#!/usr/bin/env bash
set -euo pipefail

########################################
# Seby's Ephemeral Debian Env
# curl | bash safe
########################################

########################################
# Styling
########################################
TTY="/dev/tty"

BOLD="\033[1m"
GREEN="\033[32m"
YELLOW="\033[33m"
RED="\033[31m"
BLUE="\033[34m"
RESET="\033[0m"

section() { printf "\n${BLUE}${BOLD}==> %s${RESET}\n" "$*"; }
say()     { printf "${GREEN}✔ %s${RESET}\n" "$*"; }
warn()    { printf "${YELLOW}⚠ %s${RESET}\n" "$*"; }
err()     { printf "${RED}✖ %s${RESET}\n" "$*"; }

have() { command -v "$1" >/dev/null 2>&1; }

need_tty() {
  if [[ ! -r "$TTY" || ! -w "$TTY" ]]; then
    err "No interactive TTY available."
    exit 1
  fi
}

prompt() {
  local msg="$1"
  local default="${2:-}"
  local out
  if [[ -n "$default" ]]; then
    printf "${BOLD}%s${RESET} " "$msg [$default]:" >"$TTY"
  else
    printf "${BOLD}%s${RESET} " "$msg:" >"$TTY"
  fi
  IFS= read -r out <"$TTY"
  printf "%s" "${out:-$default}"
}

confirm_default_no() {
  local msg="$1"
  local ans
  ans="$(prompt "$msg [y/N]")"
  [[ "${ans,,}" == "y" || "${ans,,}" == "yes" ]]
}

confirm_default_yes() {
  local msg="$1"
  local ans
  ans="$(prompt "$msg [Y/n]" "y")"
  [[ "${ans,,}" == "y" || "${ans,,}" == "yes" ]]
}

########################################
# Spinner (writes to /dev/tty so curl|bash stays safe)
########################################
run_with_spinner() {
  local label="$1"; shift

  ("$@") &
  local pid=$!

  local spin='|/-\'
  local i=0

  printf "\033[?25l" >"$TTY" || true

  while kill -0 "$pid" 2>/dev/null; do
    i=$(( (i + 1) % 4 ))
    printf "\r${BLUE}${BOLD}..${RESET} %s %s" "${spin:$i:1}" "$label" >"$TTY"
    sleep 0.12
  done

  wait "$pid"
  local rc=$?

  printf "\r\033[K" >"$TTY"
  printf "\033[?25h" >"$TTY" || true

  return "$rc"
}

########################################
# Header
########################################
clear
cat << "EOF"

  ______________  _______     _______   ___    __
 /_  __/ ____/  |/  / __ \   / ____/ | / / |  / /
  / / / __/ / /|_/ / /_/ /  / __/ /  |/ /| | / /
 / / / /___/ /  / / ____/  / /___/ /|  / | |/ /
/_/ /_____/_/  /_/_/      /_____/_/ |_/  |___/

        Temp Debian Environment | v1.0

EOF

need_tty

if ! have docker; then
  err "Docker not found. Install it first, then re-run this script."
  exit 1
fi
say "Docker detected: $(docker --version)"

########################################
# Configure
########################################
section "Configuration"

TAG="$(prompt "Debian tag" "bookworm")"
IMAGE="debian:${TAG}"

PACKAGES="$(prompt "Packages to install (space-separated, blank for none)")"

APT_FLAGS="$(prompt "Extra apt-get flags (e.g. --no-install-recommends)")"

MOUNT_DIR="$(prompt "Mount a local directory into the container (path or blank)")"
MOUNT_ARGS=()
if [[ -n "$MOUNT_DIR" ]]; then
  if [[ -d "$MOUNT_DIR" ]]; then
    MOUNT_ARGS=(-v "$(realpath "$MOUNT_DIR"):/mnt/host")
    say "Will mount $(realpath "$MOUNT_DIR") -> /mnt/host"
  else
    warn "Directory '$MOUNT_DIR' doesn't exist — skipping mount."
    MOUNT_DIR=""
  fi
fi

RM_IMAGE=false
if confirm_default_no "Remove image (${IMAGE}) after exiting, not just the container?"; then
  RM_IMAGE=true
fi

if [[ -n "$PACKAGES" ]]; then
  INNER_CMD="apt-get update && apt-get install -y ${APT_FLAGS} ${PACKAGES} && bash"
else
  INNER_CMD="apt-get update && bash"
fi

########################################
# Summary
########################################
section "Summary"
say "Image:      ${IMAGE}"
say "Packages:   ${PACKAGES:-<none>}"
[[ -n "$MOUNT_DIR" ]] && say "Mount:      $(realpath "$MOUNT_DIR") -> /mnt/host"
say "Cleanup:    container removed on exit$([[ "$RM_IMAGE" == true ]] && echo ", image removed too")"

if ! confirm_default_yes "Launch now?"; then
  warn "Aborted."
  exit 0
fi

########################################
# Pull image (quiet + spinner)
########################################
section "Pulling image"

if run_with_spinner "Pulling ${IMAGE}..." docker pull "$IMAGE" >/dev/null 2>&1; then
  say "Image ready: ${IMAGE}"
else
  err "Failed to pull ${IMAGE}"
  exit 1
fi

########################################
# Launch
########################################
section "Launching ephemeral environment"
say "Type 'exit' when you're done — the container cleans up automatically."

set +e
docker run --rm -it "${MOUNT_ARGS[@]}" "$IMAGE" bash -c "$INNER_CMD" <"$TTY"
EXIT_CODE=$?
set -e

section "Done"
say "Container exited (code ${EXIT_CODE}) and was automatically removed."

########################################
# Optional image cleanup
########################################
if [[ "$RM_IMAGE" == true ]]; then
  section "Image cleanup"
  IN_USE="$(docker ps -a --filter ancestor="$IMAGE" -q)"
  if [[ -n "$IN_USE" ]]; then
    warn "Other containers still reference ${IMAGE} — skipping removal:"
    docker ps -a --filter ancestor="$IMAGE"
  else
    docker rmi "$IMAGE" >/dev/null 2>&1 && say "Removed image ${IMAGE}."
  fi
fi

say "All done."