-- Add migration script here
CREATE TYPE status AS ENUM ('pending', 'accepted', 'blocked');

CREATE TABLE relationships (
    id          SERIAL PRIMARY KEY,
    from_user   INTEGER NOT NULL REFERENCES users(id),
    to_user     INTEGER NOT NULL REFERENCES users(id),
    status      status NOT NULL DEFAULT 'pending',
    created_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    CONSTRAINT no_self_relationship CHECK (from_user != to_user),
    CONSTRAINT unique_relationship UNIQUE (from_user, to_user)
);