name: "[Prod] Rollback"

# Rolls production back to an earlier image, and optionally restores the
# database from a dump taken by the deploy workflow.
#
# Rolling the image back is the normal case and loses nothing. Restoring the
# database is a last resort for when the new schema is incompatible with the
# old code: it discards EVERYTHING CUSTOMERS WROTE since the dump was taken.
# That is why a database restore additionally requires typing
# "restore-production" into the confirm field.
#
# Reuses the compose file and .env that "Deploy: app.torqvoice.com" wrote, so
# prod must have been deployed at least once before this can run.

on:
  workflow_dispatch:
    inputs:
      tag:
        description: "Version tag to roll back to (e.g. v1.2.38). 'latest' is refused."
        required: true
      restore_database:
        description: "DESTRUCTIVE. Also restore the database, discarding everything written since the dump. Leave off unless the old code cannot run against the new schema."
        type: boolean
        default: false
      dump:
        description: "Dump filename to restore from (e.g. torqvoice-20260815-120000-pre-v1.2.39.dump). Only used when restore_database is on."
        required: false
        default: ""
      confirm:
        description: "Type restore-production to allow a database restore. Ignored otherwise."
        required: false
        default: ""

jobs:
  rollback:
    runs-on: [self-hosted, Linux, X64, hetzner]

    steps:
      - name: Refuse floating tags
        run: |
          if [ "${{ inputs.tag }}" = "latest" ] || [ -z "${{ inputs.tag }}" ]; then
            echo "::error::Roll back to a version tag (e.g. v1.2.38), never 'latest'."
            exit 1
          fi

      - name: Show available dumps
        run: ls -lht "${{ secrets.DATA_PATH }}/db-backups/torqvoice" 2>/dev/null | head -20 || echo "No dumps yet."

      # Everything that can fail is checked before the app is stopped, so a bad
      # input leaves production untouched and still running.
      - name: Validate restore request
        if: inputs.restore_database
        env:
          DATABASE_URL: ${{ secrets.CLOUD_DATABASE_URL }}
        run: |
          set -euo pipefail

          if [ "${{ inputs.confirm }}" != "restore-production" ]; then
            echo "::error::Database restore requested without typing restore-production in the confirm field."
            exit 1
          fi

          # This job may only ever drop the production database. If the secret
          # is ever miswired, refuse rather than drop whatever it points at.
          DB_NAME=$(echo "$DATABASE_URL" | sed -E 's|.*/([^/?]+)(\?.*)?$|\1|')
          if [ "$DB_NAME" != "torqvoice" ]; then
            echo "::error::CLOUD_DATABASE_URL points at \"$DB_NAME\", expected \"torqvoice\". Refusing."
            exit 1
          fi

          if [ -z "${{ inputs.dump }}" ]; then
            echo "::error::restore_database is on but no dump filename was given."
            exit 1
          fi
          # The dump must belong to the production database: a staging dump
          # here would replace real customer data with test data.
          case "${{ inputs.dump }}" in
            "$DB_NAME"-[0-9]*) ;;
            *)
              echo "::error::Dump \"${{ inputs.dump }}\" is not a $DB_NAME dump. Refusing."
              exit 1
              ;;
          esac
          DUMP="${{ secrets.DATA_PATH }}/db-backups/torqvoice/${{ inputs.dump }}"
          if [ ! -f "$DUMP" ]; then
            echo "::error::Dump not found: $DUMP"
            exit 1
          fi
          docker exec -i torqvoice-db pg_restore --list < "$DUMP" > /dev/null
          echo "Dump is readable: $DUMP"

      - name: Stop prod app
        run: |
          cd $HOME/torqvoice-deploy/prod
          docker compose stop torqvoice-app

      - name: Restore database
        if: inputs.restore_database
        env:
          DATABASE_URL: ${{ secrets.CLOUD_DATABASE_URL }}
        run: |
          set -euo pipefail
          DUMP="${{ secrets.DATA_PATH }}/db-backups/torqvoice/${{ inputs.dump }}"
          DB_USER=$(echo "$DATABASE_URL" | sed -E 's|^[^:]+://([^:]+):.*|\1|')
          DB_NAME=$(echo "$DATABASE_URL" | sed -E 's|.*/([^/?]+)(\?.*)?$|\1|')

          echo "Restoring $DB_NAME from $(basename "$DUMP")"
          docker exec -i torqvoice-db psql -U "$DB_USER" -d postgres -c "DROP DATABASE \"$DB_NAME\" WITH (FORCE);"
          docker exec -i torqvoice-db psql -U "$DB_USER" -d postgres -c "CREATE DATABASE \"$DB_NAME\" OWNER \"$DB_USER\";"
          docker exec -i torqvoice-db pg_restore -U "$DB_USER" -d "$DB_NAME" --no-owner < "$DUMP"
          echo "Restore complete."

      - name: Deploy previous tag
        run: |
          cd $HOME/torqvoice-deploy/prod
          APP_TAG=${{ inputs.tag }} docker compose up -d --pull always

      - name: Health check
        run: |
          echo "Waiting for prod container to be ready..."
          for i in $(seq 1 12); do
            STATUS=$(docker inspect --format='{{.State.Status}}' torqvoice-app 2>/dev/null || echo "not found")
            if [ "$STATUS" = "running" ]; then
              echo "Rolled back to ${{ inputs.tag }}."
              exit 0
            fi
            echo "Status: $STATUS, retrying in 5s..."
            sleep 5
          done
          echo "::error::Container failed to start after rollback"
          docker logs torqvoice-app --tail 50
          exit 1