#include "configuration.h"
#if HAS_SCREEN
#include "FSCommon.h"
#include "MessageStore.h"
#include "NodeDB.h"
#include "SPILock.h"
#include "SafeFile.h"
#include "gps/RTC.h"
#include "graphics/draw/MessageRenderer.h"

#include <algorithm> // std::min, std::find_if

using graphics::MessageRenderer::setThreadMode;
using graphics::MessageRenderer::ThreadMode;

// Calculate serialized size for a StoredMessage
static inline size_t getMessageSize(const StoredMessage &m)
{
    return 16 + std::min(static_cast<size_t>(MAX_MESSAGE_SIZE), m.text.size());
}

// Helper: assign a timestamp (RTC if available, else boot-relative)
static inline void assignTimestamp(StoredMessage &sm)
{
    uint32_t nowSecs = getValidTime(RTCQuality::RTCQualityDevice, true);
    if (nowSecs) {
        sm.timestamp = nowSecs;
        sm.isBootRelative = false;
    } else {
        sm.timestamp = millis() / 1000;
        sm.isBootRelative = true;
    }
}

// Generic push with cap (used by live + persisted queues)
template <typename T> static inline void pushWithLimit(std::deque<T> &queue, const T &msg)
{
    if (queue.size() >= MAX_MESSAGES_SAVED)
        queue.pop_front();
    queue.push_back(msg);
}

template <typename T> static inline void pushWithLimit(std::deque<T> &queue, T &&msg)
{
    if (queue.size() >= MAX_MESSAGES_SAVED)
        queue.pop_front();
    queue.emplace_back(std::move(msg));
}

void MessageStore::logMemoryUsage(const char *context) const
{
    size_t total = 0;
    for (const auto &m : messages) {
        total += getMessageSize(m);
    }

    LOG_DEBUG("MessageStore[%s]: %u messages, est %u bytes (~%u KB)", context, (unsigned)messages.size(), (unsigned)total,
              (unsigned)(total / 1024));
}

MessageStore::MessageStore(const std::string &label)
{
    filename = "/Messages_" + label + ".msgs";
}

// Live message handling (RAM only)
void MessageStore::addLiveMessage(StoredMessage &&msg)
{
    pushWithLimit(liveMessages, std::move(msg));
}
void MessageStore::addLiveMessage(const StoredMessage &msg)
{
    pushWithLimit(liveMessages, msg);
}

// Persistence queue (used only on shutdown/reboot)
void MessageStore::addMessage(StoredMessage &&msg)
{
    pushWithLimit(messages, std::move(msg));
}
void MessageStore::addMessage(const StoredMessage &msg)
{
    pushWithLimit(messages, msg);
}

// Add from incoming/outgoing packet
const StoredMessage &MessageStore::addFromPacket(const meshtastic_MeshPacket &packet)
{
    StoredMessage sm;
    // Always use our local time (helper handles RTC vs boot time)
    assignTimestamp(sm);

    sm.channelIndex = packet.channel;

    // Text from packet → std::string (fast, no extra copies)
    sm.text = std::string(reinterpret_cast<const char *>(packet.decoded.payload.bytes));

    if (packet.from == 0) {
        // Phone-originated (outgoing)
        sm.sender = nodeDB->getNodeNum(); // our node ID
        if (packet.decoded.dest == 0 || packet.decoded.dest == NODENUM_BROADCAST) {
            sm.dest = NODENUM_BROADCAST;
            sm.type = MessageType::BROADCAST;
        } else {
            sm.dest = packet.decoded.dest;
            sm.type = MessageType::DM_TO_US;
        }

        // Outgoing messages start as NONE until ACK/NACK arrives
        sm.ackStatus = AckStatus::NONE;
    } else {
        // Normal incoming
        sm.sender = packet.from;
        if (packet.to == NODENUM_BROADCAST || packet.decoded.dest == NODENUM_BROADCAST) {
            sm.dest = NODENUM_BROADCAST;
            sm.type = MessageType::BROADCAST;
        } else if (packet.to == nodeDB->getNodeNum()) {
            sm.dest = nodeDB->getNodeNum(); // DM to us
            sm.type = MessageType::DM_TO_US;
        } else {
            sm.dest = NODENUM_BROADCAST; // fallback
            sm.type = MessageType::BROADCAST;
        }

