#include "external/mtr/mtr.h"
#include "external/mtr/line_info.h"
#include "external/mtr/station_info.h"
#include "external/mtr/arrival.h"
#include "assets/MTR_LINE_STATION.h"
#include "network/network.h"
#include "network/http_handler.h"
#include "cJSON.h"
#include "esp_log.h"
#include <string>
#include <stdlib.h>
#include <string.h>
#include "esp_crt_bundle.h"

static const char* TAG = "MTRNextTrainHandler";

// MTR Next Train API endpoint
static const char* MTR_API_BASE = "https://rt.data.gov.hk/v1/transport/mtr/getSchedule.php";

MTRNextTrainHandler::MTRNextTrainHandler() {
  ESP_LOGI(TAG, "Initializing MTR Next Train Handler");
  mtr_data = cJSON_Parse(MTR_LINE_STATION_JSON);
  if (!mtr_data) {
    ESP_LOGE(TAG, "Failed to parse MTR line station JSON");
  } else {
    ESP_LOGI(TAG, "Successfully parsed MTR line station JSON");
  }
}

MTRNextTrainHandler::~MTRNextTrainHandler() {
  if (mtr_data) {
    cJSON_Delete(mtr_data);
    mtr_data = nullptr;
  }
  ESP_LOGI(TAG, "MTR Next Train Handler destroyed");
}

std::vector<LineInfo> MTRNextTrainHandler::get_lines() {
  std::vector<LineInfo> lines;

  if (!mtr_data) {
    ESP_LOGE(TAG, "MTR data not initialized");
    return lines;
  }

  // Iterate through all line objects in the JSON
  cJSON* line_json = mtr_data->child;
  while (line_json) {
    if (cJSON_IsObject(line_json)) {
      lines.push_back(LineInfo(line_json));
    }
    line_json = line_json->next;
  }

  ESP_LOGI(TAG, "Retrieved %zu MTR lines", lines.size());
  return lines;
}

MtrArrivalErrorCode MTRNextTrainHandler::get_next_arrival_info(
  NetworkHandler* network_handler,
  std::string& line_code,
  std::string& station_code,
  StationArrivalInfo*& out_info,
  Language lang
) {
  if (!network_handler) {
    ESP_LOGE(TAG, "NetworkHandler is null");
    return MtrArrivalErrorCode::UNKNOWN;
  }

  if (!mtr_data) {
    ESP_LOGE(TAG, "MTR data not initialized");
    return MtrArrivalErrorCode::UNKNOWN;
  }

  // Verify line exists
  cJSON* line_json = cJSON_GetObjectItem(mtr_data, line_code.c_str());
  if (!line_json) {
    ESP_LOGW(TAG, "Line not found: %s", line_code.c_str());
    return MtrArrivalErrorCode::LINE_NOT_FOUND;
  }

  // Verify station exists in line
  bool station_found = false;
  cJSON* stations_json = cJSON_GetObjectItem(line_json, "stations");
  if (stations_json && cJSON_IsArray(stations_json)) {
    int station_count = cJSON_GetArraySize(stations_json);
    for (int i = 0; i < station_count; i++) {
      cJSON* station = cJSON_GetArrayItem(stations_json, i);
      cJSON* code_json = cJSON_GetObjectItem(station, "code");
      if (code_json && cJSON_IsString(code_json)) {
        if (station_code == code_json->valuestring) {
          station_found = true;
          break;
        }
      }
    }
  }

  if (!station_found) {
    ESP_LOGW(TAG, "Station not found: %s in line %s", station_code.c_str(), line_code.c_str());
    return MtrArrivalErrorCode::STATION_NOT_FOUND;
  }

  // Build API URL
  std::string url_str = MTR_API_BASE;
  url_str += "?line=";
  url_str += line_code;
  url_str += "&sta=";
  url_str += station_code;
  if (lang == Language::EN) {
    url_str += "&lang=en";
  }
  ESP_LOGI(TAG, "Fetching arrival info from: %s", url_str.c_str());

