name: 'Build FUSE-BPF Userspace Daemon'
description: 'Build the FUSE-BPF userspace daemon from kernel source for Android arm64'

inputs:
  version:
    description: 'Kernel config version (e.g., android16-6.12)'
    required: true
  kernel_version:
    description: 'Kernel version (e.g., 6.12)'
    required: true
  android_version:
    description: 'Android version (e.g., android16)'
    required: true

runs:
  using: "composite"
  steps:
    - name: Install Build Dependencies
      shell: bash
      run: |
        set -euo pipefail

        echo "Installing FUSE-BPF build dependencies..."
        sudo apt-get update -qq
        sudo apt-get install -y -qq \
          clang llvm binutils-aarch64-linux-gnu \
          libelf-dev \
          gcc-aarch64-linux-gnu \
          elfutils

    - name: Generate kernel UAPI + arch headers
      shell: bash
      run: |
        set -euo pipefail
        GEN_DIR="$(mktemp -d)"
        echo "GENERATED_HDR_DIR=${GEN_DIR}" >> "$GITHUB_ENV"
        KSRC="${{ github.workspace }}/kernel/common"

        # Build a small stub tree for the arch "asm/" headers that kbuild
        # normally generates (asm/types.h -> asm-generic/types.h). Deterministic,
        # no kernel configure required.
        mkdir -p "$GEN_DIR/usr/include/asm"
        printf '%s\n' '#include <asm-generic/types.h>' > "$GEN_DIR/usr/include/asm/types.h"
        printf '%s\n' '#include <asm-generic/int-ll64.h>' > "$GEN_DIR/usr/include/asm/byteorder.h"
        # Generated arch headers kbuild normally emits; provide them so the
        # UAPI int-ll64 typedefs (uint8_t..uint64_t) actually resolve.
        printf '%s\n' '#define __BITS_PER_LONG 64' > "$GEN_DIR/usr/include/asm/bitsperlong.h"
        printf '%s\n' '#include <asm-generic/int-ll64.h>' > "$GEN_DIR/usr/include/asm/int-ll64.h"
        # kbuild generates every generic-y arch header as:
        #   asm/<name>.h  ->  #include <asm-generic/<name>.h>
        # Provide them all up front so UAPI headers (linux/errno.h etc.) resolve
        # without needing a full kernel configure.
        for name in errno byteorder socket siginfo unistd ioctls \
                    termbits termios fcntl param resource stat statfs \
                    signal types posix_types auxvec bitsperlong \
                    section-core; do
          printf '%s\n' "#include <asm-generic/${name}.h>" \
            > "$GEN_DIR/usr/include/asm/${name}.h"
        done
        # Provide uintNN_t/intNN_t without pulling in glibc stdint.h (absent in
        # bare -target bpf). Define from the __uNN/__sNN primitives the kernel
        # UAPI headers already provide.
        printf '%s\n' \
          '#ifndef TYPES_OVERRIDE_H' \
          '#define TYPES_OVERRIDE_H' \
          'typedef unsigned char        uint8_t;' \
          'typedef unsigned short       uint16_t;' \
          'typedef unsigned int         uint32_t;' \
          'typedef unsigned long long   uint64_t;' \
          'typedef signed char          int8_t;' \
          'typedef signed short         int16_t;' \
          'typedef signed int           int32_t;' \
          'typedef signed long long     int64_t;' \
          'typedef __SIZE_TYPE__        size_t;' \
          'typedef __PTRDIFF_TYPE__     ptrdiff_t;' \
          'typedef __SSIZE_TYPE__       ssize_t;' \
          '#endif' > "$GEN_DIR/usr/include/types_override.h"
        for d in asm-generic linux mtd rdma sound video; do
          if [ -d "$KSRC/include/uapi/$d" ]; then
            ln -sfn "$KSRC/include/uapi/$d" "$GEN_DIR/usr/include/$d"
          fi
        done
        echo "Stub header tree ready."

    - name: Build BPF Object (fd_bpf.bpf) for arm64
      shell: bash
      run: |
        set -euo pipefail

        FUSE_DIR="${{ github.workspace }}/kernel/common/tools/testing/selftests/filesystems/fuse"

        if [ ! -d "$FUSE_DIR" ]; then
          echo "ERROR: FUSE selftests directory not found at: $FUSE_DIR"
          echo "Kernel source may not be downloaded yet."
          exit 1
        fi

        cd "$FUSE_DIR"

        # Use Android NDK compiler if available, otherwise use system cross-compiler
        if command -v aarch64-linux-android34-clang &>/dev/null; then
          BPF_CC="aarch64-linux-android34-clang"
        elif command -v aarch64-linux-gnu-clang &>/dev/null; then
          BPF_CC="aarch64-linux-gnu-clang"
        elif command -v clang &>/dev/null; then
          BPF_CC="clang"
        else
          echo "ERROR: No suitable BPF compiler found"
          exit 1
        fi

        echo "Using BPF compiler: $BPF_CC"
        echo "Compiling fd_bpf.c → fd_bpf.bpf..."

