#include "webserver.h"

#include <Arduino.h>
#include <ESPAsyncWebServer.h>
#include <LittleFS.h>
#include <Elog.h>
#include <AsyncTCP.h>
#include <Preferences.h>
#include "tools/log.h"
#include "AsyncJson.h"
#include <ArduinoJson.h>
#include <SPIFFS.h>
#include <freertos/FreeRTOS.h>
#include <freertos/semphr.h>
#include <freertos/queue.h>

#include "../global_data/global_data.h"
#include "../tools/tools.h"
#include "../tools/readers_writer_lock.h"
#include "../tools/ota.h"
#include "../global_data/defines.h"
#include "json_builder.h"

AsyncWebServer server(80);

// Queue handles (initialized in webserver_task)
static QueueHandle_t g_dataQueue = NULL;
static QueueHandle_t g_prefsQueue = NULL;


WaterData local_water_data;
SensorData local_sensor_data;
NetworkData local_wifi_data;
NetworkData local_ethernet_data;
DeviceTelemetry local_telemetry;
OTAStatus local_ota_status;

// Local preference storage for template processing
float local_level_sensor_range = -1.0f;
float local_water_level_min = 0.0f;
float local_water_level_max = 200.0f;
float local_water_volume = 10000.0f;
char local_ssid[33] = "";
char local_wifi_password[65] = "";

ReadersWriterLock waterDataLock;
ReadersWriterLock sensorDataLock;
ReadersWriterLock networkDataLock;
ReadersWriterLock telemetryDataLock;
ReadersWriterLock otaStatusLock;



// ======================
// Template Processor
// ======================

/**
 * @brief Template processor for substituting variables in HTML/JavaScript templates.
 * 
 * Replaces template placeholders with values from preferences.
 * Used by AsyncWebServer when serving template files.
 * 
 * @param var The template variable name to replace
 * @return String The value to substitute, or empty string if not found
 */
String processor(const String& var)
{
  if (var == level_sensor_range_key) {
    return String(local_level_sensor_range);
  } else if (var == water_level_min_key) {
    return String(local_water_level_min);
  } else if (var == water_level_max_key) {
    return String(local_water_level_max);
  } else if (var == water_volume_key) {
    return String(local_water_volume);
  } else if (var == ssid_key) {
    return String(local_ssid);
  }
    
  return String("");
}


// ======================
// Webserver Setup
// ======================

/**
 * @brief Sets up all routes for the webserver.
 * 
 * Configures routes for serving HTML pages, handling form submissions,
 * REST API endpoints and static assets.
 * 
 * @note Calls setup_api_endpoints() to configure API-specific routes.
 */
void setup_routes() {
    server.on("/", HTTP_GET, [](AsyncWebServerRequest* request) { request->send(LittleFS, "/status.html", "text/html", false, processor); });

    server.on("/settings", HTTP_GET, [](AsyncWebServerRequest* request) { request->send(LittleFS, "/settings.html", "text/html", false, processor); });

    server.on("/export", HTTP_GET, [](AsyncWebServerRequest* request) { request->send(LittleFS, "/data_export.html", "text/html", false); });

    server.on("/logic.js", HTTP_GET, [](AsyncWebServerRequest* request) { request->send(LittleFS, "/logic.js", "application/javascript", false, processor); });

    server.on("/update", HTTP_GET, [](AsyncWebServerRequest* request) { request->send(LittleFS, "/update_progress.html", "text/html", false, processor); });

    // API stuff - internal
    server.on("/update_wifi_credentials", HTTP_POST, [](AsyncWebServerRequest* request) {
        handle_update_wifi_credentials(request);
    });

    server.on("/update_sensor_settings", HTTP_POST, [](AsyncWebServerRequest* request) {
        handle_update_sensor_settings(request);
    });
    
    setup_api_endpoints();

    server.on("/chota.css", HTTP_GET, [](AsyncWebServerRequest* request) { request->send(LittleFS, "/chota.css", "text/css", false); });
    server.on("/gauge.js", HTTP_GET, [](AsyncWebServerRequest* request) { request->send(LittleFS, "/gauge.js", "application/javascript", false); });
}

