tmctx

#!/usr/bin/env bash
# @file tmctx
# Simple switch TMC contexts
# @author Alister Lewis-Bowen <alister@lewis-bowen.org>
# Adapted for TMC from kubectx
# @ref https://github.com/ahmetb/TMCTX

[[ -n $DEBUG ]] && set -x
set -eou pipefail

IFS=$'\n\t'
SELF_CMD="$0"
TMCTX="$HOME/.config/tmctx"
TMC_CONFIG_DIR="$HOME/.vmware-cna-saas"

usage() {
    cat <<EOF
USAGE:
  tmctx                       : list the contexts
  tmctx <NAME>                : switch to context <NAME>
  tmctx -                     : switch to the previous context
  tmctx -c, --current         : show the current context name
  tmctx -h,--help             : show this message
EOF
}

exit_err() { echo >&2 "${1}"; exit 1; }

current_context() {
    # Current context direct from tmc command...
    # !! Need to parse yaml, e.g. tmc system context current | yq e '.full_name.name' -
    grep name "$TMC_CONFIG_DIR/current-context" 2>/dev/null | \
        cut -d':' -f2 | \
        sed -e 's/^[ ]*//'
}

get_contexts() {
    tmc system context list | \
        awk '{print $1}' | \
        grep -v NAME | \
        sort -n
}

list_contexts() {
    set -u pipefail
    local cur ctx_list
    cur="$(current_context)" || exit_err "error getting current context"
    ctx_list=$(get_contexts) || exit_err "error getting context list"

    local yellow darkbg normal
    yellow=$(tput setaf 3 || true)
    darkbg=$(tput setab 0 || true)
    normal=$(tput sgr0 || true)

    local cur_ctx_fg cur_ctx_bg
    cur_ctx_fg=${TMCTX_CURRENT_FGCOLOR:-$yellow}
    cur_ctx_bg=${TMCTX_CURRENT_BGCOLOR:-$darkbg}

    for c in $ctx_list; do
        if [[ -n "${_TMCTX_FORCE_COLOR:-}" || \
              -t 1 && -z "${NO_COLOR:-}" ]]; then
          # colored output mode
          if [[ "${c}" = "${cur}" ]]; then
              echo "${cur_ctx_bg}${cur_ctx_fg}${c}${normal}"
          else
              echo "${c}"
          fi
        else
            echo "${c}"
        fi
    done
}

read_context() {
  if [[ -f "${TMCTX}" ]]; then
    cat "${TMCTX}"
  fi
}

save_context() {
    local saved
    saved="$(read_context)"
    [ "${saved}" != "${1}" ] && printf %s "${1}" > "${TMCTX}"
}

switch_context() {
  tmc system context use "${1}"
}

choose_context_interactive() {
    local choice
    choice="$(_TMCTX_FORCE_COLOR=1 \
        FZF_DEFAULT_COMMAND="${SELF_CMD}" \
        fzf --height=40% --layout=reverse --info=inline --border --ansi --no-preview || true)"
    if [[ -z "${choice}" ]]; then
        echo 2>&1 "error: you did not choose any of the options"
        exit 1
    else
        set_context "${choice}"
    fi
}

set_context() {
    local prev
    prev="$(current_context)" || exit_err "error getting current context"

    switch_context "${1}"

    if [[ "${prev}" != "${1}" ]]; then
        save_context "${prev}"
    fi
}

swap_context() {
    local ctx
    ctx="$(read_context)"
    if [[ -z "${ctx}" ]]; then
        echo "error: No previous context found." >&2
        exit 1
    fi
    set_context "${ctx}"
}

main() {
    if [[ "$#" -eq 0 ]]; then
        if [[ -t 1 &&  -z "${TMCTX_IGNORE_FZF:-}" && "$(type fzf &>/dev/null; echo $?)" -eq 0 ]]; then
            choose_context_interactive
        else
            list_contexts
        fi
    elif [[ "$#" -gt 1 ]]; then
        echo "error: too many arguments" >&2
        usage
        exit 1
    elif [[ "$#" -eq 1 ]]; then
        if [[ "${1}" == "-" ]]; then
            swap_context
        elif [[ "${1}" == '-c' || "${1}" == '--current' ]]; then
            current_context
        elif [[ "${1}" == '-h' || "${1}" == '--help' ]]; then
            usage
        elif [[ "${1}" =~ ^-(.*) ]]; then
            echo "error: unrecognized flag \"${1}\"" >&2
            usage
            exit 1
        else
            set_context "${1}"
        fi
    else
        usage
        exit 1
    fi
}

main "$@"