$merge_ref" | tr '/' '-')"
            if ! git -C "$git_folder" fetch -q "$remote_name" "$merge_ref:$tmp_ref"; then
                echo "  !! Could not fetch $merge_ref from $remote_name — skipping"
                continue
            fi
            if ! git -C "$git_folder" merge -q --no-edit "$tmp_ref"; then
                echo "  !! Merge conflict in $git_folder ($remote_name/$merge_ref) — resolve manually"
            fi
        done < <(git config -f .gitmodules --get-regexp "merge\.$git_folder\.")
    done
}