/**
TYPICAL COMMANDS:
high-viwi start
high-viwi get {"name":"/car/doors/"}
high-viwi get {"name":"/car/doors/6078d4-23b89b-8faaa9-8bd0f3"}
high-viwi get {"name":"/car/doors/","fields":["isDoorOpen"]}
high-viwi subscribe {"name":"/car/doors/6078d4-23b89b-8faaa9-8bd0f3"} note: fields parameter on subscribe is not implemented yet
high-viwi unsubscribe {"name":"/car/doors/6078d4-23b89b-8faaa9-8bd0f3"}
high-viwi subscribe {"name":"/car/doors/"}
high-viwi subscribe {"name":"/car/doors/6078d4-23b89b-8faaa9-8bd0f3","interval":5000}
high-viwi subscribe {"name":"/car/doors/","interval":5000}
high-viwi unsubscribe {"name":"/car/doors/","interval":5000}
*/

#include <json-c/json.h>
#include <algorithm>
#include "high.hpp"
#include "high-viwi-binding-hat.hpp"
#include <time.h>
#include <sstream>
#include <iterator>
/// @brief Split a std::string in several string, based on a delimeter
///
/// @param[in] string: the string to be splitted, delim: the delimeter to use for splitting.
///
/// @return std::vector<std::string> : a vector containing each individual string after the split.
using namespace std;
template<typename Out>
void split(const std::string &s, char delim, Out result) {
    std::stringstream ss;
    ss.str(s);
    std::string item;
    while (std::getline(ss, item, delim)) {
        *(result++) = item;
    }
}
std::vector<std::string> split(const std::string &s, char delim) {
    std::vector<std::string> elems;
    split(s, delim, std::back_inserter(elems));
    return elems;
}

/// @brief Main high binding class: maintains resources status, subcriptions and timers
High::High()
{
}

/// @brief Reads the json configuration and generates accordingly the resources container. An UID is generated for each resource.
///        Makes necessary subscriptions to low-level, eventually with a frequency.
///
void High::parseConfigAndSubscribe()
{
    json_object *config = json_object_from_file("high.json");
    json_object *jvalue, *jarray1, *jarray2, *obj;
    std::map<std::string, std::map<std::string, Property>> properties;

