/*
 * Copyright 2020 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.
 */

#include "ProcPidDir.h"
#include "UidProcStatsCollector.h"
#include "UidProcStatsCollectorTestUtils.h"

#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <gmock/gmock.h>

#include <inttypes.h>

#include <algorithm>
#include <string>

namespace android {
namespace automotive {
namespace watchdog {

using ::android::automotive::watchdog::testing::populateProcPidDir;
using ::android::base::StringAppendF;
using ::android::base::StringPrintf;
using ::testing::UnorderedPointwise;

namespace {

MATCHER(UidProcStatsByUidEq, "") {
    const auto& actual = std::get<0>(arg);
    const auto& expected = std::get<1>(arg);
    return actual.first == expected.first &&
            ExplainMatchResult(UidProcStatsEq(expected.second), actual.second, result_listener);
}

std::string pidStatusStr(pid_t pid, uid_t uid) {
    return StringPrintf("Pid:\t%" PRIu32 "\nTgid:\t%" PRIu32 "\nUid:\t%" PRIu32 "\n", pid, pid,
                        uid);
}

std::string toString(const std::unordered_map<uid_t, UidProcStats>& uidProcStatsByUid) {
    std::string buffer;
    StringAppendF(&buffer, "Number of UIDs: %" PRIi32 "\n",
                  static_cast<int>(uidProcStatsByUid.size()));
    for (const auto& [uid, stats] : uidProcStatsByUid) {
        StringAppendF(&buffer, "{UID: %d, %s}", uid, stats.toString().c_str());
    }
    return buffer;
}

}  // namespace

TEST(UidProcStatsCollectorTest, TestValidStatFiles) {
    std::unordered_map<pid_t, std::vector<pid_t>> pidToTids = {
            {1, {1, 453}},
            {1000, {1000, 1100}},
    };

    std::unordered_map<pid_t, std::string> perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 220 0 0 0 0 0 0 0 2 0 0\n"},
            {1000, "1000 (system_server) D 1 0 0 0 0 0 0 0 600 0 0 0 0 0 0 0 2 0 13400\n"},
    };

    std::unordered_map<pid_t, std::string> perProcessStatus = {
            {1, pidStatusStr(1, 0)},
            {1000, pidStatusStr(1000, 10001234)},
    };

    std::unordered_map<pid_t, std::string> perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 2 0 0\n"},
            {453, "453 (init) D 0 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 2 0 275\n"},
            {1000, "1000 (system_server) D 1 0 0 0 0 0 0 0 250 0 0 0 0 0 0 0 2 0 13400\n"},
            {1100, "1100 (system_server) D 1 0 0 0 0 0 0 0 350 0 0 0 0 0 0 0 2 0 13900\n"},
    };

    std::unordered_map<uid_t, UidProcStats> expected =
            {{0,
              UidProcStats{.totalMajorFaults = 220,
                           .totalTasksCount = 2,
                           .ioBlockedTasksCount = 1,
                           .processStatsByPid = {{1, {"init", 0, 220, 2, 1}}}}},
             {10001234,
              UidProcStats{.totalMajorFaults = 600,
                           .totalTasksCount = 2,
                           .ioBlockedTasksCount = 2,
                           .processStatsByPid = {{1000, {"system_server", 13'400, 600, 2, 2}}}}}};

    TemporaryDir firstSnapshot;
    ASSERT_RESULT_OK(populateProcPidDir(firstSnapshot.path, pidToTids, perProcessStat,
                                        perProcessStatus, perThreadStat));

    UidProcStatsCollector collector(firstSnapshot.path);

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << firstSnapshot.path << "` are inaccessible";
    ASSERT_RESULT_OK(collector.collect());

    auto actual = collector.deltaStats();