/**
 * @brief Configures REST API endpoints for data retrieval.
 * 
 * Sets up endpoints to fetch sensor data, water data, telemetry,
 * network information, and OTA update status in JSON format.
 * 
 * @note These endpoints are used by the frontend to dynamically
 *       display device status and configuration.
 */
void setup_api_endpoints(){
    server.on("/sensor_data", HTTP_GET, [](AsyncWebServerRequest* request) {
      rwLockAcquireRead(&sensorDataLock);
      String output;
      build_shunt_data_json(local_sensor_data, output);
      rwLockReleaseRead(&sensorDataLock);
      request->send(200, "application/json", output); });

    server.on("/water_data", HTTP_GET, [](AsyncWebServerRequest* request) {
      rwLockAcquireRead(&waterDataLock);
      String output;
      build_water_data_json(local_water_data, output);
      rwLockReleaseRead(&waterDataLock);
      request->send(200, "application/json", output);
    });

    server.on("/raw_percent", HTTP_GET, [](AsyncWebServerRequest* request) {
      rwLockAcquireRead(&waterDataLock);
      String output = String(local_water_data.percentage);
      rwLockReleaseRead(&waterDataLock);
      request->send(200, "text/raw", output);
    });

    server.on("/raw_level", HTTP_GET, [](AsyncWebServerRequest* request) {
      rwLockAcquireRead(&waterDataLock);
      String output = String(local_water_data.level);
      rwLockReleaseRead(&waterDataLock);
      request->send(200, "text/raw", output);
    });
  
    server.on("/telemetry", HTTP_GET, [](AsyncWebServerRequest* request) {
      rwLockAcquireRead(&telemetryDataLock);
      String output;
      build_telemetry_json(local_telemetry, output);
      rwLockReleaseRead(&telemetryDataLock);
      request->send(200, "application/json", output); });

    server.on("/network_info", HTTP_GET, [](AsyncWebServerRequest* request) {
        rwLockAcquireRead(&networkDataLock);
        String output;
        build_network_json(local_ethernet_data, local_wifi_data, output);
        rwLockReleaseRead(&networkDataLock);
        request->send(200, "application/json", output);
    });

    server.on("/ota_update_status", HTTP_GET, [](AsyncWebServerRequest* request) {
      rwLockAcquireRead(&otaStatusLock);
      String output;
      build_ota_json(local_ota_status, output);
      rwLockReleaseRead(&otaStatusLock);
      request->send(200, "application/json", output); });

    server.on("/run_ota_update", HTTP_GET, [](AsyncWebServerRequest* request) {
      if (local_ota_status.update_progress > -1) {
        request->send(200, "text/plain", "OTA Update already in progress");
        return;
      } else if (!local_ota_status.update_available) {
        request->send(200, "text/plain", "No update available");
        return;
      }

      static TaskArgs_t args = {
        .ota_status = local_ota_status
      };

      xTaskCreate(run_ota_update_task, "RunOTAUpdate", 1024 * 8, (void *)&args, 1, NULL);
      request->send(LittleFS, "/update_progress.html", "text/html", false, processor);
    });
}

// ======================
// Helper Functions
// ======================

/**
 * @brief Handles the update of WiFi credentials.
 * 
 * Validates and sends SSID and password update request to main task.
 * Main task will write to preferences and distribute to tasks.
 * 
 * @param request The web server request object.
 */
void handle_update_wifi_credentials(AsyncWebServerRequest* request) {
    if (request->hasParam(ssid_key, true) && request->hasParam(wifi_password_key, true)) {
        LOG(ELOG_LEVEL_DEBUG, "Updating SSID config");
        const AsyncWebParameter* ssid_param = request->getParam(ssid_key, true);
        const AsyncWebParameter* password_param = request->getParam(wifi_password_key, true);
        