        // Received messages don’t wait for ACK mark as ACKED
        sm.ackStatus = AckStatus::ACKED;
    }

    addLiveMessage(sm);

    // Return reference to the most recently stored message
    return liveMessages.back();
}

// Outgoing/manual message
void MessageStore::addFromString(uint32_t sender, uint8_t channelIndex, const std::string &text)
{
    StoredMessage sm;

    // Always use our local time (helper handles RTC vs boot time)
    assignTimestamp(sm);

    sm.sender = sender;
    sm.channelIndex = channelIndex;
    sm.text = text;

    // Default manual adds to broadcast
    sm.dest = NODENUM_BROADCAST;
    sm.type = MessageType::BROADCAST;

    // Outgoing messages start as NONE until ACK/NACK arrives
    sm.ackStatus = AckStatus::NONE;

    addLiveMessage(sm);
}

#if ENABLE_MESSAGE_PERSISTENCE
// Save RAM queue to flash (called on shutdown)
void MessageStore::saveToFlash()
{
#ifdef FSCom
    // Copy live RAM buffer into persistence queue
    messages = liveMessages;

    spiLock->lock();
    FSCom.mkdir("/"); // ensure root exists
    spiLock->unlock();

    SafeFile f(filename.c_str(), false);

    spiLock->lock();
    uint8_t count = messages.size();
    f.write(&count, 1);

    for (uint8_t i = 0; i < count && i < MAX_MESSAGES_SAVED; i++) {
        const StoredMessage &m = messages.at(i);
        f.write((uint8_t *)&m.timestamp, sizeof(m.timestamp));
        f.write((uint8_t *)&m.sender, sizeof(m.sender));
        f.write((uint8_t *)&m.channelIndex, sizeof(m.channelIndex));
        f.write((uint8_t *)&m.dest, sizeof(m.dest));

        // Write text payload (capped at MAX_MESSAGE_SIZE)
        const size_t toWrite = std::min(static_cast<size_t>(MAX_MESSAGE_SIZE), m.text.size());
        if (toWrite)
            f.write((const uint8_t *)m.text.data(), toWrite);
        f.write('\0');

        uint8_t bootFlag = m.isBootRelative ? 1 : 0;
        f.write(&bootFlag, 1); // persist boot-relative flag

        uint8_t statusByte = static_cast<uint8_t>(m.ackStatus);
        f.write(&statusByte, 1); // persist ackStatus
    }
    spiLock->unlock();

    f.close();

    // Debug after saving
    logMemoryUsage("saveToFlash");
#else
    // Filesystem not available, skip persistence
#endif
}

// Load persisted messages into RAM (called at boot)
void MessageStore::loadFromFlash()
{
    messages.clear();
    liveMessages.clear();
#ifdef FSCom
    concurrency::LockGuard guard(spiLock);

    if (!FSCom.exists(filename.c_str()))
        return;
    auto f = FSCom.open(filename.c_str(), FILE_O_READ);
    if (!f)
        return;

    uint8_t count = 0;
    f.readBytes((char *)&count, 1);

    for (uint8_t i = 0; i < count && i < MAX_MESSAGES_SAVED; i++) {
        StoredMessage m;
        f.readBytes((char *)&m.timestamp, sizeof(m.timestamp));
        f.readBytes((char *)&m.sender, sizeof(m.sender));
        f.readBytes((char *)&m.channelIndex, sizeof(m.channelIndex));
        f.readBytes((char *)&m.dest, sizeof(m.dest));

        m.text.clear();
        m.text.reserve(64);
        char c;
        size_t readCount = 0;
        while (readCount < MAX_MESSAGE_SIZE) {
            if (f.readBytes(&c, 1) <= 0)
                break;
            if (c == '\0')
                break;
            m.text.push_back(c);
            ++readCount;
        }

        // Try to read boot-relative flag
        uint8_t bootFlag = 0;
        if (f.available() > 0) {
            if (f.readBytes((char *)&bootFlag, 1) == 1) {
                m.isBootRelative = (bootFlag != 0);
            } else {
                m.isBootRelative = (m.timestamp < 60u * 60u * 24u * 7u);
            }
        } else {
            m.isBootRelative = (m.timestamp < 60u * 60u * 24u * 7u);
        }

