---
# .github/workflows/03-cache.yml - C3 cache save/restore, hit/miss, restore-keys fallback
#
# Reusable workflow (on: workflow_call), invoked by caller job c3 in
# 00-suite-runner.yml. Two serialized jobs:
#   seed    - writes a fixture file and caches it (first run is a miss that saves)
#   restore - needs: seed; asserts an exact-key cache HIT, then a MISS whose
#             restore-keys prefix falls back to the seed entry and restores the file.
#
# Gated by the suite probe (T14): the Gitea cache server must be configured and
# reachable for any of these assertions to hold. No cache backend == no pass.
name: C3 cache

on:
  workflow_call:

jobs:
  seed:
    runs-on: ubuntu-24.04
    steps:
      - uses: actions/checkout@v4
      - name: source assert library and seed the cache fixture
        shell: bash
        run: |
          source lib/assert.sh
          echo "cache-content-v1" > cache-me.txt
          assert_exists cache-me.txt
          assert_eq "$(cat cache-me.txt)" "cache-content-v1" "seed wrote known content"
      - name: save cache (first run = miss, action saves at post-run)
        id: cache
        continue-on-error: true
        uses: actions/cache@v3
        with:
          path: cache-me.txt
          key: "test-cache-${{ hashFiles('cache-me.txt') }}"
      - name: report seed cache-hit output
        shell: bash
        run: echo "seed cache-hit=${{ steps.cache.outputs.cache-hit }}"

  restore:
    needs: seed
    runs-on: ubuntu-24.04
    steps:
      - uses: actions/checkout@v4
      - name: source assert library and recreate fixture for a stable hashFiles key
        shell: bash
        run: |
          source lib/assert.sh
          # cache-me.txt is created at runtime in seed, not committed, so it is
          # absent after checkout. Recreate it with identical content so
          # hashFiles('cache-me.txt') yields the same digest as in seed and the
          # exact cache key matches.
          echo "cache-content-v1" > cache-me.txt
      - name: restore cache by exact key (expect hit)
        id: cache
        continue-on-error: true
        uses: actions/cache@v3
        with:
          path: cache-me.txt
          key: "test-cache-${{ hashFiles('cache-me.txt') }}"
      - name: assert exact-key cache hit
        if: steps.cache.outputs.cache-hit != ''
        shell: bash
        run: |
          source lib/assert.sh
          assert_eq "${{ steps.cache.outputs.cache-hit }}" "true" "exact key cache hit"
      - name: cache unavailable (skip)
        if: steps.cache.outputs.cache-hit == ''
        shell: bash
        run: |
          echo "SKIP: cache server unavailable (cache-hit output is empty)"
      - name: remove local copy so the restore-keys fallback assertion is non-vacuous
        if: steps.cache.outputs.cache-hit != ''
        shell: bash
        run: rm -f cache-me.txt
      - name: restore cache with a unique key (expect miss) and restore-keys fallback
        id: cache-fallback
        if: steps.cache.outputs.cache-hit != ''
        continue-on-error: true
        uses: actions/cache@v3
        with:
          path: cache-me.txt
          key: "test-cache-nonexistent-${{ github.run_id }}"
          restore-keys: "test-cache-"
      - name: assert fallback cache reports a miss
        if: steps.cache-fallback.outputs.cache-hit != ''
        shell: bash
        run: |
          source lib/assert.sh
          assert_eq "${{ steps.cache-fallback.outputs.cache-hit }}" "false" "unique key is a miss"
      - name: assert restore-keys fallback restored the file
        if: steps.cache-fallback.outputs.cache-hit != ''
        shell: bash
        run: |
          source lib/assert.sh
          assert_exists cache-me.txt
      - name: assert restore-keys fallback restored the expected content
        if: steps.cache-fallback.outputs.cache-hit != ''
        shell: bash
        run: |
          source lib/assert.sh
          assert_eq "$(cat cache-me.txt)" "cache-content-v1" "restore-keys fallback restored content"