#!/bin/bash
set -euo pipefail

if [ "$#" -ne 1 ]; then
    echo "Usage: $0 <target-dir>"
    exit 1
fi

TARGET_DIR="$1"
TARGET_ABS="$(cd "$TARGET_DIR" && pwd)"
COMMON_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
BASENAME="$(basename "$TARGET_ABS")"
BUILD_DIR="$TARGET_ABS/build"
DOCKERFILE="$TARGET_ABS/Dockerfile.alpine-musl"

if [ ! -f "$DOCKERFILE" ]; then
    echo "ERROR: Missing Dockerfile: $DOCKERFILE"
    exit 1
fi

if ! command -v docker >/dev/null 2>&1; then
    echo "ERROR: docker is not installed or not in PATH"
    exit 1
fi

if ! docker info >/dev/null 2>&1; then
    echo "ERROR: docker daemon is not reachable"
    exit 1
fi

HOST_ARCH="$(uname -m)"
REQUESTED_ARCH="${ARCH:-}"

if [ -n "$REQUESTED_ARCH" ]; then
    case "$REQUESTED_ARCH" in
        arm64|aarch64)
            PLATFORM="linux/arm64"
            OUTPUT_ARCH="arm64"
            ;;
        amd64|x86_64)
            PLATFORM="linux/amd64"
            OUTPUT_ARCH="x86_64"
            ;;
        *)
            echo "ERROR: Unsupported ARCH='$REQUESTED_ARCH' (supported: arm64, amd64)"
            exit 1
            ;;
    esac
else
    case "$HOST_ARCH" in
        x86_64)
            PLATFORM="linux/amd64"
            OUTPUT_ARCH="x86_64"
            ;;
        aarch64|arm64)
            PLATFORM="linux/arm64"
            OUTPUT_ARCH="arm64"
            ;;
        *)
            echo "WARNING: Unknown host architecture '$HOST_ARCH', defaulting to linux/amd64"
            PLATFORM="linux/amd64"
            OUTPUT_ARCH="$HOST_ARCH"
            ;;
    esac
fi

OUTPUT_NAME="${BASENAME}_static_${OUTPUT_ARCH}"
BASE_IMAGE_TAG="n-os-tr/alpine-musl-base:3.19"
APP_IMAGE_TAG="n-os-tr/${BASENAME}-musl-builder:latest"

mkdir -p "$BUILD_DIR"

echo "=========================================="
echo "n-OS-tr Alpine/musl static build"
echo "=========================================="
echo "Target:     $TARGET_ABS"
echo "Platform:   $PLATFORM"
echo "Output:     $BUILD_DIR/$OUTPUT_NAME"
echo ""

echo "[1/3] Building shared base image ($BASE_IMAGE_TAG)"
docker build \
    --platform "$PLATFORM" \
    -f "$COMMON_DIR/Dockerfile.alpine-musl" \
    -t "$BASE_IMAGE_TAG" \
    "$COMMON_DIR"

echo "[2/3] Building application image ($APP_IMAGE_TAG)"
docker build \
    --platform "$PLATFORM" \
    -f "$DOCKERFILE" \
    -t "$APP_IMAGE_TAG" \
    "$TARGET_ABS"

echo "[3/3] Extracting binary"
CONTAINER_ID="$(docker create "$APP_IMAGE_TAG" "/$BASENAME")"
trap 'docker rm -f "$CONTAINER_ID" >/dev/null 2>&1 || true' EXIT

docker cp "$CONTAINER_ID:/$BASENAME" "$BUILD_DIR/$OUTPUT_NAME"
chmod +x "$BUILD_DIR/$OUTPUT_NAME"

FILE_INFO="$(file "$BUILD_DIR/$OUTPUT_NAME")"
echo "$FILE_INFO"

if LDD_OUT="$(ldd "$BUILD_DIR/$OUTPUT_NAME" 2>&1 || true)"; then
    echo "$LDD_OUT"
fi

echo "Built: $BUILD_DIR/$OUTPUT_NAME"
echo "Size:  $(stat -c '%s bytes' "$BUILD_DIR/$OUTPUT_NAME")"