#!/bin/bash
# Build script for Alpine Unbound DNS containers
# Supports building for multiple architectures

set -e

IMAGE_NAME="${IMAGE_NAME:-alpine-unbound}"
REGISTRY="${REGISTRY:-}"
VERSION="${VERSION:-latest}"

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

print_status() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

print_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# Build for specific architecture
build_single() {
    local arch=$1
    local dockerfile="Dockerfile.${arch}"
    local tag="${IMAGE_NAME}:${VERSION}-${arch}"
    
    if [[ -n "$REGISTRY" ]]; then
        tag="${REGISTRY}/${tag}"
    fi
    
    print_status "Building for ${arch}..."
    docker build -f "$dockerfile" -t "$tag" .
    print_status "Successfully built: $tag"
}

# Build multi-arch image using buildx
build_multiarch() {
    local tag="${IMAGE_NAME}:${VERSION}"
    
    if [[ -n "$REGISTRY" ]]; then
        tag="${REGISTRY}/${tag}"
    fi
    
    print_status "Building multi-architecture image..."
    
    # Check if buildx is available
    if ! docker buildx version &>/dev/null; then
        print_error "Docker buildx is not available. Please install it first."
        exit 1
    fi
    
    # Create builder if not exists
    if ! docker buildx inspect multiarch-builder &>/dev/null; then
        print_status "Creating buildx builder..."
        docker buildx create --name multiarch-builder --driver docker-container --use
    else
        docker buildx use multiarch-builder
    fi
    
    # Build and push (or load for local use)
    if [[ -n "$REGISTRY" ]] && [[ "$PUSH" == "true" ]]; then
        docker buildx build \
            --platform linux/amd64,linux/arm64 \
            -t "$tag" \
            --push \
            .
    else
        print_warning "Building for local use only. Use PUSH=true REGISTRY=your-registry to push."
        docker buildx build \
            --platform linux/amd64,linux/arm64 \
            -t "$tag" \
            --load \
            .
    fi
    
    print_status "Successfully built: $tag"
}

# Show help
show_help() {
    echo "Usage: $0 [COMMAND] [OPTIONS]"
    echo ""
    echo "Commands:"
    echo "  amd64       Build for x86_64/AMD64 architecture"
    echo "  arm64       Build for ARM64/aarch64 architecture"
    echo "  multiarch   Build for all architectures (requires buildx)"
    echo "  all         Build separate images for each architecture"
    echo "  help        Show this help message"
    echo ""
    echo "Environment variables:"
    echo "  IMAGE_NAME  Image name (default: alpine-unbound)"
    echo "  VERSION     Image version tag (default: latest)"
    echo "  REGISTRY    Docker registry to use (optional)"
    echo "  PUSH        Set to 'true' to push multiarch images"
    echo ""
    echo "Examples:"
    echo "  $0 amd64                           # Build for x86_64"
    echo "  $0 arm64                           # Build for ARM64"
    echo "  $0 all                             # Build for all architectures"
    echo "  REGISTRY=ghcr.io/user PUSH=true $0 multiarch  # Build and push multiarch"
}

# Main
case "${1:-help}" in
    amd64)
        build_single "amd64"
        ;;
    arm64)
        build_single "arm64"
        ;;
    multiarch)
        build_multiarch
        ;;
    all)
        build_single "amd64"
        build_single "arm64"
        ;;
    help|--help|-h)
        show_help
        ;;
    *)
        print_error "Unknown command: $1"
        show_help
        exit 1
        ;;
esac