#include "http_request_idf.h"

#ifdef USE_ESP32

#include "esphome/components/network/util.h"
#include "esphome/components/watchdog/watchdog.h"

#include "esphome/core/application.h"
#include "esphome/core/log.h"

#if CONFIG_MBEDTLS_CERTIFICATE_BUNDLE
#include "esp_crt_bundle.h"
#endif

#include "esp_task_wdt.h"

namespace esphome::http_request {

static const char *const TAG = "http_request.idf";

struct UserData {
  const std::set<std::string> &collect_headers;
  std::map<std::string, std::list<std::string>> response_headers;
};

void HttpRequestIDF::dump_config() {
  HttpRequestComponent::dump_config();
  ESP_LOGCONFIG(TAG,
                "  Buffer Size RX: %u\n"
                "  Buffer Size TX: %u",
                this->buffer_size_rx_, this->buffer_size_tx_);
}

esp_err_t HttpRequestIDF::http_event_handler(esp_http_client_event_t *evt) {
  UserData *user_data = (UserData *) evt->user_data;

  switch (evt->event_id) {
    case HTTP_EVENT_ON_HEADER: {
      const std::string header_name = str_lower_case(evt->header_key);
      if (user_data->collect_headers.count(header_name)) {
        const std::string header_value = evt->header_value;
        ESP_LOGD(TAG, "Received response header, name: %s, value: %s", header_name.c_str(), header_value.c_str());
        user_data->response_headers[header_name].push_back(header_value);
      }
      break;
    }
    default: {
      break;
    }
  }
  return ESP_OK;
}

std::shared_ptr<HttpContainer> HttpRequestIDF::perform(const std::string &url, const std::string &method,
                                                       const std::string &body,
                                                       const std::list<Header> &request_headers,
                                                       const std::set<std::string> &collect_headers) {
  if (!network::is_connected()) {
    this->status_momentary_error("failed", 1000);
    ESP_LOGE(TAG, "HTTP Request failed; Not connected to network");
    return nullptr;
  }

  esp_http_client_method_t method_idf;
  if (method == "GET") {
    method_idf = HTTP_METHOD_GET;
  } else if (method == "POST") {
    method_idf = HTTP_METHOD_POST;
  } else if (method == "PUT") {
    method_idf = HTTP_METHOD_PUT;
  } else if (method == "DELETE") {
    method_idf = HTTP_METHOD_DELETE;
  } else if (method == "PATCH") {
    method_idf = HTTP_METHOD_PATCH;
  } else {
    this->status_momentary_error("failed", 1000);
    ESP_LOGE(TAG, "HTTP Request failed; Unsupported method");
    return nullptr;
  }

  bool secure = url.find("https:") != std::string::npos;

  esp_http_client_config_t config = {};

  config.url = url.c_str();
  config.method = method_idf;
  config.timeout_ms = this->timeout_;
  config.disable_auto_redirect = !this->follow_redirects_;
  config.max_redirection_count = this->redirect_limit_;
  config.auth_type = HTTP_AUTH_TYPE_BASIC;
#if CONFIG_MBEDTLS_CERTIFICATE_BUNDLE
  if (secure && this->verify_ssl_) {
    config.crt_bundle_attach = esp_crt_bundle_attach;
  }
#endif

  if (this->useragent_ != nullptr) {
    config.user_agent = this->useragent_;
  }

  config.buffer_size = this->buffer_size_rx_;
  config.buffer_size_tx = this->buffer_size_tx_;

  const uint32_t start = millis();
  watchdog::WatchdogManager wdm(this->get_watchdog_timeout());

  config.event_handler = http_event_handler;
  auto user_data = UserData{collect_headers, {}};
  config.user_data = static_cast<void *>(&user_data);

  esp_http_client_handle_t client = esp_http_client_init(&config);

  std::shared_ptr<HttpContainerIDF> container = std::make_shared<HttpContainerIDF>(client);
  container->set_parent(this);

  container->set_secure(secure);

  for (const auto &header : request_headers) {
    esp_http_client_set_header(client, header.name.c_str(), header.value.c_str());
  }

  const int body_len = body.length();

  esp_err_t err = esp_http_client_open(client, body_len);
  if (err != ESP_OK) {
    this->status_momentary_error("failed", 1000);
    ESP_LOGE(TAG, "HTTP Request failed: %s", esp_err_to_name(err));
    esp_http_client_cleanup(client);
    return nullptr;
  }

  if (body_len > 0) {
    int write_left = body_len;
    int write_index = 0;
    const char *buf = body.c_str();
    while (write_left > 0) {
      int written = esp_http_client_write(client, buf + write_index, write_left);
      if (written < 0) {
        err = ESP_FAIL;
        break;
      }
      write_left -= written;
      write_index += written;
    }
  }

  if (err != ESP_OK) {
    this->status_momentary_error("failed", 1000);
    ESP_LOGE(TAG, "HTTP Request failed: %s", esp_err_to_name(err));
    esp_http_client_cleanup(client);
    return nullptr;
  }

