# TEMPORARY — milestone 328 steps 1-2. Delete once the baseline is stamped.
#
# Squashing 87 alembic revisions into one baseline has exactly one dangerous
# failure: the generated baseline does not reproduce the schema the chain
# produced, `alembic stamp` writes a version string anyway (it validates
# NOTHING), and the divergence surfaces on the next real migration against the
# operator's live data.
#
# So this workflow does the comparison in CI, where a pgvector Postgres already
# gets built from the chain on every integration run, and nothing is at risk.
# It answers one question: does `upgrade head` on the collapsed chain produce a
# byte-identical schema to `upgrade head` on the 87-revision chain?
#
# The chain is read from git rather than from the working tree, so this keeps
# working AFTER the old revisions are deleted — `chain_ref` names a commit that
# still has them. That is what makes this the proof for step 1 and the
# pre-flight for step 2, rather than a one-shot script.
#
# `generate: true` additionally autogenerates a candidate baseline from the
# models and uploads it. That is a starting point, NOT the answer: autogenerate
# reads SQLAlchemy metadata, and three things in this schema do not live there —
#   * CREATE EXTENSION vector           (0001)
#   * CREATE EXTENSION tsm_system_rows  (0004)
#   * the HNSW index on image_record.siglip_embedding, which is raw SQL
#     because alembic's create_index cannot express `USING hnsw (...)`  (0036)
# plus any CHECK constraint or server_default that a migration added without
# the model declaring it. Those must be hand-added, and the diff below is what
# proves none were missed.
name: Alembic baseline

on:
  workflow_dispatch:
    inputs:
      chain_ref:
        description: 'Commit/tag that still carries the full 0001..0087 chain'
        type: string
        default: '0a5bbe8'
      generate:
        description: 'Also autogenerate a candidate baseline from the models'
        type: boolean
        default: false

jobs:
  compare:
    runs-on: python-ci
    container:
      image: git.fabledsword.com/bvandeusen/ci-python:3.14
    env:
      DB_USER: fabledcurator
      DB_PASSWORD: ci_integration
      DB_PORT: "5432"
      DB_NAME: fabledcurator_test
      SECRET_KEY: ci_integration_placeholder
    services:
      postgres:
        image: pgvector/pgvector:pg16
        env:
          POSTGRES_USER: fabledcurator
          POSTGRES_PASSWORD: ci_integration
          POSTGRES_DB: fabledcurator_test
        options: >-
          --health-cmd "pg_isready -U fabledcurator"
          --health-interval 10s
          --health-timeout 5s
          --health-retries 10
    steps:
      - uses: actions/checkout@v4
        with:
          # Full history is the point: `chain_ref` is read out of git, so a
          # shallow clone would not have the revisions to compare against.
          fetch-depth: 0

      - name: Resolve the Postgres service and install deps
        run: |
          set -eux
          # Same service-IP dance as ci.yml's integration job; see the long
          # comment there for why the job name must stay separator-free.
          PG=$(docker ps --filter "name=compare" --filter "ancestor=pgvector/pgvector:pg16" -q | head -n1)
          test -n "$PG"
          PG_IP=$(docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' "$PG")
          test -n "$PG_IP"
          echo "PG_CONTAINER=$PG" >> "$GITHUB_ENV"
          echo "DB_HOST=$PG_IP" >> "$GITHUB_ENV"
          for i in $(seq 1 60); do
            (echo > "/dev/tcp/$PG_IP/5432") >/dev/null 2>&1 && break
            sleep 2
          done
          if command -v uv >/dev/null 2>&1; then
            uv pip install --system -r requirements.txt
          else
            pip install -r requirements.txt
          fi

      # DB 1: the 87-revision chain, read out of git at `chain_ref`.
      #
      # A git worktree rather than a checkout, so the current tree — which is
      # what we are testing — is left completely alone.
      - name: Build the schema the OLD chain produces
        env:
          CHAIN_REF: ${{ github.event.inputs.chain_ref }}
        run: |
          set -eux
          docker exec "$PG_CONTAINER" createdb -U fabledcurator fc_chain
          git worktree add /tmp/chain "$CHAIN_REF"
          ls /tmp/chain/alembic/versions/*.py | wc -l
          cd /tmp/chain
          DB_NAME=fc_chain alembic upgrade head
          cd -
          docker exec "$PG_CONTAINER" pg_dump -U fabledcurator --schema-only \
            --no-owner --no-privileges -d fc_chain > chain.sql
          wc -l chain.sql

      # Optional: a candidate baseline, autogenerated from the models against an
      # EMPTY database so every table shows up as a create. Uploaded for a human
      # to finish — it will be missing the three raw-SQL items named at the top.
      - name: Autogenerate a candidate baseline
        if: ${{ github.event.inputs.generate == 'true' }}
        run: |
          set -eux
          docker exec "$PG_CONTAINER" createdb -U fabledcurator fc_gen
          # Hide the existing revisions so alembic sees an empty history and
          # emits the whole schema rather than a delta.
          mkdir -p /tmp/versions_held
          mv alembic/versions/*.py /tmp/versions_held/ 2>/dev/null || true
          DB_NAME=fc_gen alembic revision --autogenerate -m "baseline" || true
          # Printed in full rather than uploaded. ci-requirements.md records
          # that this runner cannot do actions/upload-artifact@v4+, and the
          # repo dropped the action entirely in 2026-05; the job log is the
          # retrieval channel that is actually proven here.
          echo "===== BEGIN CANDIDATE BASELINE ====="
          cat alembic/versions/*.py
          echo "===== END CANDIDATE BASELINE ====="
          # Put the tree back exactly as it was; this job never mutates state.
          rm -f alembic/versions/*.py
          mv /tmp/versions_held/*.py alembic/versions/ 2>/dev/null || true

      # DB 2: whatever the CURRENT tree's alembic/versions produces. Before the
      # squash that is the same 87 revisions and the diff is trivially clean —
      # which is worth running once as a control, so a clean diff after the
      # squash means something.
      - name: Build the schema the CURRENT tree produces
        run: |
          set -eux
          docker exec "$PG_CONTAINER" createdb -U fabledcurator fc_base
          ls alembic/versions/*.py | wc -l
          DB_NAME=fc_base alembic upgrade head
          docker exec "$PG_CONTAINER" pg_dump -U fabledcurator --schema-only \
            --no-owner --no-privileges -d fc_base > baseline.sql
          wc -l baseline.sql

      # The verdict.
      #
      # pg_dump orders dumpable objects by name within type, not by creation
      # order, so two schemas built by different routes are directly
      # comparable. The only normalisation applied is dropping blank lines,
      # comment lines and the alembic_version row-count noise — deliberately
      # minimal, because a filter that hides a real difference is the one way
      # this check passes when it should fail. Whatever is normalised is
      # printed, so the filtering itself is reviewable.
      - name: Diff
        run: |
          set -eu
          norm() {
            grep -vE '^\s*(--|$)' "$1" | sed 's/[[:space:]]*$//'
          }
          norm chain.sql > a.txt
          norm baseline.sql > b.txt
          echo "normalised: chain=$(wc -l < a.txt) lines, current=$(wc -l < b.txt) lines"
          if diff -u a.txt b.txt > schema.diff; then
            echo "SCHEMAS IDENTICAL — the collapsed chain reproduces the old one."
          else
            echo "SCHEMAS DIFFER — $(grep -cE '^[+-]' schema.diff) changed lines:"
            cat schema.diff
            echo
            echo "The baseline is wrong, not the database. Do not stamp."
            exit 1
          fi