# syntax=docker/dockerfile:1.7
# Cross-platform build workflow — produces up to 6 static binaries under ./bin/
# Each binary embeds the compiled frontend and is stamped with VERSION.
#
# Build args:
#   VERSION     — version string injected at link time (default: dev)
#   TARGET_OS   — restrict to one OS:   linux | darwin | windows  (default: all)
#   TARGET_ARCH — restrict to one arch: amd64 | arm64             (default: all)
#
# Usage:
#   docker build -f docker/Dockerfile.cross --output ./bin .
#   docker build -f docker/Dockerfile.cross \
#     --build-arg VERSION=v1.2.3 --output ./bin .
#   docker build -f docker/Dockerfile.cross \
#     --build-arg TARGET_OS=linux --build-arg TARGET_ARCH=arm64 \
#     --output ./bin .
#
# Or via Makefile:
#   make cross-build
#   make cross-build VERSION=v1.2.3
#   make cross-build GOOS=linux GOARCH=arm64
#   make cross-build GOOS=darwin

ARG GO_VERSION=1.25
ARG NODE_VERSION=22
ARG ALPINE_VERSION=3.23

# ── Stage 1: Build frontend (static export for embedding) ────────────────────
FROM node:${NODE_VERSION}-alpine AS frontend-builder

ARG VERSION=dev
ARG BUILD_DATE=""

ENV PNPM_HOME="/pnpm"
ENV PATH="$PNPM_HOME:$PATH"
ENV NODE_ENV=production
ENV NEXT_STANDALONE_EXPORT=true
ENV NEXT_PUBLIC_APP_VERSION=${VERSION}
ENV NEXT_PUBLIC_APP_BUILD_DATE=${BUILD_DATE}

RUN corepack enable && corepack prepare pnpm@10.10.0 --activate

WORKDIR /workspace/frontend

# Cache dependency layer
COPY frontend/package.json frontend/pnpm-lock.yaml ./
RUN pnpm install --frozen-lockfile

COPY frontend/ ./

RUN pnpm build:embed

# ── Stage 2: Cross-compile Go backend ──────────────────────────────────────
FROM golang:${GO_VERSION}-alpine${ALPINE_VERSION} AS builder

ARG VERSION=dev
ARG BUILD_DATE=""
# Empty string means "build all"; set to a specific value to filter.
ARG TARGET_OS=
ARG TARGET_ARCH=

# git  — needed by go mod download for VCS-stamped modules
# ca-certificates — needed for HTTPS during module download
RUN apk add --no-cache ca-certificates git

WORKDIR /workspace

# Cache dependency layer
COPY go.mod go.sum ./
RUN go mod download

COPY . .

# Overlay the compiled frontend into the embed path
COPY --from=frontend-builder /workspace/frontend/out ./internal/router/root/dist

# Build matrix: GOOS × GOARCH
# CGO_ENABLED=0 — fully static, no libc dependency, required for cross-compilation.
# -trimpath    — strip local filesystem paths from the binary.
# -s -w        — omit symbol table and DWARF debug info (smaller output).
# -X           — stamp version string at link time.
# TARGET_OS / TARGET_ARCH — when non-empty, skip non-matching combinations.
RUN set -e; \
    mkdir -p /out; \
    FILTER_OS="${TARGET_OS}"; \
    FILTER_ARCH="${TARGET_ARCH}"; \
    for GOOS in linux darwin windows; do \
      [ -n "$FILTER_OS" ] && [ "$GOOS" != "$FILTER_OS" ] && continue; \
      for GOARCH in amd64 arm64; do \
        [ -n "$FILTER_ARCH" ] && [ "$GOARCH" != "$FILTER_ARCH" ] && continue; \
        EXT=""; \
        [ "$GOOS" = "windows" ] && EXT=".exe"; \
        OUTPUT="/out/openflare-server_${GOOS}_${GOARCH}${EXT}"; \
        echo "==> Building ${OUTPUT} (version=${VERSION})..."; \
        CGO_ENABLED=0 GOOS=${GOOS} GOARCH=${GOARCH} \
          go build \
            -tags embed_frontend \
            -trimpath \
            -ldflags="-s -w -X github.com/Rain-kl/Wavelet/internal/buildinfo.Version=${VERSION} -X github.com/Rain-kl/Wavelet/internal/buildinfo.BuildTime=${BUILD_DATE}" \
            -o "${OUTPUT}" \
            ./main.go; \
      done; \
    done

# ── Export stage ─────────────────────────────────────────────────────────────
# `docker build --output ./bin .` copies everything from /out to the host.
FROM scratch AS export
COPY --from=builder /out/ /