        // Try to read ackStatus
        if (f.available() > 0) {
            uint8_t statusByte = 0;
            if (f.readBytes((char *)&statusByte, 1) == 1) {
                m.ackStatus = static_cast<AckStatus>(statusByte);
            } else {
                m.ackStatus = AckStatus::NONE;
            }
        } else {
            m.ackStatus = AckStatus::NONE;
        }

        // Recompute type from dest
        if (m.dest == NODENUM_BROADCAST) {
            m.type = MessageType::BROADCAST;
        } else {
            m.type = MessageType::DM_TO_US;
        }

        messages.push_back(m);
        liveMessages.push_back(m); // restore into RAM buffer
    }
    f.close();

    // Debug after loading
    logMemoryUsage("loadFromFlash");
#endif
}
#else
// Persistence disabled (saves flash space)
void MessageStore::saveToFlash() {}
void MessageStore::loadFromFlash() {}
#endif

// Clear all messages (RAM + persisted queue)
void MessageStore::clearAllMessages()
{
    liveMessages.clear();
    messages.clear();

#ifdef FSCom
    SafeFile f(filename.c_str(), false);
    uint8_t count = 0;
    f.write(&count, 1); // write "0 messages"
    f.close();
#endif
}

// Internal helper: erase first or last message matching a predicate
template <typename Predicate> static void eraseIf(std::deque<StoredMessage> &deque, Predicate pred, bool fromBack = false)
{
    if (fromBack) {
        // Iterate from the back and erase the first match from the end
        for (auto it = deque.rbegin(); it != deque.rend(); ++it) {
            if (pred(*it)) {
                deque.erase(std::next(it).base());
                break;
            }
        }
    } else {
        // Erase the first matching message from the front
        auto it = std::find_if(deque.begin(), deque.end(), pred);
        if (it != deque.end())
            deque.erase(it);
    }
}

// Dismiss oldest message (RAM + persisted queue)
void MessageStore::dismissOldestMessage()
{
    eraseIf(liveMessages, [](StoredMessage &) { return true; });
    eraseIf(messages, [](StoredMessage &) { return true; });
    saveToFlash();
}

// Dismiss oldest message in a specific channel
void MessageStore::dismissOldestMessageInChannel(uint8_t channel)
{
    auto pred = [channel](const StoredMessage &m) { return m.type == MessageType::BROADCAST && m.channelIndex == channel; };
    eraseIf(liveMessages, pred);
    eraseIf(messages, pred);
    saveToFlash();
}

// Dismiss oldest message in a direct conversation with a peer
void MessageStore::dismissOldestMessageWithPeer(uint32_t peer)
{
    auto pred = [peer](const StoredMessage &m) {
        if (m.type == MessageType::DM_TO_US) {
            uint32_t other = (m.sender == nodeDB->getNodeNum()) ? m.dest : m.sender;
            return other == peer;
        }
        return false;
    };
    eraseIf(liveMessages, pred);
    eraseIf(messages, pred);
    saveToFlash();
}

// Helper filters for future use
std::deque<StoredMessage> MessageStore::getChannelMessages(uint8_t channel) const
{
    std::deque<StoredMessage> result;
    for (const auto &m : liveMessages) {
        if (m.type == MessageType::BROADCAST && m.channelIndex == channel) {
            result.push_back(m);
        }
    }
    return result;
}

std::deque<StoredMessage> MessageStore::getDirectMessages() const
{
    std::deque<StoredMessage> result;
    for (const auto &m : liveMessages) {
        if (m.type == MessageType::DM_TO_US) {
            result.push_back(m);
        }
    }
    return result;
}

// Upgrade boot-relative timestamps once RTC is valid
// Only same-boot boot-relative messages are healed.
// Persisted boot-relative messages from old boots stay ??? forever.
void MessageStore::upgradeBootRelativeTimestamps()
{
    uint32_t nowSecs = getValidTime(RTCQuality::RTCQualityDevice, true);
    if (nowSecs == 0)
        return; // Still no valid RTC

    uint32_t bootNow = millis() / 1000;

    auto fix = [&](std::deque<StoredMessage> &dq) {
        for (auto &m : dq) {
            if (m.isBootRelative && m.timestamp <= bootNow) {
                uint32_t bootOffset = nowSecs - bootNow;
                m.timestamp += bootOffset;
                m.isBootRelative = false;
            }
            // else: persisted from old boot → stays ??? forever
        }
    };
    fix(liveMessages);
    fix(messages);
}

// Global definition
MessageStore messageStore("default");
#endif