    json_object_object_get_ex(config, "definitions", &jarray1);
    int arraylen1 = json_object_array_length(jarray1);
    for(int n = 0; n < arraylen1; ++n) {
        obj = json_object_array_get_idx(jarray1, n);
        json_object_object_get_ex(obj, "name", &jvalue);
        const std::string name = json_object_get_string(jvalue);
        json_object_object_get_ex(obj, "properties", &jarray2);
        std::map<std::string, Property> props;
        json_object_object_foreach(jarray2, key, val) {
            Property p;
            json_object_object_get_ex(val, "type", &jvalue);
            p.type = json_object_get_string(jvalue);
            json_object_object_get_ex(val, "description", &jvalue);
            p.description = json_object_get_string(jvalue);
            props[key] = p;
        }
        properties[name] = props;
    }
    json_object_object_get_ex(config, "resources", &jarray1);
    arraylen1 = json_object_array_length(jarray1);
    std::map<std::string, int> toSubscribe;
    for(int n = 0; n < arraylen1; ++n) {
        obj = json_object_array_get_idx(jarray1, n);
        json_object_object_get_ex(obj, "name", &jvalue);
        const std::string name = json_object_get_string(jvalue);
        json_object_object_get_ex(obj, "values", &jarray2);
        const int arraylen2 = json_object_array_length(jarray2);
        for(int i = 0; i < arraylen2; ++i) {
            const std::string id = generateId();
            const std::string uri = name + id;
            jvalue = json_object_array_get_idx(jarray2, i);
            if(properties.find(name) == properties.end()) {
                AFB_WARNING("Unable to find name %s in properties", name.c_str());
                continue;
            }
            const std::map<std::string, Property> props = properties[name];
            std::map<std::string, Property> localProps; //note that local props can have less members than defined.
            localProps["id"] = props.at("id");
            localProps["name"] = props.at("name");
            localProps["uri"] = props.at("uri");
            localProps["id"].value_string = std::string(id);
            localProps["uri"].value_string = std::string(uri);
            json_object_object_foreach(jvalue, key, val) {
                const std::string value = json_object_get_string(val);
                if(props.find(key) == props.end()) {
                    AFB_WARNING("Unable to find key %s in properties", value.c_str());
                    continue;
                }
                Property prop = props.at(key);
                if(startsWith(value, "${")) {
                    const std::string canMessage = value.substr(2, value.size() - 1);
                    const std::vector<std::string> params = split(canMessage, ',');
                    if(params.size() != 2) {
                        AFB_WARNING("Invalid CAN message definition %s", value.c_str());
                        continue;
                    }
                    prop.lowMessageName = params.at(0);
                    prop.interval = stoi(params.at(1));
                    if(toSubscribe.find(prop.lowMessageName) != toSubscribe.end()) {
                        if(toSubscribe.at(prop.lowMessageName) > prop.interval)
                            toSubscribe[prop.lowMessageName] = prop.interval;
                    } else {
                        toSubscribe[prop.lowMessageName] = prop.interval;
                    }
                    if(prop.type == "string")
                        prop.value_string = std::string("nul");
                    else if(prop.type == "boolean")
                        prop.value_bool = false;
                    else if(prop.type == "double")
                        prop.value_double = 0.0;
                    else if(prop.type == "int")
                        prop.value_int = 0;
                    else
                        AFB_ERROR("ERROR 2! unexpected type in parseConfig %s %s", prop.description.c_str(), prop.type.c_str());
                } else {
                    prop.value_string= std::string(value);
                }
                localProps[key] = prop;
            }
            registeredObjects[uri] = localProps;
            for(const auto &p : localProps) {
                if(p.second.lowMessageName.size() > 0) {
                    std::set<std::string> objectList;
                    if(lowMessagesToObjects.find(p.second.lowMessageName) != lowMessagesToObjects.end())
                        objectList = lowMessagesToObjects.at(p.second.lowMessageName);
                    objectList.insert(uri);
                    lowMessagesToObjects[p.second.lowMessageName] = objectList;
                }
            }
        }
    }
    for(const auto &p : toSubscribe) {
        json_object *jobj = json_object_new_object();
        json_object_object_add(jobj,"event", json_object_new_string(p.first.c_str()));
        if(p.second > 0) {
            json_object *filter = json_object_new_object();
            json_object_object_add(filter, "frequency", json_object_new_double(1000.0 / (double)p.second));
            json_object_object_add(jobj, "filter", filter);
        }
        json_object *dummy;
        const std::string js = json_object_get_string(jobj);
        if(afb_service_call_sync("low-can", "subscribe", jobj, &dummy) < 0)
            AFB_ERROR("high-viwi subscription to low-can FAILED %s", js.c_str());
        else
            AFB_NOTICE("high-viwi subscribed to low-can %s", js.c_str());
        json_object_put(dummy);
    }
    json_object_put(config);
    AFB_NOTICE("configuration loaded");
}

/// @brief Create and start a systemD timer. Only one timer is created per frequency.
///
/// @param[in] t: interval in ms.
///
void High::startTimer(const int &t)
{
    if(timers.find(t) != timers.end())
        return;
    struct timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
    sd_event_add_time(afb_daemon_get_event_loop(), NULL, CLOCK_MONOTONIC, (ts.tv_sec + 1) * 1000000, 0, &ticked, new int(t));
}
High::~High()
{
    timers.clear();
}

/// @brief callback called after subscription to low-level binding.
///
void High::callBackFromSubscribe(void *handle, int iserror, json_object *result)
{
    AFB_NOTICE("high level callBackFromSubscribe method called %s", json_object_get_string(result));
}

