#!/bin/sh
# Installs Cueball: curl -fsSL https://cueball.dev/install.sh | sh
#
# What it does, all in your home folder (nothing needs sudo):
#   1. downloads the latest release for your Mac's chip and checks its SHA-256
#   2. unpacks it into ~/.local/share/cueball/versions/<version>/ and points
#      ~/.local/share/cueball/current at it (the one before: previous), and
#      ~/.local/bin/cueball at current/cueball
#   3. checks for what Cueball needs (tmux, a coding agent) and says how to get what's missing
#   4. runs `cueball setup`, which asks before changing anything
# It never edits your shell's startup files. `cueball uninstall` takes it all out again.
#
# CUEBALL_RELEASES_URL: where the releases are (https://cueball.dev/releases).
# CUEBALL_NO_SETUP=1: stop after installing (also when there's no terminal to ask in).
set -eu

RELEASES=${CUEBALL_RELEASES_URL:-https://cueball.dev/releases}
SHARE="$HOME/.local/share/cueball"
BIN="$HOME/.local/bin"

say() { printf '%s\n' "$@"; }
die() { printf 'cueball install: %s\n' "$*" >&2; exit 1; }

[ "$(uname -s)" = Darwin ] || die "Cueball runs on macOS only, for now."
case "$(uname -m)" in
  arm64) arch=arm64 ;;
  # An Apple silicon Mac in a Rosetta terminal says x86_64: it gets the arm64 build all the same.
  x86_64) if [ "$(sysctl -n sysctl.proc_translated 2>/dev/null)" = 1 ]; then arch=arm64; else arch=x64; fi ;;
  *) die "unknown chip: $(uname -m)" ;;
esac

tmp=$(mktemp -d)
trap 'rm -rf "$tmp"' EXIT

# The feed: latest.json names the version and each chip's file and checksum (macOS's plutil reads JSON).
curl -fsSL "$RELEASES/latest.json" -o "$tmp/latest.json" || die "couldn't fetch $RELEASES/latest.json"
field() { plutil -extract "$1" raw -o - "$tmp/latest.json" 2>/dev/null; }
version=$(field version) || die "latest.json has no version"
url=$(field "assets.darwin-$arch.url") || die "there's no release for this Mac (darwin-$arch) yet"
sha=$(field "assets.darwin-$arch.sha256") || die "latest.json has no checksum for darwin-$arch"
case "$url" in *://*) ;; *) url="$RELEASES/$url" ;; esac

say "Downloading Cueball $version ($arch)…"
curl -fSL --progress-bar "$url" -o "$tmp/cueball.tar.gz" || die "the download failed: $url"
got=$(shasum -a 256 "$tmp/cueball.tar.gz" | cut -d' ' -f1)
[ "$got" = "$sha" ] || die "the download's checksum is wrong (expected $sha, got $got): nothing was installed"

# A cueball of yours already there: a link (a checkout's bin/cueball) is replaced, and said; a file isn't.
was=$(readlink "$BIN/cueball" 2>/dev/null || true)
[ -e "$BIN/cueball" ] && [ -z "$was" ] && die "$BIN/cueball is a file of yours: move it away and run this again"

# Unpacked beside the other versions, then the links switched in one step each (a link made under
# a temporary name, then renamed over the old one), so a failure leaves the old version working.
mkdir -p "$SHARE/versions" "$BIN"
tar -xzf "$tmp/cueball.tar.gz" -C "$tmp"
[ -x "$tmp/cueball-$version/cueball" ] || die "the download doesn't hold cueball-$version/cueball"
previous=$(readlink "$SHARE/current" 2>/dev/null || true)
rm -rf "$SHARE/versions/$version.old"
[ -e "$SHARE/versions/$version" ] && mv "$SHARE/versions/$version" "$SHARE/versions/$version.old"
mv "$tmp/cueball-$version" "$SHARE/versions/$version"
rm -rf "$SHARE/versions/$version.old"
ln -sfn "versions/$version" "$SHARE/current.new" && mv -fh "$SHARE/current.new" "$SHARE/current"
# The one it replaced becomes `previous` (what `cueball update --rollback` goes back to).
if [ -n "$previous" ] && [ "$previous" != "versions/$version" ]; then
  ln -sfn "$previous" "$SHARE/previous.new" && mv -fh "$SHARE/previous.new" "$SHARE/previous"
fi
previous=$(readlink "$SHARE/previous" 2>/dev/null || true)
ln -sfn "$SHARE/current/cueball" "$BIN/cueball.new" && mv -fh "$BIN/cueball.new" "$BIN/cueball"
[ -n "$was" ] && [ "$was" != "$SHARE/current/cueball" ] && say "($BIN/cueball pointed at $was; it's the installed one now)"

# Kept: this version and `previous` (to go back to); older ones go.
for dir in "$SHARE/versions"/*; do
  name=${dir##*/}
  [ "$name" = "$version" ] || [ "versions/$name" = "$previous" ] || rm -rf "$dir"
done
say "Installed Cueball $version in $SHARE/versions/$version"

# What Cueball needs that isn't Cueball's to install.
missing=0
if ! command -v tmux >/dev/null 2>&1; then
  say "" "Cueball runs in tmux, which isn't installed:  brew install tmux"
  missing=1
else
  tmux_version=$(tmux -V | sed 's/[^0-9.]*\([0-9][0-9]*\.[0-9][0-9]*\).*/\1/')
  case "$tmux_version" in
    [0-2].* | 3.[0-7]) say "" "tmux $tmux_version works, but Cueball's classic look needs 3.8 or later:  brew upgrade tmux" ;;
  esac
fi
if ! command -v claude >/dev/null 2>&1 && ! command -v codex >/dev/null 2>&1; then
  say "" "Cueball talks to Claude Code or Codex, and neither is installed. Either one:" \
    "  Claude Code:  curl -fsSL https://claude.ai/install.sh | bash" \
    "  Codex:        brew install codex"
fi
if [ "$missing" = 1 ] && ! command -v brew >/dev/null 2>&1; then
  say "  (brew is Homebrew: https://brew.sh)"
fi

# ~/.local/bin on the PATH: said, never done for you.
case ":$PATH:" in
  *":$BIN:"*) cueball="cueball" ;;
  *)
    cueball="$BIN/cueball"
    say "" "$BIN isn't on your PATH. Add this line to your shell's startup file (~/.zshrc for zsh):" \
      "  export PATH=\"\$HOME/.local/bin:\$PATH\""
    ;;
esac

# Setup asks its questions in this terminal (curl | sh has the script on its input, so it reads
# the terminal itself); with no terminal, or CUEBALL_NO_SETUP, it's left for later.
if [ -z "${CUEBALL_NO_SETUP:-}" ] && [ "$missing" = 0 ] && (: </dev/tty) 2>/dev/null; then
  say ""
  "$BIN/cueball" setup </dev/tty || say "" "Setup didn't finish: run $cueball setup any time."
else
  say "" "Next: $cueball setup"
fi