#!/usr/bin/env bash
# Fetch a musl cross gcc for a static Linux release build.
#   scripts/ci_linux_toolchain.sh x86_64|x86|aarch64
# Prints "HOST BINDIR" on stdout (e.g. "x86_64-buildroot-linux-musl
# /opt/x86-64--musl--stable-2025.08-1/bin"); progress goes to stderr.
# Bootlin's pinned stable release first, musl.cc as a fallback.
set -euo pipefail

ARCH="${1:?usage: $0 x86_64|x86|aarch64}"
BOOTLIN_VER="${CST_BOOTLIN_VER:-2025.08-1}"
case "$ARCH" in
x86_64)
  bl=x86-64 bl_host=x86_64-buildroot-linux-musl mc=x86_64-linux-musl
  sha=09fca3aa89540f1b01b5f4210d488cbeb00f522044c53e9989b1dd8a38076912
  ;;
x86)
  bl=x86-i686 bl_host=i686-buildroot-linux-musl mc=i686-linux-musl
  sha=3a340ebc386a057f5ddb24d8f4bbde07d2c013c99cebc02ac38565e2849bfda0
  ;;
aarch64)
  bl=aarch64 bl_host=aarch64-buildroot-linux-musl mc=aarch64-linux-musl
  sha=defba831ffa1175236f137069333e21ed46d4d19feb5080a90cf248b6fc2cb08
  ;;
*)
  echo "unknown arch: $ARCH" >&2
  exit 1
  ;;
esac
[[ "$BOOTLIN_VER" == 2025.08-1 ]] || sha="" # other releases: no pinned hash

if [[ -n "${CST_TOOLCHAIN_ROOT:-}" ]]; then
  ROOT_DIR="$CST_TOOLCHAIN_ROOT"
elif [[ -w /opt || "$(id -u)" -eq 0 ]]; then
  ROOT_DIR=/opt
else
  ROOT_DIR="$HOME/.local/toolchains"
fi
mkdir -p "$ROOT_DIR"

fetch() { # out url...
  local out="$1" u
  shift
  for u in "$@"; do
    echo "  try $u" >&2
    if curl -fsSL --retry 2 --connect-timeout 15 --max-time 900 -o "$out" "$u"; then
      return 0
    fi
  done
  return 1
}

emit() { # host bindir
  "$2/$1-gcc" -dumpmachine >&2
  [[ -n "${GITHUB_PATH:-}" ]] && echo "$2" >>"$GITHUB_PATH"
  echo "$1 $2"
}

name="$bl--musl--stable-$BOOTLIN_VER"
dir="$ROOT_DIR/$name"
if [[ -x "$dir/bin/$bl_host-gcc" ]]; then
  emit "$bl_host" "$dir/bin"
  exit 0
fi

echo "==> toolchain $name" >&2
tmp="$ROOT_DIR/$name.tar.xz"
if fetch "$tmp" "https://toolchains.bootlin.com/downloads/releases/toolchains/$bl/tarballs/$name.tar.xz" &&
    { [[ -z "$sha" ]] || echo "$sha  $tmp" | sha256sum -c --quiet - >&2; }; then
  tar -C "$ROOT_DIR" -xJf "$tmp"
  rm -f "$tmp"
  # Bootlin toolchains are relocatable but must be told once where they are.
  [[ -x "$dir/relocate-sdk.sh" ]] && "$dir/relocate-sdk.sh" >&2
  emit "$bl_host" "$dir/bin"
  exit 0
fi
rm -f "$tmp"

echo "==> bootlin unavailable, falling back to musl.cc" >&2
mdir="$ROOT_DIR/$mc-cross"
if [[ ! -x "$mdir/bin/$mc-gcc" ]]; then
  tgz="$ROOT_DIR/$mc-cross.tgz"
  fetch "$tgz" "https://musl.cc/$mc-cross.tgz" "https://more.musl.cc/x86_64-linux-musl/$mc-cross.tgz" ||
    { echo "no musl toolchain for $ARCH" >&2; exit 1; }
  tar -C "$ROOT_DIR" -xzf "$tgz"
  rm -f "$tgz"
fi
emit "$mc" "$mdir/bin"