#include "AutoDmp.h"
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <chrono>
#include <algorithm>
#include <vector>
#include <cstring>
#include <ctime>
#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <dlfcn.h>

// 静态成员初始化
AutoDmp* AutoDmp::instance_ = nullptr;

// Linux 信号处理列表
const int AutoDmp::handledSignals_[] = {
    SIGSEGV,  // 段错误
    SIGABRT,  // 异常终止
    SIGFPE,   // 浮点异常
    SIGILL,   // 非法指令
    SIGBUS,   // 总线错误
    SIGSYS,   // 系统调用错误
    SIGPIPE,  // 管道错误
    SIGQUIT   // 退出信号
};

const size_t AutoDmp::handledSignalCount_ = sizeof(handledSignals_) / sizeof(handledSignals_[0]);

// 构造函数
AutoDmp::AutoDmp(const CrashConfig& config) : config_(config) {
    if (instance_ == nullptr) {
        instance_ = this;
        if (initializeHandlers()) {
            initialized_.store(true);
        }
    }
}

// 析构函数
AutoDmp::~AutoDmp() {
    if (instance_ == this) {
        cleanupHandlers();
        instance_ = nullptr;
        initialized_.store(false);
    }
}

// Linux 信号处理器
void AutoDmp::signalHandler(int sig, siginfo_t* info, void* context) {
    // 防止重入
    static volatile sig_atomic_t handling = 0;
    if (handling || !instance_ || instance_->crashInProgress_.exchange(true)) {
        return;
    }
    handling = 1;

    const CrashConfig* config = getInstanceConfig();
    if (!config) {
        // 恢复默认处理并重新触发
        signal(sig, SIG_DFL);
        raise(sig);
        return;
    }

    // 使用异步安全的方式输出基本信息
    if (config->enableConsoleOutput) {
        safeWriteToFd(STDERR_FILENO, "\n*** LINUX CRASH DETECTED ***\n");
        safeWriteToFd(STDERR_FILENO, "Signal: ");
        safeWriteNumber(STDERR_FILENO, sig);
        safeWriteToFd(STDERR_FILENO, " (");
        safeWriteToFd(STDERR_FILENO, getSignalName(sig).c_str());
        safeWriteToFd(STDERR_FILENO, ")\n");

        if (info->si_addr) {
            safeWriteToFd(STDERR_FILENO, "Fault Address: ");
            safeWritePointer(STDERR_FILENO, info->si_addr);
            safeWriteToFd(STDERR_FILENO, "\n");
        }

        safeWriteToFd(STDERR_FILENO, "Process ID: ");
        safeWriteNumber(STDERR_FILENO, getpid());
        safeWriteToFd(STDERR_FILENO, "\n");

        safeWriteToFd(STDERR_FILENO, "Thread ID: ");
        safeWriteNumber(STDERR_FILENO, syscall(SYS_gettid));
        safeWriteToFd(STDERR_FILENO, "\n");

        // 输出调用栈到stderr（异步安全）
        if (config->enableBacktrace) {
            safeWriteToFd(STDERR_FILENO, "\nBacktrace:\n");
            void* frames[128];
            int numFrames = backtrace(frames, 128);
            if (numFrames > 0) {
                backtrace_symbols_fd(frames, numFrames, STDERR_FILENO);
            }
        }

        safeWriteToFd(STDERR_FILENO, "****************************\n\n");
    }

    // 设置 core dump
    if (config->enableCoreDump) {
        setupCoreDump();
    }

    // 恢复默认信号处理并重新触发
    struct sigaction sa;
    sa.sa_handler = SIG_DFL;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;
    sigaction(sig, &sa, nullptr);

