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

stable_toolchain="${1:-1.88.0}"
nightly_toolchain="${2:-nightly}"

if ! command -v rustup >/dev/null 2>&1; then
  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs \
    | sh -s -- -y --profile minimal --default-toolchain none
fi

if [ -f "${HOME}/.cargo/env" ]; then
  # shellcheck disable=SC1091
  source "${HOME}/.cargo/env"
fi
command -v rustup >/dev/null 2>&1 || {
  echo "rustup is required after bootstrap" >&2
  exit 1
}

export RUSTUP_MAX_RETRIES="${RUSTUP_MAX_RETRIES:-3}"

toolchain_is_installed() {
  local requested="$1"
  local installed

  while read -r installed _; do
    if [[ "${installed}" == "${requested}" || "${installed}" == "${requested}-"* ]]; then
      return 0
    fi
  done < <(rustup toolchain list)

  return 1
}

component_is_installed() {
  local toolchain="$1"
  local component="$2"

  rustup component list --toolchain "${toolchain}" --installed \
    | awk '{ print $1 }' \
    | grep -Fxq "${component}"
}

ensure_toolchain() {
  local toolchain="$1"
  shift
  local missing_components=()
  local install_args=()
  local component

  if toolchain_is_installed "${toolchain}"; then
    for component in "$@"; do
      if ! component_is_installed "${toolchain}" "${component}"; then
        missing_components+=("${component}")
      fi
    done

    if [ "${#missing_components[@]}" -eq 0 ]; then
      echo "rustup: reusing installed ${toolchain}"
      return 0
    fi

    rustup component add --toolchain "${toolchain}" "${missing_components[@]}"
    return 0
  fi

  for component in "$@"; do
    install_args+=(--component "${component}")
  done

  rustup toolchain install "${toolchain}" --profile minimal "${install_args[@]}"
}

ensure_toolchain "${stable_toolchain}" rustfmt clippy rust-src
if [ "${nightly_toolchain}" != "none" ]; then
  ensure_toolchain "${nightly_toolchain}" rust-src
fi
rustup default "${stable_toolchain}"

cargo --version
rustc --version
rustup show active-toolchain