cast/install.sh

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

# cast installer — intended for: curl -fsSL .../install.sh | bash
#
# Downloads the cast repo tarball, installs the tree under $DEST, builds it,
# and puts a `cast` symlink on PATH via $BINDIR. Re-run any time to upgrade.
#
# Unlike rig (pure bash, runs on bare boxes), cast runs on YOUR machine and
# needs node — it is an API client, never something a server installs.

REPO="${CAST_REPO:-heavy-duty/cast}"
REF="${CAST_REF:-main}"
DEST="${CAST_HOME:-$HOME/.local/share/cast}"
if [ "$(id -u)" -eq 0 ]; then
  BINDIR="${CAST_BIN:-/usr/local/bin}"
else
  BINDIR="${CAST_BIN:-$HOME/.local/bin}"
fi

log() { printf 'cast-install: %s\n' "$*"; }
warn() { printf 'cast-install: WARNING: %s\n' "$*" >&2; }
die() { printf 'cast-install: ERROR: %s\n' "$*" >&2; exit 1; }

# --- prerequisites -----------------------------------------------------------
command -v curl >/dev/null 2>&1 || die "curl is required but was not found."
command -v tar  >/dev/null 2>&1 || die "tar is required but was not found."
command -v node >/dev/null 2>&1 || die "node >=22.12 is required but was not found."
command -v npm  >/dev/null 2>&1 || die "npm is required but was not found."

NODE_MAJOR="$(node -p 'process.versions.node.split(".")[0]')"
[ "$NODE_MAJOR" -ge 22 ] || die "node >=22.12 is required (found $(node -v))."

# age is what decrypts the state repo's secrets — apply/diff shell out to it.
if ! command -v age >/dev/null 2>&1; then
  warn "age not found — 'cast apply' and 'cast diff' will fail until it is installed."
  warn "  Debian/Ubuntu: sudo apt install age | Arch: sudo pacman -S age"
  warn "  Fedora: sudo dnf install age | macOS: brew install age"
fi

# --- temp workspace ----------------------------------------------------------
TMPDIR="$(mktemp -d)"
cleanup() { rm -rf "$TMPDIR"; }
trap cleanup EXIT

URL="https://github.com/$REPO/archive/refs/heads/$REF.tar.gz"

log "installing cast ($REPO@$REF)"
log "downloading $URL"
curl -fsSL "$URL" -o "$TMPDIR/cast.tar.gz" \
  || die "failed to download $URL"

log "extracting archive"
tar -xzf "$TMPDIR/cast.tar.gz" -C "$TMPDIR" \
  || die "failed to extract archive"

# GitHub archives extract to a single top-level dir like cast-<ref>/
EXTRACTED="$(find "$TMPDIR" -maxdepth 1 -type d -name 'cast-*' | head -n1)"
[ -n "$EXTRACTED" ] || die "could not find extracted cast-* directory in archive"
[ -f "$EXTRACTED/bin/cast" ] || die "archive does not contain bin/cast — is $REPO@$REF correct?"

# --- build (deps + tsc), then drop the dev deps -------------------------------
log "building (npm ci && npm run build)"
( cd "$EXTRACTED" && npm ci --silent && npm run build --silent ) \
  || die "build failed"
( cd "$EXTRACTED" && npm prune --omit=dev --silent ) || warn "could not prune dev dependencies"

# --- atomically replace $DEST --------------------------------------------------
log "installing into $DEST"
rm -rf "$DEST"
mkdir -p "$(dirname "$DEST")"
mv "$EXTRACTED" "$DEST"

chmod +x "$DEST/bin/cast" "$DEST"/scripts/*.sh

# --- put cast on PATH ----------------------------------------------------------
mkdir -p "$BINDIR"
ln -sf "$DEST/bin/cast" "$BINDIR/cast"
log "linked $BINDIR/cast -> $DEST/bin/cast"

# --- wire $BINDIR onto PATH, durably -------------------------------------------
# `curl | bash` runs in a subshell, so exporting PATH here would die with this
# process. The only durable place is the user's shell profile — so append there,
# once, marked. Opt out with CAST_NO_MODIFY_PATH=1 and wire it yourself.
MARKER='# added by cast-install'

on_path() {
  case ":$PATH:" in
    *":$1:"*) return 0 ;;
    *) return 1 ;;
  esac
}

# Which file a *login/interactive* shell of this flavour actually reads.
profile_for_shell() {
  case "${SHELL##*/}" in
    zsh) printf '%s\n' "${ZDOTDIR:-$HOME}/.zshrc" ;;
    bash)
      # macOS terminals start login shells (.bash_profile); Linux does not.
      if [ "$(uname -s)" = "Darwin" ]; then
        printf '%s\n' "$HOME/.bash_profile"
      else
        printf '%s\n' "$HOME/.bashrc"
      fi
      ;;
    fish) printf '%s\n' "${XDG_CONFIG_HOME:-$HOME/.config}/fish/config.fish" ;;
    *) printf '%s\n' "$HOME/.profile" ;;
  esac
}

path_line_for() {
  case "$1" in
    */config.fish) printf 'fish_add_path %s\n' "$BINDIR" ;;
    *) printf 'export PATH="%s:$PATH"\n' "$BINDIR" ;;
  esac
}

if on_path "$BINDIR"; then
  : # already reachable — nothing to wire
elif [ -n "${CAST_NO_MODIFY_PATH:-}" ]; then
  warn "$BINDIR is not on your PATH (CAST_NO_MODIFY_PATH set — leaving your profile alone)."
  warn "  add: $(path_line_for "$(profile_for_shell)")"
else
  PROFILE="$(profile_for_shell)"
  if [ -f "$PROFILE" ] && grep -qF "$MARKER" "$PROFILE"; then
    log "$PROFILE already puts $BINDIR on PATH — this shell just predates it."
  else
    mkdir -p "$(dirname "$PROFILE")"
    { printf '\n%s\n' "$MARKER"; path_line_for "$PROFILE"; } >>"$PROFILE" \
      || die "could not write $PROFILE — add this line yourself: $(path_line_for "$PROFILE")"
    log "wired $BINDIR onto PATH in $PROFILE"
  fi
  log "this shell does not have it yet — open a new one, or: source $PROFILE"
fi

log "done — try: cast --help"