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

fail() { printf '\nMacish failed: %s\n' "$*" >&2; exit 1; }
step() { printf '\n==> %s\n' "$*"; }
run() { printf '    %s\n' "$*"; "$@"; }
append_once() {
  local file="$1" line="$2"
  touch "$file"
  if ! grep -Fqx "$line" "$file"; then printf '\n%s\n' "$line" >>"$file"; fi
}

require_ready() {
  [[ "$(uname -s)" == "Darwin" ]] || fail "macOS is required."
  [[ "$EUID" -ne 0 ]] || fail "Run as your normal user, not with sudo."
  if [[ "${MACISH_YES:-${MACI_YES:-}}" != "1" && "${CI:-}" != "true" ]]; then
    if { exec 3<>/dev/tty; } 2>/dev/null; then
      printf '\nPress return to install, or Ctrl-C to stop. ' >&3
      read -r _ <&3 || fail "Confirmation cancelled."
      exec 3>&-
    else
      fail "No terminal for confirmation. Review the script, then set MACISH_YES=1 to run unattended."
    fi
  fi
  if ! xcode-select -p >/dev/null 2>&1; then
    xcode-select --install || true
    fail "Finish installing Xcode Command Line Tools, then run this script again."
  fi
}

printf '\nMacish / Rust\nStable Rust, Cargo, rustfmt, and Clippy. No database services.\n'
require_ready
cargo_bin="${CARGO_HOME:-$HOME/.cargo}/bin"
[[ "$cargo_bin" == /* ]] || fail "CARGO_HOME must be an absolute path."
export PATH="$cargo_bin:$PATH"
step "Installing the Rust toolchain"
if command -v rustup >/dev/null 2>&1; then
  run rustup toolchain install stable --profile default
else
  installer="$(curl --proto '=https' --tlsv1.2 -fsSL https://sh.rustup.rs)" || fail "Could not download rustup."
  sh -c "$installer" -- -y --no-modify-path --default-toolchain stable --profile default
fi
run rustup component add --toolchain stable rustfmt clippy
printf -v cargo_path 'export PATH=%q:"$PATH"' "$cargo_bin"
append_once "$HOME/.zshrc" "$cargo_path"
step "Verifying tools"
run rustup run stable rustc --version
run rustup run stable cargo --version
run rustup run stable rustfmt --version
run rustup run stable cargo clippy --version
printf '\nDone. Open a new terminal to use Rust. Existing default toolchains are preserved.\n'