# .gitea/workflows/merge-gate.yaml
# CI merge gate (T-0.2, R-GITOPS-01, R-TEST-02/03) for the home k3s + Longhorn
# platform. Enforces docs/14 (Testing & Conformance) gating rules as Gitea Actions.
#
# Pipeline (docs/14 "Where each layer runs"):
#   lint  ->  schema  ->  kyverno-L0  ->  L1-render        [no cluster; live now]
#                                          |
#                                          v
#                            conformance-L2-L3 (in-cluster Chainsaw Job)
#                                          |                [cluster-gated; SKIPS in Phase 0]
#                                          v
#                                     merge-gate decision  [R-TEST-03: touched subset green]
#
# Transition (CONTRIBUTING.md / docs/05 §"local bootstrap -> self-hosted Gitea"):
# Today there is no Gitea host, so this file is dormant. The SAME gate is runnable
# now via `make -C ci gate` (R-TEST-02). Once Gitea is self-hosted and Gitea
# Actions is enabled, this workflow becomes the ENFORCED PR merge gate into main —
# no code change required, only turning on the runner and setting CLUSTER_AVAILABLE.
#
# CI holds NO broad kubeconfig. L2/L3 run as an in-cluster Chainsaw Job whose own
# scoped ServiceAccount holds cluster access (docs/14, R-SEC-02); CI uses only a
# narrow trigger credential referenced BY SECRET NAME below.
---
name: merge-gate

on:
  pull_request:
    branches: [main]           # PRs are the enforced merge gate into main (CONTRIBUTING.md)
  push:
    branches:
      - 'feature/**'           # feature-branch -> main workflow (no work on main)
      - 'fix/**'
      - 'docs/**'
      - 'chore/**'

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

# Repo/org variables & secrets (set in Gitea, referenced by NAME only — no plaintext):
#   vars.CLUSTER_AVAILABLE            'true' once a dev/test cluster exists (Phase 1+); else L2/L3 SKIP
#   secrets.CONFORMANCE_TRIGGER_KUBECONFIG   narrow creds to CREATE/AWAIT the in-cluster Chainsaw Job only
env:
  CLUSTER_AVAILABLE: ${{ vars.CLUSTER_AVAILABLE }}

jobs:
  # R-TEST-06 hard gate: the specification is read-only to agents. Fail the whole run
  # if the spec repo is modified or has drifted from ci/SPEC_PIN. Runs first; everything
  # else depends on it. Requires the spec repo checked out beside the impl repo — wired
  # for when Gitea hosts both. If the spec repo is unavailable the guard SKIPS (exit 3),
  # tolerated here (surfaced, never a fake green); a real violation (exit 1) blocks.
  spec-immutability:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4                 # the implementation repo
      - name: Check out the read-only spec (sibling path)
        uses: actions/checkout@v4
        with:
          repository: ${{ vars.SPEC_REPO_SLUG }}  # e.g. Home-Network/home-network-k3s (set in Gitea)
          path: ../home-network-k3s
          fetch-depth: 0
      - name: Verify spec immutability (R-TEST-06)
        run: make -C ci spec-immutability || [ $? -eq 3 ]

  lint:
    runs-on: ubuntu-latest
    needs: [spec-immutability]
    steps:
      - uses: actions/checkout@v4
        with: { fetch-depth: 0 }          # full history so touched-requirement diff works
      - name: Install pinned tools
        run: ./.gitea/workflows/scripts/install-tools.sh lint
      - name: yaml/lint
        run: make -C ci lint

  l0:
    runs-on: ubuntu-latest
    needs: [lint]
    steps:
      - uses: actions/checkout@v4
        with: { fetch-depth: 0 }
      - name: Install pinned tools
        run: ./.gitea/workflows/scripts/install-tools.sh l0
      - name: Schema validation + Kyverno L0
        run: make -C ci l0

  l1:
    runs-on: ubuntu-latest
    needs: [l0]
    steps:
      - uses: actions/checkout@v4
        with: { fetch-depth: 0 }
      - name: Install pinned tools
        run: ./.gitea/workflows/scripts/install-tools.sh l1
      - name: L1 rendering checks
        run: make -C ci l1
      - name: Upload L1 artifacts
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: l1-junit-coverage
          path: |
            results/junit/*.xml
            reports/coverage/**
          if-no-files-found: ignore

  # L2/L3 behavioral + fault-injection. Runs ONLY when a cluster is declared.
  # In Phase 0 (CLUSTER_AVAILABLE unset) this job is SKIPPED by Gitea — shown as
  # skipped, never as passed. It never fakes green (HARD RULE 4).
  conformance:
    runs-on: ubuntu-latest
    needs: [l1]
    if: ${{ vars.CLUSTER_AVAILABLE == 'true' }}
    steps:
      - uses: actions/checkout@v4
        with: { fetch-depth: 0 }
      - name: Install pinned tools
        run: ./.gitea/workflows/scripts/install-tools.sh conformance
      - name: Trigger in-cluster Chainsaw Job (L2/L3) and collect artifacts
        env:
          # Narrow trigger credential; the Job's scoped SA holds real cluster access.
          CONFORMANCE_TRIGGER_KUBECONFIG: ${{ secrets.CONFORMANCE_TRIGGER_KUBECONFIG }}
        run: make -C ci conformance
      - name: Upload L2/L3 artifacts
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: conformance-junit-coverage
          path: |
            results/junit/*.xml
            reports/coverage/**
          if-no-files-found: ignore

  # Final decision. Applies R-TEST-03 honestly over the upstream job results:
  #   any L0/L1 failure         -> BLOCK
  #   conformance failed        -> BLOCK
  #   conformance skipped + cluster available -> BLOCK (should have run)
  #   conformance skipped + no cluster        -> report UNVERIFIED (Phase 0), do not fake green
  merge-gate:
    runs-on: ubuntu-latest
    needs: [lint, l0, l1, conformance]
    if: always()
    steps:
      - uses: actions/checkout@v4
      - name: Decide
        env:
          R_LINT: ${{ needs.lint.result }}
          R_L0: ${{ needs.l0.result }}
          R_L1: ${{ needs.l1.result }}
          R_CONF: ${{ needs.conformance.result }}
        run: ./.gitea/workflows/scripts/decide.sh