#include "SdCardManager.h"
#include "scratchApi.h"

#include "linux/utility/utility.h"

#include "fsfw/ipc/MutexFactory.h"
#include "fsfw/serviceinterface/ServiceInterface.h"

#include <fstream>
#include <memory>
#include <filesystem>

SdCardManager* SdCardManager::factoryInstance = nullptr;

SdCardManager::SdCardManager() {
}

SdCardManager::~SdCardManager() {
}

void SdCardManager::create() {
    if(factoryInstance == nullptr) {
        factoryInstance = new SdCardManager();
    }
}

SdCardManager* SdCardManager::instance() {
    SdCardManager::create();
    return SdCardManager::factoryInstance;
}

ReturnValue_t SdCardManager::switchOnSdCard(sd::SdCard sdCard, bool doMountSdCard,
        SdStatusPair* statusPair) {
    ReturnValue_t result = HasReturnvaluesIF::RETURN_OK;
    if(statusPair == nullptr) {
        statusPair = std::make_unique<SdStatusPair>().get();
        result = getSdCardActiveStatus(*statusPair);
        if(result != HasReturnvaluesIF::RETURN_OK) {
            return result;
        }
    }

    // Not allowed, this function turns on one SD card
    if(sdCard == sd::SdCard::BOTH) {
        sif::warning << "SdCardManager::switchOffSdCard: API does not allow sd::SdStatus::BOTH"
                << std::endl;
        return HasReturnvaluesIF::RETURN_FAILED;
    }

    sd::SdStatus targetStatus;
    if(sdCard == sd::SdCard::SLOT_0) {
        targetStatus = statusPair->first;
    }
    else if(sdCard == sd::SdCard::SLOT_1) {
        targetStatus = statusPair->second;
    }

    auto switchCall = [&]() {
        if(targetStatus == sd::SdStatus::ON) {
            if(not doMountSdCard) {
                return ALREADY_ON;
            }
            else {
                return mountSdCard(sdCard);
            }
        }
        else if(targetStatus == sd::SdStatus::MOUNTED) {
            return ALREADY_MOUNTED;
        }
        else if(targetStatus == sd::SdStatus::OFF) {
            return setSdCardState(sdCard, true);
        }
        else {
            return HasReturnvaluesIF::RETURN_FAILED;
        }
    };

    result = switchCall();

    if(result != HasReturnvaluesIF::RETURN_OK or not doMountSdCard) {
        return result;
    }

    return mountSdCard(sdCard);
}

ReturnValue_t SdCardManager::switchOffSdCard(sd::SdCard sdCard, bool doUnmountSdCard,
        SdStatusPair* statusPair) {
    std::pair<sd::SdStatus, sd::SdStatus> active;
    ReturnValue_t result = getSdCardActiveStatus(active);
    if(result != HasReturnvaluesIF::RETURN_OK) {
        return result;
    }
    // Not allowed, this function turns off one SD card
    if(sdCard == sd::SdCard::BOTH) {
        sif::warning << "SdCardManager::switchOffSdCard: API does not allow sd::SdStatus::BOTH"
                << std::endl;
        return HasReturnvaluesIF::RETURN_FAILED;
    }
    if(sdCard == sd::SdCard::SLOT_0) {
        if(active.first == sd::SdStatus::OFF) {
            return ALREADY_OFF;
        }
    }
    else if(sdCard == sd::SdCard::SLOT_1) {
        if(active.second == sd::SdStatus::OFF) {
            return ALREADY_OFF;
        }
    }

    if(doUnmountSdCard) {
        result = unmountSdCard(sdCard);
        if(result != HasReturnvaluesIF::RETURN_OK) {
            return result;
        }
    }

    return setSdCardState(sdCard, false);
}

ReturnValue_t SdCardManager::setSdCardState(sd::SdCard sdCard, bool on) {
    using namespace std;
    string sdstring = "";
    string statestring = "";
    if(sdCard == sd::SdCard::SLOT_0) {
        sdstring = "0";
    }
    else if(sdCard == sd::SdCard::SLOT_1) {
        sdstring = "1";
    }
    if(on) {
        statestring = "on";
    }
    else {
        statestring = "off";
    }
    ostringstream command;
    command << "q7hw sd set " << sdstring << " " << statestring;
    int result = system(command.str().c_str());
    if(result == 0) {
        return HasReturnvaluesIF::RETURN_OK;
    }
    sif::warning << "SdCardManager::setSdCardState: system call failed with code " <<
            result << std::endl;
    return SYSTEM_CALL_ERROR;
}

ReturnValue_t SdCardManager::getSdCardActiveStatus(SdStatusPair& active) {
    using namespace std;
    if(not filesystem::exists(SD_STATE_FILE)) {
        return STATUS_FILE_NEXISTS;
    }

    // Now the file should exist in any case. Still check whether it exists.
    fstream sdStatus(SD_STATE_FILE);
    if (not sdStatus.good()) {
        return STATUS_FILE_NEXISTS;
    }
    string line;
    uint8_t idx = 0;
    sd::SdCard currentSd = sd::SdCard::SLOT_0;
    // Process status file line by line
    while (std::getline(sdStatus, line)) {
        processSdStatusLine(active, line, idx, currentSd);
    }
    return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t SdCardManager::mountSdCard(sd::SdCard sdCard) {
    using namespace std;
    if(sdCard == sd::SdCard::BOTH) {
        sif::warning << "SdCardManager::mountSdCard: API does not allow sd::SdStatus::BOTH"
                << std::endl;
        return HasReturnvaluesIF::RETURN_FAILED;
    }
    string mountDev;
    string mountPoint;
    if(sdCard == sd::SdCard::SLOT_0) {
        mountDev = SD_0_DEV_NAME;
        mountPoint = SD_0_MOUNT_POINT;
    }
    else if(sdCard == sd::SdCard::SLOT_1) {
        mountDev = SD_1_DEV_NAME;
        mountPoint = SD_1_MOUNT_POINT;
    }
    if(not filesystem::exists(mountDev)) {
        sif::warning << "SdCardManager::mountSdCard: Device file does not exists. Make sure to"
                " turn on the SD card" << std::endl;
        return MOUNT_ERROR;
    }

