-- v0.2.00: scholen, klassen, rollen en sessies.
-- Rollen: super (overkoepelend beheerder), admin (schoolbeheerder),
--         teacher (groepsleiding), pupil (leerling).

CREATE TABLE IF NOT EXISTS schools (
    id          BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    name        TEXT NOT NULL,
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE IF NOT EXISTS classes (
    id          BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    school_id   BIGINT NOT NULL REFERENCES schools(id) ON DELETE CASCADE,
    name        TEXT NOT NULL,
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
);

ALTER TABLE users
    ADD COLUMN IF NOT EXISTS school_id      BIGINT REFERENCES schools(id) ON DELETE CASCADE,
    ADD COLUMN IF NOT EXISTS display_name   TEXT,
    ADD COLUMN IF NOT EXISTS password_hash  TEXT,
    -- alleen voor leerlingen: wachtwoord dat groepsleiding/beheer mag inzien
    ADD COLUMN IF NOT EXISTS password_plain TEXT,
    -- eenmalige koppelcode waarmee nieuwe gebruikers hun account activeren
    ADD COLUMN IF NOT EXISTS link_code      TEXT UNIQUE,
    ADD COLUMN IF NOT EXISTS class_id       BIGINT REFERENCES classes(id) ON DELETE SET NULL,
    -- alle app-gegevens van de gebruiker (borden, thema's, eigen woorden)
    ADD COLUMN IF NOT EXISTS data           JSONB NOT NULL DEFAULT '{}'::jsonb;

-- gebruikersnaam uniek binnen een school; supers (school_id IS NULL) landelijk uniek
ALTER TABLE users DROP CONSTRAINT IF EXISTS users_username_key;
CREATE UNIQUE INDEX IF NOT EXISTS idx_users_school_username
    ON users (school_id, lower(username)) WHERE school_id IS NOT NULL;
CREATE UNIQUE INDEX IF NOT EXISTS idx_users_super_username
    ON users (lower(username)) WHERE school_id IS NULL;

-- welke groepsleiding hoort bij welke klas
CREATE TABLE IF NOT EXISTS class_teachers (
    class_id    BIGINT NOT NULL REFERENCES classes(id) ON DELETE CASCADE,
    user_id     BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    PRIMARY KEY (class_id, user_id)
);

CREATE TABLE IF NOT EXISTS sessions (
    token       TEXT PRIMARY KEY,
    user_id     BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    expires_at  TIMESTAMPTZ NOT NULL,
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
);
CREATE INDEX IF NOT EXISTS idx_sessions_user ON sessions(user_id);
CREATE INDEX IF NOT EXISTS idx_users_school ON users(school_id);
CREATE INDEX IF NOT EXISTS idx_users_class ON users(class_id);