# Dockerfile Template Generator with cargo-chef Multi-Stage Build
# Generates optimized 4-stage Dockerfile with dependency caching
#
# Usage:
#   Pass build config as parameter:
#   let template = import "this-file.ncl" in
#   let defaults = import "../../defaults/orchestrator-defaults.ncl" in
#   template defaults.orchestrator.build
#
# Stages:
#   1. PLANNER   - Generate cargo-chef recipe.json (dependency graph)
#   2. CACHER    - Build dependencies only (cached layer)
#   3. BUILDER   - Build source code (uses CACHER artifacts)
#   4. RUNTIME   - Minimal runtime image with binary only

# Template function that takes build_config record
fun build_config =>
  let package = build_config.package in
  let binary = build_config.binary in
  let base_image = build_config.base_image in
  let runtime_image = build_config.runtime_image in
  let port = build_config.port in
  let health_path = build_config.health_path in
  let features = build_config.features in
  let extra_runtime_pkgs = build_config.extra_runtime_pkgs in
  let user_id = build_config.user_id in
  let config_file = build_config.config_file in
  let chef_enabled = build_config.chef_enabled in
  let sccache_enabled = build_config.sccache.enabled in
  let buildkit_jobs = build_config.buildkit.parallel_jobs in

  # Conditional string generation helpers
  let features_arg =
    if std.array.length features > 0 then
      "--features " ++ (std.string.join "," features)
    else
      "" in

  let sccache_install =
    if sccache_enabled then
      "RUN cargo install sccache --version 0.8.0\nENV RUSTC_WRAPPER=sccache"
    else
      "" in

  let extra_pkgs_str =
    if std.array.length extra_runtime_pkgs > 0 then
      " \\\n    " ++ (std.string.join " \\\n    " extra_runtime_pkgs)
    else
      "" in

  let config_copy =
    if config_file != "" then
      "COPY crates/" ++ package ++ "/" ++ config_file ++ " /etc/provisioning/config.defaults.toml"
    else
      "# No config file to copy" in

  # Generate Dockerfile content
  std.string.join "\n" [
    "# Multi-stage build for " ++ package,
    "# Generated from Nickel template - DO NOT EDIT DIRECTLY",
    "# Source: provisioning/schemas/platform/templates/docker/Dockerfile.chef.ncl",
    "",
    "# ============================================================================",
    "# Stage 1: PLANNER - Generate dependency recipe",
    "# ============================================================================",
    "FROM " ++ base_image ++ " AS planner",
    "",
    "WORKDIR /workspace",
    "",
    "# Install cargo-chef",
    "RUN cargo install cargo-chef --version 0.1.67",
    "",
    "# Copy workspace manifests",
    "COPY Cargo.toml Cargo.lock ./",
    "COPY crates ./crates",
    "COPY daemon-cli ./daemon-cli",
    "COPY secretumvault ./secretumvault",
    "COPY prov-ecosystem ./prov-ecosystem",
    "COPY stratumiops ./stratumiops",
    "",
    "# Generate recipe.json (dependency graph)",
    "RUN cargo chef prepare --recipe-path recipe.json --bin " ++ binary,
    "",
    "# ============================================================================",
    "# Stage 2: CACHER - Build dependencies only",
    "# ============================================================================",
    "FROM " ++ base_image ++ " AS cacher",
    "",
    "WORKDIR /workspace",
    "",
    "# Install build dependencies",
    "RUN apt-get update && apt-get install -y \\",
    "    pkg-config \\",
    "    libssl-dev \\",
    "    && rm -rf /var/lib/apt/lists/*",
    "",
    "# Install cargo-chef",
    "RUN cargo install cargo-chef --version 0.1.67",
    "",
    (if sccache_enabled then sccache_install else "# sccache disabled"),
    "",
    "# Copy recipe from planner",
    "COPY --from=planner /workspace/recipe.json recipe.json",
    "",
    "# Build dependencies - This layer will be cached",
    "RUN cargo chef cook --release --recipe-path recipe.json " ++ features_arg,
    "",
    "# ============================================================================",
    "# Stage 3: BUILDER - Build source code",
    "# ============================================================================",
    "FROM " ++ base_image ++ " AS builder",
    "",
    "WORKDIR /workspace",
    "",
    "# Install build dependencies",
    "RUN apt-get update && apt-get install -y \\",
    "    pkg-config \\",
    "    libssl-dev \\",
    "    && rm -rf /var/lib/apt/lists/*",
    "",
    (if sccache_enabled then sccache_install else "# sccache disabled"),
    "",
    "# Copy cached dependencies from cacher stage",
    "COPY --from=cacher /workspace/target target",
    "COPY --from=cacher /usr/local/cargo /usr/local/cargo",
    "",
    "# Copy source code",
    "COPY Cargo.toml Cargo.lock ./",
    "COPY crates ./crates",
    "COPY daemon-cli ./daemon-cli",
    "COPY secretumvault ./secretumvault",
    "COPY prov-ecosystem ./prov-ecosystem",
    "COPY stratumiops ./stratumiops",
    "",
    "# Build release binary with parallelism",
    "ENV CARGO_BUILD_JOBS=" ++ std.string.from_number buildkit_jobs,
    "RUN cargo build --release --package " ++ package ++ " " ++ features_arg,
    "",
    "# ============================================================================",
    "# Stage 4: RUNTIME - Minimal runtime image",
    "# ============================================================================",
    "FROM " ++ runtime_image,
    "",
    "# Install runtime dependencies",
    "RUN apt-get update && apt-get install -y \\",
    "    ca-certificates \\",
    "    curl" ++ extra_pkgs_str ++ " \\",
    "    && rm -rf /var/lib/apt/lists/*",
    "",
    "# Create non-root user",
    "RUN useradd -m -u " ++ std.string.from_number user_id ++ " provisioning && \\",
    "    mkdir -p /data /var/log/" ++ package ++ " && \\",
    "    chown -R provisioning:provisioning /data /var/log/" ++ package,
    "",
    "# Copy binary from builder",
    "COPY --from=builder /workspace/target/release/" ++ binary ++ " /usr/local/bin/" ++ binary,
    "RUN chmod +x /usr/local/bin/" ++ binary,
    "",
    config_copy,
    "",
    "# Switch to non-root user",
    "USER provisioning",
    "WORKDIR /app",
    "",
    "# Expose service port",
    "EXPOSE " ++ std.string.from_number port,
    "",
    "# Environment variables",
    "ENV RUST_LOG=info",
    "ENV DATA_DIR=/data",
    "",
    "# Health check",
    "HEALTHCHECK --interval=30s --timeout=10s --start-period=30s --retries=3 \\",
    "    CMD curl -f http://localhost:" ++ std.string.from_number port ++ health_path ++ " || exit 1",
    "",
    "# Run the binary",
    "CMD [\"" ++ binary ++ "\"]",
    "",
  ]