        // Send preference update to main task
        DataMessage prefsMessage;
        prefsMessage.type = DATA_TYPE_PREFERENCES;
        prefsMessage.data.preferencesData.level_sensor_range = local_level_sensor_range; // Keep existing values
        prefsMessage.data.preferencesData.water_level_min = local_water_level_min;
        prefsMessage.data.preferencesData.water_level_max = local_water_level_max;
        prefsMessage.data.preferencesData.water_volume = local_water_volume;
        strncpy(prefsMessage.data.preferencesData.ssid, ssid_param->value().c_str(), sizeof(prefsMessage.data.preferencesData.ssid) - 1);
        prefsMessage.data.preferencesData.ssid[sizeof(prefsMessage.data.preferencesData.ssid) - 1] = '\0';
        strncpy(prefsMessage.data.preferencesData.wifi_password, password_param->value().c_str(), sizeof(prefsMessage.data.preferencesData.wifi_password) - 1);
        prefsMessage.data.preferencesData.wifi_password[sizeof(prefsMessage.data.preferencesData.wifi_password) - 1] = '\0';
        
        if (g_dataQueue != NULL && xQueueSend(g_dataQueue, &prefsMessage, 100 / portTICK_PERIOD_MS) != pdTRUE) {
            LOG(ELOG_LEVEL_ERROR, "Failed to send WiFi credentials update to main");
        }
    } else {
        request->send(400, "text/plain", "Missing parameters");
        return;
    }
    request->send(LittleFS, "/settings.html", "text/html", false, processor);
}

/**
 * @brief Handles the update of sensor settings.
 * 
 * Validates and updates sensor configuration parameters in preferences.
 * 
 * @param request The web server request object.
 */
void handle_update_sensor_settings(AsyncWebServerRequest* request) {
    int params = request->params();

    if (request->hasParam(level_sensor_range_key, true) && request->hasParam(water_level_min_key, true) && 
        request->hasParam(water_level_max_key, true) && request->hasParam(water_volume_key, true)) {
        LOG(ELOG_LEVEL_DEBUG, "Updating Sensor config");
        const AsyncWebParameter* range_param = request->getParam(level_sensor_range_key, true);
        const AsyncWebParameter* level_min_param = request->getParam(water_level_min_key, true);
        const AsyncWebParameter* level_max_param = request->getParam(water_level_max_key, true);
        const AsyncWebParameter* liters_param = request->getParam(water_volume_key, true);

        String range_str = range_param->value();
        String level_min_str = level_min_param->value();
        String level_max_str = level_max_param->value();
        String liters_str = liters_param->value();

        float range_float = range_str.toFloat();
        float level_min_float = level_min_str.toFloat();
        float level_max_float = level_max_str.toFloat();
        float liters_float = liters_str.toFloat();

        LOG(ELOG_LEVEL_DEBUG, "range_float:%D:", range_float);

        // Send preference update to main task
        DataMessage prefsMessage;
        prefsMessage.type = DATA_TYPE_PREFERENCES;
        prefsMessage.data.preferencesData.level_sensor_range = range_float;
        prefsMessage.data.preferencesData.water_level_min = level_min_float;
        prefsMessage.data.preferencesData.water_level_max = level_max_float;
        prefsMessage.data.preferencesData.water_volume = liters_float;
        strncpy(prefsMessage.data.preferencesData.ssid, local_ssid, sizeof(prefsMessage.data.preferencesData.ssid) - 1);
        prefsMessage.data.preferencesData.ssid[sizeof(prefsMessage.data.preferencesData.ssid) - 1] = '\0';
        strncpy(prefsMessage.data.preferencesData.wifi_password, local_wifi_password, sizeof(prefsMessage.data.preferencesData.wifi_password) - 1);
        prefsMessage.data.preferencesData.wifi_password[sizeof(prefsMessage.data.preferencesData.wifi_password) - 1] = '\0';
        
        if (g_dataQueue != NULL && xQueueSend(g_dataQueue, &prefsMessage, 100 / portTICK_PERIOD_MS) != pdTRUE) {
            LOG(ELOG_LEVEL_ERROR, "Failed to send sensor settings update to main");
        }

