#!/bin/bash

# vars
SELF="${BASH_SOURCE[0]}"
SELF_DIR=$(cd $(dirname "${BASH_SOURCE[0]}") && pwd -P)
SELF_DIR="${SELF_DIR:-$(pwd)}"
TOOLS_BIN="${SELF_DIR}/../tools/local/bin"

function backup_original {  # backup_original $FILE
    local FILE FILE_BASE FILE_EXT
    FILE="${1}"
    if [[ "${FILE:-}" == "" ]]; then
        echo "file not specified" >&2
        return 1
    fi
    if [[ ! -e "${FILE}" ]]; then
        echo "file does not exist: ${FILE}" >&2
        return 1
    fi
    FILE_BASE="${FILE%.*}"
    FILE_EXT="${FILE##*.}"
    if [[ -e "${FILE_BASE}-original.${FILE_EXT}" ]]; then
        echo "backup already exists for file: ${FILE}" >&2
        return 1
    fi
    cp "${FILE}" "${FILE_BASE}-original.${FILE_EXT}"
    return 0
}

if [[ "${#@}" -eq 0 ]]; then
    echo "no files specified" >&2
    exit 1
fi

ERRORS=()
for IMAGE in "${@}"; do
    if [[ -e "${IMAGE}" ]]; then
        IMAGE_SIZE=$(wc -c <"${IMAGE}")
        IMAGE_EXT="${IMAGE##*.}"
        case "${IMAGE_EXT}" in
            png)
                if backup_original "${IMAGE}" && "${TOOLS_BIN}/pngquant" 256 --speed 3 --quality 80-100 --force --skip-if-larger --output "${IMAGE}" "${IMAGE}" >/dev/null 2>&1 && "${TOOLS_BIN}/zopflipng" --lossy_transparent --filters=0pme -y "${IMAGE}" "${IMAGE}" >/dev/null 2>&1; then
                    IMAGE_SIZE_NEW=$(wc -c <"${IMAGE}")
                    IMAGE_SIZE_PERCENT=$(awk -v s1="${IMAGE_SIZE}" -v s2="${IMAGE_SIZE_NEW}" 'BEGIN { printf "%.1f", (s2/s1) * 100 }')
                    echo -n "[${IMAGE_SIZE_PERCENT}%]"
                    echo -ne "\t"
                    echo "${IMAGE}"
                else
                    echo "unable to process file: ${IMAGE}" >&2
                    ERRORS+="${IMAGE}"
                fi
                ;;
            *)
                echo "file type '${IMAGE_EXT}' not handled: ${IMAGE}" >&2
                ERRORS+="${IMAGE}"
                ;;
        esac
    else
        ERRORS+="${IMAGE}"
    fi
done
if [[ "${#ERRORS[@]}" -ne 0 ]]; then
    exit 1
fi

# done
exit 0