CREATE DOMAIN sha1 AS bytea CHECK (length(value) = 20);

CREATE TABLE content (
    id     sha1    PRIMARY KEY,  -- SHA1 checksum
    length integer
);

CREATE TABLE chunk (
    id     sha1    PRIMARY KEY,  -- SHA1 checksum
    length integer
);

CREATE TYPE chunking_hash as enum ('rabin', 'buzhash');

CREATE TABLE chunking_method (
    id                  serial    PRIMARY KEY,
    hash                chunking_hash,
    min_block_size      bigint,
    average_block_size  bigint,
    hash_window_size    bigint,
);

CREATE TABLE chunked_content (
    content_id sha1    REFERENCES content(id),
    chunk_id   sha1    REFERENCES chunk(id),
    method_id  integer REFERENCES chunking_method(id),
    position   integer
);

CREATE INDEX        ON chunked_content (content_id);
CREATE INDEX        ON chunked_content (content_id);
CREATE UNIQUE INDEX ON chunked_content (content_id, chunk_id, position);