#!/usr/bin/env bash
# ------------------------------------------------------------------------------
# Copyright (c) 2013-2026 Geoffray Levasseur <fatalerrors@geoffray-levasseur.org>
# Protected by the BSD3 license. Please read bellow for details.
#
# * Redistribution and use in source and binary forms,
# * with or without modification, are permitted provided
# * that the following conditions are met:
# *
# *   Redistributions of source code must retain the above
# *   copyright notice, this list of conditions and the
# *   following disclaimer.
# *
# *   Redistributions in binary form must reproduce the above
# *   copyright notice, this list of conditions and the following
# *   disclaimer in the documentation and/or other materials
# *   provided with the distribution.
# *
# *   Neither the name of the copyright holder nor the names
# *   of any other contributors may be used to endorse or
# *   promote products derived from this software without
# *   specific prior written permission.
# *
# * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
# * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
# * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
# * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# * OF SUCH DAMAGE.
# ------------------------------------------------------------------------------

locale_check()
{
    locale -a | grep -qx "$1" || {
        disp W "Locale '$1' is not installed on this system."
        return 1
    }
    return 0
}


# ------------------------------------------------------------------------------
# Change locale to the given one in parameter
# Usage: setlocale <locale>
setlocale()
{
    local PARSED
    PARSED=$(getopt -o h --long help -n 'setlocale' -- "$@")
    if [[ $? -ne 0 ]]; then
        disp E "Invalid options, use \"setlocale --help\" to display usage."
        return 1
    fi
    eval set -- "$PARSED"
    while true; do
        case "$1" in
            -h|--help)
                printf "setlocale: Configure system environment locale variables.\n\n"
                printf "Usage: setlocale <locale>\n\n"
                printf "Options:\n"
                printf "  -h, --help        Display this help screen\n"
                return 0
                ;;
            --)
                shift
                break
                ;;
            *)
                disp E "Invalid options, use \"setlocale --help\" to display usage."
                return 1
                ;;
        esac
    done

    local loc=$1
    [[ -z $loc ]] && disp E "No locale specified." && return 1

    locale_check "$loc" || return 1

    export LANG=$loc
    export LC_MESSAGES=$loc
    export LC_TIME=$loc
    export LC_NUMERIC=$loc
    export LC_MONETARY=$loc
    export LC_COLLATE=$loc
    export LC_CTYPE=$loc

    disp I "Locale set to $loc."
}
export -f setlocale
# ------------------------------------------------------------------------------


# ------------------------------------------------------------------------------
# Special case : change locale to C standard
# Usage: setc
setc()
{
    # Locale definitions
    export LC_ALL=C
    disp I "Locale changed to standard C (POSIX)."
}
export -f setc
# ------------------------------------------------------------------------------


# ------------------------------------------------------------------------------
# Build dynamic locale shortcuts from SET_LOCALE
# Expected format:
#   SET_LOCALE="fr:fr_FR.UTF-8,us:en_US.UTF-8,es:es_ES.UTF-8"
# This creates functions:
#   setfr, setus, setes, ...
build_locale_shortcuts()
{
    local cfg="${SET_LOCALE:-}"
    local item="" alias="" loc="" fname=""
    local -a locale_items=()

    [[ -z "$cfg" ]] && return 0

    IFS=',' read -r -a locale_items <<< "$cfg"
    for item in "${locale_items[@]}"; do
        # Trim surrounding spaces
        item="${item#"${item%%[![:space:]]*}"}"
        item="${item%"${item##*[![:space:]]}"}"

        [[ -z "$item" ]] && continue

        if [[ "$item" != *:* ]]; then
            disp W "Ignoring invalid SET_LOCALE entry: '$item' (expected alias:locale)."
            continue
        fi

        alias="${item%%:*}"
        loc="${item#*:}"

        # Trim alias/locale spaces
        alias="${alias#"${alias%%[![:space:]]*}"}"
        alias="${alias%"${alias##*[![:space:]]}"}"
        loc="${loc#"${loc%%[![:space:]]*}"}"
        loc="${loc%"${loc##*[![:space:]]}"}"

        # Validate alias for safe function names
        if [[ ! "$alias" =~ ^[A-Za-z_][A-Za-z0-9_]*$ ]]; then
            disp W "Ignoring unsafe locale alias '$alias' in SET_LOCALE."
            continue
        fi

        [[ -z "$loc" ]] && {
            disp W "Ignoring empty locale for alias '$alias' in SET_LOCALE."
            continue
        }

        fname="set${alias}"

        # Optional collision warning
        if declare -F "$fname" >/dev/null 2>&1; then
            disp W "Overriding existing function '$fname'."
        fi

        # Build function dynamically
        # shellcheck disable=SC2016
        eval "${fname}() { setlocale \"$loc\"; }"
        # shellcheck disable=SC2163
        export -f "$fname"
    done

    unset cfg item alias loc fname locale_items
}
export -f build_locale_shortcuts
# ------------------------------------------------------------------------------


load_conf lang
build_locale_shortcut
# ------------------------------------------------------------------------------
# EOF