# shellcheck shell=bash
# Bash completion for terractl (terraria-server-manager)
#
# Installed to <prefix>/share/bash-completion/completions/terractl, where the
# bash-completion package loads it automatically. Also works with 'sudo terractl'.

# Instances directory: default, or TERRARIA_BASE from /etc/default/terractl.
# The file is parsed rather than sourced, so nothing runs in your shell.
_terractl_base() {
    local base=/var/lib/terraria/instances value
    if [[ -r /etc/default/terractl ]]; then
        value=$(sed -n 's/^[[:space:]]*TERRARIA_BASE=//p' /etc/default/terractl | tail -n 1)
        value=${value%\"}; value=${value#\"}; value=${value%\'}; value=${value#\'}
        if [[ -n $value ]]; then base=$value; fi
    fi
    printf '%s\n' "$base"
}

# Instance names. Reading the directory needs root or the 'terraria' group; if
# it isn't readable, fall back to the terraria@ services systemd knows about.
_terractl_instances() {
    local base conf
    base=$(_terractl_base)
    if [[ -r $base && -x $base ]]; then
        while IFS= read -r conf; do
            conf=${conf%/instance.conf}
            printf '%s\n' "${conf##*/}"
        done < <(compgen -G "$base/*/instance.conf")
    elif command -v systemctl >/dev/null 2>&1; then
        systemctl list-units --all --plain --no-legend 'terraria@*.service' 2>/dev/null |
            sed -n 's/^terraria@\([^ ]*\)\.service.*/\1/p'
    fi
}

# Mods installed in an instance (*.tmod files), or enabled ones (enabled.json)
_terractl_mods() {
    local mdir f
    mdir="$(_terractl_base)/$1/data/Mods"
    if [[ $2 == enabled ]]; then
        [[ -r $mdir/enabled.json ]] && grep -o '"[^"]*"' "$mdir/enabled.json" | tr -d '"'
    else
        while IFS= read -r f; do
            f=${f##*/}
            printf '%s\n' "${f%.tmod}"
        done < <(compgen -G "$mdir/*.tmod")
    fi
}

# Set COMPREPLY to the words matching what's typed so far
_terractl_reply() {
    mapfile -t COMPREPLY < <(compgen -W "$1" -- "$cur")
}

_terractl() {
    local cur words cword
    if declare -F _init_completion >/dev/null 2>&1; then
        # shellcheck disable=SC2034  # prev is set by _init_completion but not needed here
        local prev
        _init_completion || return
    else
        cur=${COMP_WORDS[COMP_CWORD]}
        words=("${COMP_WORDS[@]}")
        cword=$COMP_CWORD
    fi

    local commands="new list attach cmd mods reinstall delete prepare run --help --version"
    local console="save say playing kick ban motd password time dawn noon dusk midnight settle seed version maxplayers port clear help"

    if (( cword == 1 )); then
        _terractl_reply "$commands"
        return
    fi

    local command=${words[1]}
    case $command in
        list|help|-h|--help|version|-V|--version)
            return ;;
        new)
            # new <new name> [vanilla|tmodloader] [port]: the name is new, so nothing to offer
            if (( cword == 3 )); then _terractl_reply "vanilla tmodloader"; fi
            return ;;
    esac

    if (( cword == 2 )); then
        _terractl_reply "$(_terractl_instances)"
        return
    fi

    local instance=${words[2]}
    case $command in
        cmd)
            if (( cword == 3 )); then _terractl_reply "$console"; fi ;;
        reinstall)
            if (( cword == 3 )); then _terractl_reply "--clean"; fi ;;
        delete)
            _terractl_reply "-y --yes --no-backup" ;;
        mods)
            if (( cword == 3 )); then
                _terractl_reply "list add enable disable remove"
                return
            fi
            case ${words[3]} in
                add)
                    # .tmod files and folders (e.g. the Windows export folder)
                    if declare -F _filedir >/dev/null 2>&1; then
                        _filedir tmod
                    else
                        compopt -o filenames 2>/dev/null
                        mapfile -t COMPREPLY < <(compgen -d -- "$cur"; compgen -f -X '!*.tmod' -- "$cur")
                    fi ;;
                enable|remove)
                    _terractl_reply "$(_terractl_mods "$instance" installed)" ;;
                disable)
                    _terractl_reply "$(_terractl_mods "$instance" enabled)" ;;
            esac ;;
    esac
}

complete -F _terractl terractl