/*
 * Copyright 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * IptablesBaseTest.cpp - utility class for tests that use iptables
 */

#include <deque>
#include <string>
#include <vector>

#include <gtest/gtest.h>

#include <android-base/stringprintf.h>

#include "IptablesBaseTest.h"
#include "NetdConstants.h"

#define LOG_TAG "IptablesBaseTest"
#include <cutils/log.h>

IptablesBaseTest::IptablesBaseTest() {
    sCmds.clear();
    sRestoreCmds.clear();
}

int IptablesBaseTest::fake_android_fork_exec(int argc, char* argv[], int *status, bool, bool) {
    std::string cmd = argv[0];
    for (int i = 1; i < argc; i++) {
        if (argv[i] == NULL) break;  // NatController likes to pass in invalid argc values.
        cmd += " ";
        cmd += argv[i];
    }
    sCmds.push_back(cmd);
    if (status) {
        *status = 0;
    }
    return 0;
}

int IptablesBaseTest::fakeExecIptables(IptablesTarget target, ...) {
    std::string cmd = " -w";
    va_list args;
    va_start(args, target);
    const char *arg;
    do {
        arg = va_arg(args, const char *);
        if (arg != nullptr) {
            cmd += " ";
            cmd += arg;
        }
    } while (arg);

    if (target == V4 || target == V4V6) {
        sCmds.push_back(IPTABLES_PATH + cmd);
    }
    if (target == V6 || target == V4V6) {
        sCmds.push_back(IP6TABLES_PATH + cmd);
    }

    return 0;
}

FILE *IptablesBaseTest::fake_popen(const char * /* cmd */, const char *type) {
    if (sPopenContents.empty() || strcmp(type, "r") != 0) {
        return NULL;
    }

    std::string realCmd = android::base::StringPrintf("echo '%s'", sPopenContents.front().c_str());
    sPopenContents.pop_front();
    return popen(realCmd.c_str(), "r");
}

int IptablesBaseTest::fakeExecIptablesRestore(IptablesTarget target, const std::string& commands) {
    sRestoreCmds.push_back({ target, commands });
    return 0;
}

int IptablesBaseTest::expectIptablesCommand(IptablesTarget target, int pos,
                                            const std::string& cmd) {

    if ((unsigned) pos >= sCmds.size()) {
        ADD_FAILURE() << "Expected too many iptables commands, want command "
               << pos + 1 << "/" << sCmds.size();
        return -1;
    }

    if (target == V4 || target == V4V6) {
        EXPECT_EQ("/system/bin/iptables -w " + cmd, sCmds[pos++]);
    }
    if (target == V6 || target == V4V6) {
        EXPECT_EQ("/system/bin/ip6tables -w " + cmd, sCmds[pos++]);
    }

    return target == V4V6 ? 2 : 1;
}

void IptablesBaseTest::expectIptablesCommands(const std::vector<std::string>& expectedCmds) {
    ExpectedIptablesCommands expected;
    for (auto cmd : expectedCmds) {
        expected.push_back({ V4V6, cmd });
    }
    expectIptablesCommands(expected);
}

void IptablesBaseTest::expectIptablesCommands(const ExpectedIptablesCommands& expectedCmds) {
    size_t pos = 0;
    for (size_t i = 0; i < expectedCmds.size(); i ++) {
        auto target = expectedCmds[i].first;
        auto cmd = expectedCmds[i].second;
        int numConsumed = expectIptablesCommand(target, pos, cmd);
        if (numConsumed < 0) {
            // Read past the end of the array.
            break;
        }
        pos += numConsumed;
    }

    EXPECT_EQ(pos, sCmds.size());
    sCmds.clear();
}

void IptablesBaseTest::expectIptablesCommands(
        const std::vector<ExpectedIptablesCommands>& snippets) {
    ExpectedIptablesCommands expected;
    for (const auto& snippet: snippets) {
        expected.insert(expected.end(), snippet.begin(), snippet.end());
    }
    expectIptablesCommands(expected);
}

void IptablesBaseTest::expectIptablesRestoreCommands(const std::vector<std::string>& expectedCmds) {
    ExpectedIptablesCommands expected;
    for (auto cmd : expectedCmds) {
        expected.push_back({ V4V6, cmd });
    }
    expectIptablesRestoreCommands(expected);
}

void IptablesBaseTest::expectIptablesRestoreCommands(const ExpectedIptablesCommands& expectedCmds) {
    EXPECT_EQ(expectedCmds.size(), sRestoreCmds.size());
    for (size_t i = 0; i < expectedCmds.size(); i++) {
        EXPECT_EQ(expectedCmds[i], sRestoreCmds[i]) <<
            "iptables-restore command " << i << " differs";
    }
    sRestoreCmds.clear();
}

std::vector<std::string> IptablesBaseTest::sCmds = {};
IptablesBaseTest::ExpectedIptablesCommands IptablesBaseTest::sRestoreCmds = {};
std::deque<std::string> IptablesBaseTest::sPopenContents = {};