homeassistant_service.h

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#pragma once
 
#include "api_server.h"
#ifdef USE_API
#ifdef USE_API_HOMEASSISTANT_SERVICES
#include <functional>
#include <string>
#include <type_traits>
#include <utility>
#include "api_pb2.h"
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
#include "esphome/components/json/json_util.h"
#endif
#include "esphome/core/automation.h"
#include "esphome/core/helpers.h"
#include "esphome/core/progmem.h"
#include "esphome/core/string_ref.h"
 
namespace esphome::api {
 
// Converts a lambda result to the string sent to Home Assistant
template<typename T>
requires(!std::is_pointer_v<std::remove_cvref_t<T>>) std::string field_to_string(T &&val) {
  return to_string(std::forward<T>(val));  // NOLINT
}
inline std::string field_to_string(const char *val) { return val ? std::string(val) : std::string(); }
inline std::string field_to_string(std::string val) { return val; }
inline std::string field_to_string(StringRef val) { return val.str(); }
 
template<typename... Ts> struct HomeAssistantField {
  const char *key;
  const char *value;
  std::string (*fn)(const Ts &...);
 
  template<typename F> static constexpr HomeAssistantField from_lambda(const char *key, F /*lambda*/) {
    return {key, nullptr, &call_lambda<F>};
  }
  template<typename F> static std::string call_lambda(const Ts &...x) { return field_to_string(F{}(x...)); }
};
 
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
// Represents the response data from a Home Assistant action
// Note: This class holds a StringRef to the error_message from the protobuf message.
// The protobuf message must outlive the ActionResponse (which is guaranteed since
// the callback is invoked synchronously while the message is on the stack).
class ActionResponse {
 public:
  ActionResponse(bool success, StringRef error_message) : success_(success), error_message_(error_message) {}
 
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
  ActionResponse(bool success, StringRef error_message, const uint8_t *data, size_t data_len)
      : success_(success), error_message_(error_message) {
    if (data == nullptr || data_len == 0)
      return;
    JsonDocument tmp = json::parse_json(data, data_len);
    swap(this->json_document_, tmp);
  }
#endif
 
  bool is_success() const { return this->success_; }
  // Returns reference to error message - can be implicitly converted to std::string if needed
  const StringRef &get_error_message() const { return this->error_message_; }
 
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
  // Get data as parsed JSON object (const version returns read-only view)
  JsonObjectConst get_json() const { return this->json_document_.as<JsonObjectConst>(); }
#endif
 
 protected:
  bool success_;
  StringRef error_message_;
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
  JsonDocument json_document_;
#endif
};
 
// Callback type for action responses
template<typename... Ts> using ActionResponseCallback = std::function<void(const ActionResponse &, Ts...)>;
#endif
 
template<typename... Ts> class HomeAssistantServiceCallAction final : public Action<Ts...> {
 public:
  using Field = HomeAssistantField<Ts...>;
 
  HomeAssistantServiceCallAction(APIServer *parent, bool is_event, const Field *fields, uint8_t data_count,
                                 uint8_t data_template_count, uint8_t variables_count)
      : parent_(parent),
        fields_(fields),
        data_count_(data_count),
        data_template_count_(data_template_count),
        variables_count_(variables_count) {
    this->flags_.is_event = is_event;
  }
 
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
  template<typename T> void set_response_template(T response_template) {
    this->response_template_ = response_template;
    this->flags_.has_response_template = true;
  }
 
  void set_wants_status() { this->flags_.wants_status = true; }
  void set_wants_response() { this->flags_.wants_response = true; }
 
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
  Trigger<JsonObjectConst, Ts...> *get_success_trigger_with_response() { return &this->success_trigger_with_response_; }
#endif
  Trigger<Ts...> *get_success_trigger() { return &this->success_trigger_; }
  Trigger<std::string, Ts...> *get_error_trigger() { return &this->error_trigger_; }
#endif  // USE_API_HOMEASSISTANT_ACTION_RESPONSES
 
  void play(const Ts &...x) override {
    const Field *fields = this->fields_;
    const size_t total = 1 + this->data_count_ + this->data_template_count_ + this->variables_count_;
 
