#!/bin/sh
# Installs berth: https://berth.lol
#
#   curl -fsSL https://get.berth.lol | sh
#
# Picks the build for this OS and CPU, checks it against SHA256SUMS and puts
# it in ~/.local/bin (or $BERTH_INSTALL_DIR). No sudo, nothing else changed.
#
# Everything is inside main(), run on the last line, so a download cut short
# runs nothing.

set -eu

BASE="${BERTH_BASE:-https://get.berth.lol}"
DIR="${BERTH_INSTALL_DIR:-$HOME/.local/bin}"

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

fetch() { # URL FILE
  if command -v curl >/dev/null 2>&1; then
    curl -fsSL --retry 2 -o "$2" "$1"
  elif command -v wget >/dev/null 2>&1; then
    wget -q -O "$2" "$1"
  else
    fail "needs curl or wget"
  fi
}

sha256() {
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$1" | cut -d' ' -f1
  elif command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$1" | cut -d' ' -f1
  else
    fail "needs sha256sum or shasum to check the download"
  fi
}

target() {
  os=$(uname -s)
  arch=$(uname -m)
  case "$os-$arch" in
    Darwin-arm64 | Darwin-aarch64) echo berth-macos-arm64 ;;
    Darwin-x86_64) echo berth-macos-x64 ;;
    Linux-aarch64 | Linux-arm64) echo berth-linux-arm64 ;;
    Linux-x86_64 | Linux-amd64) echo berth-linux-x64 ;;
    *) fail "no berth build for $os $arch (there are: macOS and Linux, arm64 and x64)" ;;
  esac
}

main() {
  file=$(target)
  tmp=$(mktemp -d 2>/dev/null || mktemp -d -t berth)
  trap 'rm -rf "$tmp"' EXIT INT TERM

  say "⚓ downloading $file…"
  fetch "$BASE/latest/$file" "$tmp/berth" || fail "couldn't download $BASE/latest/$file"
  fetch "$BASE/latest/SHA256SUMS" "$tmp/SHA256SUMS" || fail "couldn't download $BASE/latest/SHA256SUMS"

  want=$(grep " $file\$" "$tmp/SHA256SUMS" | cut -d' ' -f1)
  [ -n "$want" ] || fail "$file isn't listed in SHA256SUMS"
  got=$(sha256 "$tmp/berth")
  [ "$got" = "$want" ] || fail "checksum mismatch for $file (got $got, expected $want) — not installed"

  chmod 755 "$tmp/berth"
  mkdir -p "$DIR" || fail "couldn't create $DIR (set BERTH_INSTALL_DIR to install elsewhere)"
  # A new file rather than overwriting in place: macOS caches code signatures
  # per file and kills a binary whose contents changed under it.
  if ! { cp "$tmp/berth" "$DIR/.berth.new" && mv -f "$DIR/.berth.new" "$DIR/berth"; }; then
    fail "couldn't write to $DIR (set BERTH_INSTALL_DIR to install elsewhere)"
  fi

  say "⚓ installed $("$DIR/berth" --version 2>/dev/null || echo berth) to $DIR/berth"

  case ":$PATH:" in
    *":$DIR:"*) ;;
    *)
      say ""
      say "$DIR isn't on your PATH. Add it, e.g.:"
      case "${SHELL:-}" in
        */zsh) say "  echo 'export PATH=\"$DIR:\$PATH\"' >> ~/.zshrc && exec zsh" ;;
        */fish) say "  fish_add_path $DIR" ;;
        *) say "  echo 'export PATH=\"$DIR:\$PATH\"' >> ~/.bashrc && exec bash" ;;
      esac
      ;;
  esac

  if ! command -v tmux >/dev/null 2>&1; then
    say ""
    say "berth runs on tmux, which isn't installed here:"
    case "$(uname -s)" in
      Darwin) say "  brew install tmux" ;;
      *) say "  sudo apt install tmux   (or dnf / apk / pacman)" ;;
    esac
    say "No tmux on this machine? Run berth inside a docker container: berth docker"
  fi

  say ""
  say "Start it with: berth"
}

main "$@"