name: issue-branch-preview

on:
  push:
    branches-ignore:
      - main
  workflow_dispatch:
    inputs:
      branch:
        description: "Target branch (optional, default current ref)"
        required: false
        type: string
      issue:
        description: "Issue number (optional, auto-parse from branch)"
        required: false
        type: string

jobs:
  allocate-and-deploy:
    runs-on: ubuntu-latest
    env:
      PREVIEW_SLOTS: ${{ vars.PREVIEW_SLOTS }}
      PREVIEW_URL_TEMPLATE: ${{ vars.PREVIEW_URL_TEMPLATE }}
      PREVIEW_TTL_HOURS: ${{ vars.PREVIEW_TTL_HOURS }}
      PREVIEW_STATE_FILE: .tmp/preview-slots.json
      CLIENT_DEPLOY_CMD: ${{ vars.CLIENT_DEPLOY_CMD }}
      SERVER_DEPLOY_CMD: ${{ vars.SERVER_DEPLOY_CMD }}
      FULL_STACK_DEPLOY_CMD: ${{ vars.FULL_STACK_DEPLOY_CMD }}
      INFRA_APPLY_CMD: ${{ vars.INFRA_APPLY_CMD }}
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Setup Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Resolve branch and issue
        id: target
        shell: bash
        run: |
          BRANCH="${{ inputs.branch }}"
          ISSUE_INPUT="${{ inputs.issue }}"
          if [ -z "$BRANCH" ]; then
            BRANCH="${GITHUB_REF_NAME:-$(git rev-parse --abbrev-ref HEAD)}"
          fi

          ISSUE_ID="$ISSUE_INPUT"
          if [ -z "$ISSUE_ID" ]; then
            ISSUE_ID="$(echo "$BRANCH" | sed -nE 's#^issue[-/ ]?([0-9]+).*$#\1#p')"
          fi
          if [ -z "$ISSUE_ID" ]; then
            ISSUE_ID="$(echo "$BRANCH" | sed -nE 's#^.*/([0-9]+).*$#\1#p')"
          fi
          if [ -z "$ISSUE_ID" ]; then
            ISSUE_ID="0"
          fi

          echo "branch=$BRANCH" >> "$GITHUB_OUTPUT"
          echo "issue=$ISSUE_ID" >> "$GITHUB_OUTPUT"

      - name: Detect change scope
        id: scope
        shell: bash
        run: |
          git fetch origin main --depth=1 || true
          mkdir -p .tmp
          python skills/gitea-issue-devops-agent/scripts/change_scope.py \
            --repo-path . \
            --base-ref origin/main \
            --head-ref "${{ steps.target.outputs.branch }}" > .tmp/change-scope.json
          SCOPE="$(python -c "import json;print(json.load(open('.tmp/change-scope.json', encoding='utf-8'))['scope'])")"
          echo "scope=$SCOPE" >> "$GITHUB_OUTPUT"
          cat .tmp/change-scope.json

      - name: Allocate preview slot
        id: slot
        shell: bash
        run: |
          SLOTS="${PREVIEW_SLOTS:-preview-a,preview-b}"
          TTL="${PREVIEW_TTL_HOURS:-24}"
          URL_TEMPLATE="${PREVIEW_URL_TEMPLATE:-https://{slot}.qa.example.com}"
          mkdir -p .tmp

          python skills/gitea-issue-devops-agent/scripts/preview_slot_allocator.py \
            --state-file "$PREVIEW_STATE_FILE" \
            --slots "$SLOTS" \
            --repo "${GITHUB_REPOSITORY}" \
            --issue "${{ steps.target.outputs.issue }}" \
            --branch "${{ steps.target.outputs.branch }}" \
            --ttl-hours "$TTL" \
            --url-template "$URL_TEMPLATE" \
            --evict-oldest > .tmp/slot-allocation.json

          SLOT="$(python -c "import json;d=json.load(open('.tmp/slot-allocation.json', encoding='utf-8'));print(d.get('allocation',{}).get('slot',''))")"
          URL="$(python -c "import json;d=json.load(open('.tmp/slot-allocation.json', encoding='utf-8'));print(d.get('allocation',{}).get('url',''))")"
          echo "slot=$SLOT" >> "$GITHUB_OUTPUT"
          echo "url=$URL" >> "$GITHUB_OUTPUT"
          cat .tmp/slot-allocation.json

      - name: Deploy by scope
        shell: bash
        run: |
          set -euo pipefail
          SCOPE="${{ steps.scope.outputs.scope }}"
          run_or_echo () {
            local cmd="$1"
            local fallback="$2"
            if [ -n "$cmd" ]; then
              bash -lc "$cmd"
            else
              echo "$fallback"
            fi
          }

          case "$SCOPE" in
            skip)
              echo "Scope=skip: docs/tests-only or no changes, deployment skipped."
              ;;
            client_only)
              run_or_echo "${CLIENT_DEPLOY_CMD:-}" "Scope=client_only: set repo var CLIENT_DEPLOY_CMD."
              ;;
            server_only)
              run_or_echo "${SERVER_DEPLOY_CMD:-}" "Scope=server_only: set repo var SERVER_DEPLOY_CMD."
              ;;
            full_stack)
              run_or_echo "${FULL_STACK_DEPLOY_CMD:-}" "Scope=full_stack: set repo var FULL_STACK_DEPLOY_CMD."
              ;;
            infra_only)
              run_or_echo "${INFRA_APPLY_CMD:-}" "Scope=infra_only: set repo var INFRA_APPLY_CMD."
              ;;
            *)
              echo "Unknown scope: $SCOPE"
              exit 1
              ;;
          esac

      - name: Persist preview slot state
        shell: bash
        run: |
          if [ ! -f "$PREVIEW_STATE_FILE" ]; then
            exit 0
          fi
          if [ -z "$(git status --porcelain -- "$PREVIEW_STATE_FILE")" ]; then
            exit 0
          fi

          git config user.name "gitea-actions"
          git config user.email "gitea-actions@local"
          git add "$PREVIEW_STATE_FILE"
          git commit -m "chore: update preview slot state [skip ci]" || true
          git push || true

      - name: Summary
        shell: bash
        run: |
          echo "branch: ${{ steps.target.outputs.branch }}"
          echo "issue: ${{ steps.target.outputs.issue }}"
          echo "scope: ${{ steps.scope.outputs.scope }}"
          echo "slot: ${{ steps.slot.outputs.slot }}"
          echo "url: ${{ steps.slot.outputs.url }}"