/*
 * Copyright 2020-2026 Ryan Powell <ryan@nable-embedded.io> and
 * esp-nimble-cpp, NimBLE-Arduino contributors.
 *
 * 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 "NimBLEService.h"
#if CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_PERIPHERAL

# if CONFIG_BT_NIMBLE_EXT_ADV
#  include "NimBLEExtAdvertising.h"
# else
#  include "NimBLEAdvertising.h"
# endif
# include "NimBLEDevice.h"
# include "NimBLEUtils.h"
# include "NimBLELog.h"

# include <string>

static const char* LOG_TAG = "NimBLEService";

/**
 * @brief Construct an instance of the NimBLEService
 * @param [in] uuid The UUID of the service.
 */
NimBLEService::NimBLEService(const char* uuid) : NimBLEService(NimBLEUUID(uuid)) {}

/**
 * @brief Construct an instance of the BLEService
 * @param [in] uuid The UUID of the service.
 */
NimBLEService::NimBLEService(const NimBLEUUID& uuid)
    : NimBLELocalAttribute{uuid, 0}, m_pSvcDef{{0, getUUID().getBase(), nullptr, nullptr},{}} {}

/**
 * @brief Destructor, make sure we release the resources allocated for the service.
 */
NimBLEService::~NimBLEService() {
    clearServiceDefinitions();

    for (const auto& it : m_vChars) {
        delete it;
    }
} // ~NimBLEService

/**
 * @brief Dump details of this BLE GATT service.
 */
void NimBLEService::dump() const {
    NIMBLE_LOGD(LOG_TAG, "Service: uuid:%s, handle: 0x%2x", getUUID().toString().c_str(), getHandle());

    std::string res;
    int         count = 0;
    char        hex[5];
    for (const auto& it : m_vChars) {
        if (count > 0) {
            res += "\n";
        }
        snprintf(hex, sizeof(hex), "%04x", it->getHandle());
        count++;
        res += "handle: 0x";
        res += hex;
        res += ", uuid: " + std::string(it->getUUID());
    }

    NIMBLE_LOGD(LOG_TAG, "Characteristics:\n%s", res.c_str());
} // dump

/**
 * @brief Builds the database of characteristics/descriptors for the service
 * and registers it with the NimBLE stack.
 * @return bool success/failure .
 */
bool NimBLEService::start_internal() {
    NIMBLE_LOGD(LOG_TAG, ">> start(): Starting service: UUID: %s", getUUID().toString().c_str());
    // Make sure the definitions are cleared first
    clearServiceDefinitions();

    size_t numChrs = 0;
    for (const auto& chr : m_vChars) {
        if (chr->getRemoved()) {
            continue;
        }
        ++numChrs;
    }

    NIMBLE_LOGD(LOG_TAG, "Adding %zu characteristics for service %s", numChrs, getUUID().toString().c_str());
    if (numChrs) {
        int i = 0;

        // Nimble requires the last characteristic to have it's uuid = 0 to indicate the end
        // of the characteristics for the service. We create 1 extra and set it to null
        // for this purpose.
        ble_gatt_chr_def* pChrs = new ble_gatt_chr_def[numChrs + 1]{};
        for (const auto& chr : m_vChars) {
            if (chr->getRemoved()) {
                continue;
            }

            size_t numDscs = 0;
            for (const auto& dsc : chr->m_vDescriptors) {
                if (dsc->getRemoved()) {
                    continue;
                }
                ++numDscs;
            }

            if (numDscs) {
                int j = 0;

                // Must have last descriptor uuid = 0 so we have to create 1 extra
                ble_gatt_dsc_def* pDscs = new ble_gatt_dsc_def[numDscs + 1]{};
                for (const auto& dsc : chr->m_vDescriptors) {
                    if (dsc->getRemoved()) {
                        continue;
                    }

                    pDscs[j].uuid         = dsc->getUUID().getBase();
                    pDscs[j].att_flags    = dsc->getProperties();
                    pDscs[j].min_key_size = 0;
                    pDscs[j].access_cb    = NimBLEServer::handleGattEvent;
                    pDscs[j].arg          = dsc;
                    ++j;
                }