/// @brief Entry point for all timer events. Treats all requests linked to the specific timer frequency.
///        Restarts the timer, or cancels it if no requests are anymore linked to it.
///
/// @param[in] source: systemD timer, now: tick timestamp, interv: specific timer interval in ms.
///
void High::tick(sd_event_source *source, const long &now, void *interv)
{
    const int interval = *(int*)interv;
    AFB_NOTICE("tick! %d %ld", interval, now);
    bool hasEvents = false;
    if(timedEvents.find(interval) != timedEvents.end()) {
        std::vector<TimedEvent> evts  = timedEvents[interval];
        for(int i = (int)evts.size() - 1; i >= 0; --i) {
            const TimedEvent e = evts.at(i);
            std::map<std::string, json_object*> jsons;
            for(const auto &pp : registeredObjects) {
                if(startsWith(pp.first, e.name)) {
                    jsons[pp.first] = generateJson(pp.first);
                }
            }
            json_object *j = json_object_new_object();
            if(jsons.size() == 1) {
                j = jsons[0];
            } else if(jsons.size() > 1) {
                for(const auto &pp : jsons)
                    json_object_object_add(j, pp.first.c_str(), pp.second);
            }
            const int nbSubscribers = afb_event_push(e.event, j);
            if(nbSubscribers == 0) {
                afb_event_drop(e.event);
                evts.erase(evts.begin() + i);
                timedEvents[interval] = evts;
            }
            //AFB_NOTICE("%s event pushed to %d subscribers", e.eventName.c_str(), nbSubscribers);
        }
        if(evts.size() > 0)
            hasEvents = true;
    }
    if(hasEvents) {
        sd_event_source_set_time(source, now + interval * 1000);
        sd_event_source_set_enabled(source, SD_EVENT_ON);
    } else {
        //AFB_NOTICE("timer removed %d", interval);
        delete (int*)interv;
        if(timers.find(interval) != timers.end()) {
            timers.erase(interval);
        }
        sd_event_source_unref(source);
    }
}

/// @brief Entry point for low-binding events. Updates all resources linked to this event and eventually
///        sends back events to subscribers, if any.
///
/// @param[in] message: json low-level message.
///
void High::treatMessage(json_object *message)
{
    json_object *nameJson, *jvalue;
    json_object_object_get_ex(message, "name", &nameJson);
    json_object_object_get_ex(message, "value", &jvalue);
    const std::string messageName(json_object_get_string(nameJson));
    if(lowMessagesToObjects.find(messageName) == lowMessagesToObjects.end()) {
        AFB_ERROR("message not linked to any object %s", json_object_get_string(message));
        return;
    }
//    AFB_NOTICE("message received %s", json_object_get_string(message));
    const std::set<std::string> objects = lowMessagesToObjects.at(messageName);
    std::vector<std::string> candidateMessages;
    for(const std::string &uri : objects) {
        std::map<std::string, Property> properties = registeredObjects.at(uri);
        std::string foundProperty;
        for(const auto &p : properties) {
            if(p.second.lowMessageName != messageName)
                continue;
            foundProperty = p.first;
            candidateMessages.push_back(uri);
            break;
        }

        if(foundProperty.size() > 0) {
            Property property = properties.at(foundProperty);
            if(property.type == "boolean")
                property.value_bool = json_object_get_boolean(jvalue);
            else if(property.type == "string")
                property.value_string = std::string(json_object_get_string(jvalue));
            else if(property.type == "double")
                property.value_double = json_object_get_double(jvalue);
            else if(property.type == "int")
                property.value_int = json_object_get_int(jvalue);
            else
                AFB_ERROR("ERROR 3! unexpected type %s %s", property.description.c_str(), property.type.c_str());
            properties[foundProperty] = property;
            registeredObjects[uri] = properties;
        }
    }
/** at that point all objects have been updated. Now lets see if we should also send back messages to our subscribers. */
    for(const std::string &m : candidateMessages) {
        for(const auto &p : events) {
            if(startsWith(m, p.first)) {
                std::map<std::string, json_object*> jsons;
                for(const auto &pp : registeredObjects) {
                    if(startsWith(pp.first, p.first)) {
                        jsons[pp.first] = generateJson(pp.first);
                    }
                }
                json_object *j = json_object_new_object();
                if(jsons.size() == 1) {
                    j = jsons[0];
                } else if(jsons.size() > 1) {
                    for(const auto &pp : jsons)
                        json_object_object_add(j, pp.first.c_str(), pp.second);
                }
                const int nbSubscribers = afb_event_push(p.second, j);
                if(nbSubscribers == 0) {
                    afb_event_drop(p.second);
                    events.erase(p.first);
                }
            }
        }
    }
}