    // Lambda results, and on ESP8266 the RAM copies of the flash strings, must live until the send
    size_t lambda_count = 0;
#ifdef USE_ESP8266
    size_t flash_len = 0;
#endif
    for (size_t i = 0; i < total; i++) {
      lambda_count += fields[i].fn != nullptr;
#ifdef USE_ESP8266
      if (fields[i].fn == nullptr)
        flash_len += ESPHOME_strlen_P(fields[i].value);
      if (fields[i].key != nullptr)
        flash_len += ESPHOME_strlen_P(fields[i].key);
#endif
    }
    FixedVector<std::string> results;
    results.init(lambda_count);
#ifdef USE_ESP8266
    SmallBufferWithHeapFallback<128, char> flash_copy(flash_len);
    char *cursor = flash_copy.get();
#endif
    auto string_ref = [&](const char *str) {
#ifdef USE_ESP8266
      size_t len = ESPHOME_strlen_P(str);
      memcpy_P(cursor, str, len);
      StringRef ref(cursor, len);
      cursor += len;
      return ref;
#else
      return StringRef(str);
#endif
    };
    auto value_ref = [&](const Field &field) {
      if (field.fn == nullptr)
        return string_ref(field.value);
      results.push_back(field.fn(x...));
      return StringRef(results.back());
    };
    auto fill = [&](FixedVector<HomeassistantServiceMap> &dest, uint8_t count) {
      dest.init(count);
      for (uint8_t i = 0; i < count; i++, fields++) {
        auto &kv = dest.emplace_back();
        kv.key = string_ref(fields->key);
        kv.value = value_ref(*fields);
      }
    };
 
    HomeassistantActionRequest resp;
    resp.service = value_ref(*fields++);
    resp.is_event = this->flags_.is_event;
    fill(resp.data, this->data_count_);
    fill(resp.data_template, this->data_template_count_);
    fill(resp.variables, this->variables_count_);
 
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
    // IMPORTANT: Declare at outer scope so it lives until send_homeassistant_action returns.
    std::string response_template_value;
#endif
    if (this->flags_.wants_status) {
      // Generate a unique call ID for this service call
      static uint32_t call_id_counter = 1;
      uint32_t call_id = call_id_counter++;
      resp.call_id = call_id;
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
      if (this->flags_.wants_response) {
        resp.wants_response = true;
        // Set response template if provided
        if (this->flags_.has_response_template) {
          response_template_value = this->response_template_.value(x...);
          resp.response_template = StringRef(response_template_value);
        }
      }
#endif
 
      auto captured_args = std::make_tuple(x...);
      this->parent_->register_action_response_callback(call_id, [this, captured_args](const ActionResponse &response) {
        std::apply(
            [this, &response](auto &&...args) {
              if (response.is_success()) {
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
                if (this->flags_.wants_response) {
                  this->success_trigger_with_response_.trigger(response.get_json(), args...);
                } else
#endif
                {
                  this->success_trigger_.trigger(args...);
                }
              } else {
                this->error_trigger_.trigger(response.get_error_message(), args...);
              }
            },
            captured_args);
      });
    }
#endif
 
    this->parent_->send_homeassistant_action(resp);
  }
 
 protected:
  APIServer *parent_;
  const Field *fields_;
  uint8_t data_count_;
  uint8_t data_template_count_;
  uint8_t variables_count_;
  struct Flags {
    uint8_t is_event : 1;
    uint8_t wants_status : 1;
    uint8_t wants_response : 1;
    uint8_t has_response_template : 1;
    uint8_t reserved : 4;
  } flags_{0};
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
#ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
  TemplatableValue<std::string, Ts...> response_template_{};
  Trigger<JsonObjectConst, Ts...> success_trigger_with_response_;
#endif  // USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
  Trigger<Ts...> success_trigger_;
  Trigger<std::string, Ts...> error_trigger_;
#endif  // USE_API_HOMEASSISTANT_ACTION_RESPONSES
};
 
}  // namespace esphome::api
 
#endif
#endif