#!/usr/bin/env bash

function remove-whitespace {
    # exclude file types
    # (ignore generated files/directories)
    exclude_paths=(
        "*/.git/*"
    )
    exclude_files=(
        "*.lst"
        "*.map"
        "*.svd"
        "*.sym"
    )

    unset help
    unset silent
    unset no_action
    unset path_args
    unset file_args
    unset ffunix
    unset files

    for arg in $@; do
        unset arg_found
        case ${arg} in
        -*u* | --unix)
            arg_found="true"
            ffunix="true"
            ;;
        -*h* | --help)
            arg_found="true"
            help="true"
            ;;
        -*n* | --no-action)
            arg_found="true"
            no_action="true"
            ;;
        -*s* | --silent)
            arg_found="true"
            silent="true"
            ;;
        *) ;;
        esac

        if [[ -n "${arg_found}" ]]; then
            continue
        fi

        if [[ -d "${arg}" ]]; then
            path_args+=("${arg}")
            continue
        elif [[ -f "${arg}" ]]; then
            file_args+=("${arg}")
            continue
        fi

        echo "(unrecognised argument: '${arg}')"
    done

    if [[ -n "${ffunix}" ]]; then
        sed_cmd='s/[[:space:]]\+$//'
        grep_regex=$'[[:space:]]+$'
    else
        sed_cmd='s/[[:blank:]]\+\(\r\?\)$/\1/'
        grep_regex=$'[[:blank:]]+\r?$'
    fi

    for arg in ${path_args[@]}; do
        files+=($(
            find "${arg}" \
                ${exclude_paths[@]/#/-not -path } \
                ${exclude_files[@]/#/-not -name } \
                -type f \
                -exec grep -EIq "${grep_regex}" {} \; \
                -print
        ))
    done
    for arg in ${file_args[@]}; do
        grep -EIq "${grep_regex}" ${arg} && files+=("${arg}")
    done

    if [[ -z "${files[@]}" ]] && [[ -n "${path_args}" ]]; then
        echo "no files with trailing whitespace or dos style line endings found"
        return 0
    fi

    if [[ -n "${help}" ]] || [[ -z "${files[@]}" ]]; then
        cat <<EOF
Usage: remove-whitespace [-h] [-n] path [path]

Remove trailing whitespace from plain text files.
Path points to either a file or directory, or both.
Directories are searched recursively.
If no paths are provided, the current working
directory is searched.

Options:
  -u, --unix        convert all line endings to unix style
                    line endings
  -h, --help        show this help
  -n, --no-action   do not delete, only detect whitespace
                    this switch forces silent=false
  -s, --silent      suppress output
EOF

        return 0
    fi

    if [[ -z "${no_action}" ]]; then
        for file in ${files[@]}; do
            if [[ -n "${ffunix}" ]]; then
                sed -i "${sed_cmd}" ${file}
            else
                sed -i "${sed_cmd}" ${file}
            fi
        done
    fi

    echo ""

    if [[ -z "${silent} ${no_action}" ]] &&
        [[ -n "${files}" ]]; then
        tput setaf 1
        tput smso
        echo "The following files contained whitespace:"
        tput sgr0
        for file in ${files[@]}; do
            echo "${file}"
        done
    fi
}