/// @brief Generate json message for a resource, in ViWi format. Based on resource definition extracted from json
///        configuration file. If vector "fields" is not empty, will included only properties present in the vector.
///
/// @param[in] messageObject: resource's name, fields: list of properties to be included (NULL = all).
///
/// @return jsonObject containing the resource status for this resource's name.
json_object *High::generateJson(const std::string &messageObject, std::vector<std::string> *fields)
{
    json_object *json = json_object_new_object();
    const std::map<std::string, Property> props = registeredObjects.at(messageObject);
    for(const auto &p : props) {
        if(fields && fields->size() > 0 && p.first != "id" && p.first != "uri" && p.first != "name") {
            if(std::find(fields->begin(), fields->end(), p.first) == fields->end())
                continue;
        }
        if(p.second.type == "string") {
            const std::string value = p.second.value_string;
            json_object_object_add(json, p.first.c_str(), json_object_new_string(value.c_str()));
        } else if(p.second.type == "boolean") {
            const bool value = p.second.value_bool;
            json_object_object_add(json, p.first.c_str(), json_object_new_boolean(value));
        } else if(p.second.type == "double") {
            const double value = p.second.value_double;
            json_object_object_add(json, p.first.c_str(), json_object_new_double(value));
        } else if(p.second.type == "int") {
            const int value = p.second.value_int;
            json_object_object_add(json, p.first.c_str(), json_object_new_int(value));
        } else {
            AFB_ERROR("ERROR 1! unexpected type %s %s %s", p.first.c_str(), p.second.description.c_str(), p.second.type.c_str());
        }
    }
    return json;
}

/// @brief Generates a random UID
///
/// @return string containing the generated UID.
std::string High::generateId() const
{
    char id[50];
    sprintf(id, "%x-%x-%x-%x", (rand()%(int)1e7 + 1), (rand()%(int)1e7 + 1), (rand()%(int)1e7 + 1), (rand()%(int)1e7 + 1));
    return std::string(id);
}

/// @brief Entry point for subscribing to a resource. Can optionnally include a time interval in ms.
///
/// @param[in] request: afb-request containing a json request, for instance {"name":"/car/demoboard/", "interval":1000}
///
/// @return true if subscribed succeeded, false otherwise.
bool High::subscribe(afb_req request)
{
    /** /car/doors/3901a278-ba17-44d6-9aef-f7ca67c04840 */
    bool ok = false;
    json_object *args = afb_req_json(request);
    json_object *nameJson = NULL;
    json_object *intervalJson = NULL;
    if(!json_object_object_get_ex(args, "name", &nameJson))
        return false;
    json_object_object_get_ex(args, "interval", &intervalJson);
    int ms = -1;
    if(intervalJson)
        ms = json_object_get_int(intervalJson);
    std::string message(json_object_get_string(nameJson));
    if(message.size() == 0)
        return ok;
    for(const auto &p : registeredObjects) {
        if(startsWith(p.first, message)) {
            afb_event event;
            if(ms <= 0) {
                if(events.find(message) != events.end()) {
                    event = events.at(message);
                } else {
                    event = afb_daemon_make_event(p.first.c_str());
                    events[message] = event;
                }
                if (afb_event_is_valid(event) && afb_req_subscribe(request, event) == 0) {
                    ok = true;
                }
            } else {
                std::vector<TimedEvent> evts;
                if(timedEvents.find(ms) != timedEvents.end())
                    evts = timedEvents.at(ms);
                afb_event afbEvent;
                bool found = false;
                for(const auto & e : evts) {
                    if(e.name == message) {
                        afbEvent = e.event;
                        found = true;
                        break;
                    }
                }
                if(!found) {
                    char ext[20];
                    sprintf(ext, "_%d", ms);
                    std::string messageName = message + std::string(ext);
                    //AFB_NOTICE("subscribe with interval %s", messageName.c_str());
                    afbEvent = afb_daemon_make_event(messageName.c_str());
                    if (!afb_event_is_valid(afbEvent)) {
                        AFB_ERROR("unable to create event");
                        return false;
                    }
                    TimedEvent e;
                    e.name = message;
                    e.eventName = messageName;
                    e.event = afbEvent;
                    e.interval = ms;
                    evts.push_back(e);
                    timedEvents[ms] = evts;
                }
                if(afb_req_subscribe(request, afbEvent) == 0) {
                    ok = true;
                } else {
                    if(!found) {
                        evts.erase(evts.end() - 1);
                        timedEvents[ms] = evts;
                    }
                }
                if(timedEvents.size() == 0) {
                    timers.clear();
                } else if(ok) {
                    startTimer(ms);
                }
            }
            break;
        }
    }
    return ok;
}

