-- B05正文版本只追加；段落身份与显式换行保留在受限文档树中。
CREATE TABLE public.muse_document (
    document_id uuid PRIMARY KEY,
    chapter_id text NOT NULL REFERENCES public.muse_chapter(chapter_id),
    branch_id text NOT NULL,
    current_revision bigint NOT NULL CHECK(current_revision>0),
    UNIQUE(chapter_id,branch_id)
);
CREATE TABLE public.muse_document_version (
    document_id uuid NOT NULL REFERENCES public.muse_document(document_id),
    revision bigint NOT NULL CHECK(revision>0),
    document jsonb NOT NULL,
    document_hash text NOT NULL,
    visible_text_hash text NOT NULL,
    author_id text NOT NULL,
    restored_from bigint,
    created_at timestamptz NOT NULL DEFAULT clock_timestamp(),
    PRIMARY KEY(document_id,revision),
    FOREIGN KEY(document_id,restored_from) REFERENCES public.muse_document_version(document_id,revision)
);
ALTER TABLE public.muse_document ADD CONSTRAINT document_current_version_fk
    FOREIGN KEY(document_id,current_revision) REFERENCES public.muse_document_version(document_id,revision)
    DEFERRABLE INITIALLY DEFERRED;

-- 作者改稿先存候选，决定记录由S01拥有；生成候选的证据绑定由后续写作任务扩展。
CREATE TABLE public.muse_writing_candidate (
    candidate_id uuid PRIMARY KEY,
    chapter_id text NOT NULL REFERENCES public.muse_chapter(chapter_id),
    branch_id text NOT NULL,
    origin text NOT NULL CHECK(origin='author'),
    current_revision bigint NOT NULL CHECK(current_revision>0)
);
CREATE TABLE public.muse_writing_candidate_version (
    candidate_id uuid NOT NULL REFERENCES public.muse_writing_candidate(candidate_id),
    revision bigint NOT NULL CHECK(revision>0),
    base_revision bigint NOT NULL CHECK(base_revision>=0),
    base_hash text NOT NULL,
    document jsonb NOT NULL,
    document_hash text NOT NULL,
    visible_text_hash text NOT NULL,
    candidate_hash text NOT NULL,
    checks jsonb NOT NULL,
    author_id text NOT NULL,
    created_at timestamptz NOT NULL DEFAULT clock_timestamp(),
    PRIMARY KEY(candidate_id,revision)
);
ALTER TABLE public.muse_writing_candidate ADD CONSTRAINT writing_candidate_version_fk
    FOREIGN KEY(candidate_id,current_revision)
    REFERENCES public.muse_writing_candidate_version(candidate_id,revision)
    DEFERRABLE INITIALLY DEFERRED;