# Optimized Multi-stage Dockerfile for Attune Rust services
# This Dockerfile minimizes layer invalidation by selectively copying only required crates
#
# Key optimizations:
# 1. Copy only Cargo.toml files first to cache dependency downloads
# 2. Build dummy binaries to cache compiled dependencies
# 3. Copy only the specific crate being built (plus common)
# 4. Use BuildKit cache mounts for cargo registry and build artifacts
#
# Usage: DOCKER_BUILDKIT=1 docker build --build-arg SERVICE=api -f docker/Dockerfile.optimized -t attune-api .
#
# Build time comparison (after common crate changes):
# - Old: ~5 minutes (rebuilds all dependencies)
# - New: ~30 seconds (only recompiles changed code)
#
# Note: This Dockerfile does NOT copy packs into the image.
# Packs are mounted as volumes at runtime from the packs_data volume.
# The init-packs service in docker-compose.yaml handles pack initialization.

ARG RUST_VERSION=1.92
ARG DEBIAN_VERSION=bookworm

# ============================================================================
# Stage 1: Planner - Extract dependency information
# ============================================================================
FROM rust:${RUST_VERSION}-${DEBIAN_VERSION} AS planner

# Install build dependencies
RUN apt-get update && apt-get install -y \
    pkg-config \
    libssl-dev \
    ca-certificates \
    && rm -rf /var/lib/apt/lists/*

WORKDIR /build

# Copy only Cargo.toml and Cargo.lock to understand dependencies
COPY Cargo.toml Cargo.lock ./

# Copy all crate manifests (but not source code)
# This allows cargo to resolve the workspace without needing source
COPY crates/common/Cargo.toml ./crates/common/Cargo.toml
COPY crates/api/Cargo.toml ./crates/api/Cargo.toml
COPY crates/executor/Cargo.toml ./crates/executor/Cargo.toml
COPY crates/sensor/Cargo.toml ./crates/sensor/Cargo.toml
COPY crates/core-timer-sensor/Cargo.toml ./crates/core-timer-sensor/Cargo.toml
COPY crates/worker/Cargo.toml ./crates/worker/Cargo.toml
COPY crates/notifier/Cargo.toml ./crates/notifier/Cargo.toml
COPY crates/cli/Cargo.toml ./crates/cli/Cargo.toml

# Create dummy lib.rs and main.rs files for all crates
# This allows us to build dependencies without the actual source code
RUN mkdir -p crates/common/src && echo "fn main() {}" > crates/common/src/lib.rs
RUN mkdir -p crates/api/src && echo "fn main() {}" > crates/api/src/main.rs
RUN mkdir -p crates/executor/src && echo "fn main() {}" > crates/executor/src/main.rs
RUN mkdir -p crates/executor/benches && echo "fn main() {}" > crates/executor/benches/context_clone.rs
RUN mkdir -p crates/sensor/src && echo "fn main() {}" > crates/sensor/src/main.rs
RUN mkdir -p crates/core-timer-sensor/src && echo "fn main() {}" > crates/core-timer-sensor/src/main.rs
RUN mkdir -p crates/worker/src && echo "fn main() {}" > crates/worker/src/main.rs
RUN mkdir -p crates/notifier/src && echo "fn main() {}" > crates/notifier/src/main.rs
RUN mkdir -p crates/cli/src && echo "fn main() {}" > crates/cli/src/main.rs

# Copy SQLx metadata for compile-time query checking
COPY .sqlx/ ./.sqlx/

# Build argument to specify which service to build
ARG SERVICE=api

# Build dependencies only (with dummy source)
# This layer is only invalidated when Cargo.toml or Cargo.lock changes
# BuildKit cache mounts persist cargo registry and git cache
# - registry/git use sharing=shared (cargo handles concurrent access safely)
# - target uses service-specific cache ID to avoid conflicts between services
RUN --mount=type=cache,target=/usr/local/cargo/registry,sharing=shared \
    --mount=type=cache,target=/usr/local/cargo/git,sharing=shared \
    --mount=type=cache,target=/build/target,id=target-planner-${SERVICE} \
    cargo build --release --bin attune-${SERVICE} || true

# ============================================================================
# Stage 2: Builder - Compile the actual service
# ============================================================================
FROM rust:${RUST_VERSION}-${DEBIAN_VERSION} AS builder

# Install build dependencies
RUN apt-get update && apt-get install -y \
    pkg-config \
    libssl-dev \
    ca-certificates \
    && rm -rf /var/lib/apt/lists/*