        # Include generated UAPI headers AND the object-tree arch/asm headers
        # (contain asm/types.h generated by make prepare), then kernel source.
        GEN_HDR="${GENERATED_HDR_DIR}/usr/include"
        GEN_OBJ="${GENERATED_HDR_DIR}/build"

        $BPF_CC -target bpf \
          -include "types_override.h" \
          -D__TARGET_ARCH_arm64 \
          -I "$GEN_HDR" \
          -idirafter "${GEN_OBJ}/arch/arm64/include/generated/uapi" \
          -idirafter "${GEN_OBJ}/arch/arm64/include/generated" \
          -idirafter "${GEN_OBJ}/include/generated/uapi" \
          -idirafter "${GEN_OBJ}/include/generated" \
          -idirafter "${{ github.workspace }}/kernel/common/arch/arm64/include/generated/uapi" \
          -idirafter "${{ github.workspace }}/kernel/common/arch/arm64/include/uapi" \
          -idirafter "${{ github.workspace }}/kernel/common/include/uapi" \
          -idirafter "${{ github.workspace }}/kernel/common/arch/arm64/include" \
          -idirafter "${{ github.workspace }}/kernel/common/include" \
          -Wall -O2 -g \
          -emit-llvm -c fd_bpf.c -o fd_bpf.ir

        if command -v llc &>/dev/null; then
          llc -march=bpf -filetype=obj -o fd_bpf.bpf fd_bpf.ir
        else
          $BPF_CC -target bpf \
            -D__TARGET_ARCH_arm64 \
            -I "$GEN_HDR" \
            -idirafter "${GEN_OBJ}/arch/arm64/include/generated" \
            -idirafter "${GEN_OBJ}/include/generated" \
            -Wall -O2 -g \
            -c fd_bpf.c -o fd_bpf.bpf
        fi

        echo "BPF bytecode compiled:"
        ls -la fd_bpf.bpf

    - name: Build FUSE-BPF Userspace Daemon for arm64
      shell: bash
      run: |
        set -euo pipefail

        FUSE_DIR="${{ github.workspace }}/kernel/common/tools/testing/selftests/filesystems/fuse"
        cd "$FUSE_DIR"

        # Use Android NDK compiler if available, otherwise use system cross-compiler
        if command -v aarch64-linux-android34-clang &>/dev/null; then
          CC="aarch64-linux-android34-clang"
        elif command -v aarch64-linux-gnu-clang &>/dev/null; then
          CC="aarch64-linux-gnu-clang"
        elif command -v aarch64-linux-gnu-gcc &>/dev/null; then
          CC="aarch64-linux-gnu-gcc"
        elif command -v clang &>/dev/null; then
          CC="clang --target=aarch64-linux-gnu"
        else
          echo "ERROR: No suitable compiler found for arm64"
          exit 1
        fi

        echo "Using compiler: $CC"

        # Compile bpf_loader.c (BPF program loader utilities)
        # Note: test_framework.c does NOT exist - only test_framework.h is in this directory
        # test_framework.h includes linux/compiler.h which we need to provide
        echo "Compiling bpf_loader.c..."
        $CC -target aarch64-linux-android \
          -D_FILE_OFFSET_BITS=64 \
          -D_GNU_SOURCE \
          -D__KERNEL__ \
          -D__EXPORTED_HEADERS__ \
          -I "${GENERATED_HDR_DIR}/usr/include" \
          -I "${{ github.workspace }}/kernel/common/include/uapi" \
          -I "${{ github.workspace }}/kernel/common/include" \
          -I "${{ github.workspace }}/kernel/common/arch/arm64/include" \
          -I "${{ github.workspace }}/kernel/common/arch/arm64/include/uapi" \
          -I "${{ github.workspace }}/kernel/common/tools/testing/selftests" \
          -Wall \
          -c bpf_loader.c -o bpf_loader.o 2>&1 || true

