#!/bin/sh
# Installs the peep CLI.
#
#   curl -fsSL https://peep.noise.cam/install | sh
#
# PEEP_VERSION   version to install, for example 0.2.2 or v0.2.2 (default: latest)
# PEEP_INSTALL   install directory (default: ~/.local/bin)
#
# Release layout, all under https://peep.noise.cam:
#   /releases/latest.json                       {"version": "X.Y.Z", ...}
#   /releases/vX.Y.Z/peep-<os>-<arch>.tar.gz    one file, `peep`
#   /releases/vX.Y.Z/SHA256SUMS                 `<sha256>  peep-<os>-<arch>.tar.gz`
# <os> is linux or darwin; <arch> is x64 or arm64.
#
# The download is verified against SHA256SUMS before anything is installed;
# the installer refuses to continue if no SHA-256 tool is available.
#
# PEEP_BASE_URL (mirrors and tests) replaces https://peep.noise.cam. It must be
# https://, or http://localhost / http://127.0.0.1 / file:// for local testing.
set -eu

die() {
  echo "peep: $*" >&2
  exit 1
}

# The whole script is wrapped in a function so a truncated download never runs
# a partial command sequence.
main() {
  base="${PEEP_BASE_URL:-https://peep.noise.cam}"
  base="${base%/}"
  case "$base" in
    https://?*) ;;
    http://localhost | http://localhost[:/]* | http://127.0.0.1 | http://127.0.0.1[:/]* | file://?*) ;;
    *) die "PEEP_BASE_URL must be an https:// URL" ;;
  esac

  case "$(uname -s)" in
    Linux) os="linux" ;;
    Darwin) os="darwin" ;;
    *) die "unsupported operating system $(uname -s)" ;;
  esac

  case "$(uname -m)" in
    x86_64 | amd64) arch="x64" ;;
    arm64 | aarch64) arch="arm64" ;;
    *) die "unsupported architecture $(uname -m)" ;;
  esac

  # A shell running under Rosetta reports x86_64 on Apple silicon.
  if [ "$os" = "darwin" ] && [ "$arch" = "x64" ] &&
    [ "$(sysctl -n sysctl.proc_translated 2>/dev/null || true)" = "1" ]; then
    arch="arm64"
  fi

  if command -v curl >/dev/null 2>&1; then
    fetch() { curl -fsSL --retry 2 --connect-timeout 15 -o "$2" "$1"; }
  elif command -v wget >/dev/null 2>&1; then
    fetch() { wget -q -O "$2" "$1"; }
  else
    die "curl or wget is required"
  fi

  if command -v sha256sum >/dev/null 2>&1; then
    sha256() { sha256sum "$1" | cut -d ' ' -f 1; }
  elif command -v shasum >/dev/null 2>&1; then
    sha256() { shasum -a 256 "$1" | cut -d ' ' -f 1; }
  elif command -v openssl >/dev/null 2>&1; then
    sha256() { openssl dgst -sha256 "$1" | sed 's/^.*= *//'; }
  else
    die "sha256sum, shasum, or openssl is required to verify the download"
  fi

  dir="${PEEP_INSTALL:-$HOME/.local/bin}"
  tmp="$(mktemp -d "${TMPDIR:-/tmp}/peep-install.XXXXXX")" || die "could not create a temporary directory"
  trap 'rm -rf "$tmp"' EXIT
  trap 'exit 130' INT
  trap 'exit 143' TERM HUP

  version="${PEEP_VERSION:-}"
  version="${version#v}"
  if [ -z "$version" ]; then
    echo "Looking up the latest peep release..."
    fetch "$base/releases/latest.json" "$tmp/latest.json" || die "could not download $base/releases/latest.json"
    version="$(sed -n 's/.*"version"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' "$tmp/latest.json" | head -n 1)"
    [ -n "$version" ] || die "$base/releases/latest.json has no version"
  fi
  # The version becomes part of a URL and a path; accept only release numbers.
  case "$version" in
    *[!0-9A-Za-z.+-]* | "" | -* | .*) die "invalid version '$version'" ;;
  esac
  case "$version" in
    [0-9]*.[0-9]*.[0-9]*) ;;
    *) die "invalid version '$version'" ;;
  esac

  asset="peep-$os-$arch.tar.gz"
  release="$base/releases/v$version"

  echo "Downloading peep $version for $os-$arch..."
  fetch "$release/$asset" "$tmp/$asset" || die "could not download $release/$asset (does version $version exist for $os-$arch?)"
  fetch "$release/SHA256SUMS" "$tmp/SHA256SUMS" || die "could not download $release/SHA256SUMS"

  expected="$(awk -v name="$asset" '$2 == name || $2 == "*" name { print $1; exit }' "$tmp/SHA256SUMS")"
  [ -n "$expected" ] || die "SHA256SUMS has no entry for $asset"
  actual="$(sha256 "$tmp/$asset")"
  if [ "$actual" != "$expected" ]; then
    die "checksum mismatch for $asset: expected $expected, got $actual; nothing was installed"
  fi

  # The archive must contain exactly one file, `peep`.
  listing="$(tar -tzf "$tmp/$asset")" || die "$asset is not a valid archive"
  [ "$listing" = "peep" ] || [ "$listing" = "./peep" ] || die "$asset has unexpected contents; nothing was installed"
  mkdir "$tmp/extract"
  tar -xzf "$tmp/$asset" -C "$tmp/extract"
  [ -f "$tmp/extract/peep" ] && [ ! -L "$tmp/extract/peep" ] || die "$asset does not contain a peep binary"
  chmod 755 "$tmp/extract/peep"

  # Prove the binary runs on this machine before replacing a working install.
  installed_version="$("$tmp/extract/peep" --version)" || die "the downloaded peep binary does not run on this system"

  mkdir -p "$dir" || die "could not create $dir"
  # Stage next to the destination so the final rename is atomic and a running
  # peep is never overwritten in place.
  stage="$dir/.peep.$$"
  cp "$tmp/extract/peep" "$stage" || die "could not write to $dir"
  chmod 755 "$stage"
  mv -f "$stage" "$dir/peep" || {
    rm -f "$stage"
    die "could not install to $dir/peep"
  }

  echo "Installed $installed_version to $dir/peep"
  case ":$PATH:" in
    *":$dir:"*) ;;
    *)
      echo "Add $dir to your PATH to run peep, for example:"
      echo "  export PATH=\"$dir:\$PATH\""
      ;;
  esac
  echo "Get started: peep route add tom 3000"
}

main "$@"