ffenc_converter

#!/usr/bin/env bash

readonly SCRIPT_NAME="$(basename ${0})"
readonly TAIL=".converted"
readonly TAB_NUM=4

usage()
{
    cat << EOF >&2
USAGE: $SCRIPT_NAME [-h | --help]
                        [--name <pattern>] [--iname <pattern>]
                        [-f <from encoding> | --from <from encoding>]
                        [-t <to encoding> | --to <to encoding>]
                        [-d | --dos2unix] [-m | --mac2unix]
                        [-o | --override]
                        [-e | --expand]
                        FILE

OPTIONS
        --name <pattern>

        --iname <pattern>
            Like --name, but the match is case insensitive.

        -f <from encoding>, --from <from encoding>

        -t <to encoding>, --to <to encoding>

        -d, --dos2unix

        -m, --mac2unix

        -o, --override

        -e, --expand
            Convert tabs to spaces.

EOF
    exit
}

join_by()
{
    local d="${1}"; shift; echo -n "$1"; shift; printf "%s" "${@/#/$d}";
}

__log_field_delimiter=': '
readonly CO_NORMAL=$(echo -en "\e[0m")
readonly CO_RED=$(echo -en "\e[31m")

log_info()
{
    local line=$(join_by "${__log_field_delimiter}" 'info' "${SCRIPT_NAME}" "${@}")
    echo -e "${line}" >&2
}

log_error()
{
    local line=$(join_by "${__log_field_delimiter}" 'error' "${SCRIPT_NAME}" "${@}")
    echo -e "${CO_RED}${line}${CO_NORMAL}" >&2
}

is_number()
{
    [[ "${1}" =~ ^-?[0-9]+$ ]]
}

declare -r EC_ILLEGAL_CMD=127       # Command not found
declare -r EC_FATAL_SIGNAL_BASE=128 # Base value for fatal error signal "n"

# Default trap handler
on_trapped()
{
    local num name
    if is_number "${1}"; then
        num="${1}"
        name=$(kill -l "${1}")
    else
        name="${1}"
        num=$(kill -l "${1}")
    fi
    log_info "Interrupted by signal $name"
    exit "$((EC_FATAL_SIGNAL_BASE + num))"
}

set_trap_handler()
{
    local func="${1}" sig; shift
    for sig ; do
        trap "$func $sig" "$sig"
    done
}

has_command()
{
    command -v "${1}" &> /dev/null
}

convert_file()
{
    infile="${1}"
    if [ -n "$fmt_cmd" ]; then
        command="$fmt_cmd -q -k ${override:--n} $infile"
        if [ -z "$override" ]; then
            command="$command ${1}${TAIL}"
            infile="${1}${TAIL}"
        fi
        rs=$(eval "$command" 2>&1); rv="${?}"
        if [ "$rv" != 0 ] || [ "${#rs}" != 0 ]; then
            log_error "${1}" "$rs"
            #log_error "${1}" 'File format conversion failed'
            return 1
        fi
    fi
    if [ -n "$from" ] && [ -n "$to" ]; then
        command="iconv -f $from -t $to $infile"
        if [ -z "$override" ]; then
            command="$command | sponge ${1}${TAIL}"
            infile="${1}${TAIL}"
        else
            command="$command | sponge ${infile}"
        fi
        rs=$(eval "$command" 2>&1); rv="${?}"
        if [ "$rv" != 0 ] || [ "${#rs}" != 0 ]; then
            log_error "${1}" "$rs"
            #log_error "${1}" 'File encoding conversion failed'
            return 1
        fi
    fi
    if [ -n "$toexpand" ]; then
        command="expand -t $TAB_NUM $infile"
        if [ -z "$override" ]; then
            command="$command | sponge ${1}${TAIL}"
        else
            command="$command | sponge ${infile}"
        fi
        rs=$(eval "$command" 2>&1); rv="${?}"
        if [ "$rv" != 0 ] || [ "${#rs}" != 0 ]; then
            log_error "${1}" "$rs"
            #log_error "${1}" 'Tabs conversion failed'
            return 1
        fi
    fi
}

convert_dir()
{
    names=$(join_by ' -o ' "${patterns[@]}")
    file_list=$(eval "find ${1} -type f $names" 2> /dev/null)
    for f in $file_list; do
        convert_file "$f"
    done
}

main()
{
    if ! has_command dos2unix || ! has_command mac2unix; then
        log_error 'Running this script require the dos2unix<http://waterlan.home.xs4all.nl/dos2unix.html> to be installed'
        exit "$EC_ILLEGAL_CMD"
    fi
    if ! has_command sponge; then
        log_error 'Running this script require the moreutils<https://joeyh.name/code/moreutils/> to be installed'
        exit "$EC_ILLEGAL_CMD"
    fi

    # Interrupted script by SIGHUP / SIGINT / SIGQUIT / SIGTERM
    set_trap_handler on_trapped SIGHUP SIGINT SIGQUIT SIGTERM

    [ "${#}" = 0 ] && usage
    opts=$(getopt -o f:t:dmoeh --long name:,iname:,from:,to:,dos2unix,mac2unix,override,expand,help -n "$SCRIPT_NAME" -- "$@")
    if [ "${?}" != 0 ]; then
        log_error 'Failed to parsing options'
        usage
    fi
    patterns=()
    eval set -- "$opts"
    while true; do
        case "${1}" in
            --name )            patterns+=("-name '${2}'"); shift 2 ;;
            --iname )           patterns+=("-iname '${2}'"); shift 2 ;;
            -f | --from )       from="${2}"; shift 2 ;;
            -t | --to )         to="${2}"; shift 2 ;;
            -d | --dos2unix )   fmt_cmd='dos2unix'; shift ;;
            -m | --mac2unix )   fmt_cmd='mac2unix'; shift ;;
            -o | --override )   override='-o'; shift ;;
            -e | --expand )     toexpand=1; shift ;;
            -h | --help)        usage ;;
            -- )                shift; break ;;
            * )                 log_error 'Internal error'; usage ;;
        esac
    done
    [ -z "$fmt_cmd" ] && [ -z "$from" -o -z "$to" ] && usage
    [ "${#}" -eq 0 ] && usage
    while [ "${#}" -gt 0 ]; do
        if [ -f "${1}" ]; then
            convert_file "${1}"
        elif [ -d "${1}" ]; then
            convert_dir "${1}"
        else
            logerr "${1}" 'Target does not exist'
        fi
        shift
    done
}

main "${@}"