/// @brief Entry point for unsubscribing to a resource. Can optionnally include a time interval in ms.
///
/// @param[in] request: afb-request containing a json request, for instance {"name":"/car/demoboard/", "interval":1000}
///
/// @return true if unsubscription succeeded, false otherwise.
bool High::unsubscribe(afb_req request)
{
    json_object *args = afb_req_json(request);
    json_object *nameJson = NULL;
    json_object *intervalJson = NULL;
    if(!json_object_object_get_ex(args, "name", &nameJson))
        return false;
    json_object_object_get_ex(args, "interval", &intervalJson);
    int ms = -1;
    if(intervalJson)
        ms = json_object_get_int(intervalJson);
    std::string message(json_object_get_string(nameJson));
    if(message.size() == 0)
        return false;
    if(ms <= 0) {
        if(events.find(message) != events.end()) {
            if(afb_req_unsubscribe(request, events.at(message)) == 0)
                return true;
        }
    } else {
        if(timedEvents.find(ms) == timedEvents.end())
            return false;
        const auto evts = timedEvents.at(ms);
        afb_event afbEvent;
        bool found = false;
        for(const auto & e : evts) {
            if(e.name == message) {
                afbEvent = e.event;
                found = true;
                break;
            }
        }
        if(!found)
            return false;
        if(afb_req_unsubscribe(request, afbEvent) == 0)
            return true;
    }
    return false;
}

/// @brief entry point for get requests. Accepts an optional list of properties to be included.
///
/// @param[in] request: afb-request containing a json request, for instance {"name":"/car/demoboard/", "fields":["vehicleSpeed"]},
///            **json: a pointer to a json object to be used for the reply.
///
/// @return true if get succeeded, false otherwise, and **json object generated with the reply.
bool High::get(afb_req request, json_object **json)
{
    json_object *args = afb_req_json(request);
    json_object *nameJson;
    json_object *fieldsJson;
    if(!json_object_object_get_ex(args, "name", &nameJson))
            return false;
    bool hasFields = json_object_object_get_ex(args, "fields", &fieldsJson);
    std::vector<std::string> fields;
    if(hasFields) {
        int arraylen = json_object_array_length(fieldsJson);
        json_object * jvalue;
        for(int i = 0; i < arraylen; ++i) {
          jvalue = json_object_array_get_idx(fieldsJson, i);
          fields.push_back(json_object_get_string(jvalue));
        }
    }
    const std::string name(json_object_get_string(nameJson));
    std::map<std::string, json_object*> jsons;
    for(const auto &p : registeredObjects) {
        if(startsWith(p.first, name))
            jsons[p.first] = generateJson(p.first, &fields);
    }
    if(jsons.size() == 0) {
        return false;
    }
    json_object *j = json_object_new_object();
    for(const auto &p : jsons) {
        json_object_object_add(j, p.first.c_str(), p.second);
    }
    *json = j;
    return true;
}

/// @brief Sub-routine (static) to check whether a string starts with another string
///
/// @param[in] s: string to scan, val: string to start with.
///
/// @return true if s starts with val, false otherwise.
bool High::startsWith(const std::string &s, const std::string &val)
{
    if(val.size() > s.size())
        return false;
    return s.substr(0, val.size()) == val;
}