    string sdMountCommand = "mount " + mountDev + " " + mountPoint;
    int result = system(sdMountCommand.c_str());
    if (result != 0) {
        utility::handleSystemError(result, "SdCardManager::mountSdCard");
        return SYSTEM_CALL_ERROR;
    }
    return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t SdCardManager::unmountSdCard(sd::SdCard sdCard) {
    using namespace std;
    if(sdCard == sd::SdCard::BOTH) {
        sif::warning << "SdCardManager::unmountSdCard: API does not allow sd::SdStatus::BOTH"
                << std::endl;
        return HasReturnvaluesIF::RETURN_FAILED;
    }
    string mountPoint;
    if(sdCard == sd::SdCard::SLOT_0) {
        mountPoint = SD_0_MOUNT_POINT;
    }
    else if(sdCard == sd::SdCard::SLOT_1) {
        mountPoint = SD_1_MOUNT_POINT;
    }
    if(filesystem::is_empty(mountPoint)) {
        // The mount point will always exist, but if it is empty, that is strong hint that
        // the SD card was not mounted properly. Still proceed with operation.
        sif::warning << "SdCardManager::unmountSdCard: Mount point is empty!" << std::endl;
    }
    string sdUnmountCommand = "umount " + mountPoint;
    int result = system(sdUnmountCommand.c_str());
    if (result != 0) {
        utility::handleSystemError(result, "SdCardManager::unmountSdCard");
        return SYSTEM_CALL_ERROR;
    }
    return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t SdCardManager::sanitizeState(sd::SdCard* prefSdCard, SdStatusPair* statusPair) {
    if(prefSdCard == nullptr) {
        prefSdCard = std::make_unique<sd::SdCard>(sd::SdCard::SLOT_0).get();
        getPreferredSdCard(*prefSdCard);
    }
    if(statusPair == nullptr) {
        statusPair = std::make_unique<SdStatusPair>().get();
        getSdCardActiveStatus(*statusPair);
    }

    auto sanitizerFunc = [&](sd::SdCard prefSdCard) {
        if(statusPair->first == sd::SdStatus::ON) {
            return mountSdCard(prefSdCard);
        }
        else {
            return switchOnSdCard(prefSdCard, true, statusPair);
        }
    };

    return sanitizerFunc(*prefSdCard);
}

void SdCardManager::processSdStatusLine(std::pair<sd::SdStatus, sd::SdStatus> &active,
        std::string& line, uint8_t& idx, sd::SdCard& currentSd) {
    using namespace std;
    istringstream iss(line);
    string word;
    bool slotLine = false;
    bool mountLine = false;
    while(iss >> word) {
        if (word == "Slot") {
            slotLine = true;
        }
        if(word == "Mounted") {
            mountLine = true;
        }

        if(slotLine) {
            if (word == "1:") {
                currentSd = sd::SdCard::SLOT_1;
            }

            if(word == "on") {
                if(currentSd == sd::SdCard::SLOT_0) {
                    active.first = sd::SdStatus::ON;
                }
                else {
                    active.second = sd::SdStatus::ON;
                }
            }
            else if (word == "off") {
                if(currentSd == sd::SdCard::SLOT_0) {
                    active.first = sd::SdStatus::OFF;
                }
                else {
                    active.second = sd::SdStatus::OFF;
                }
            }
        }

        if(mountLine) {
            if(currentSd == sd::SdCard::SLOT_0) {
                active.first = sd::SdStatus::MOUNTED;
            }
            else {
                active.second = sd::SdStatus::MOUNTED;
            }
        }

        if(idx > 5) {
            sif::warning << "SdCardManager::sdCardActive: /tmp/sd_status.txt has more than 6 "
                    "lines and might be invalid!" << std::endl;
        }
    }
    idx++;
}

ReturnValue_t SdCardManager::getPreferredSdCard(sd::SdCard& sdCard) const {
    uint8_t prefSdCard = 0;
    ReturnValue_t result = scratch::readNumber(scratch::PREFERED_SDC_KEY, prefSdCard);
    if(result != HasReturnvaluesIF::RETURN_OK) {
        return result;
    }
    sdCard = static_cast<sd::SdCard>(prefSdCard);
    return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t SdCardManager::setPreferredSdCard(sd::SdCard sdCard) {
    if(sdCard == sd::SdCard::BOTH) {
        return HasReturnvaluesIF::RETURN_FAILED;
    }
    return scratch::writeNumber(scratch::PREFERED_SDC_KEY, static_cast<uint8_t>(sdCard));
}

ReturnValue_t SdCardManager::updateSdCardStateFile() {
    // Use q7hw utility and pipe the command output into the state file
    std::string updateCmd = "q7hw sd info all > " + std::string(SD_STATE_FILE);
    int result = std::system(updateCmd.c_str());
    if(result == 0) {
        return HasReturnvaluesIF::RETURN_OK;
    }
    sif::warning << "SdCardManager::updateSdCardStateFile: system call failed with code " <<
            result << std::endl;
    return HasReturnvaluesIF::RETURN_FAILED;
}