                pChrs[i].descriptors = pDscs;
            }

            pChrs[i].uuid         = chr->getUUID().getBase();
            pChrs[i].access_cb    = NimBLEServer::handleGattEvent;
            pChrs[i].arg          = chr;
            pChrs[i].flags        = chr->getProperties();
            pChrs[i].min_key_size = 0;
            pChrs[i].val_handle   = nullptr;
            ++i;
        }

        m_pSvcDef->characteristics = pChrs;
    }

    m_pSvcDef->type = BLE_GATT_SVC_TYPE_PRIMARY;

    int rc = ble_gatts_count_cfg(m_pSvcDef);
    if (rc != 0) {
        NIMBLE_LOGE(LOG_TAG, "ble_gatts_count_cfg failed, rc= %d, %s", rc, NimBLEUtils::returnCodeToString(rc));
        clearServiceDefinitions(); // Clear the definitions to free memory and reset the service for re-registration.
        return false;
    }

    rc = ble_gatts_add_svcs(m_pSvcDef);
    if (rc != 0) {
        NIMBLE_LOGE(LOG_TAG, "ble_gatts_add_svcs, rc= %d, %s", rc, NimBLEUtils::returnCodeToString(rc));
        clearServiceDefinitions(); // Clear the definitions to free memory and reset the service for re-registration.
        return false;
    }

    NIMBLE_LOGD(LOG_TAG, "<< start()");
    return true;
} // start

/**
 * @brief Clear the service definitions to free memory and reset the service for re-registration.
 */
void NimBLEService::clearServiceDefinitions() {
    if (m_pSvcDef->characteristics) {
        const ble_gatt_chr_def* chrDef = m_pSvcDef->characteristics;
        while (chrDef->uuid != nullptr) {
            if (chrDef->descriptors) {
                delete[] chrDef->descriptors;
            }
            ++chrDef;
        }
        delete[] m_pSvcDef->characteristics;
        m_pSvcDef->characteristics = nullptr;
    }

    m_pSvcDef->type = 0; // Clear the type to indicate the service is not started/registered.
} // clearServiceDefinitions

/**
 * @brief Create a new BLE Characteristic associated with this service.
 * @param [in] uuid - The UUID of the characteristic.
 * @param [in] properties - The properties of the characteristic.
 * @param [in] max_len - The maximum length in bytes that the characteristic value can hold.
 * @return The new BLE characteristic.
 */
NimBLECharacteristic* NimBLEService::createCharacteristic(const char* uuid, uint32_t properties, uint16_t max_len) {
    return createCharacteristic(NimBLEUUID(uuid), properties, max_len);
} // createCharacteristic

/**
 * @brief Create a new BLE Characteristic associated with this service.
 * @param [in] uuid - The UUID of the characteristic.
 * @param [in] properties - The properties of the characteristic.
 * @param [in] max_len - The maximum length in bytes that the characteristic value can hold.
 * @return The new BLE characteristic.
 */
NimBLECharacteristic* NimBLEService::createCharacteristic(const NimBLEUUID& uuid, uint32_t properties, uint16_t max_len) {
    NimBLECharacteristic* pChar = new NimBLECharacteristic(uuid, properties, max_len, this);
    if (getCharacteristic(uuid) != nullptr) {
        NIMBLE_LOGD(LOG_TAG, "Adding a duplicate characteristic with UUID: %s", std::string(uuid).c_str());
    }

    addCharacteristic(pChar);
    return pChar;
} // createCharacteristic

/**
 * @brief Add a characteristic to the service.
 * @param[in] pChar A pointer to the characteristic instance to add to the service.
 */
void NimBLEService::addCharacteristic(NimBLECharacteristic* pChar) {
    bool foundRemoved = false;
    if (pChar->getRemoved() > 0) {
        for (const auto& chr : m_vChars) {
            if (chr == pChar) {
                foundRemoved = true;
                pChar->setRemoved(0);
            }
        }
    }

    // Check if the characteristic is already in the service and if so, return.
    for (const auto& chr : m_vChars) {
        if (chr == pChar) {
            pChar->setService(this); // Update the service pointer in the characteristic.
            return;
        }
    }

    if (!foundRemoved) {
        m_vChars.push_back(pChar);
    }

    pChar->setService(this);
    getServer()->serviceChanged();
} // addCharacteristic

