-- Posts are public quotes pulled from the knowledgebase. Each carries the
-- selected text verbatim as its caption (immutable after create) plus a link
-- back to the source URL the user was reading. Optional images are stored in
-- the `post_images` table, one row per image, ordered by `position`.
--
-- Posts are always public — visibility is a per-user concern (the user's
-- /u/<handle> feed), not a per-post one. Private saves should use bookmarks.
CREATE TABLE IF NOT EXISTS posts (
    id            UUID         PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id       UUID         NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    caption       TEXT         NOT NULL,
    source_url    TEXT         NOT NULL,
    source_title  VARCHAR(200),
    created_at    TIMESTAMPTZ  NOT NULL DEFAULT now(),
    updated_at    TIMESTAMPTZ  NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS posts_user_created_idx
    ON posts (user_id, created_at DESC);

CREATE TABLE IF NOT EXISTS post_images (
    id          UUID         PRIMARY KEY DEFAULT gen_random_uuid(),
    post_id     UUID         NOT NULL REFERENCES posts(id) ON DELETE CASCADE,
    url         TEXT         NOT NULL,
    position    INT          NOT NULL DEFAULT 0,
    created_at  TIMESTAMPTZ  NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS post_images_post_idx
    ON post_images (post_id, position);