WORKDIR /build

# Copy workspace configuration
COPY Cargo.toml Cargo.lock ./

# Copy all crate manifests (required for workspace resolution)
COPY crates/common/Cargo.toml ./crates/common/Cargo.toml
COPY crates/api/Cargo.toml ./crates/api/Cargo.toml
COPY crates/executor/Cargo.toml ./crates/executor/Cargo.toml
COPY crates/sensor/Cargo.toml ./crates/sensor/Cargo.toml
COPY crates/core-timer-sensor/Cargo.toml ./crates/core-timer-sensor/Cargo.toml
COPY crates/worker/Cargo.toml ./crates/worker/Cargo.toml
COPY crates/notifier/Cargo.toml ./crates/notifier/Cargo.toml
COPY crates/cli/Cargo.toml ./crates/cli/Cargo.toml

# Create dummy source files for workspace members that won't be built
# This satisfies workspace resolution without copying full source
RUN mkdir -p crates/api/src && echo "fn main() {}" > crates/api/src/main.rs
RUN mkdir -p crates/executor/src && echo "fn main() {}" > crates/executor/src/main.rs
RUN mkdir -p crates/executor/benches && echo "fn main() {}" > crates/executor/benches/context_clone.rs
RUN mkdir -p crates/sensor/src && echo "fn main() {}" > crates/sensor/src/main.rs
RUN mkdir -p crates/core-timer-sensor/src && echo "fn main() {}" > crates/core-timer-sensor/src/main.rs
RUN mkdir -p crates/worker/src && echo "fn main() {}" > crates/worker/src/main.rs
RUN mkdir -p crates/notifier/src && echo "fn main() {}" > crates/notifier/src/main.rs
RUN mkdir -p crates/cli/src && echo "fn main() {}" > crates/cli/src/main.rs

# Copy SQLx metadata
COPY .sqlx/ ./.sqlx/

# Copy migrations (required for some services)
COPY migrations/ ./migrations/

# Copy the common crate (almost all services depend on this)
COPY crates/common/ ./crates/common/

# Build the specified service
# The cargo registry and git cache are pre-populated from the planner stage
# Only the actual compilation happens here
# - registry/git use sharing=shared (concurrent builds of different services are safe)
# - target uses service-specific cache ID (each service compiles different crates)
RUN --mount=type=cache,target=/usr/local/cargo/registry,sharing=shared \
    --mount=type=cache,target=/usr/local/cargo/git,sharing=shared \
    --mount=type=cache,target=/build/target,sharing=locked \
    cargo build --release --lib -p attune-common


# Build argument to specify which service to build
ARG SERVICE=api

# Copy only the source for the service being built
# This is the key optimization: changes to other crates won't invalidate this layer
COPY crates/${SERVICE}/ ./crates/${SERVICE}/

# Build the specified service
# The cargo registry and git cache are pre-populated from the planner stage
# Only the actual compilation happens here
# - registry/git use sharing=shared (concurrent builds of different services are safe)
# - target uses service-specific cache ID (each service compiles different crates)
RUN --mount=type=cache,target=/usr/local/cargo/registry,sharing=shared \
    --mount=type=cache,target=/usr/local/cargo/git,sharing=shared \
    --mount=type=cache,target=/build/target,sharing=shared \
    cargo build --release --bin attune-${SERVICE} && \
    cp /build/target/release/attune-${SERVICE} /build/attune-service-binary

# ============================================================================
# Stage 3: Runtime - Create minimal runtime image
# ============================================================================
FROM debian:${DEBIAN_VERSION}-slim AS runtime

# Install runtime dependencies
RUN apt-get update && apt-get install -y \
    ca-certificates \
    libssl3 \
    curl \
    && rm -rf /var/lib/apt/lists/*

# Create non-root user and directories
# Note: /opt/attune/packs is mounted as a volume at runtime, not copied in
RUN useradd -m -u 1000 attune && \
    mkdir -p /opt/attune/packs /opt/attune/logs && \
    chown -R attune:attune /opt/attune

WORKDIR /opt/attune

# Copy the service binary from builder
COPY --from=builder /build/attune-service-binary /usr/local/bin/attune-service

# Copy configuration file for Docker Compose development
# In production, mount config files as a volume instead of baking them into the image
COPY config.docker.yaml ./config.yaml

# Copy migrations for services that need them
COPY migrations/ ./migrations/

# Note: Packs are NOT copied into the image
# They are mounted as a volume at runtime from the packs_data volume
# The init-packs service populates the packs_data volume from ./packs directory
# Pack binaries (like attune-core-timer-sensor) are also in the mounted volume

# Set ownership (packs will be mounted at runtime)
RUN chown -R attune:attune /opt/attune

# Switch to non-root user
USER attune

# Environment variables (can be overridden at runtime)
ENV RUST_LOG=info
ENV ATTUNE_CONFIG=/opt/attune/config.yaml

# Health check (will be overridden per service in docker-compose)
HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
    CMD curl -f http://localhost:8080/health || exit 1

# Expose default port (override per service)
EXPOSE 8080

# Run the service
CMD ["/usr/local/bin/attune-service"]