name: Setup pinned root implementation
description: Clone exactly one supported root implementation at a verified commit
inputs:
  flavor:
    description: 'kernelsu, next, resukisu, or sukisu-ultra'
    required: true
  commit:
    description: 'Full immutable commit SHA'
    required: true

runs:
  using: composite
  steps:
    - name: Clone and integrate selected root
      shell: bash
      working-directory: ${{ github.workspace }}/kernel
      run: |
        set -euo pipefail

        flavor="${{ inputs.flavor }}"
        expected_commit="${{ inputs.commit }}"
        case "$flavor" in
          kernelsu)
            repo="https://github.com/tiann/KernelSU.git"
            directory="KernelSU"
            manager="KernelSU Manager"
            ;;
          next)
            repo="https://github.com/KernelSU-Next/KernelSU-Next.git"
            directory="KernelSU-Next"
            manager="KernelSU Next Manager"
            ;;
          resukisu)
            repo="https://github.com/ReSukiSU/ReSukiSU.git"
            directory="ReSukiSU"
            manager="ReSukiSU Manager"
            ;;
          sukisu-ultra)
            repo="https://github.com/SukiSU-Ultra/SukiSU-Ultra.git"
            directory="SukiSU-Ultra"
            manager="SukiSU-Ultra Manager"
            ;;
          *)
            echo "Unsupported root flavor: $flavor" >&2
            exit 2
            ;;
        esac

        if ! [[ "$expected_commit" =~ ^[0-9a-f]{40}$ ]]; then
          echo "Root commit must be a full 40-character SHA." >&2
          exit 2
        fi

        for candidate in KernelSU KernelSU-Next ReSukiSU SukiSU-Ultra; do
          if [ "$candidate" != "$directory" ] && [ -e "$candidate" ]; then
            echo "Refusing mixed root implementations: found $candidate." >&2
            exit 1
          fi
        done

        if [ -d common/drivers ]; then
          drivers_dir="common/drivers"
        elif [ -d drivers ]; then
          drivers_dir="drivers"
        else
          echo "Kernel drivers directory not found." >&2
          exit 1
        fi

        if [ -e "$drivers_dir/kernelsu" ] || [ -L "$drivers_dir/kernelsu" ]; then
          echo "Refusing to replace an existing kernelsu integration." >&2
          exit 1
        fi
        if [ -e "$directory" ]; then
          echo "Refusing to reuse an existing root checkout: $directory." >&2
          exit 1
        fi

        git clone --no-checkout "$repo" "$directory"
        git -C "$directory" fetch --depth=1 origin "$expected_commit"
        git -C "$directory" checkout --detach "$expected_commit"
        actual_commit="$(git -C "$directory" rev-parse HEAD)"
        if [ "$actual_commit" != "$expected_commit" ]; then
          echo "Root commit mismatch: expected $expected_commit, got $actual_commit." >&2
          exit 1
        fi
        if [ ! -f "$directory/kernel/Kconfig" ] || [ ! -f "$directory/kernel/Makefile" ]; then
          echo "Selected root checkout does not contain a kernel integration." >&2
          exit 1
        fi
        root_version="$(git -C "$directory" describe --tags --always --dirty)"

        relative_kernel="$(realpath --relative-to="$drivers_dir" "$PWD/$directory/kernel")"
        ln -s "$relative_kernel" "$drivers_dir/kernelsu"
        grep -q 'obj-$(CONFIG_KSU) += kernelsu/' "$drivers_dir/Makefile" ||
          printf '\nobj-$(CONFIG_KSU) += kernelsu/\n' >> "$drivers_dir/Makefile"
        grep -q 'source "drivers/kernelsu/Kconfig"' "$drivers_dir/Kconfig" ||
          sed -i '/endmenu/i source "drivers/kernelsu/Kconfig"' "$drivers_dir/Kconfig"

        echo "ROOT_IMPLEMENTATION=$flavor" >> "$GITHUB_ENV"
        echo "ROOT_MANAGER=$manager" >> "$GITHUB_ENV"
        echo "ROOT_VERSION=$root_version" >> "$GITHUB_ENV"
        echo "ROOT_COMMIT=$actual_commit" >> "$GITHUB_ENV"

    - name: Enable root configuration
      uses: ./.github/actions/set-kernel-config
      with:
        config_list: |
          CONFIG_KSU=y

    - name: Disable multi-manager for ReSukiSU
      if: inputs.flavor == 'resukisu'
      uses: ./.github/actions/set-kernel-config
      with:
        config_list: |
          CONFIG_KSU_MULTI_MANAGER_SUPPORT=n
          CONFIG_KSU_TOOLKIT_SUPPORT=y