#!/bin/bash
set -e

usage() {
cat &2
                exit
            fi
            BASE_IMAGE_TAG_OVERRIDE="$2"
            shift # skip the flag value
            ;;
        -t|--target)
            if [[ -z "$2" ]]; then
                usage
                printf 'ERROR: No IMAGE specified after the %s flag.\n' "$1" >&2
                exit
            fi
            TARGET_IMAGE_TAG_OVERRIDE="$2"
            shift # skip the flag value
            ;;
        -p|--package)
            if [[ -z "$2" ]]; then
                usage
                printf 'ERROR: No PACKAGE specified after the %s flag.\n' "$1" >&2
                exit
            fi
            PACKAGE_NAME="$2"
            shift # skip the flag value
            ;;
        -?*)
            usage
            printf 'ERROR: Unknown option: %s\n' "$1" >&2
            exit
            ;;
        *)            
            break
    esac

    shift
done

if [[ -n "$BASE_IMAGE_TAG_OVERRIDE" ]]; then
    BASE_IMAGE_TAG="$BASE_IMAGE_TAG_OVERRIDE"
fi

if [[ -n "$TARGET_IMAGE_TAG_OVERRIDE" ]]; then
    TARGET_IMAGE_TAG="$TARGET_IMAGE_TAG_OVERRIDE"
fi

readonly BASE_IMAGE_TAG
readonly TARGET_IMAGE_TAG

echo "Base: $BASE_IMAGE_TAG"
echo "Target: $TARGET_IMAGE_TAG"

if [[ "$BASE_IMAGE_TAG" == "gcr.io/"* ]]; then
    docker pull "$BASE_IMAGE_TAG"
fi


if [[ -n "$PACKAGE_NAME" ]]; then
    echo "Package: $PACKAGE_NAME"
    CMDS=("python /tools/pip_list_versions.py $PACKAGE_NAME | sort")
else
    CMDS=("pip list --format=freeze" 'cat /etc/os-release | grep -oP "PRETTY_NAME=\"\K([^\"]*)"' "uname -r" "dpkg --list | awk '{print \$2\"==\"\$3}'" "printenv | sort")
fi

for cmd in "${CMDS[@]}"; do
    echo "== Comparing $cmd =="
    diff --suppress-common-lines --side-by-side \