#!/bin/sh
set -eu

VERSION="${1:?usage: build_gdu.sh <version> [output_dir]}"
OUTPUT_DIR="${2:-$PWD/dist}"
PREFIX_NAME="gdu-${VERSION}-linux-amd64-musl-static"

# strip leading 'v' if passed
VERSION="${VERSION#v}"

mkdir -p "$OUTPUT_DIR"

apk add --no-cache \
  curl \
  file \
  go \
  git \
  tar \
  xz

# gdu uses Go modules, pull source from GitHub
SRCDIR="${TMPDIR:-/tmp}/gdu-src-${VERSION}"
rm -rf "$SRCDIR"
mkdir -p "$SRCDIR"

curl -fsSL "https://github.com/dundee/gdu/archive/refs/tags/v${VERSION}.tar.gz" \
  | tar -xz -C "$SRCDIR" --strip-components=1

cd "$SRCDIR"

# Build fully static with musl toolchain
# CGO_ENABLED=0 forces pure-Go, which means no C deps at all
# ldflags: strip debug + disable dynamic linking
CGO_ENABLED=0 GOARCH=amd64 GOOS=linux \
  go build \
    -trimpath \
    -ldflags="-s -w -extldflags=-static" \
    -o "$OUTPUT_DIR/$PREFIX_NAME" \
    ./cmd/gdu

strip "$OUTPUT_DIR/$PREFIX_NAME" 2>/dev/null || true

(
  cd "$OUTPUT_DIR"
  tar -czf "${PREFIX_NAME}.tar.gz" "$PREFIX_NAME"
  sha256sum "$PREFIX_NAME" "${PREFIX_NAME}.tar.gz" > "${PREFIX_NAME}.sha256"
)

file "$OUTPUT_DIR/$PREFIX_NAME"
ldd "$OUTPUT_DIR/$PREFIX_NAME" || true

if file "$OUTPUT_DIR/$PREFIX_NAME" | grep -qi 'dynamically linked'; then
  echo "error: output binary is still dynamically linked" >&2
  exit 1
fi

echo "build OK: $OUTPUT_DIR/$PREFIX_NAME"