    EXPECT_THAT(actual, UnorderedPointwise(UidProcStatsByUidEq(), expected))
            << "First snapshot doesn't match.\nExpected:\n"
            << toString(expected) << "\nActual:\n"
            << toString(actual);
    pidToTids = {
            {1, {1, 453}}, {1000, {1000, 1400}},  // TID 1100 terminated and 1400 instantiated.
    };

    perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 920 0 0 0 0 0 0 0 2 0 0\n"},
            {1000, "1000 (system_server) R 1 0 0 0 0 0 0 0 1550 0 0 0 0 0 0 0 2 0 13400\n"},
    };

    perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 600 0 0 0 0 0 0 0 2 0 0\n"},
            {453, "453 (init) S 0 0 0 0 0 0 0 0 320 0 0 0 0 0 0 0 2 0 275\n"},
            {1000, "1000 (system_server) R 1 0 0 0 0 0 0 0 600 0 0 0 0 0 0 0 2 0 13400\n"},
            // TID 1100 hits +400 major page faults before terminating. This is counted against
            // PID 1000's perProcessStat.
            {1400, "1400 (system_server) S 1 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 2 0 8977476\n"},
    };

    expected = {{0,
                 {.totalMajorFaults = 700,
                  .totalTasksCount = 2,
                  .ioBlockedTasksCount = 0,
                  .processStatsByPid = {{1, {"init", 0, 700, 2, 0}}}}},
                {10001234,
                 {.totalMajorFaults = 950,
                  .totalTasksCount = 2,
                  .ioBlockedTasksCount = 0,
                  .processStatsByPid = {{1000, {"system_server", 13'400, 950, 2, 0}}}}}};

    TemporaryDir secondSnapshot;
    ASSERT_RESULT_OK(populateProcPidDir(secondSnapshot.path, pidToTids, perProcessStat,
                                        perProcessStatus, perThreadStat));

    collector.mPath = secondSnapshot.path;

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << secondSnapshot.path << "` are inaccessible";
    ASSERT_RESULT_OK(collector.collect());

    actual = collector.deltaStats();
    EXPECT_THAT(actual, UnorderedPointwise(UidProcStatsByUidEq(), expected))
            << "Second snapshot doesn't match.\nExpected:\n"
            << toString(expected) << "\nActual:\n"
            << toString(actual);
}

TEST(UidProcStatsCollectorTest, TestHandlesProcessTerminationBetweenScanningAndParsing) {
    std::unordered_map<pid_t, std::vector<pid_t>> pidToTids = {
            {1, {1}},
            {100, {100}},          // Process terminates after scanning PID directory.
            {1000, {1000}},        // Process terminates after reading stat file.
            {2000, {2000}},        // Process terminates after scanning task directory.
            {3000, {3000, 3300}},  // TID 3300 terminates after scanning task directory.
    };

    std::unordered_map<pid_t, std::string> perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 220 0 0 0 0 0 0 0 1 0 0\n"},
            // Process 100 terminated.
            {1000, "1000 (system_server) R 1 0 0 0 0 0 0 0 600 0 0 0 0 0 0 0 1 0 1000\n"},
            {2000, "2000 (logd) R 1 0 0 0 0 0 0 0 1200 0 0 0 0 0 0 0 1 0 4567\n"},
            {3000, "3000 (disk I/O) R 1 0 0 0 0 0 0 0 10300 0 0 0 0 0 0 0 2 0 67890\n"},
    };

    std::unordered_map<pid_t, std::string> perProcessStatus = {
            {1, pidStatusStr(1, 0)},
            // Process 1000 terminated.
            {2000, pidStatusStr(2000, 10001234)},
            {3000, pidStatusStr(3000, 10001234)},
    };

    std::unordered_map<pid_t, std::string> perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 1 0 0\n"},
            // Process 2000 terminated.
            {3000, "3000 (disk I/O) R 1 0 0 0 0 0 0 0 2400 0 0 0 0 0 0 0 2 0 67890\n"},
            // TID 3300 terminated.
    };

    std::unordered_map<uid_t, UidProcStats> expected =
            {{0,
              UidProcStats{.totalMajorFaults = 220,
                           .totalTasksCount = 1,
                           .ioBlockedTasksCount = 0,
                           .processStatsByPid = {{1, {"init", 0, 220, 1, 0}}}}},
             {10001234,
              UidProcStats{.totalMajorFaults = 11500,
                           .totalTasksCount = 2,
                           .ioBlockedTasksCount = 0,
                           .processStatsByPid = {{2000, {"logd", 4567, 1200, 1, 0}},
                                                 {3000, {"disk I/O", 67890, 10'300, 1, 0}}}}}};

