#!/bin/sh
set -eu

# Turmeric installer -- https://turmeric-lang.com
#
# Installs tvm (the Turmeric version manager) and then the latest release.
# The release tarball is verified against the release's sha256sums.txt.
#
#   TVM_DIR=~/somewhere   install tvm elsewhere (default ~/.tvm)

REPO="turmeric-lang/turmeric"
API="${TUR_INSTALL_API:-https://api.github.com/repos/$REPO}"
RAW="${TUR_INSTALL_RAW:-https://raw.githubusercontent.com/$REPO}"
ASSETS="${TUR_INSTALL_ASSETS:-https://github.com/$REPO/releases/download}"

have() { command -v "$1" >/dev/null 2>&1; }

fetch() {
  if have curl; then curl -fsSL "$1"
  elif have wget; then wget -qO - "$1"
  else
    echo "The Turmeric installer needs curl or wget." >&2
    exit 1
  fi
}

# --- which release? --------------------------------------------------------
# Resolved at run time rather than baked in, so this script does not need
# redeploying on every release. sed rather than jq: jq is not standard.
TAG="$(fetch "$API/releases/latest" \
        | sed -n 's/.*"tag_name"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' \
        | head -n1)"
if [ -z "$TAG" ]; then
  echo "Could not determine the latest Turmeric release." >&2
  echo "Check https://github.com/$REPO/releases and install with tvm:" >&2
  echo "  https://github.com/turmeric-lang/tvm#readme" >&2
  exit 1
fi
VER="${TAG#v}"
echo "Turmeric $VER"

# --- bootstrap tvm, pinned to that release's tag ---------------------------
TMP="$(mktemp -d "${TMPDIR:-/tmp}/tur-install.XXXXXX")"
trap 'rm -rf "$TMP"' EXIT INT TERM
mkdir -p "$TMP/tvm"
for f in tvm.sh install.sh; do
  # tvm lives in turmeric-lang/tvm; the release workflow attaches the copy it
  # was tested with to each release. A release cut BEFORE that move has no such
  # asset but still has tvm/ in its tagged tree, so fall back to that.
  if ! fetch "$ASSETS/$TAG/$f" > "$TMP/tvm/$f" 2>/dev/null || [ ! -s "$TMP/tvm/$f" ]; then
    fetch "$RAW/$TAG/tvm/$f" > "$TMP/tvm/$f" || {
      echo "Could not download $f for $TAG." >&2; exit 1; }
  fi
  # A proxy that 200s an error page would otherwise be sourced as a shell
  # script. Non-empty is a weak check, but it is the cheap one worth having.
  [ -s "$TMP/tvm/$f" ] || { echo "$f downloaded empty." >&2; exit 1; }
done

sh "$TMP/tvm/install.sh"

# --- install the compiler --------------------------------------------------
TVM_DIR="${TVM_DIR:-$HOME/.tvm}"
# shellcheck disable=SC1090
. "$TVM_DIR/tvm.sh"

# Branch on whether a prebuilt asset EXISTS for this host, not on whether the
# install failed. Falling back to a source build on any error would quietly
# paper over a checksum mismatch -- the one failure that must be loud.
if __tvm_target >/dev/null 2>&1; then
  tvm install --activate "$VER"
else
  echo ""
  echo "No prebuilt binary for $(uname -s)/$(uname -m) -- building $VER from source."
  echo "This needs cmake and a C compiler, and takes a few minutes."
  echo ""
  tvm install --build --activate "$VER"
fi

cat <<EOF

Turmeric $VER installed.

  Open a new shell (your shell rc was updated), or run:
      export TVM_DIR="$TVM_DIR"
      . "$TVM_DIR/tvm.sh"

  Then:
      tur --help

  Other versions:      tvm ls-remote / tvm install <version>
  Build main instead:  brew install --HEAD ${REPO}/turmeric
  Playground:          https://turmeric-lang.com/try

EOF