name: CI

on:
  push:
    branches: [main, develop]
  pull_request:
    branches: [main, develop]
  schedule:
    # Weekly security scan on Mondays at 00:00 UTC
    - cron: '0 0 * * 1'

jobs:
  # ── Stage 1: Lint (gates everything else) ────────────────────────────────
  lint:
    name: Lint
    runs-on: ubuntu-latest
    permissions:
      contents: read

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

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

      - name: Cache pip packages
        uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: ${{ runner.os }}-pip-${{ hashFiles('backend/requirements.txt') }}
          restore-keys: ${{ runner.os }}-pip-

      - name: Install linting tools
        run: |
          python -m pip install --upgrade pip
          pip install black isort flake8 pylint
          cd backend && pip install -r requirements.txt

      - name: Black – format check
        run: black --check backend/app

      - name: isort – import order check
        run: isort --check-only backend/app

      - name: Flake8
        run: flake8 backend/app

      - name: Pylint
        run: pylint backend/app
        continue-on-error: true

  # ── Stage 2 (parallel): Test, Security, CodeQL, Dependency Review ────────
  test:
    name: Test
    runs-on: ubuntu-latest
    needs: lint
    permissions:
      contents: read

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

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

      - name: Cache pip packages
        uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: ${{ runner.os }}-pip-${{ hashFiles('backend/requirements.txt') }}
          restore-keys: ${{ runner.os }}-pip-

      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          cd backend && pip install -r requirements.txt

      - name: Run tests with coverage
        run: |
          cd backend
          pytest --cov=app --cov-report=xml --cov-report=term-missing

      - name: Upload coverage to Codecov
        uses: codecov/codecov-action@v4
        with:
          file: ./backend/coverage.xml
          flags: unittests
          name: codecov-umbrella
          fail_ci_if_error: false

  security:
    name: Security Scan
    runs-on: ubuntu-latest
    needs: lint
    permissions:
      contents: read

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

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

      - name: Cache pip packages
        uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: ${{ runner.os }}-pip-${{ hashFiles('backend/requirements.txt') }}
          restore-keys: ${{ runner.os }}-pip-

      - name: Install security tools
        run: |
          python -m pip install --upgrade pip
          pip install bandit pip-audit
          cd backend && pip install -r requirements.txt

      - name: Bandit – Python security linter
        run: bandit -r backend/app -f json -o bandit-report.json
        continue-on-error: true

      - name: Upload Bandit report
        uses: actions/upload-artifact@v4
        if: always()
        with:
          name: bandit-security-report
          path: bandit-report.json

      - name: pip-audit – dependency vulnerability check
        run: pip-audit --requirement backend/requirements.txt
        continue-on-error: true

  codeql:
    name: CodeQL Analysis
    runs-on: ubuntu-latest
    needs: lint
    # CodeQL is only meaningful on real pushes/PRs, not the weekly schedule alone
    if: github.event_name != 'schedule'
    permissions:
      actions: read
      contents: read
      security-events: write

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

      - name: Initialize CodeQL
        uses: github/codeql-action/init@v3
        with:
          languages: python
          queries: security-and-quality

      - name: Autobuild
        uses: github/codeql-action/autobuild@v3

      - name: Perform CodeQL Analysis
        uses: github/codeql-action/analyze@v3
        with:
          category: /language:python

  dependency-review:
    name: Dependency Review
    runs-on: ubuntu-latest
    needs: lint
    if: github.event_name == 'pull_request'
    permissions:
      contents: read

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

      - name: Dependency Review
        uses: actions/dependency-review-action@v4
        with:
          fail-on-severity: moderate

  # ── Stage 3: Docker Build & Publish (only on main push) ──────────────────
  docker:
    name: Docker Build & Publish
    runs-on: ubuntu-latest
    needs: [test, security]
    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
    permissions:
      contents: read
      packages: write

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

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Log in to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata for Docker
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ghcr.io/${{ github.repository }}
          tags: |
            type=ref,event=branch
            type=sha,prefix=
            type=raw,value=latest,enable={{is_default_branch}}

      - name: Build and push Docker image
        uses: docker/build-push-action@v6
        with:
          context: ./backend
          file: ./backend/Dockerfile
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max