-- Core tables for c77_rbac

CREATE TABLE public.c77_rbac_users (
                                       user_id BIGSERIAL PRIMARY KEY,
                                       username TEXT NOT NULL UNIQUE,
                                       scope_type TEXT,
                                       scope_id TEXT
);

CREATE TABLE public.c77_rbac_roles (
                                       role_id BIGSERIAL PRIMARY KEY,
                                       name TEXT NOT NULL UNIQUE
);

CREATE TABLE public.c77_rbac_user_roles (
                                            user_id BIGINT NOT NULL REFERENCES public.c77_rbac_users(user_id),
                                            role_id BIGINT NOT NULL REFERENCES public.c77_rbac_roles(role_id),
                                            scope_type TEXT,
                                            scope_id TEXT,
                                            PRIMARY KEY (user_id, role_id, scope_type, scope_id)
);

CREATE TABLE public.c77_rbac_features (
                                          feature_id BIGSERIAL PRIMARY KEY,
                                          name TEXT NOT NULL UNIQUE
);

CREATE TABLE public.c77_rbac_role_features (
                                               role_id BIGINT NOT NULL REFERENCES public.c77_rbac_roles(role_id),
                                               feature_id BIGINT NOT NULL REFERENCES public.c77_rbac_features(feature_id),
                                               PRIMARY KEY (role_id, feature_id)
);

CREATE TABLE public.c77_rbac_entities (
                                          entity_id BIGSERIAL PRIMARY KEY,
                                          entity_type TEXT NOT NULL,
                                          entity_name TEXT NOT NULL,
                                          parent_id BIGINT REFERENCES public.c77_rbac_entities(entity_id),
                                          UNIQUE (entity_type, entity_name)
);

CREATE OR REPLACE FUNCTION public.c77_rbac_assign_user(
    p_username TEXT,
    p_role_name TEXT,
    p_scope_type TEXT,
    p_scope_id TEXT
) RETURNS VOID AS $$
DECLARE
    v_user_id BIGINT;
    v_role_id BIGINT;
BEGIN
    -- Insert or get user
    INSERT INTO public.c77_rbac_users (username, scope_type, scope_id)
    VALUES (p_username, p_scope_type, p_scope_id)
    ON CONFLICT (username) DO UPDATE
        SET scope_type = EXCLUDED.scope_type,
            scope_id = EXCLUDED.scope_id
    RETURNING user_id INTO v_user_id;

    -- Insert or get role
    INSERT INTO public.c77_rbac_roles (name)
    VALUES (p_role_name)
    ON CONFLICT (name) DO NOTHING
    RETURNING role_id INTO v_role_id;

    -- If role wasn't inserted, get existing role_id
    IF v_role_id IS NULL THEN
        SELECT role_id INTO v_role_id
        FROM public.c77_rbac_roles
        WHERE name = p_role_name;
    END IF;

    -- Assign role to user with scope
    INSERT INTO public.c77_rbac_user_roles (user_id, role_id, scope_type, scope_id)
    VALUES (v_user_id, v_role_id, p_scope_type, p_scope_id)
    ON CONFLICT (user_id, role_id, scope_type, scope_id) DO NOTHING;
END;
$$ LANGUAGE plpgsql;


CREATE OR REPLACE FUNCTION public.c77_rbac_grant_feature(
    p_role_name TEXT,
    p_feature_name TEXT
) RETURNS VOID AS $$
DECLARE
    v_role_id BIGINT;
    v_feature_id BIGINT;
BEGIN
    -- Insert or get role
    INSERT INTO public.c77_rbac_roles (name)
    VALUES (p_role_name)
    ON CONFLICT (name) DO NOTHING
    RETURNING role_id INTO v_role_id;

    IF v_role_id IS NULL THEN
        SELECT role_id INTO v_role_id
        FROM public.c77_rbac_roles
        WHERE name = p_role_name;
    END IF;

    -- Insert or get feature
    INSERT INTO public.c77_rbac_features (name)
    VALUES (p_feature_name)
    ON CONFLICT (name) DO NOTHING
    RETURNING feature_id INTO v_feature_id;

