# Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
# All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause

# Multi-GPU distributed training validation
#
# This workflow validates that multi-GPU training works correctly across:
# - Physics backends: PhysX, Newton
# - Rendering backends: none (physics-only), Isaac RTX, Newton Warp
#
# Runs on a dedicated multi-GPU runner (separate from standard CI) to minimize costs.
# Only triggered on PRs that touch distributed training code paths.

name: Multi-GPU Training Tests

on:
  pull_request:
    paths:
      - "source/isaaclab/isaaclab/app/app_launcher.py"
      - "source/isaaclab_tasks/isaaclab_tasks/utils/sim_launcher.py"
      - "scripts/reinforcement_learning/**/train.py"
      - ".github/workflows/test-multi-gpu.yaml"
  workflow_dispatch:

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  test-multi-gpu:
    name: Multi-GPU (${{ matrix.physics }}, ${{ matrix.renderer }})
    # Use dedicated multi-GPU runner to avoid blocking standard CI resources
    # Configure this label on a runner with 2+ GPUs (e.g., g5.12xlarge with 4x A10G)
    runs-on: [self-hosted, linux, x64, gpu, multi-gpu]
    timeout-minutes: 30
    strategy:
      fail-fast: false
      matrix:
        include:
          # PhysX physics-only
          - physics: physx
            renderer: none
            task: Isaac-Cartpole-Direct-v0
            extra_args: ""

          # PhysX + Isaac RTX renderer
          - physics: physx
            renderer: isaac-rtx
            task: Isaac-Cartpole-Camera-Presets-Direct-v0
            extra_args: ""
            trainer: skrl

          # PhysX + Newton Warp renderer (hybrid)
          - physics: physx
            renderer: newton-warp
            task: Isaac-Cartpole-Camera-Presets-Direct-v0
            extra_args: "env.tiled_camera.renderer_cfg=newton_renderer"
            trainer: skrl

          # Newton physics-only
          - physics: newton
            renderer: none
            task: Isaac-Cartpole-Direct-v0
            extra_args: "+sim=newton"

          # Newton + Newton Warp renderer
          - physics: newton
            renderer: newton-warp
            task: Isaac-Cartpole-Camera-Presets-Direct-v0
            extra_args: "+sim=newton env.tiled_camera.renderer_cfg=newton_renderer"
            trainer: skrl

          # Newton + Isaac RTX renderer (hybrid)
          - physics: newton
            renderer: isaac-rtx
            task: Isaac-Cartpole-Camera-Presets-Direct-v0
            extra_args: "+sim=newton"
            trainer: skrl

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

      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.10"

      - name: Install Isaac Lab
        run: |
          ./isaaclab.sh --install

      - name: Verify multi-GPU availability
        run: |
          echo "=== GPU Info ==="
          nvidia-smi --query-gpu=index,name,memory.total --format=csv

          GPU_COUNT=$(python -c "import torch; print(torch.cuda.device_count())")
          echo "Detected $GPU_COUNT GPU(s)"

          if [ "$GPU_COUNT" -lt 2 ]; then
            echo "::error::At least 2 GPUs required for multi-GPU tests, found $GPU_COUNT"
            exit 1
          fi

      - name: Run multi-GPU training (${{ matrix.physics }}, ${{ matrix.renderer }})
        env:
          NCCL_DEBUG: WARN
        run: |
          TRAINER="${{ matrix.trainer || 'rsl_rl' }}"

          echo "=========================================="
          echo "Physics: ${{ matrix.physics }}"
          echo "Renderer: ${{ matrix.renderer }}"
          echo "Task: ${{ matrix.task }}"
          echo "Trainer: $TRAINER"
          echo "Extra args: ${{ matrix.extra_args }}"
          echo "=========================================="

          # Run 2-GPU distributed training for 3 iterations
          ./isaaclab.sh -p -m torch.distributed.run --nproc_per_node=2 \
            scripts/reinforcement_learning/${TRAINER}/train.py \
            --task=${{ matrix.task }} \
            --headless \
            --distributed \
            --max_iterations=3 \
            --num_envs=16 \
            ${{ matrix.extra_args }}

      - name: Verify training completed
        run: |
          # Find the most recent log directory
          LATEST_LOG=$(ls -td logs/*/*/*/ 2>/dev/null | head -1)

          if [ -z "$LATEST_LOG" ]; then
            echo "::error::No training log directory found"
            exit 1
          fi

          echo "Log directory: $LATEST_LOG"
          ls -la "$LATEST_LOG"

          # Check for model checkpoints
          MODELS=$(find "$LATEST_LOG" -name "*.pt" | wc -l)
          echo "Model checkpoints found: $MODELS"

          if [ "$MODELS" -lt 1 ]; then
            echo "::error::No model checkpoints found - training may have failed"
            exit 1
          fi

          echo "✅ Multi-GPU training completed successfully (${{ matrix.physics }}, ${{ matrix.renderer }})"