    // 如果不是在异步安全模式，尝试写入详细日志
    if (!config->asyncSafeOnly) {
        try {
            // 收集详细崩溃信息
            CrashInfo crashInfo;
            crashInfo.timestamp = getCurrentTimestamp();
            crashInfo.processName = getProcessName();
            crashInfo.processId = getpid();
            crashInfo.threadId = syscall(SYS_gettid);
            crashInfo.buildInfo = std::string(__DATE__) + " " + __TIME__;
            crashInfo.signalNumber = sig;
            crashInfo.signalName = getSignalName(sig);
            crashInfo.faultAddress = info->si_addr;
            crashInfo.signalDescription = getSignalDescription(sig, info);
            crashInfo.backtrace = getBacktrace(context, config->maxBacktraceDepth);

            // 确保目录存在
            createDirectory(config->crashDirectory);

            // 写入详细日志
            if (config->enableLogFile) {
                std::string logFileName = "crash_" + crashInfo.timestamp + ".log";
                std::string logPath = config->crashDirectory + "/" + logFileName;
                writeCrashLog(crashInfo, logPath);
                cleanupOldFiles(config->crashDirectory, config->maxCrashFiles);
            }

            // 输出详细信息到控制台
            if (config->enableDetailedInfo && config->enableConsoleOutput) {
                outputDetailedInfo(crashInfo);
            }
        } catch (...) {
            // 在信号处理器中不抛出异常
            safeWriteToFd(STDERR_FILENO, "Warning: Failed to write detailed crash log\n");
        }
    }

    // 触发默认处理（生成core dump并终止进程）
    raise(sig);
}

// 异步安全的写入函数
void AutoDmp::safeWriteToFd(int fd, const char* msg) {
    if (msg) {
        size_t len = strlen(msg);
        write(fd, msg, len);
    }
}

void AutoDmp::safeWriteNumber(int fd, long number) {
    char buffer[32];
    char* p = buffer + sizeof(buffer) - 1;
    *p = '\0';

    bool negative = number < 0;
    if (negative) number = -number;

    if (number == 0) {
        *--p = '0';
    } else {
        while (number > 0) {
            *--p = '0' + (number % 10);
            number /= 10;
        }
    }

    if (negative) {
        *--p = '-';
    }

    safeWriteToFd(fd, p);
}

void AutoDmp::safeWritePointer(int fd, void* ptr) {
    char buffer[32];
    snprintf(buffer, sizeof(buffer), "%p", ptr);
    safeWriteToFd(fd, buffer);
}

// 获取调用栈
std::string AutoDmp::getBacktrace(void* context, size_t maxDepth) {
    void* frames[maxDepth];
    int numFrames = backtrace(frames, maxDepth);

    if (numFrames <= 0) {
        return "Unable to get backtrace";
    }

    // 获取符号信息
    char** symbols = backtrace_symbols(frames, numFrames);
    if (!symbols) {
        return "Unable to get symbol information";
    }

    std::ostringstream oss;
    for (int i = 0; i < numFrames; ++i) {
        oss << "#" << std::setw(2) << std::setfill('0') << i
            << ": " << symbols[i] << "\n";
    }

    free(symbols);
    return oss.str();
}

// 设置 core dump
bool AutoDmp::setupCoreDump() {
    struct rlimit coreLimit;
    coreLimit.rlim_cur = RLIM_INFINITY;
    coreLimit.rlim_max = RLIM_INFINITY;

    return setrlimit(RLIMIT_CORE, &coreLimit) == 0;
}

// 获取信号名
std::string AutoDmp::getSignalName(int sig) {
    switch (sig) {
        case SIGSEGV: return "SIGSEGV";
        case SIGABRT: return "SIGABRT";
        case SIGFPE:  return "SIGFPE";
        case SIGILL:  return "SIGILL";
        case SIGBUS:  return "SIGBUS";
        case SIGSYS:  return "SIGSYS";
        case SIGPIPE: return "SIGPIPE";
        case SIGQUIT: return "SIGQUIT";
        default:      return "UNKNOWN";
    }
}