    TemporaryDir procDir;
    ASSERT_RESULT_OK(populateProcPidDir(procDir.path, pidToTids, perProcessStat, perProcessStatus,
                                        perThreadStat));

    UidProcStatsCollector collector(procDir.path);

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << procDir.path << "` are inaccessible";
    ASSERT_RESULT_OK(collector.collect());

    auto actual = collector.deltaStats();
    EXPECT_THAT(actual, UnorderedPointwise(UidProcStatsByUidEq(), expected))
            << "Proc pid contents doesn't match.\nExpected:\n"
            << toString(expected) << "\nActual:\n"
            << toString(actual);
}

TEST(UidProcStatsCollectorTest, TestHandlesPidTidReuse) {
    std::unordered_map<pid_t, std::vector<pid_t>> pidToTids = {
            {1, {1, 367, 453, 589}},
            {1000, {1000}},
            {2345, {2345}},
    };

    std::unordered_map<pid_t, std::string> perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 1200 0 0 0 0 0 0 0 4 0 0\n"},
            {1000, "1000 (system_server) R 1 0 0 0 0 0 0 0 250 0 0 0 0 0 0 0 1 0 1000\n"},
            {2345, "2345 (logd) R 1 0 0 0 0 0 0 0 54354 0 0 0 0 0 0 0 1 0 456\n"},
    };

    std::unordered_map<pid_t, std::string> perProcessStatus = {
            {1, pidStatusStr(1, 0)},
            {1000, pidStatusStr(1000, 10001234)},
            {2345, pidStatusStr(2345, 10001234)},
    };

    std::unordered_map<pid_t, std::string> perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 4 0 0\n"},
            {367, "367 (init) S 0 0 0 0 0 0 0 0 400 0 0 0 0 0 0 0 4 0 100\n"},
            {453, "453 (init) S 0 0 0 0 0 0 0 0 100 0 0 0 0 0 0 0 4 0 275\n"},
            {589, "589 (init) D 0 0 0 0 0 0 0 0 500 0 0 0 0 0 0 0 4 0 600\n"},
            {1000, "1000 (system_server) R 1 0 0 0 0 0 0 0 250 0 0 0 0 0 0 0 1 0 1000\n"},
            {2345, "2345 (logd) R 1 0 0 0 0 0 0 0 54354 0 0 0 0 0 0 0 1 0 456\n"},
    };

    std::unordered_map<uid_t, UidProcStats> expected =
            {{0,
              UidProcStats{.totalMajorFaults = 1200,
                           .totalTasksCount = 4,
                           .ioBlockedTasksCount = 1,
                           .processStatsByPid = {{1, {"init", 0, 1200, 4, 1}}}}},
             {10001234,
              UidProcStats{.totalMajorFaults = 54'604,
                           .totalTasksCount = 2,
                           .ioBlockedTasksCount = 0,
                           .processStatsByPid = {{1000, {"system_server", 1000, 250, 1, 0}},
                                                 {2345, {"logd", 456, 54'354, 1, 0}}}}}};

    TemporaryDir firstSnapshot;
    ASSERT_RESULT_OK(populateProcPidDir(firstSnapshot.path, pidToTids, perProcessStat,
                                        perProcessStatus, perThreadStat));

    UidProcStatsCollector collector(firstSnapshot.path);

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << firstSnapshot.path << "` are inaccessible";
    ASSERT_RESULT_OK(collector.collect());

    auto actual = collector.deltaStats();