  container->feed_wdt();
  // esp_http_client_fetch_headers() returns 0 for chunked transfer encoding (no Content-Length header).
  // The read() method handles content_length == 0 specially to support chunked responses.
  container->content_length = esp_http_client_fetch_headers(client);
  container->set_chunked(esp_http_client_is_chunked_response(client));
  container->feed_wdt();
  container->status_code = esp_http_client_get_status_code(client);
  container->feed_wdt();
  container->set_response_headers(user_data.response_headers);
  container->duration_ms = millis() - start;
  if (is_success(container->status_code)) {
    return container;
  }

  if (this->follow_redirects_) {
    auto num_redirects = this->redirect_limit_;
    while (is_redirect(container->status_code) && num_redirects > 0) {
      err = esp_http_client_set_redirection(client);
      if (err != ESP_OK) {
        ESP_LOGE(TAG, "esp_http_client_set_redirection failed: %s", esp_err_to_name(err));
        this->status_momentary_error("failed", 1000);
        esp_http_client_cleanup(client);
        return nullptr;
      }
#if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
      char redirect_url[256]{};
      if (esp_http_client_get_url(client, redirect_url, sizeof(redirect_url) - 1) == ESP_OK) {
        ESP_LOGV(TAG, "redirecting to url: %s", redirect_url);
      }
#endif
      err = esp_http_client_open(client, 0);
      if (err != ESP_OK) {
        ESP_LOGE(TAG, "esp_http_client_open failed: %s", esp_err_to_name(err));
        this->status_momentary_error("failed", 1000);
        esp_http_client_cleanup(client);
        return nullptr;
      }

      container->feed_wdt();
      container->content_length = esp_http_client_fetch_headers(client);
      container->set_chunked(esp_http_client_is_chunked_response(client));
      container->feed_wdt();
      container->status_code = esp_http_client_get_status_code(client);
      container->feed_wdt();
      container->duration_ms = millis() - start;
      if (is_success(container->status_code)) {
        return container;
      }

      num_redirects--;
    }

    if (num_redirects == 0) {
      ESP_LOGW(TAG, "Reach redirect limit count=%d", this->redirect_limit_);
    }
  }

  ESP_LOGE(TAG, "HTTP Request failed; URL: %s; Code: %d", url.c_str(), container->status_code);
  this->status_momentary_error("failed", 1000);
  return container;
}

// ESP-IDF HTTP read implementation (blocking mode)
//
// WARNING: Return values differ from BSD sockets! See http_request.h for full documentation.
//
// esp_http_client_read() in blocking mode returns:
//   > 0: bytes read
//   0: connection closed (end of stream)
//   < 0: error
//
// We normalize to HttpContainer::read() contract:
//   > 0: bytes read
//   0: all content read (only returned when content_length is known and fully read)
//   < 0: error/connection closed
//
// Note on chunked transfer encoding:
//   esp_http_client_fetch_headers() returns 0 for chunked responses (no Content-Length header).
//   We handle this by skipping the content_length check when content_length is 0,
//   allowing esp_http_client_read() to handle chunked decoding internally and signal EOF
//   by returning 0.
int HttpContainerIDF::read(uint8_t *buf, size_t max_len) {
  const uint32_t start = millis();
  watchdog::WatchdogManager wdm(this->parent_->get_watchdog_timeout());

  // Check if we've already read all expected content (non-chunked only)
  // For chunked responses (content_length == 0), esp_http_client_read() handles EOF
  if (this->is_read_complete()) {
    return 0;  // All content read successfully
  }

  this->feed_wdt();
  int read_len_or_error = esp_http_client_read(this->client_, (char *) buf, max_len);
  this->feed_wdt();

  this->duration_ms += (millis() - start);

  if (read_len_or_error > 0) {
    this->bytes_read_ += read_len_or_error;
    return read_len_or_error;
  }

  // esp_http_client_read() returns 0 in two cases:
  // 1. Known content_length: connection closed before all data received (error)
  // 2. Chunked encoding (content_length == 0): end of stream reached (EOF)
  // For case 1, returning HTTP_ERROR_CONNECTION_CLOSED is correct.
  // For case 2, 0 indicates that all chunked data has already been delivered
  // in previous successful read() calls, so treating this as a closed
  // connection does not cause any loss of response data.
  if (read_len_or_error == 0) {
    return HTTP_ERROR_CONNECTION_CLOSED;
  }

  // Negative value - error, return the actual error code for debugging
  return read_len_or_error;
}

void HttpContainerIDF::end() {
  if (this->client_ == nullptr) {
    return;  // Already cleaned up
  }
  watchdog::WatchdogManager wdm(this->parent_->get_watchdog_timeout());

  esp_http_client_close(this->client_);
  esp_http_client_cleanup(this->client_);
  this->client_ = nullptr;
}

void HttpContainerIDF::feed_wdt() {
  // Tests to see if the executing task has a watchdog timer attached
  if (esp_task_wdt_status(nullptr) == ESP_OK) {
    App.feed_wdt();
  }
}

}  // namespace esphome::http_request

#endif  // USE_ESP32
