#!/bin/sh
# Build a Docker image. If an image name is provided, builds multi-arch and pushes to registry.
# Otherwise builds locally for the current platform only.
#
# Usage (interactive):
#   ./ops/build-image.sh
#
# Usage (non-interactive):
#   ./ops/build-image.sh <tag> [image]
#
# Examples:
#   ./ops/build-image.sh                                        # prompts for tag and image
#   ./ops/build-image.sh v1.0                                   # prompts for image
#   ./ops/build-image.sh v1.0 registry.example.com/org/myapp   # local only (no push)
#   ./ops/build-image.sh v1.0 ""                                # local build, no push

set -eu

ROOT_DIR=$(CDPATH= cd -- "$(dirname "$0")/.." && pwd)

die() { echo "error: $*" >&2; exit 1; }

command -v docker >/dev/null 2>&1 || die "docker not found in PATH"

DEFAULT_TAG=$(git -C "${ROOT_DIR}" rev-parse --short HEAD 2>/dev/null || echo dev)

ask() {
    # $1=varname  $2=prompt  $3=default
    if [ -n "$3" ]; then
        printf "%s [%s]: " "$2" "$3" >&2
    else
        printf "%s (leave empty to build locally only): " "$2" >&2
    fi
    read -r _val
    eval "$1=\"\${_val:-$3}\""
}

if [ $# -ge 2 ]; then
    IMAGE_TAG="$1"
    IMAGE="$2"
elif [ $# -ge 1 ]; then
    IMAGE_TAG="$1"
    ask IMAGE "Image" ""
else
    ask IMAGE_TAG "Tag"   "${DEFAULT_TAG}"
    ask IMAGE     "Image" ""
fi

if [ -n "${IMAGE}" ]; then
    # multi-arch build + push
    docker buildx version >/dev/null 2>&1 || die "docker buildx not available"

    PLATFORMS="${PLATFORMS:-linux/amd64,linux/arm64}"
    BUILDER_NAME="jukebox-multiarch"

    if ! docker buildx inspect "${BUILDER_NAME}" >/dev/null 2>&1; then
        echo "creating buildx builder: ${BUILDER_NAME}"
        docker buildx create \
            --name "${BUILDER_NAME}" \
            --driver docker-container \
            --bootstrap
    fi
    docker buildx use "${BUILDER_NAME}"

    echo "building and pushing ${IMAGE}:${IMAGE_TAG} (${PLATFORMS})"
    docker buildx build \
        --platform "${PLATFORMS}" \
        --file "${ROOT_DIR}/Dockerfile" \
        -t "${IMAGE}:${IMAGE_TAG}" \
        -t "${IMAGE}:latest" \
        --push \
        "${ROOT_DIR}"

    echo ""
    echo "pushed:"
    echo "  ${IMAGE}:${IMAGE_TAG}"
    echo "  ${IMAGE}:latest"
else
    # local build only
    echo "building locally (no push)"
    docker build \
        --file "${ROOT_DIR}/Dockerfile" \
        -t "jukebox-maker:${IMAGE_TAG}" \
        -t "jukebox-maker:latest" \
        "${ROOT_DIR}"

    echo ""
    echo "built:"
    echo "  jukebox-maker:${IMAGE_TAG}"
    echo "  jukebox-maker:latest"
fi