// 获取信号描述
std::string AutoDmp::getSignalDescription(int sig, siginfo_t* info) {
    std::ostringstream oss;
    oss << getSignalName(sig) << " - ";

    switch (sig) {
        case SIGSEGV:
            oss << "Segmentation fault";
            if (info) {
                switch (info->si_code) {
                    case SEGV_MAPERR: oss << " (address not mapped)"; break;
                    case SEGV_ACCERR: oss << " (invalid permissions)"; break;
                    default: break;
                }
            }
            break;
        case SIGABRT:
            oss << "Abort signal";
            break;
        case SIGFPE:
            oss << "Floating point exception";
            if (info) {
                switch (info->si_code) {
                    case FPE_INTDIV: oss << " (integer divide by zero)"; break;
                    case FPE_INTOVF: oss << " (integer overflow)"; break;
                    case FPE_FLTDIV: oss << " (floating point divide by zero)"; break;
                    case FPE_FLTOVF: oss << " (floating point overflow)"; break;
                    case FPE_FLTUND: oss << " (floating point underflow)"; break;
                    case FPE_FLTRES: oss << " (floating point inexact result)"; break;
                    case FPE_FLTINV: oss << " (floating point invalid operation)"; break;
                    default: break;
                }
            }
            break;
        case SIGILL:
            oss << "Illegal instruction";
            if (info) {
                switch (info->si_code) {
                    case ILL_ILLOPC: oss << " (illegal opcode)"; break;
                    case ILL_ILLOPN: oss << " (illegal operand)"; break;
                    case ILL_ILLADR: oss << " (illegal addressing mode)"; break;
                    case ILL_ILLTRP: oss << " (illegal trap)"; break;
                    default: break;
                }
            }
            break;
        case SIGBUS:
            oss << "Bus error";
            if (info) {
                switch (info->si_code) {
                    case BUS_ADRALN: oss << " (invalid address alignment)"; break;
                    case BUS_ADRERR: oss << " (non-existent physical address)"; break;
                    case BUS_OBJERR: oss << " (object specific hardware error)"; break;
                    default: break;
                }
            }
            break;
        case SIGSYS:
            oss << "Bad system call";
            break;
        case SIGPIPE:
            oss << "Broken pipe";
            break;
        case SIGQUIT:
            oss << "Quit signal";
            break;
        default:
            oss << "Unknown signal (" << sig << ")";
            break;
    }

    return oss.str();
}

// 获取当前时间戳
std::string AutoDmp::getCurrentTimestamp() {
    auto now = std::chrono::system_clock::now();
    auto time_t = std::chrono::system_clock::to_time_t(now);
    auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(
        now.time_since_epoch()) % 1000;

    std::tm* tm = std::localtime(&time_t);
    std::ostringstream oss;
    oss << std::put_time(tm, "%Y%m%d-%H%M%S")
        << "." << std::setfill('0') << std::setw(3) << ms.count();
    return oss.str();
}

// 获取进程名
std::string AutoDmp::getProcessName() {
    std::string processName = "Unknown";
    char buffer[PATH_MAX];
    ssize_t len = readlink("/proc/self/exe", buffer, sizeof(buffer) - 1);
    if (len > 0) {
        buffer[len] = '\0';
        std::string fullPath = buffer;
        size_t pos = fullPath.find_last_of('/');
        if (pos != std::string::npos) {
            processName = fullPath.substr(pos + 1);
        }
    }
    return processName;
}

// 创建目录
bool AutoDmp::createDirectory(const std::string& path) {
    if (path.empty()) return false;
    return (mkdir(path.c_str(), 0755) == 0) || (errno == EEXIST);
}

// 清理旧文件
void AutoDmp::cleanupOldFiles(const std::string& directory, size_t maxFiles) {
    if (maxFiles == 0) return;

    std::vector<std::pair<std::string, std::time_t>> files;

    DIR* dir = opendir(directory.c_str());
    if (dir) {
        struct dirent* entry;
        while ((entry = readdir(dir)) != nullptr) {
            std::string filename = entry->d_name;
            if (filename.find("crash_") == 0 && filename.find(".log") != std::string::npos) {
                std::string fullPath = directory + "/" + filename;
                struct stat fileStat;
                if (stat(fullPath.c_str(), &fileStat) == 0) {
                    files.emplace_back(fullPath, fileStat.st_mtime);
                }
            }
        }
        closedir(dir);
    }

