#include <climits>
#include <cstring>
#include <optional>
#include <stdexcept>

#include "logcat_entry.h"
#include "pcre2_wrapper.h"

static const Pcre2Regex LogcatEntryRegex("^\\s*(\\d+)(?:\\.\\d+)?(?:\\s+([\\w\\d._-]+))?\\s+(\\d+)\\s+(\\d+)\\s+([A-Z])\\s+(.+?)\\s*:\\s(.*)$");
static const Pcre2Regex BufferRegex("^--------- (?:beginning of|switch to) (\\w+)$");

const char* to_string(Priority priority) {
    switch (priority) {
        case Priority::Verbose: return "Verbose";
        case Priority::Debug: return "Debug";
        case Priority::Info: return "Info";
        case Priority::Warn: return "Warning";
        case Priority::Error: return "Error";
        case Priority::Fatal: return "Fatal";
        case Priority::Unknown: return "Unknown";
    }
}

const char* to_string(Buffer buffer) {
    switch (buffer) {
        case Buffer::Main: return "Main";
        case Buffer::System: return "System";
        case Buffer::Radio: return "Radio";
        case Buffer::Events: return "Events";
        case Buffer::Crash: return "Crash";
        case Buffer::Unknown: return "Unknown";
    }
}

static inline Priority priority_from(char c) {
    switch (c) {
        case 'V': return Priority::Verbose;
        case 'D': return Priority::Debug;
        case 'I': return Priority::Info;
        case 'W': return Priority::Warn;
        case 'E': return Priority::Error;
        case 'F': return Priority::Fatal;
        default: return Priority::Unknown;
    }
}

static inline long to_long(const char* str, const char* expected_end) {
    char* endptr;

    errno = 0;
    long res = strtol(str, &endptr, 10);
    if (endptr != expected_end) {
        throw std::invalid_argument(std::string(str) + " has trailing text");
    } else if (res == LONG_MAX && errno == ERANGE) {
        throw std::overflow_error(std::string(str) + " is too big");
    } else if (res == LONG_MIN && errno == ERANGE) {
        throw std::underflow_error(std::string(str) + " is too small");
    }
    return res;
}

static unsigned long long to_unsigned_long_long(const char* str, const char* expected_end) {
    char* endptr;

    errno = 0;
    unsigned long long res = strtoull(str, &endptr, 10);
    if (endptr != expected_end) {
        throw std::invalid_argument(std::string(str) + " has trailing text");
    } else if (res == ULLONG_MAX && errno == ERANGE) {
        throw std::overflow_error(std::string(str) + " is too big");
    }
    return res;
}

std::optional<LogcatEntry> try_parse_logcat_entry(char* buf, size_t length, Buffer buffer) {
    regmatch_t matches[8];
    matches[0].rm_so = 0;
    matches[0].rm_eo = static_cast<regoff_t>(length);
    if (static_cast<size_t>(matches[0].rm_eo) != length) {
        throw std::range_error("Logcat entry line too long for int");
    }

    if (!LogcatEntryRegex.match(buf, sizeof(matches) / sizeof(regmatch_t), matches, REG_STARTEND)) {
        return std::nullopt;
    }

    std::optional<std::string> user;
    if (matches[2].rm_so > -1 && matches[2].rm_eo > -1) {
        user = std::string(&buf[matches[2].rm_so], static_cast<size_t>(matches[2].rm_eo - matches[2].rm_so));
    }
    // if pcre2 gives us negative offsets then i'll die
    LogcatEntry logcat_entry = {
        .buffer = buffer,
        .time = to_long(&buf[matches[1].rm_so], &buf[matches[1].rm_eo]),
        .user = std::move(user),
        .pid = to_unsigned_long_long(&buf[matches[3].rm_so], &buf[matches[3].rm_eo]),
        .tid = to_unsigned_long_long(&buf[matches[4].rm_so], &buf[matches[4].rm_eo]),
        .priority = priority_from(buf[matches[5].rm_so]),
        .tag = std::string(&buf[matches[6].rm_so], static_cast<size_t>(matches[6].rm_eo - matches[6].rm_so)),
        .message = std::string(&buf[matches[7].rm_so], static_cast<size_t>(matches[7].rm_eo - matches[7].rm_so)),
    };
    return std::move(logcat_entry);
}

std::optional<Buffer> try_parse_buffer(char* buf, size_t length) {
    regmatch_t matches[2];
    matches[0].rm_so = 0;
    matches[0].rm_eo = static_cast<regoff_t>(length);
    if (static_cast<size_t>(matches[0].rm_eo) != length) {
        throw std::range_error("Buffer line too long for int");
    }

    if (!BufferRegex.match(buf, sizeof(matches) / sizeof(regmatch_t), matches, REG_STARTEND)) {
        return std::nullopt;
    }

    const char* buffer_str = &buf[matches[1].rm_so];
    if (!strncmp(buffer_str, "main", 4)) return Buffer::Main;
    if (!strncmp(buffer_str, "system", 6)) return Buffer::System;
    if (!strncmp(buffer_str, "radio", 5)) return Buffer::Radio;
    if (!strncmp(buffer_str, "events", 6)) return Buffer::Events;
    if (!strncmp(buffer_str, "crash", 5)) return Buffer::Crash;
    return Buffer::Unknown;
}


void from_json(const nlohmann::json& j, Buffer& buffer) {
    const std::string& str = j.get_ref<const nlohmann::json::string_t&>();

    if (str == "UNKNOWN") buffer = Buffer::Unknown;
    else if (str == "MAIN") buffer = Buffer::Main;
    else if (str == "SYSTEM") buffer = Buffer::System;
    else if (str == "RADIO") buffer = Buffer::Radio;
    else if (str == "EVENTS") buffer = Buffer::Events;
    else if (str == "CRASH") buffer = Buffer::Crash;
    else throw std::invalid_argument(std::string("Unknown buffer value: ") + str);
}

void to_json(nlohmann::json& j, const Buffer& buffer) {
    switch (buffer) {
        case Buffer::Unknown: j = "UNKNOWN"; break;
        case Buffer::Main: j = "MAIN"; break;
        case Buffer::System: j = "SYSTEM"; break;
        case Buffer::Radio: j = "RADIO"; break;
        case Buffer::Events: j = "EVENTS"; break;
        case Buffer::Crash: j = "CRASH"; break;
    }
}

void from_json(const nlohmann::json& j, Priority& priority) {
    const std::string& str = j.get_ref<const nlohmann::json::string_t&>();

    if (str == "UNKNOWN") priority = Priority::Unknown;
    else if (str == "VERBOSE") priority = Priority::Verbose;
    else if (str == "DEBUG") priority = Priority::Debug;
    else if (str == "INFO") priority = Priority::Info;
    else if (str == "WARN") priority = Priority::Warn;
    else if (str == "ERROR") priority = Priority::Error;
    else if (str == "FATAL") priority = Priority::Fatal;
    else throw std::invalid_argument(std::string("Unknown priority value: ") + str);
}

void to_json(nlohmann::json& j, const Priority& priority) {
    switch (priority) {
        case Priority::Unknown: j = "UNKNOWN"; break;
        case Priority::Verbose: j = "VERBOSE"; break;
        case Priority::Debug: j = "DEBUG"; break;
        case Priority::Info: j = "INFO"; break;
        case Priority::Warn: j = "WARN"; break;
        case Priority::Error: j = "ERROR"; break;
        case Priority::Fatal: j = "FATAL"; break;
    }
}