#!/usr/bin/env bash
# bin/cgo/zig — CGO toolchain: zig cc (not gcc) + pinned liblbug + libtokenizers.
#
#   eval "$(bin/cgo/zig env)"     # export CC/CXX/CGO_*
#   bin/cgo/zig go build ...      # ensure, then exec with env
#   bin/cgo/zig ./bin/brain/search.go "query"
#
# Pins live in this file. Downloads land in var/ (gitignored).
set -euo pipefail

ROOT="$(CDPATH= cd -- "$(dirname "$0")/../.." && pwd)"
ZIG_VERSION=0.14.1
LBUG_VERSION=0.19.1
TOKENIZERS_VERSION=1.27.0

arch="$(uname -m)"
case "$arch" in
  x86_64|amd64)
    ZIG_ARCH=x86_64
    LBUG_ARCH=x86_64
    TOK_ARCH=x86_64
    ZIG_SHA=24aeeec8af16c381934a6cd7d95c807a8cb2cf7df9fa40d359aa884195c4716c
    LBUG_SHA=ed263ae913f68cb0ddba0b98548b58edaac49929766d03bdaaa83be46c68847d
    TOK_SHA=72556cdca798dd4ea7cdaba308e5f0d68a8cb93b67c96edf485b7a0edd7b07f4
    ;;
  aarch64|arm64)
    ZIG_ARCH=aarch64
    LBUG_ARCH=aarch64
    TOK_ARCH=aarch64
    ZIG_SHA=f7a654acc967864f7a050ddacfaa778c7504a0eca8d2b678839c21eea47c992b
    LBUG_SHA=b07df2cd533c3976a2a3025866d6420a5f35514d0a822ecc4b2902d55b4725b7
    TOK_SHA=e96545ad05930c26f51f63d932ee6d3bbd32bbed149e102c5290d587a2293067
    ;;
  *)
    echo "bin/cgo/zig: unsupported arch $arch" >&2
    exit 2
    ;;
esac

CACHE="$ROOT/var/cache"
LIB="$ROOT/lib-ladybug"
ZIG_DIR="$ROOT/var/zig-dist"
ZIG_BIN="$ROOT/var/zig/zig"

sha256of() {
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$1" | awk '{print $1}'
  else
    shasum -a 256 "$1" | awk '{print $1}'
  fi
}

fetch() {
  local url="$1" dest="$2" expect="$3"
  if [ -f "$dest" ] && [ "$(sha256of "$dest")" = "$expect" ]; then
    return 0
  fi
  mkdir -p "$(dirname "$dest")"
  echo "fetch $url" >&2
  curl -fsSL "$url" -o "$dest"
  local got
  got="$(sha256of "$dest")"
  if [ "$got" != "$expect" ]; then
    echo "checksum mismatch $dest: got $got want $expect" >&2
    rm -f "$dest"
    exit 1
  fi
}

ensure_zig() {
  if [ -n "${ZIG:-}" ] && [ -x "$ZIG" ]; then
    return 0
  fi
  if [ -x "$ZIG_BIN" ]; then
    export ZIG="$ZIG_BIN"
    return 0
  fi
  if command -v zig >/dev/null 2>&1; then
    export ZIG
    ZIG="$(command -v zig)"
    return 0
  fi
  local tar="$CACHE/zig-${ZIG_ARCH}-linux-${ZIG_VERSION}.tar.xz"
  fetch "https://ziglang.org/download/${ZIG_VERSION}/zig-${ZIG_ARCH}-linux-${ZIG_VERSION}.tar.xz" \
    "$tar" "$ZIG_SHA"
  mkdir -p "$CACHE"
  rm -rf "$ZIG_DIR"
  tar -xJf "$tar" -C "$CACHE"
  mv "$CACHE/zig-${ZIG_ARCH}-linux-${ZIG_VERSION}" "$ZIG_DIR"
  mkdir -p "$ROOT/var/zig"
  ln -sfn "$ZIG_DIR/zig" "$ZIG_BIN"
  export ZIG="$ZIG_BIN"
}

ensure_libs() {
  mkdir -p "$LIB"
  if [ ! -f "$LIB/liblbug.so" ]; then
    local tar="$CACHE/liblbug-linux-${LBUG_ARCH}.tar.gz"
    fetch "https://github.com/LadybugDB/ladybug/releases/download/v${LBUG_VERSION}/liblbug-linux-${LBUG_ARCH}.tar.gz" \
      "$tar" "$LBUG_SHA"
    tar -xzf "$tar" -C "$LIB"
  fi
  if [ ! -f "$LIB/libtokenizers.a" ]; then
    local tar="$CACHE/libtokenizers.linux-${TOK_ARCH}.tar.gz"
    fetch "https://github.com/daulet/tokenizers/releases/download/v${TOKENIZERS_VERSION}/libtokenizers.linux-${TOK_ARCH}.tar.gz" \
      "$tar" "$TOK_SHA"
    tar -xzf "$tar" -C "$LIB"
  fi
}

print_env() {
  printf 'export ZIG=%q\n' "$ZIG"
  printf 'export CC=%q\n' "$ROOT/bin/cgo/zcc"
  printf 'export CXX=%q\n' "$ROOT/bin/cgo/zc++"
  printf 'export CGO_ENABLED=1\n'
  printf 'export CGO_CFLAGS=%q\n' "-I$LIB"
  printf 'export CGO_LDFLAGS=%q\n' "-L$LIB -Wl,-rpath,${CGO_RPATH:-$LIB}"
}

ensure_zig
ensure_libs

cmd="${1:-env}"
if [ "$cmd" = "env" ]; then
  print_env
  exit 0
fi

eval "$(print_env)"
exec "$@"