# 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
}

# Remotes this user added with 'terractl remote add'
_terractl_remotes() {
    local f=${TERRACTL_CONFIG_DIR:-${XDG_CONFIG_HOME:-$HOME/.config}/terractl}/remotes.json
    [[ -r $f ]] || return 0
    python3 -c 'import json, sys; print("\n".join(json.load(open(sys.argv[1]))["remotes"]))' "$f" 2>/dev/null
}

# Instance names on a remote. This asks its daemon, so it can take a moment.
_terractl_remote_instances() {
    timeout 5 terractl --host "$1" info 2>/dev/null </dev/null | sed -n 's/^instance=//p'
}

# [<remote>:]<name> for copy and move
_terractl_places() {
    if [[ $cur == -* ]]; then
        _terractl_reply "--with-server"
    elif [[ $cur == *:* ]]; then
        mapfile -t COMPREPLY < <(compgen -P "${cur%:*}:" -W "$(_terractl_remote_instances "${cur%:*}")" -- "${cur##*:}")
    else
        mapfile -t COMPREPLY < <(compgen -W "$(_terractl_instances) $(_terractl_remotes | sed 's/$/:/')" -- "$cur")
        # After "<remote>:" comes an instance name, not a space
        if [[ ${#COMPREPLY[@]} -eq 1 && ${COMPREPLY[0]} == *: ]]; then compopt -o nospace 2>/dev/null; fi
    fi
    # Readline sees only the part after the last ':'
    if declare -F __ltrim_colon_completions >/dev/null 2>&1; then __ltrim_colon_completions "$cur"; 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
}

# File names, optionally only those ending in .<extension> (folders always offered)
_terractl_files() {
    if declare -F _filedir >/dev/null 2>&1; then
        _filedir "$@"
    else
        compopt -o filenames 2>/dev/null
        if [[ -n ${1:-} ]]; then
            mapfile -t COMPREPLY < <(compgen -d -- "$cur"; compgen -f -X "!*.$1" -- "$cur")
        else
            mapfile -t COMPREPLY < <(compgen -f -- "$cur")
        fi
    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
        # -n : keeps "<remote>:<name>" (copy, move) in one word
        _init_completion -n : || return
    else
        cur=${COMP_WORDS[COMP_CWORD]}
        words=("${COMP_WORDS[@]}")
        cword=$COMP_CWORD
    fi

    local commands="new list info start stop restart enable disable attach watch cmd mods reinstall delete rename export import"
    local console="save say playing kick ban motd password time dawn noon dusk midnight settle seed version maxplayers port clear help"

    # terractl --host <remote> <command> ...: the same as on this host, except
    # that instance names come from the remote and mod names aren't offered
    local host=""
    if [[ ${words[1]:-} == --host || ${words[1]:-} == -H ]]; then
        if (( cword == 2 )); then
            _terractl_reply "$(_terractl_remotes)"
            return
        fi
        host=${words[2]}
        words=("${words[0]}" "${words[@]:3}")
        cword=$((cword - 2))
        commands+=" --help --version"
    else
        commands+=" copy move remote daemon prepare run --host --help --version"
    fi

    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 ;;
        import)
            # import <new name> <file.tar.gz>: the name is new, so nothing to offer
            if (( cword == 3 )); then _terractl_files tar.gz; fi
            return ;;
        copy|move)
            _terractl_places
            return ;;
        remote)
            if (( cword == 2 )); then
                _terractl_reply "add list remove"
            elif (( cword == 3 )) && [[ ${words[2]} == remove ]]; then
                _terractl_reply "$(_terractl_remotes)"
            fi
            return ;;
        daemon)
            if (( cword == 2 )); then
                _terractl_reply "enable disable status token revoke"
            fi
            return ;;
    esac

    if (( cword == 2 )); then
        if [[ -n $host ]]; then
            _terractl_reply "$(_terractl_remote_instances "$host")"
        else
            _terractl_reply "$(_terractl_instances)"
        fi
        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 ;;
        enable|disable)
            if (( cword == 3 )); then _terractl_reply "--now"; fi ;;
        watch)
            # the number after -n is free-form
            if [[ $cur == -* ]]; then _terractl_reply "-n -q"; fi ;;
        delete)
            _terractl_reply "-y --yes --no-backup" ;;
        export)
            if [[ $cur == -* ]]; then _terractl_reply "--with-server"; else _terractl_files tar.gz; fi ;;
        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)
                    _terractl_files tmod ;;
                enable|remove)
                    if [[ -z $host ]]; then _terractl_reply "$(_terractl_mods "$instance" installed)"; fi ;;
                disable)
                    if [[ -z $host ]]; then _terractl_reply "$(_terractl_mods "$instance" enabled)"; fi ;;
            esac ;;
    esac
}

complete -F _terractl terractl