    EXPECT_THAT(actual, UnorderedPointwise(UidProcStatsByUidEq(), expected))
            << "First snapshot doesn't match.\nExpected:\n"
            << toString(expected) << "\nActual:\n"
            << toString(actual);

    pidToTids = {
            {1, {1, 589}},       // TID 589 reused by the same process.
            {367, {367, 2000}},  // TID 367 reused as a PID. PID 2000 reused as a TID.
            // PID 1000 reused as a new PID. TID 453 reused by a different PID.
            {1000, {1000, 453}},
    };

    perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 1800 0 0 0 0 0 0 0 2 0 0\n"},
            {367, "367 (system_server) R 1 0 0 0 0 0 0 0 100 0 0 0 0 0 0 0 2 0 3450\n"},
            {1000, "1000 (logd) R 1 0 0 0 0 0 0 0 2000 0 0 0 0 0 0 0 2 0 4650\n"},
    };

    perProcessStatus = {
            {1, pidStatusStr(1, 0)},
            {367, pidStatusStr(367, 10001234)},
            {1000, pidStatusStr(1000, 10001234)},
    };

    perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 500 0 0 0 0 0 0 0 2 0 0\n"},
            {589, "589 (init) S 0 0 0 0 0 0 0 0 300 0 0 0 0 0 0 0 2 0 2345\n"},
            {367, "367 (system_server) R 1 0 0 0 0 0 0 0 50 0 0 0 0 0 0 0 2 0 3450\n"},
            {2000, "2000 (system_server) R 1 0 0 0 0 0 0 0 50 0 0 0 0 0 0 0 2 0 3670\n"},
            {1000, "1000 (logd) R 1 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 2 0 4650\n"},
            {453, "453 (logd) D 1 0 0 0 0 0 0 0 1800 0 0 0 0 0 0 0 2 0 4770\n"},
    };

    expected = {{0,
                 UidProcStats{.totalMajorFaults = 600,
                              .totalTasksCount = 2,
                              .ioBlockedTasksCount = 0,
                              .processStatsByPid = {{1, {"init", 0, 600, 2, 0}}}}},
                {10001234,
                 UidProcStats{.totalMajorFaults = 2100,
                              .totalTasksCount = 4,
                              .ioBlockedTasksCount = 1,
                              .processStatsByPid = {{367, {"system_server", 3450, 100, 2, 0}},
                                                    {1000, {"logd", 4650, 2000, 2, 1}}}}}};

    TemporaryDir secondSnapshot;
    ASSERT_RESULT_OK(populateProcPidDir(secondSnapshot.path, pidToTids, perProcessStat,
                                        perProcessStatus, perThreadStat));

    collector.mPath = secondSnapshot.path;

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << secondSnapshot.path << "` are inaccessible";
    ASSERT_RESULT_OK(collector.collect());

    actual = collector.deltaStats();

    EXPECT_THAT(actual, UnorderedPointwise(UidProcStatsByUidEq(), expected))
            << "Second snapshot doesn't match.\nExpected:\n"
            << toString(expected) << "\nActual:\n"
            << toString(actual);
}

TEST(UidProcStatsCollectorTest, TestErrorOnCorruptedProcessStatFile) {
    std::unordered_map<pid_t, std::vector<pid_t>> pidToTids = {
            {1, {1}},
    };

    std::unordered_map<pid_t, std::string> perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 CORRUPTED DATA\n"},
    };

    std::unordered_map<pid_t, std::string> perProcessStatus = {
            {1, pidStatusStr(1, 0)},
    };

    std::unordered_map<pid_t, std::string> perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 1 0 0\n"},
    };

    TemporaryDir procDir;
    ASSERT_RESULT_OK(populateProcPidDir(procDir.path, pidToTids, perProcessStat, perProcessStatus,
                                        perThreadStat));

    UidProcStatsCollector collector(procDir.path);

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << procDir.path << "` are inaccessible";
    ASSERT_FALSE(collector.collect().ok()) << "No error returned for invalid process stat file";
}