    IF v_feature_id IS NULL THEN
        SELECT feature_id INTO v_feature_id
        FROM public.c77_rbac_features
        WHERE name = p_feature_name;
    END IF;

    -- Grant feature to role
    INSERT INTO public.c77_rbac_role_features (role_id, feature_id)
    VALUES (v_role_id, v_feature_id)
    ON CONFLICT (role_id, feature_id) DO NOTHING;
END;
$$ LANGUAGE plpgsql;


CREATE OR REPLACE FUNCTION public.c77_rbac_can_access(
    p_username TEXT,
    p_feature_name TEXT,
    p_scope_type TEXT DEFAULT NULL,
    p_scope_id TEXT DEFAULT NULL
) RETURNS BOOLEAN AS $$
BEGIN
    RETURN EXISTS (
        SELECT 1
        FROM public.c77_rbac_users u
                 JOIN public.c77_rbac_user_roles ur ON u.user_id = ur.user_id
                 JOIN public.c77_rbac_roles r ON ur.role_id = r.role_id
                 JOIN public.c77_rbac_role_features rf ON r.role_id = rf.role_id
                 JOIN public.c77_rbac_features f ON rf.feature_id = f.feature_id
        WHERE u.username = p_username
          AND f.name = p_feature_name
          AND (p_scope_type IS NULL OR u.scope_type = p_scope_type)
          AND (p_scope_id IS NULL OR u.scope_id = p_scope_id)
    );
END;
$$ LANGUAGE plpgsql SECURITY INVOKER;


CREATE OR REPLACE FUNCTION public.c77_rbac_get_current_user() RETURNS TEXT AS $$
BEGIN
    RETURN current_setting('c77_rbac.current_user', true);
EXCEPTION WHEN OTHERS THEN
    RETURN NULL; -- Fallback if not set
END;
$$ LANGUAGE plpgsql STABLE;


CREATE OR REPLACE FUNCTION public.c77_rbac_apply_policy(
    p_schema_name TEXT,
    p_table_name TEXT,
    p_feature_name TEXT,
    p_scope_column TEXT DEFAULT 'campus'
) RETURNS VOID AS $$
BEGIN
    SET LOCAL search_path TO public;
    RAISE NOTICE 'Enabling RLS on %.%', p_schema_name, p_table_name;
    EXECUTE format('ALTER TABLE %I.%I ENABLE ROW LEVEL SECURITY', p_schema_name, p_table_name);
    RAISE NOTICE 'Dropping existing policy on %.%', p_schema_name, p_table_name;
    EXECUTE format('DROP POLICY IF EXISTS rbac_policy ON %I.%I', p_schema_name, p_table_name);
    RAISE NOTICE 'Creating policy on %.% with feature %, scope column %', p_schema_name, p_table_name, p_feature_name, p_scope_column;
    EXECUTE format(
            'CREATE POLICY rbac_policy ON %I.%I FOR ALL TO PUBLIC USING (
                c77_rbac.can_access(c77_rbac_get_current_user(), %L, ''campus'', %I)
            )',
            p_schema_name, p_table_name, p_feature_name, p_scope_column
            );
END;
$$ LANGUAGE plpgsql;


-- Permissions for Tables
GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO PUBLIC;
GRANT USAGE, SELECT ON ALL SEQUENCES IN SCHEMA public TO PUBLIC;


-- Grant permissions on functions
GRANT EXECUTE ON FUNCTION public.c77_rbac_assign_user(TEXT, TEXT, TEXT, TEXT) TO PUBLIC;
GRANT EXECUTE ON FUNCTION public.c77_rbac_grant_feature(TEXT, TEXT) TO PUBLIC;
GRANT EXECUTE ON FUNCTION public.c77_rbac_can_access(TEXT, TEXT, TEXT, TEXT) TO PUBLIC;
GRANT EXECUTE ON FUNCTION public.c77_rbac_get_current_user() TO PUBLIC;
GRANT EXECUTE ON FUNCTION public.c77_rbac_apply_policy(TEXT, TEXT, TEXT, TEXT) TO PUBLIC;