CREATE TABLE app_user (
    id            BIGINT       GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
    username      VARCHAR(64)  NOT NULL,
    password_hash VARCHAR(100) NOT NULL,
    role          VARCHAR(16)  NOT NULL,
    created_at    TIMESTAMP    NOT NULL,
    CONSTRAINT uq_app_user_username UNIQUE (username)
);

CREATE TABLE resource (
    id          BIGINT       GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
    name        VARCHAR(128) NOT NULL,
    description VARCHAR(512),
    created_at  TIMESTAMP    NOT NULL,
    version     BIGINT       NOT NULL DEFAULT 0
);

CREATE TABLE reservation (
    id          BIGINT      GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
    resource_id BIGINT      NOT NULL,
    user_id     BIGINT      NOT NULL,
    start_time  TIMESTAMP   NOT NULL,
    end_time    TIMESTAMP   NOT NULL,
    status      VARCHAR(16) NOT NULL,
    created_at  TIMESTAMP   NOT NULL,
    version     BIGINT      NOT NULL DEFAULT 0,
    CONSTRAINT fk_reservation_resource FOREIGN KEY (resource_id) REFERENCES resource (id),
    CONSTRAINT fk_reservation_user FOREIGN KEY (user_id) REFERENCES app_user (id)
);

CREATE INDEX idx_reservation_resource_status ON reservation (resource_id, status);
CREATE INDEX idx_reservation_user ON reservation (user_id);