TEST(UidProcStatsCollectorTest, TestErrorOnCorruptedProcessStatusFile) {
    std::unordered_map<pid_t, std::vector<pid_t>> pidToTids = {
            {1, {1}},
    };

    std::unordered_map<pid_t, std::string> perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 1 0 0\n"},
    };

    std::unordered_map<pid_t, std::string> perProcessStatus = {
            {1, "Pid:\t1\nTgid:\t1\nCORRUPTED DATA\n"},
    };

    std::unordered_map<pid_t, std::string> perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 1 0 0\n"},
    };

    TemporaryDir procDir;
    ASSERT_RESULT_OK(populateProcPidDir(procDir.path, pidToTids, perProcessStat, perProcessStatus,
                                        perThreadStat));

    UidProcStatsCollector collector(procDir.path);

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << procDir.path << "` are inaccessible";
    ASSERT_FALSE(collector.collect().ok()) << "No error returned for invalid process status file";
}

TEST(UidProcStatsCollectorTest, TestErrorOnCorruptedThreadStatFile) {
    std::unordered_map<pid_t, std::vector<pid_t>> pidToTids = {
            {1, {1, 234}},
    };

    std::unordered_map<pid_t, std::string> perProcessStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 2 0 678\n"},
    };

    std::unordered_map<pid_t, std::string> perProcessStatus = {
            {1, pidStatusStr(1, 0)},
    };

    std::unordered_map<pid_t, std::string> perThreadStat = {
            {1, "1 (init) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 2 0 678\n"},
            {234, "234 (init) D 0 0 0 0 0 0 0 0 200 0 0 0 CORRUPTED DATA\n"},
    };

    TemporaryDir procDir;
    ASSERT_RESULT_OK(populateProcPidDir(procDir.path, pidToTids, perProcessStat, perProcessStatus,
                                        perThreadStat));

    UidProcStatsCollector collector(procDir.path);

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << procDir.path << "` are inaccessible";
    ASSERT_FALSE(collector.collect().ok()) << "No error returned for invalid thread stat file";
}

TEST(UidProcStatsCollectorTest, TestHandlesSpaceInCommName) {
    std::unordered_map<pid_t, std::vector<pid_t>> pidToTids = {
            {1, {1}},
    };

    std::unordered_map<pid_t, std::string> perProcessStat = {
            {1, "1 (random process name with space) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 1 0 0\n"},
    };

    std::unordered_map<pid_t, std::string> perProcessStatus = {
            {1, pidStatusStr(1, 0)},
    };

    std::unordered_map<pid_t, std::string> perThreadStat = {
            {1, "1 (random process name with space) S 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 1 0 0\n"},
    };

    std::unordered_map<uid_t, UidProcStats> expected = {
            {0,
             UidProcStats{.totalMajorFaults = 200,
                          .totalTasksCount = 1,
                          .ioBlockedTasksCount = 0,
                          .processStatsByPid = {
                                  {1, {"random process name with space", 0, 200, 1, 0}}}}}};

    TemporaryDir procDir;
    ASSERT_RESULT_OK(populateProcPidDir(procDir.path, pidToTids, perProcessStat, perProcessStatus,
                                        perThreadStat));

    UidProcStatsCollector collector(procDir.path);

    ASSERT_TRUE(collector.enabled())
            << "Files under the path `" << procDir.path << "` are inaccessible";
    ASSERT_RESULT_OK(collector.collect());

    auto actual = collector.deltaStats();

    EXPECT_THAT(actual, UnorderedPointwise(UidProcStatsByUidEq(), expected))
            << "Proc pid contents doesn't match.\nExpected:\n"
            << toString(expected) << "\nActual:\n"
            << toString(actual);
}

TEST(UidProcStatsCollectorTest, TestUidProcStatsCollectorContentsFromDevice) {
    UidProcStatsCollector collector;
    ASSERT_TRUE(collector.enabled()) << "/proc/[pid]/.* files are inaccessible";
    ASSERT_RESULT_OK(collector.collect());

    const auto& processStats = collector.deltaStats();

    // The below check should pass because there should be at least one process.
    EXPECT_GT(processStats.size(), 0);
}

}  // namespace watchdog
}  // namespace automotive
}  // namespace android