    // 按时间排序，最新的在前
    std::sort(files.begin(), files.end(),
              [](const auto& a, const auto& b) { return a.second > b.second; });

    // 删除超过限制的文件
    for (size_t i = maxFiles; i < files.size(); ++i) {
        std::remove(files[i].first.c_str());
    }
}

// 写入崩溃日志
void AutoDmp::writeCrashLog(const CrashInfo& crashInfo, const std::string& filePath) {
    std::ofstream logFile(filePath, std::ios::app);
    if (!logFile.is_open()) return;

    logFile << "==================== LINUX CRASH REPORT ====================\n";
    logFile << "Timestamp: " << crashInfo.timestamp << "\n";
    logFile << "Process: " << crashInfo.processName << " (PID: " << crashInfo.processId << ")\n";
    logFile << "Thread ID: " << crashInfo.threadId << "\n";
    logFile << "Build Info: " << crashInfo.buildInfo << "\n";
    logFile << "Signal: " << crashInfo.signalName << " (" << crashInfo.signalNumber << ")\n";
    logFile << "Signal Description: " << crashInfo.signalDescription << "\n";
    logFile << "Fault Address: " << crashInfo.faultAddress << "\n";
    logFile << "\nDetailed Backtrace:\n";
    logFile << crashInfo.backtrace << "\n";
    logFile << "============================================================\n\n";
    logFile.close();
}

// 输出详细信息
void AutoDmp::outputDetailedInfo(const CrashInfo& crashInfo) {
    std::cerr << "\n========== DETAILED CRASH INFORMATION ==========\n";
    std::cerr << "Timestamp: " << crashInfo.timestamp << "\n";
    std::cerr << "Process: " << crashInfo.processName << " (PID: " << crashInfo.processId << ")\n";
    std::cerr << "Thread: " << crashInfo.threadId << "\n";
    std::cerr << "Build: " << crashInfo.buildInfo << "\n";
    std::cerr << "Signal: " << crashInfo.signalDescription << "\n";
    std::cerr << "Address: " << crashInfo.faultAddress << "\n";
    std::cerr << "\nBacktrace:\n" << crashInfo.backtrace;
    std::cerr << "===============================================\n\n";
}

// 初始化处理器
bool AutoDmp::initializeHandlers() {
    if (!createDirectory(config_.crashDirectory)) {
        return false;
    }

    // 设置 core dump
    if (config_.enableCoreDump) {
        setupCoreDump();
    }

    // 安装信号处理器
    struct sigaction sa;
    sa.sa_sigaction = signalHandler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_SIGINFO | SA_RESTART;

    bool success = true;
    for (size_t i = 0; i < handledSignalCount_; ++i) {
        if (sigaction(handledSignals_[i], &sa, &oldActions_[i]) != 0) {
            success = false;
        }
    }

    return success;
}

// 清理处理器
void AutoDmp::cleanupHandlers() {
    for (size_t i = 0; i < handledSignalCount_; ++i) {
        sigaction(handledSignals_[i], &oldActions_[i], nullptr);
    }
}

// 获取实例配置
const CrashConfig* AutoDmp::getInstanceConfig() {
    return instance_ ? &instance_->config_ : nullptr;
}

// 生成测试崩溃
bool AutoDmp::generateTestCrash() const {
    if (!initialized_.load()) {
        return false;
    }

    // 触发一个安全的测试信号
    raise(SIGUSR1);
    return true;
}

// 更新配置
void AutoDmp::updateConfig(const CrashConfig& newConfig) {
    config_ = newConfig;
    createDirectory(config_.crashDirectory);
}

// 获取支持的信号列表
const int* AutoDmp::getSupportedSignals() {
    return handledSignals_;
}

size_t AutoDmp::getSupportedSignalCount() {
    return handledSignalCount_;
}