name: Prepare

on:
  push:
    branches:
      - main
  workflow_dispatch:

concurrency:
  group: prepare-${{ github.repository }}
  cancel-in-progress: false

env:
  WORKSPACE_ROOT: "/data/workspace"

jobs:
  prepare:
    runs-on: standard-ubuntu-22
    steps:
      - name: 准备共享仓库和持久 Worktree
        run: |
          set -euo pipefail

          REPO_NAME="${{ github.event.repository.name }}"
          REPO_URL="${{ github.server_url }}/${{ github.repository }}.git"
          HEAD_SHA="${{ github.sha }}"
          REPOSITORY_DIR="${WORKSPACE_ROOT}/${REPO_NAME}/repository.git"
          WORKTREE_ROOT="${WORKSPACE_ROOT}/${REPO_NAME}/worktrees"

          case "$HEAD_SHA" in
            ''|*[!0-9a-fA-F]*)
              echo "无效的触发提交 SHA: $HEAD_SHA" >&2
              exit 1
              ;;
          esac

          echo "===== [$(date '+%F %T')] 开始准备共享仓库 ====="
          echo "共享仓库: $REPOSITORY_DIR"
          echo "Worktree 根目录: $WORKTREE_ROOT"
          echo "仓库地址: $REPO_URL"
          echo "触发提交: $HEAD_SHA"

          mkdir -p "$(dirname "$REPOSITORY_DIR")" "$WORKTREE_ROOT"

          if [ ! -d "$REPOSITORY_DIR" ]; then
            echo "首次使用，初始化 bare 仓库..."
            git init --bare "$REPOSITORY_DIR"
          elif [ "$(git --git-dir="$REPOSITORY_DIR" rev-parse --is-bare-repository)" != "true" ]; then
            echo "共享仓库目录不是 bare 仓库: $REPOSITORY_DIR" >&2
            exit 1
          fi

          if git --git-dir="$REPOSITORY_DIR" remote get-url origin >/dev/null 2>&1; then
            git --git-dir="$REPOSITORY_DIR" remote set-url origin "$REPO_URL"
          else
            git --git-dir="$REPOSITORY_DIR" remote add origin "$REPO_URL"
          fi

          echo "----- 从远端集中 fetch 一次 -----"
          git --git-dir="$REPOSITORY_DIR" fetch \
            --prune --prune-tags --tags --force origin \
            '+refs/heads/*:refs/remotes/origin/*'

          if ! git --git-dir="$REPOSITORY_DIR" cat-file -e "${HEAD_SHA}^{commit}"; then
            echo "共享仓库中不存在触发提交: $HEAD_SHA" >&2
            exit 1
          fi

          ensure_worktree() {
            role=$1
            worktree_dir="${WORKTREE_ROOT}/${role}"

            if [ -e "$worktree_dir" ]; then
              if [ ! -f "$worktree_dir/.git" ]; then
                echo "Worktree 路径已存在但不是 linked worktree: $worktree_dir" >&2
                return 1
              fi

              common_dir=$(git -C "$worktree_dir" rev-parse --path-format=absolute --git-common-dir)
              if [ "$common_dir" != "$(realpath "$REPOSITORY_DIR")" ]; then
                echo "Worktree 不属于共享仓库: $worktree_dir" >&2
                return 1
              fi

              echo "复用持久 Worktree: $worktree_dir"
              return 0
            fi

            echo "首次创建持久 Worktree: $worktree_dir"
            git --git-dir="$REPOSITORY_DIR" worktree add --detach "$worktree_dir" "$HEAD_SHA"
          }

          ensure_worktree "print1"
          ensure_worktree "print2"

          echo "----- 当前共享仓库状态 -----"
          git --git-dir="$REPOSITORY_DIR" log -1 --oneline "$HEAD_SHA"
          git --git-dir="$REPOSITORY_DIR" worktree list
          echo "===== Prepare 完成 ====="

      - name: 模拟准备耗时
        run: |
          echo "[$(date '+%F %T')] Prepare 开始 sleep 10s ..."
          sleep 10
          echo "[$(date '+%F %T')] Prepare 完成"