# Multi-arch Dockerfile for building Flutter Linux app images
# - Uses BuildKit platform args to avoid hardcoding platforms in FROM
# - Builds on the target architecture (via qemu when needed)
# - Fixes: https://docs.docker.com/reference/build-checks/from-platform-flag-const-disallowed/

# BuildKit-provided args available before FROM. Used to parameterize platforms.
ARG TARGETPLATFORM
ARG TARGETARCH
ARG BUILDPLATFORM

# Build with (single arch, locally loadable):
#   docker buildx build --platform linux/amd64 -f Dockerfile.arm64 -t pdf_signature:amd64 --load .
#   docker buildx build --platform linux/arm64 -f Dockerfile.arm64 -t pdf_signature:arm64 --load .
# Build multi-arch (requires a registry):
#   docker buildx build --platform linux/amd64,linux/arm64 -f Dockerfile.arm64 -t <your-registry>/pdf_signature:latest --push .

# ----------------------------------------------------------------------------
# Build stage (Ubuntu 18.04) — glibc 2.27 to maximize compatibility (<= 2.30)
# ----------------------------------------------------------------------------
FROM ubuntu:18.04 AS build

# Re-declare BuildKit args within the stage for RUN/CMD/ENV usage
ARG TARGETPLATFORM
ARG TARGETARCH
ARG BUILDPLATFORM

ENV DEBIAN_FRONTEND=noninteractive \
    TZ=UTC \
    FLUTTER_CHANNEL=stable

# Install build dependencies and tooling
RUN apt-get update && apt-get install -y \
    ca-certificates \
    curl \
    git \
    unzip \
    xz-utils \
    clang \
    ninja-build \
    pkg-config \
    libgtk-3-dev \
    libblkid-dev \
    liblzma-dev \
    && rm -rf /var/lib/apt/lists/*

# Install a newer CMake (>= 3.13 required by Flutter linux build) per-arch
ARG CMAKE_VERSION=3.27.9
RUN set -eux; \
    case "$TARGETARCH" in \
        arm64) CMAKE_ARCH="aarch64" ;; \
        amd64) CMAKE_ARCH="x86_64" ;; \
        *) echo "Unsupported TARGETARCH for CMake: $TARGETARCH" >&2; exit 1 ;; \
    esac; \
    curl -fsSL -o /tmp/cmake.tar.gz \
        https://github.com/Kitware/CMake/releases/download/v${CMAKE_VERSION}/cmake-${CMAKE_VERSION}-linux-${CMAKE_ARCH}.tar.gz; \
    tar -C /opt -xzf /tmp/cmake.tar.gz; \
    ln -sf /opt/cmake-${CMAKE_VERSION}-linux-${CMAKE_ARCH}/bin/cmake /usr/local/bin/cmake; \
    ln -sf /opt/cmake-${CMAKE_VERSION}-linux-${CMAKE_ARCH}/bin/ctest /usr/local/bin/ctest; \
    ln -sf /opt/cmake-${CMAKE_VERSION}-linux-${CMAKE_ARCH}/bin/cpack /usr/local/bin/cpack; \
    rm -f /tmp/cmake.tar.gz

# Install Flutter SDK (ARM64) from source repo (channel: stable)
RUN git clone -b ${FLUTTER_CHANNEL} https://github.com/flutter/flutter.git /opt/flutter
ENV PATH="/opt/flutter/bin:/opt/flutter/bin/cache/dart-sdk/bin:${PATH}"

# Precache Linux desktop artifacts and enable linux desktop
RUN flutter config --enable-linux-desktop && \
    flutter precache --linux

# Set working directory
WORKDIR /app

# Copy pubspec files first for better caching
COPY pubspec.* ./

# Get dependencies
RUN flutter pub get

# Copy the rest of the project
COPY . .

# Ensure Linux desktop project files are present (do not overwrite existing files/pubspec)
RUN [ -d linux ] || flutter create . --platforms=linux

# Refresh dependencies after full context is copied
RUN flutter pub get

# Generate build_runner outputs if codegen files are referenced
RUN bash -lc "if grep -R \"part '.*\\.g\\.dart'\|part '.*\\.freezed\\.dart'\" -n lib >/dev/null; then dart --disable-analytics >/dev/null 2>&1 || true; dart run build_runner build --delete-conflicting-outputs; fi"

# Build the Linux app for the target architecture (x64 on amd64; arm64 on arm64)
RUN set -eux; \
    case "$TARGETARCH" in \
        amd64) FLUTTER_LINUX_TARGET="linux-x64" ;; \
        arm64) FLUTTER_LINUX_TARGET="linux-arm64" ;; \
        *) echo "Unsupported TARGETARCH for Flutter: $TARGETARCH" >&2; exit 1 ;; \
    esac; \
    flutter build linux --target-platform "${FLUTTER_LINUX_TARGET}" --release

# ----------------------------------------------------------------------------
# Runtime stage (Ubuntu 18.04) — matches glibc from builder (2.27)
# ----------------------------------------------------------------------------
FROM ubuntu:18.04 AS runtime

ENV DEBIAN_FRONTEND=noninteractive TZ=UTC

# Install runtime dependencies only (do not ship libc from builder)
RUN apt-get update && apt-get install -y \
    libgtk-3-0 \
    libblkid1 \
    liblzma5 \
    libstdc++6 \
    && rm -rf /var/lib/apt/lists/*

# Copy the built app
# Use wildcard to accommodate both x64 and arm64 bundle directories
COPY --from=build /app/build/linux/*/release/bundle /app

# Set working directory
WORKDIR /app

# Run the app with bundled libraries
CMD ["./pdf_signature"]