/* Copyright (c) 2020 Contrast Security, Inc.  See
 * https://www.contrastsecurity.com/enduser-terms-0317a for more details. */

#include "cs__assess_module.h"
#include "../cs__common/cs__common.h"
#include <ruby.h>

void contrast_assess_eval_trigger_check(VALUE module, VALUE source, VALUE ret) {
    VALUE has_trigger_check = rb_respond_to(module, trigger_check_method);

    if (RTEST(
            rb_funcall(contrast_patcher(), rb_sym_skip_contrast_analysis, 0))) {
        return;
    }

    int nested_scope =
        RTEST(rb_funcall(contrast_patcher(), rb_sym_in_scope, 0));

    rb_funcall(contrast_patcher(), rb_sym_enter_scope, 0);

    if (!nested_scope && has_trigger_check) {
        VALUE method = rb_funcall(rb_mKernel, rb_sym_method, 0);
        /* If this method ever throws an exception, the scope-leave
         * needs to be moved within a rescue call.
         */
        rb_funcall(module, trigger_check_method, 3, source, ret, method);
    }

    rb_funcall(contrast_patcher(), rb_sym_exit_scope, 0);
}

VALUE
contrast_assess_module_class_eval(const int argc, const VALUE *argv,
                                  const VALUE mod) {
    VALUE ret = rb_mod_module_eval(argc, argv, mod);

    if (argc > 0) {
        VALUE data = argv[0];
        contrast_assess_eval_trigger_check(mod, data, ret);
    }
    rb_funcall(assess_patcher, rb_sym_assess_patch_eval, 1, mod);

    return ret;
}

VALUE
contrast_assess_module_module_eval(const int argc, const VALUE *argv,
                                   const VALUE mod) {
    VALUE ret = rb_mod_module_eval(argc, argv, mod);

    if (argc > 0) {
        VALUE data = argv[0];
        contrast_assess_eval_trigger_check(mod, data, ret);
    }

    rb_funcall(assess_patcher, rb_sym_assess_patch_eval, 1, mod);

    return ret;
}

void Init_cs__assess_module(void) {
    rb_sym_assess_patch_eval = rb_intern("patch_assess_on_eval");

    VALUE assess_policy = rb_define_module_under(assess, "Policy");
    assess_patcher = rb_define_module_under(assess_policy, "Patcher");

    trigger_check_method = rb_intern("eval_trigger_check");

    contrast_alias_method(rb_cModule, "cs__patched_class_eval", "class_eval");

    rb_define_method(rb_cModule, "class_eval",
                     contrast_assess_module_class_eval, -1);

    contrast_alias_method(rb_cModule, "cs__patched_module_eval", "module_eval");

    rb_define_method(rb_cModule, "module_eval",
                     contrast_assess_module_module_eval, -1);
}