// Copyright (C) 2013-2021 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef COMMON_HOOKS_TEST_CLASS_H
#define COMMON_HOOKS_TEST_CLASS_H

#include <hooks/callout_handle.h>
#include <hooks/callout_manager.h>
#include <hooks/server_hooks.h>
#include <hooks/tests/marker_file.h>

#include <boost/shared_ptr.hpp>
#include <gtest/gtest.h>

/// @brief Common hooks test class
///
/// This class is a shared parent of the test fixture class in the tests of the
/// higher-level hooks classes (LibraryManager, LibraryManagerCollection and
/// HooksManager).  It
///
/// - sets the ServerHooks object with three hooks and stores their
///   indexes.
/// - executes the callouts (which are assumed to perform a calculation)
///   and checks the results.

class HooksCommonTestClass {
public:
    /// @brief Constructor
    HooksCommonTestClass() {

        // Set up the server hooks.  ServerHooks is a singleton, so we reset it
        // between each test.
        isc::hooks::ServerHooks& hooks =
            isc::hooks::ServerHooks::getServerHooks();
        hooks.reset();
        hookpt_one_index_ = hooks.registerHook("hookpt_one");
        hookpt_two_index_ = hooks.registerHook("hookpt_two");
        hookpt_three_index_ = hooks.registerHook("hookpt_three");
    }

    /// @brief Call callouts test
    ///
    /// All of the loaded libraries for which callouts are called register four
    /// callouts: a context_create callout and three callouts that are attached
    /// to hooks hookpt_one, hookpt_two and hookpt_three.  These four callouts,
    /// executed in sequence, perform a series of calculations. Data is passed
    /// between callouts in the argument list, in a variable named "result".
    ///
    /// context_create initializes the calculation by setting a seed
    /// value, called r0 here.  This value is dependent on the library being
    /// loaded.  Prior to that, the argument "result" is initialized to -1,
    /// the purpose being to avoid exceptions when running this test with no
    /// libraries loaded.
    ///
    /// Callout hookpt_one is passed a value d1 and performs a simple arithmetic
    /// operation on it and r0 yielding a result r1.  Hence we can say that
    /// @f[ r1 = hookpt_one(r0, d1) @f]
    ///
    /// Callout hookpt_two is passed a value d2 and performs another simple
    /// arithmetic operation on it and d2, yielding r2, i.e.
    /// @f[ r2 = hookpt_two(d1, d2) @f]
    ///
    /// hookpt_three does a similar operation giving
    /// @f[ r3 = hookpt_three(r2, d3) @f].
    ///
    /// The details of the operations hookpt_one, hookpt_two and hookpt_three
    /// depend on the library, so the results obtained not only depend on
    /// the data, but also on the library loaded.  This method is passed both
    /// data and expected results.  It executes the three callouts in sequence,
    /// checking the intermediate and final results.  Only if the expected
    /// library has been loaded correctly and the callouts in it registered
    /// correctly will be the results be as expected.
    ///
    /// It is assumed that callout_manager_ has been set up appropriately.
    ///
    /// @note The CalloutHandle used in the calls is declared locally here.
    ///       The advantage of this (apart from scope reduction) is that on
    ///       exit, it is destroyed.  This removes any references to memory
    ///       allocated by loaded libraries while they are still loaded.
    ///
    /// @param manager CalloutManager to use for the test
    /// @param r0...r3, d1..d3 Data (dN) and expected results (rN) - both
    ///        intermediate and final.  The arguments are ordered so that they
    ///        appear in the argument list in the order they are used.
    void executeCallCallouts(
            const boost::shared_ptr<isc::hooks::CalloutManager>& manager,
            int r0, int d1, int r1, int d2, int r2, int d3, int r3) {
        static const char* COMMON_TEXT = " callout returned the wrong value";
        static const char* RESULT = "result";

        int result;

        // Set up a callout handle for the calls.
        isc::hooks::CalloutHandle handle(manager);

        // Initialize the argument RESULT.  This simplifies testing by
        // eliminating the generation of an exception when we try the unload
        // test.  In that case, RESULT is unchanged.
        handle.setArgument(RESULT, -1);

        // Seed the calculation.
        manager->callCallouts(isc::hooks::ServerHooks::CONTEXT_CREATE, handle);
        handle.getArgument(RESULT, result);
        EXPECT_EQ(r0, result) << "context_create" << COMMON_TEXT;

        // Perform the first calculation.
        handle.setArgument("data_1", d1);
        manager->callCallouts(hookpt_one_index_, handle);
        handle.getArgument(RESULT, result);
        EXPECT_EQ(r1, result) << "hookpt_one" << COMMON_TEXT;

        // ... the second ...
        handle.setArgument("data_2", d2);
        manager->callCallouts(hookpt_two_index_, handle);
        handle.getArgument(RESULT, result);
        EXPECT_EQ(r2, result) << "hookpt_two" << COMMON_TEXT;

        // ... and the third.
        handle.setArgument("data_3", d3);
        manager->callCallouts(hookpt_three_index_, handle);
        handle.getArgument(RESULT, result);
        EXPECT_EQ(r3, result) << "hookpt_three" << COMMON_TEXT;
    }

    /// @brief Call command handlers test.
    ///
    /// This test is similar to @c executeCallCallouts but it uses
    /// @ref CalloutManager::callCommandHandlers to execute the command
    /// handlers for the following commands: 'command-one' and 'command-two'.
    ///
    /// @param manager CalloutManager to use for the test
    /// @param r1..r2, d1..d2 Data (dN) and expected results (rN).
    void executeCallCommandHandlers(
             const boost::shared_ptr<isc::hooks::CalloutManager>& manager,
             int d1, int r1, int d2, int r2) {
        static const char* COMMON_TEXT = " command handler returned the wrong value";
        static const char* RESULT = "result";

        int result;

        // Set up a callout handle for the calls.
        isc::hooks::CalloutHandle handle(manager);

        // Initialize the argument RESULT.  This simplifies testing by
        // eliminating the generation of an exception when we try the unload
        // test.  In that case, RESULT is unchanged.
        handle.setArgument(RESULT, -1);

        // Perform the first calculation: it should assign the data to the
        // result.
        handle.setArgument("data_1", d1);
        manager->callCommandHandlers("command-one", handle);
        handle.getArgument(RESULT, result);
        EXPECT_EQ(r1, result) << "command-one" << COMMON_TEXT;

        // Perform the second calculation: it should multiply the data by 10
        // and return in the result.
        handle.setArgument("data_2", d2);
        manager->callCommandHandlers("command-two", handle);
        handle.getArgument(RESULT, result);
        EXPECT_EQ(r2, result) << "command-two" << COMMON_TEXT;
    }


    /// Hook indexes.  These are are made public for ease of reference.
    int hookpt_one_index_;
    int hookpt_two_index_;
    int hookpt_three_index_;
};

#endif // COMMON_HOOKS_TEST_CLASS_H