        # Compile fuse_daemon.c (main daemon)
        echo "Compiling fuse_daemon.c..."
        $CC -target aarch64-linux-android \
          -D_FILE_OFFSET_BITS=64 \
          -D_GNU_SOURCE \
          -D__KERNEL__ \
          -D__EXPORTED_HEADERS__ \
          -I "${GENERATED_HDR_DIR}/usr/include" \
          -I "${{ github.workspace }}/kernel/common/include/uapi" \
          -I "${{ github.workspace }}/kernel/common/include" \
          -I "${{ github.workspace }}/kernel/common/arch/arm64/include" \
          -I "${{ github.workspace }}/kernel/common/arch/arm64/include/uapi" \
          -I "${{ github.workspace }}/kernel/common/tools/testing/selftests" \
          -Wall \
          -c fuse_daemon.c -o fuse_daemon.o 2>&1 || true

        # Link the daemon
        echo "Linking fuse-daemon-arm64..."
        $CC \
          fuse_daemon.o bpf_loader.o \
          -lelf -lpthread \
          -o fuse-daemon-arm64 2>&1 || echo "Linking failed, trying minimal build..."

        ls -la fuse-daemon-arm64 2>/dev/null || echo "fuse-daemon-arm64 not built"

    - name: Build Minimal FUSE-BPF Daemon (Fallback)
      shell: bash
      run: |
        set -euo pipefail

        mkdir -p /tmp/fuse-bpf-minimal

        # Create a minimal standalone FUSE-BPF checker daemon using base64 to avoid YAML heredoc issues
        echo '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' | base64 -d > /tmp/fuse-bpf-minimal/fuse_bpf_daemon.c

        # Setup cross-compiler for arm64
        if command -v aarch64-linux-android34-clang &>/dev/null; then
          CC="aarch64-linux-android34-clang"
        elif command -v aarch64-linux-gnu-gcc &>/dev/null; then
          CC="aarch64-linux-gnu-gcc"
        elif command -v aarch64-linux-gnu-clang &>/dev/null; then
          CC="aarch64-linux-gnu-clang"
        else
          CC="gcc"
        fi

        echo "Building minimal FUSE-BPF checker daemon..."
        $CC -o /tmp/fuse-bpf-minimal/fuse-bpf \
          /tmp/fuse-bpf-minimal/fuse_bpf_daemon.c \
          -target aarch64-linux-android 2>/dev/null || \
        $CC -o /tmp/fuse-bpf-minimal/fuse-bpf \
          /tmp/fuse-bpf-minimal/fuse_bpf_daemon.c || true

        echo "Minimal daemon built:"
        ls -la /tmp/fuse-bpf-minimal/fuse-bpf 2>/dev/null || echo "Failed to build minimal daemon"

    - name: Copy FUSE-BPF Artifacts
      shell: bash
      run: |
        set -euo pipefail

        mkdir -p "${{ github.workspace }}/artifacts/fuse-bpf"

        # Copy the full daemon if built
        if [ -f "${{ github.workspace }}/kernel/common/tools/testing/selftests/filesystems/fuse/fuse-daemon-arm64" ]; then
          cp "${{ github.workspace }}/kernel/common/tools/testing/selftests/filesystems/fuse/fuse-daemon-arm64" \
            "${{ github.workspace }}/artifacts/fuse-bpf/fuse-daemon"
          echo "Copied full FUSE-BPF daemon"
        fi

        # Copy the BPF object
        if [ -f "${{ github.workspace }}/kernel/common/tools/testing/selftests/filesystems/fuse/fd_bpf.bpf" ]; then
          cp "${{ github.workspace }}/kernel/common/tools/testing/selftests/filesystems/fuse/fd_bpf.bpf" \
            "${{ github.workspace }}/artifacts/fuse-bpf/fd_bpf.bpf"
          echo "Copied fd_bpf.bpf"
        fi

        # Copy minimal daemon as fallback
        if [ -f "/tmp/fuse-bpf-minimal/fuse-bpf" ]; then
          cp /tmp/fuse-bpf-minimal/fuse-bpf \
            "${{ github.workspace }}/artifacts/fuse-bpf/fuse-bpf-checker"
          echo "Copied minimal FUSE-BPF checker"
        fi

        # Create README with usage instructions using base64 to avoid YAML heredoc issues
        echo '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' | base64 -d > "${{ github.workspace }}/artifacts/fuse-bpf/README.txt"

        echo "FUSE-BPF artifacts:"
        ls -la "${{ github.workspace }}/artifacts/fuse-bpf/"

    - name: Upload FUSE-BPF Artifact
      uses: actions/upload-artifact@v7
      with:
        name: fuse-bpf-arm64
        path: ${{ github.workspace }}/artifacts/fuse-bpf/
        if-no-files-found: warn