  // Create HTTP client configuration
  esp_http_client_config_t http_config = {};
  http_config.url = url_str.c_str();
  http_config.timeout_ms = 15000;
  http_config.transport_type = HTTP_TRANSPORT_OVER_SSL;
  http_config.crt_bundle_attach = esp_crt_bundle_attach;

  // Retry logic for connection failures
  constexpr int MAX_RETRIES = 2;
  esp_err_t err = ESP_FAIL;
  char* buffer = nullptr;
  int total_len = 0;

  for (int retry = 0; retry <= MAX_RETRIES; retry++) {
    if (retry > 0) {
      ESP_LOGW(TAG, "Retrying HTTP request (%d/%d)", retry, MAX_RETRIES);
      vTaskDelay(pdMS_TO_TICKS(500));
    }

    // Create HTTP client configuration for each attempt
    esp_http_client_config_t http_config = {};
    http_config.url = url_str.c_str();
    http_config.timeout_ms = 15000;
    http_config.transport_type = HTTP_TRANSPORT_OVER_SSL;
    http_config.crt_bundle_attach = esp_crt_bundle_attach;

    // Get HTTP handler and perform request
    auto http_handler = network_handler->get_http_handler(std::move(http_config));
    if (!http_handler) {
      ESP_LOGE(TAG, "Failed to create HTTP handler");
      continue;
    }

    err = http_handler->perform_request();
    if (err != ESP_OK) {
      ESP_LOGE(TAG, "HTTP request failed: %s", esp_err_to_name(err));
      continue;
    }

    // Get response body
    http_handler->get_body(buffer, total_len);

    if (buffer && total_len > 0) {
      break;
    }

    if (buffer) {
      free(buffer);
      buffer = nullptr;
    }
  }

  if (err != ESP_OK || !buffer || total_len <= 0) {
    ESP_LOGE(TAG, "Failed to get response after retries");
    if (buffer) {
      free(buffer);
    }
    return MtrArrivalErrorCode::NO_ARRIVAL_INFO;
  }

  ESP_LOGI(TAG, "Received %d bytes from MTR API", total_len);

  ESP_LOGI(TAG, "Parsing full API response");
  cJSON* root_json = cJSON_Parse(buffer);
  delete[] buffer;

  if (!root_json) {
    const char* error_ptr = cJSON_GetErrorPtr();
    if (error_ptr) {
      ESP_LOGE(TAG, "Failed to parse MTR API response at position: %s", error_ptr);
    } else {
      ESP_LOGE(TAG, "Failed to parse MTR API response - unknown error");
    }
    return MtrArrivalErrorCode::NO_ARRIVAL_INFO;
  }

  cJSON* data_json = cJSON_GetObjectItem(root_json, "data");
  if (!data_json) {
    ESP_LOGE(TAG, "Could not find 'data' object in response");
    cJSON_Delete(root_json);
    return MtrArrivalErrorCode::NO_ARRIVAL_INFO;
  }

  std::string station_key = line_code + "-" + station_code;
  cJSON* station_json = cJSON_GetObjectItem(data_json, station_key.c_str());
  if (!station_json) {
    ESP_LOGE(TAG, "Could not find station key '%s' in data object", station_key.c_str());
    cJSON_Delete(root_json);
    return MtrArrivalErrorCode::NO_ARRIVAL_INFO;
  }

  cJSON* status_json = cJSON_GetObjectItem(root_json, "status");
  if (status_json && cJSON_IsNumber(status_json)) {
    cJSON_AddItemToObject(station_json, "status", cJSON_Duplicate(status_json, 1));
  }

  cJSON* message_json = cJSON_GetObjectItem(root_json, "message");
  if (message_json && cJSON_IsString(message_json)) {
    cJSON_AddItemToObject(station_json, "message", cJSON_Duplicate(message_json, 1));
  }

  out_info = new StationArrivalInfo(mtr_data, station_json, line_code, station_code);

  cJSON_Delete(root_json);

  ESP_LOGI(TAG, "Successfully retrieved arrival info for %s/%s", line_code.c_str(), station_code.c_str());
  return MtrArrivalErrorCode::NONE;
}