CREATE TABLE IF NOT EXISTS tenants (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL,
    timezone TEXT NOT NULL DEFAULT 'Europe/Berlin',
    is_active INTEGER NOT NULL DEFAULT 1,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
);

CREATE TABLE IF NOT EXISTS users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    tenant_id INTEGER NULL,
    role TEXT NOT NULL,
    email TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    first_name TEXT NOT NULL,
    last_name TEXT NOT NULL,
    is_active INTEGER NOT NULL DEFAULT 1,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    FOREIGN KEY (tenant_id) REFERENCES tenants (id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS instructors (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    tenant_id INTEGER NOT NULL,
    first_name TEXT NOT NULL,
    last_name TEXT NOT NULL,
    color TEXT NOT NULL,
    notes TEXT DEFAULT '',
    is_active INTEGER NOT NULL DEFAULT 1,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    FOREIGN KEY (tenant_id) REFERENCES tenants (id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS lesson_types (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    tenant_id INTEGER NOT NULL,
    name TEXT NOT NULL,
    color TEXT NOT NULL,
    default_duration INTEGER NOT NULL,
    category TEXT NOT NULL,
    requirement_key TEXT DEFAULT NULL,
    is_billable INTEGER NOT NULL DEFAULT 0,
    is_counted INTEGER NOT NULL DEFAULT 0,
    is_rest_relevant INTEGER NOT NULL DEFAULT 0,
    fixed_duration INTEGER NOT NULL DEFAULT 0,
    sort_order INTEGER NOT NULL DEFAULT 0,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    FOREIGN KEY (tenant_id) REFERENCES tenants (id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS license_class_templates (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    tenant_id INTEGER NOT NULL,
    code TEXT NOT NULL,
    name TEXT NOT NULL,
    is_combination INTEGER NOT NULL DEFAULT 0,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    UNIQUE (tenant_id, code),
    FOREIGN KEY (tenant_id) REFERENCES tenants (id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS license_template_requirements (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    template_id INTEGER NOT NULL,
    requirement_key TEXT NOT NULL,
    label TEXT NOT NULL,
    required_units INTEGER NOT NULL,
    sort_order INTEGER NOT NULL DEFAULT 0,
    FOREIGN KEY (template_id) REFERENCES license_class_templates (id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS students (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    tenant_id INTEGER NOT NULL,
    template_id INTEGER NOT NULL,
    first_name TEXT NOT NULL,
    last_name TEXT NOT NULL,
    phone TEXT DEFAULT '',
    notes TEXT DEFAULT '',
    status TEXT NOT NULL DEFAULT 'active',
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    FOREIGN KEY (tenant_id) REFERENCES tenants (id) ON DELETE CASCADE,
    FOREIGN KEY (template_id) REFERENCES license_class_templates (id)
);

CREATE TABLE IF NOT EXISTS student_requirement_snapshots (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    student_id INTEGER NOT NULL,
    requirement_key TEXT NOT NULL,
    label TEXT NOT NULL,
    required_units INTEGER NOT NULL,
    sort_order INTEGER NOT NULL DEFAULT 0,
    FOREIGN KEY (student_id) REFERENCES students (id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS appointments (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    tenant_id INTEGER NOT NULL,
    student_id INTEGER DEFAULT NULL,
    instructor_id INTEGER NOT NULL,
    lesson_type_id INTEGER NOT NULL,
    title TEXT NOT NULL,
    category TEXT NOT NULL,
    start_at TEXT NOT NULL,
    end_at TEXT NOT NULL,
    units INTEGER NOT NULL DEFAULT 1,
    status TEXT NOT NULL DEFAULT 'planned',
    notes TEXT DEFAULT '',
    warning_acknowledged INTEGER NOT NULL DEFAULT 0,
    created_by INTEGER NOT NULL,
    updated_by INTEGER NOT NULL,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    FOREIGN KEY (tenant_id) REFERENCES tenants (id) ON DELETE CASCADE,
    FOREIGN KEY (student_id) REFERENCES students (id) ON DELETE SET NULL,
    FOREIGN KEY (instructor_id) REFERENCES instructors (id),
    FOREIGN KEY (lesson_type_id) REFERENCES lesson_types (id),
    FOREIGN KEY (created_by) REFERENCES users (id),
    FOREIGN KEY (updated_by) REFERENCES users (id)
);

CREATE TABLE IF NOT EXISTS appointment_units (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    appointment_id INTEGER NOT NULL,
    requirement_key TEXT DEFAULT NULL,
    label TEXT DEFAULT NULL,
    units_counted INTEGER NOT NULL DEFAULT 0,
    created_at TEXT NOT NULL,
    FOREIGN KEY (appointment_id) REFERENCES appointments (id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS settings (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    tenant_id INTEGER NOT NULL,
    key_name TEXT NOT NULL,
    value TEXT NOT NULL,
    UNIQUE (tenant_id, key_name),
    FOREIGN KEY (tenant_id) REFERENCES tenants (id) ON DELETE CASCADE
);