name: Android Build

on:
  push:
    branches: [master]
    # Rebuild whenever app/engine/asset code changes.
    # Skip server-only, deploy, and doc changes.
    paths-ignore:
      - 'deploy/**'
      - 'argocd/**'
      - 'solitaire_server/**'
      - '**.md'

env:
  ANDROID_SDK_ROOT: /opt/android-sdk
  NDK_VERSION: "25.2.9519653"
  BUILD_TOOLS_VERSION: "34.0.0"

jobs:
  build-apk:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Set short SHA
        id: meta
        run: echo "sha=${GITHUB_SHA::8}" >> "$GITHUB_OUTPUT"

      # ── Android SDK + NDK ──────────────────────────────────────────────
      # Cache the entire SDK root so subsequent runs skip the ~2 GB download.
      - name: Cache Android SDK
        uses: actions/cache@v4
        id: sdk-cache
        with:
          path: ${{ env.ANDROID_SDK_ROOT }}
          key: android-sdk-ndk${{ env.NDK_VERSION }}-bt${{ env.BUILD_TOOLS_VERSION }}

      - name: Install system dependencies
        run: sudo apt-get install -y openjdk-17-jdk-headless unzip

      - name: Install Android SDK + NDK
        if: steps.sdk-cache.outputs.cache-hit != 'true'
        run: |
          mkdir -p "$ANDROID_SDK_ROOT/cmdline-tools"
          curl -sL \
            "https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip" \
            -o /tmp/cmdtools.zip
          unzip -q /tmp/cmdtools.zip -d /tmp/cmdtools
          mv /tmp/cmdtools/cmdline-tools "$ANDROID_SDK_ROOT/cmdline-tools/latest"
          # Accept all SDK licences non-interactively.
          yes | "$ANDROID_SDK_ROOT/cmdline-tools/latest/bin/sdkmanager" --licenses \
            > /dev/null 2>&1 || true
          "$ANDROID_SDK_ROOT/cmdline-tools/latest/bin/sdkmanager" \
            "build-tools;$BUILD_TOOLS_VERSION" \
            "platforms;android-34" \
            "ndk;$NDK_VERSION"

      - name: Export Android environment
        run: |
          echo "ANDROID_HOME=$ANDROID_SDK_ROOT"              >> "$GITHUB_ENV"
          echo "ANDROID_NDK_HOME=$ANDROID_SDK_ROOT/ndk/$NDK_VERSION" >> "$GITHUB_ENV"

      # ── Rust toolchain ─────────────────────────────────────────────────
      - name: Install Rust stable
        run: |
          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs \
            | sh -s -- -y --default-toolchain stable --no-modify-path
          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"

      - name: Add Android cross-compilation targets
        run: |
          rustup target add \
            aarch64-linux-android \
            armv7-linux-androideabi \
            x86_64-linux-android

      # ── Cargo caches ───────────────────────────────────────────────────
      - name: Cache Cargo registry
        uses: actions/cache@v4
        with:
          path: |
            ~/.cargo/registry/index
            ~/.cargo/registry/cache
            ~/.cargo/git/db
          key: cargo-registry-${{ hashFiles('**/Cargo.lock') }}
          restore-keys: cargo-registry-

      - name: Cache cargo-apk binary
        uses: actions/cache@v4
        id: apk-tool-cache
        with:
          path: ~/.cargo/bin/cargo-apk
          key: cargo-apk-${{ runner.os }}-stable

      - name: Cache build artifacts
        uses: actions/cache@v4
        with:
          path: target
          key: android-target-${{ hashFiles('**/Cargo.lock') }}-${{ github.sha }}
          restore-keys: android-target-${{ hashFiles('**/Cargo.lock') }}-

      # ── Build ──────────────────────────────────────────────────────────
      - name: Install cargo-apk
        if: steps.apk-tool-cache.outputs.cache-hit != 'true'
        run: cargo install cargo-apk --locked

      - name: Build debug APK
        run: cargo apk build --package solitaire_app --lib

      # ── Artifact ───────────────────────────────────────────────────────
      - name: Upload APK
        uses: actions/upload-artifact@v4
        with:
          name: solitaire-quest-debug-${{ steps.meta.outputs.sha }}
          path: target/debug/apk/solitaire-quest.apk
          retention-days: 30