        LOG(ELOG_LEVEL_DEBUG, "Sent sensor settings update to main");
    } else {
        LOG(ELOG_LEVEL_DEBUG, "!!!! FAIL lo");
        for (int i = 0; i < params; i++) {
            const AsyncWebParameter* p = request->getParam(i);
            if (p->isFile()) {
                LOG(ELOG_LEVEL_DEBUG, "POST[%s]: %s\n", p->name().c_str(), p->value().c_str());
            } else if (p->isPost()) {
                LOG(ELOG_LEVEL_DEBUG, "POST[%s]: %s\n", p->name().c_str(), p->value().c_str());
            } else {
                LOG(ELOG_LEVEL_DEBUG, "GET[%s]: %s\n", p->name().c_str(), p->value().c_str());
            }
        }
        request->send(400, "text/plain", "Missing parameters");
        return;
    }
    request->send(LittleFS, "/settings.html", "text/html", false);
}

/**
 * @brief Main task for the webserver.
 * 
 * Initializes all routes, starts the webserver, and sets up local water data.
 * Receives the current state from the main task via a queue and updates local_water_data.
 * Runs indefinitely to keep the server active.
 * 
 * @param pvParameters Task parameters (expected to be a WebserverQueues* containing stateQueue, dataQueue, and prefsQueue).
 */
void webserver_task(void *pvParameters) {
    // Extract the queue handles from the task parameters
    WebserverQueues* queues = (WebserverQueues*)pvParameters;
    if (queues == NULL || queues->stateQueue == NULL) {
        LOG(ELOG_LEVEL_ERROR, "Queue parameters are NULL");
        vTaskDelete(NULL);
        return;
    }
    
    // Store queue handles in file-scoped variables
    g_dataQueue = queues->dataQueue;
    g_prefsQueue = queues->prefsQueue;
    QueueHandle_t stateQueue = queues->stateQueue;
    
    LOG(ELOG_LEVEL_DEBUG, "Setting up routes");
    setup_routes();
    
    // Initialize the readers-writer locks
    if (!rwLockInit(&waterDataLock)) {
        LOG(ELOG_LEVEL_ERROR, "Failed to initialize water data readers-writer lock");
        vTaskDelete(NULL);
        return;
    }
    
    if (!rwLockInit(&sensorDataLock)) {
        LOG(ELOG_LEVEL_ERROR, "Failed to initialize sensor data readers-writer lock");
        vTaskDelete(NULL);
        return;
    }
    
    if (!rwLockInit(&networkDataLock)) {
        LOG(ELOG_LEVEL_ERROR, "Failed to initialize network data readers-writer lock");
        vTaskDelete(NULL);
        return;
    }
    
    if (!rwLockInit(&telemetryDataLock)) {
        LOG(ELOG_LEVEL_ERROR, "Failed to initialize telemetry data readers-writer lock");
        vTaskDelete(NULL);
        return;
    }
    
    if (!rwLockInit(&otaStatusLock)) {
        LOG(ELOG_LEVEL_ERROR, "Failed to initialize OTA status readers-writer lock");
        vTaskDelete(NULL);
        return;
    }
    
    // Initialize local water data with static values
    rwLockAcquireWrite(&waterDataLock);
    local_water_data.level = -1.0;
    local_water_data.liters = -1.0;
    local_water_data.percentage = -1.0;
    rwLockReleaseWrite(&waterDataLock);
    
    // Initialize local sensor data with static values
    rwLockAcquireWrite(&sensorDataLock);
    local_sensor_data.bus_voltage = -1.0;
    local_sensor_data.shunt_voltage = -1.0;
    local_sensor_data.shunt_current = -1.0;
    rwLockReleaseWrite(&sensorDataLock);
    
