#!/bin/bash
# Configure IREE for Bazel builds.
#
# Usage: iree-bazel-configure
#
# This script runs configure_bazel.py to detect platform/compiler and
# creates a user.bazelrc with recommended settings.

set -e

# Source shared library.
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "${SCRIPT_DIR}/iree-bazel-lib"
iree_bazel_init "iree-bazel-configure"

show_help() {
    cat << 'EOF'
iree-bazel-configure - Configure IREE for Bazel builds

USAGE
    iree-bazel-configure
    IREE_HAL_DRIVER_CUDA=ON iree-bazel-configure

WHAT IT DOES
    1. Runs configure_bazel.py to detect platform/compiler
    2. Writes HAL driver configuration from environment variables
    3. Creates user.bazelrc with recommended settings (if not exists)

GENERATED FILES
    configured.bazelrc    Platform detection + driver configuration
    user.bazelrc         Local settings (disk cache, debug config)

ENVIRONMENT VARIABLES
    IREE_BAZEL_CACHE_DIR - Bazel disk cache location
        Unix default: ~/.cache/bazel-iree
        Windows default: c:/bazelcache (avoids path length issues)

    HAL Drivers (runtime, matches CMake conventions):
      IREE_HAL_DRIVER_CUDA=ON        - Enable CUDA driver
      IREE_HAL_DRIVER_VULKAN=ON      - Enable Vulkan driver
      IREE_HAL_DRIVER_HIP=ON         - Enable HIP driver
      IREE_HAL_DRIVER_METAL=ON       - Enable Metal driver
      IREE_HAL_DRIVER_AMDGPU=ON      - Enable AMDGPU driver
      IREE_HAL_DRIVER_LOCAL_SYNC=ON  - Enable local-sync (default)
      IREE_HAL_DRIVER_LOCAL_TASK=ON  - Enable local-task (default)
      IREE_HAL_DRIVER_NULL=ON        - Enable null driver

    Values: ON/YES/TRUE/Y/1 (enabled), OFF/NO/FALSE/N/0 (disabled)
    Defaults: local-sync, local-task, vulkan enabled (matches CMake)

    Compiler Plugins:
      IREE_COMPILER_PLUGINS=all      - All default buildable plugins (default)
      IREE_COMPILER_PLUGINS=all,-X   - All default plugins except plugin X
      IREE_COMPILER_PLUGINS=X,Y      - Only plugins X and Y
      IREE_TARGET_BACKEND_WEBGPU_SPIRV=ON
                                      - Opt in to WebGPU SPIR-V/Tint support

    Plugin detection (for "all"):
      - CUDA: requires IREE_CUDA_TOOLKIT_ROOT/IREE_CUDA_DEPS_DIR,
              CUDA_ROOT/CUDA_HOME/CUDA_PATH/CUDA_TOOLKIT_ROOT_DIR, or nvcc in PATH
      - ROCm: requires ROCM_PATH/ROCM_ROOT/ROCM_HOME/HIP_PATH or hipcc in PATH
      - WebGPU SPIR-V: excluded from "all" unless
              IREE_TARGET_BACKEND_WEBGPU_SPIRV=ON is set
      - MetalSPIRV: always buildable
      - StableHLO: requires third_party/stablehlo submodule
      - Torch: requires third_party/torch-mlir submodule

    SDK detection:
      VULKAN_SDK                   - Used when set; otherwise configure probes
                                     vulkaninfo and common SDK install paths

EXAMPLES
    # Configure with defaults (all buildable plugins)
    iree-bazel-configure

    # Enable CUDA runtime driver
    IREE_HAL_DRIVER_CUDA=ON iree-bazel-configure

    # Enable multiple runtime drivers
    IREE_HAL_DRIVER_CUDA=ON IREE_HAL_DRIVER_VULKAN=ON iree-bazel-configure

    # Exclude torch plugin (faster builds)
    IREE_COMPILER_PLUGINS="all,-input_torch" iree-bazel-configure

    # Only specific plugins
    IREE_COMPILER_PLUGINS="hal_target_llvm_cpu,hal_target_vulkan_spirv" iree-bazel-configure

AFTER CONFIGURATION
    iree-bazel-build      Build IREE targets
    iree-bazel-test       Run tests with configured drivers

SEE ALSO
    iree-bazel-build, iree-bazel-test
EOF
}

# Handle help and agent-md before worktree check.
case "${1:-}" in
    -h|--help) show_help; exit 0 ;;
    --agent-md|--agent_md) iree_show_agent_md; exit 0 ;;
esac

# Set up worktree (configure doesn't call iree_ensure_configured - it IS the configure).
iree_require_worktree
cd "${IREE_BAZEL_WORKTREE_DIR}"

iree_info "Configuring IREE for Bazel in ${IREE_BAZEL_WORKTREE_DIR}..."

# Run platform detection.
if [[ -f "configure_bazel.py" ]]; then
    iree_info "Running configure_bazel.py..."
    # Default to all buildable plugins unless explicitly set.
    # Users who want selective plugins can set IREE_COMPILER_PLUGINS explicitly.
    if [[ -z "${IREE_COMPILER_PLUGINS:-}" ]]; then
        export IREE_COMPILER_PLUGINS="all"
    fi
    python3 configure_bazel.py
else
    iree_error "configure_bazel.py not found in ${IREE_BAZEL_WORKTREE_DIR}"
    exit 1
fi

# Create user.bazelrc if it doesn't exist.
if [[ ! -f "user.bazelrc" ]]; then
    iree_info "Creating user.bazelrc..."

    # Platform-specific cache directory defaults.
    if [[ -n "${IREE_BAZEL_CACHE_DIR:-}" ]]; then
        CACHE_DIR="${IREE_BAZEL_CACHE_DIR}"
    elif [[ "${OSTYPE}" == "msys" || "${OSTYPE}" == "cygwin" || "${OSTYPE}" == "win32" ]]; then
        # Windows: Use shorter path to avoid 260 character limit.
        CACHE_DIR="c:/bazelcache"
    else
        # Unix: Use XDG cache directory.
        CACHE_DIR="${HOME}/.cache/bazel-iree"
    fi

    cat > user.bazelrc << EOF
# Local Bazel configuration.
# This file is not version-controlled.

# Disk cache for faster rebuilds (override with IREE_BAZEL_CACHE_DIR).
build --disk_cache=${CACHE_DIR}

# Garbage collect disk cache to prevent unbounded growth.
# Max size 50GB, GC runs when Bazel is idle for some time.
# TODO(benvanik): disabled until we upgrade bazel version.
#build --experimental_disk_cache_gc_max_size=50G
#build --experimental_disk_cache_gc_idle_delay=120s

# Debug config: no optimizations, with assertions.
build:debug --config=asserts --compilation_mode=opt '--per_file_copt=iree|llvm@-O0' --strip=never

# Enable assertions (optimized but with runtime checks).
build:asserts --compilation_mode=opt '--copt=-UNDEBUG'
EOF

    # Add Linux-specific sandbox optimization.
    if [[ -d "/dev/shm" ]]; then
        cat >> user.bazelrc << 'EOF'

# Linux: use ramdisk for sandbox to reduce I/O with many cores.
build --sandbox_base=/dev/shm
EOF
        iree_info "Added /dev/shm sandbox optimization (Linux)"
    fi

    iree_info "Created user.bazelrc with recommended settings"
else
    iree_info "user.bazelrc already exists, skipping"
fi

iree_info "Configuration complete!"
echo ""
echo "Build with:  iree-bazel-build [target]"
echo "Test with:   iree-bazel-test [target]"