#!/usr/bin/env bash

# Recursively dump all blobs in the subtree identified by ID.

set -o pipefail

usage() {
cat <<EOF
Usage: cat-git-tree [--git-dir DIR] ID
EOF
}

cat-item()
{
    local hash="$1"
    local type="$2"
    case "$type" in
        blob)
            git cat-file blob "$hash" || exit $?
            ;;
        tree)
            local tree=$(git ls-tree "$hash") || exit $?
            while read -r line; do
                local sub_type=$(echo "$line" | cut -d' ' -f 2) || exit $?
                local sub_hash=$(echo "$line" | cut -d' ' -f 3) || exit $?
                sub_hash=$(echo "$sub_hash" | cut -d'	' -f 1) || exit $?
                cat-item "$sub_hash" "$sub_type"
            done <<< "$tree"
            ;;
        *)
            echo "Unexpected item: $type $hash" 1>&2
            exit 1
            ;;
    esac
}

case $# in
    1) ;;
    3)
        if test "$1" != --git-dir; then
            usage 1>&2
            exit 1
        fi
        export GIT_DIR="$2"
        shift 2
        ;;
    *)
        usage 1>&2
        exit 1
        ;;
esac

top="$1"
type=$(git cat-file -t "$top") || exit $?
cat-item "$top" "$type"