-- add_pages_pictures.sql
--
-- Adds the image URLs found on crawled pages to `pages.pictures`.
--
-- Purpose:
--   The crawler stores every absolute image URL of a page (img src,
--   srcset, <picture>/<source>, og:image, twitter:image, link
--   rel="image_src") in `pages.pictures`, so the search UI can offer an
--   image tab without downloading or storing the images themselves.
--
-- Run once on the jonassearch database as its owner, e.g.:
--   psql -h 127.0.0.1 -p 25432 -U jonassearch -d jonassearch \
--       -f add_pages_pictures.sql
--
-- Safe to run repeatedly (IF NOT EXISTS) and safe while the crawler is
-- running: the column is added as a nullable text[] and existing rows
-- are not rewritten. The crawler always writes an array (possibly
-- empty) from version 5 on; queries treat NULL and '{}' the same.
--
-- If the column already exists (e.g. created by an earlier schema), the
-- statement is a no-op and the stored data is left untouched.

ALTER TABLE pages ADD COLUMN IF NOT EXISTS pictures text[];

-- New rows without an explicit value get an empty array. This only
-- changes table metadata; it does not rewrite existing rows.
ALTER TABLE pages ALTER COLUMN pictures SET DEFAULT '{}';