    // Initialize local network data with static values
    rwLockAcquireWrite(&networkDataLock);
    strcpy(local_wifi_data.ip_address, "0.0.0.0");
    local_wifi_data.link = false;
    local_wifi_data.rssi = -1.0;
    strcpy(local_wifi_data.network_name, "UNKNOWN");
    
    strcpy(local_ethernet_data.ip_address, "0.0.0.0");
    local_ethernet_data.link = false;
    local_ethernet_data.rssi = -1.0;
    strcpy(local_ethernet_data.network_name, "UNKNOWN");
    rwLockReleaseWrite(&networkDataLock);
    
    // Initialize local telemetry data with static values
    rwLockAcquireWrite(&telemetryDataLock);
    local_telemetry.heap_used_percent = -1.0;
    local_telemetry.uptime_seconds = -1;
    local_telemetry.temperature = -1.0;
    rwLockReleaseWrite(&telemetryDataLock);
    
    // Initialize local OTA status with static values
    rwLockAcquireWrite(&otaStatusLock);
    local_ota_status.update_available = false;
    local_ota_status.current_version = {0, 0, 0};
    local_ota_status.latest_version = {0, 0, 0};
    local_ota_status.update_progress = -1;
    strncpy(local_ota_status.update_url, "UNKNOWN", sizeof(local_ota_status.update_url) - 1);
    local_ota_status.update_url[sizeof(local_ota_status.update_url) - 1] = '\0';
    rwLockReleaseWrite(&otaStatusLock);
    
    LOG(ELOG_LEVEL_DEBUG, "Starting webserver");
    server.begin();
    
    while (1) {
        // Check if there is new preference data in the queue
        DataMessage prefsMessage;
        if (g_prefsQueue != NULL && xQueueReceive(g_prefsQueue, &prefsMessage, 0) == pdTRUE) {
            if (prefsMessage.type == DATA_TYPE_PREFERENCES) {
                // Update local preference values
                local_level_sensor_range = prefsMessage.data.preferencesData.level_sensor_range;
                local_water_level_min = prefsMessage.data.preferencesData.water_level_min;
                local_water_level_max = prefsMessage.data.preferencesData.water_level_max;
                local_water_volume = prefsMessage.data.preferencesData.water_volume;
                strncpy(local_ssid, prefsMessage.data.preferencesData.ssid, sizeof(local_ssid) - 1);
                local_ssid[sizeof(local_ssid) - 1] = '\0';
                strncpy(local_wifi_password, prefsMessage.data.preferencesData.wifi_password, sizeof(local_wifi_password) - 1);
                local_wifi_password[sizeof(local_wifi_password) - 1] = '\0';
                LOG(ELOG_LEVEL_DEBUG, "Updated preferences: range=%F, min=%F, max=%F, volume=%F, ssid=%s",
                    local_level_sensor_range, local_water_level_min, local_water_level_max,
                    local_water_volume, local_ssid);
            }
        }
        
        // Check if there is new state data in the queue
        CurrentState currentState;
        if (xQueueReceive(stateQueue, &currentState, portMAX_DELAY) == pdTRUE) {
            // Update local_water_data with the new data from the queue
            rwLockAcquireWrite(&waterDataLock);
            local_water_data = currentState.waterData;
            rwLockReleaseWrite(&waterDataLock);
            
            // Update local_sensor_data with the new data from the queue
            rwLockAcquireWrite(&sensorDataLock);
            local_sensor_data = currentState.sensorData;
            rwLockReleaseWrite(&sensorDataLock);
            
            // Update local network data with the new data from the queue
            rwLockAcquireWrite(&networkDataLock);
            local_wifi_data = currentState.wifiData;
            local_ethernet_data = currentState.ethernetData;
            rwLockReleaseWrite(&networkDataLock);
            
            // Update local telemetry data with the new data from the queue
            rwLockAcquireWrite(&telemetryDataLock);
            local_telemetry = currentState.telemetryData;
            rwLockReleaseWrite(&telemetryDataLock);
            
            // Update local OTA status with the new data from the queue
            rwLockAcquireWrite(&otaStatusLock);
            local_ota_status = currentState.otaStatus;
            rwLockReleaseWrite(&otaStatusLock);
        }
    }
}