/**
 * @brief Remove a characteristic from the service.
 * @param[in] pChar A pointer to the characteristic instance to remove from the service.
 * @param[in] deleteChr If true it will delete the characteristic instance and free it's resources.
 */
void NimBLEService::removeCharacteristic(NimBLECharacteristic* pChar, bool deleteChr) {
    // Check if the characteristic was already removed and if so, check if this
    // is being called to delete the object and do so if requested.
    // Otherwise, ignore the call and return.
    if (pChar->getRemoved() > 0) {
        if (deleteChr) {
            for (auto it = m_vChars.begin(); it != m_vChars.end(); ++it) {
                if ((*it) == pChar) {
                    delete (*it);
                    m_vChars.erase(it);
                    break;
                }
            }
        }

        return;
    }

    pChar->setRemoved(deleteChr ? NIMBLE_ATT_REMOVE_DELETE : NIMBLE_ATT_REMOVE_HIDE);
    getServer()->serviceChanged();
} // removeCharacteristic

/**
 * @brief Get a pointer to the characteristic object with the specified UUID.
 * @param [in] uuid The UUID of the characteristic.
 * @param idx The index of the characteristic to return (used when multiple characteristics have the same UUID).
 * @return A pointer to the characteristic object or nullptr if not found.
 */
NimBLECharacteristic* NimBLEService::getCharacteristic(const char* uuid, uint16_t idx) const {
    return getCharacteristic(NimBLEUUID(uuid), idx);
} // getCharacteristic

/**
 * @brief Get a pointer to the characteristic object with the specified UUID.
 * @param [in] uuid The UUID of the characteristic.
 * @param idx The index of the characteristic to return (used when multiple characteristics have the same UUID).
 * @return A pointer to the characteristic object or nullptr if not found.
 */
NimBLECharacteristic* NimBLEService::getCharacteristic(const NimBLEUUID& uuid, uint16_t idx) const {
    uint16_t position = 0;
    for (const auto& chr : m_vChars) {
        if (chr->getUUID() == uuid) {
            if (position == idx) {
                return chr;
            }
            position++;
        }
    }

    return nullptr;
} // getCharacteristic

/**
 * @brief Get a pointer to the characteristic object with the specified handle.
 * @param handle The handle of the characteristic.
 * @return A pointer to the characteristic object or nullptr if not found.
 */
NimBLECharacteristic* NimBLEService::getCharacteristicByHandle(uint16_t handle) const {
    for (const auto& chr : m_vChars) {
        if (chr->getHandle() == handle) {
            return chr;
        }
    }

    return nullptr;
} // getCharacteristicByHandle

/**
 * @return A vector containing pointers to each characteristic associated with this service.
 */
const std::vector<NimBLECharacteristic*>& NimBLEService::getCharacteristics() const {
    return m_vChars;
} // getCharacteristics

/**
 * @return A vector containing pointers to each characteristic with the provided UUID associated with this service.
 */
std::vector<NimBLECharacteristic*> NimBLEService::getCharacteristics(const char* uuid) const {
    return getCharacteristics(NimBLEUUID(uuid));
} // getCharacteristics

/**
 * @return A vector containing pointers to each characteristic with the provided UUID associated with this service.
 */
std::vector<NimBLECharacteristic*> NimBLEService::getCharacteristics(const NimBLEUUID& uuid) const {
    std::vector<NimBLECharacteristic*> result;
    for (const auto& chr : m_vChars) {
        if (chr->getUUID() == uuid) {
            result.push_back(chr);
        }
    }

    return result;
} // getCharacteristics

/**
 * @brief Return a string representation of this service.
 * A service is defined by:
 * * Its UUID
 * * Its handle
 * @return A string representation of this service.
 */
std::string NimBLEService::toString() const {
    std::string res = "UUID: " + getUUID().toString();
    char        hex[5];
    snprintf(hex, sizeof(hex), "%04x", getHandle());
    res += ", handle: 0x";
    res += hex;
    return res;
} // toString

/**
 * @brief Get the BLE server associated with this service.
 * @return The BLEServer associated with this service.
 */
NimBLEServer* NimBLEService::getServer() const {
    return NimBLEDevice::getServer();
} // getServer

/**
 * @brief Checks if the service has been started.
 * @return True if the service has been started.
 */
bool NimBLEService::isStarted() const {
    return m_pSvcDef->type > 0;
} // isStarted

#endif // CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_PERIPHERAL
