#include "tlbmc/hal/gpio/gpio.h"

#include <gpiod.h>

#include <memory>
#include <string>

#include "absl/memory/memory.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/str_cat.h"
#include "g3/macros.h"
#include "gpio_config.pb.h"

namespace milotic_tlbmc {

namespace internal {
absl::StatusOr<int> ParseGpioRequestType(const GpioConfig& config) {
  switch (config.request_type_case()) {
    case GpioConfig::kGpioDirection:
      return config.gpio_direction() == GPIO_DIRECTION_INPUT
                 ? GPIOD_LINE_REQUEST_DIRECTION_INPUT
                 : GPIOD_LINE_REQUEST_DIRECTION_OUTPUT;
    case GpioConfig::kGpioEventConfig:
      switch (config.gpio_event_config().event_type()) {
        case GPIO_EVENT_RISING:
          return GPIOD_LINE_REQUEST_EVENT_RISING_EDGE;
        case GPIO_EVENT_FALLING:
          return GPIOD_LINE_REQUEST_EVENT_FALLING_EDGE;
        case GPIO_EVENT_BOTH:
          return GPIOD_LINE_REQUEST_EVENT_BOTH_EDGES;
        default:
          return absl::InvalidArgumentError("Unsupported GPIO event type");
      }
    default:
      return absl::InvalidArgumentError("Unsupported GPIO request type");
  }
}
}  // namespace internal

absl::StatusOr<bool> Gpio::GetValue() const {
  if (config_.gpio_direction() == GPIO_DIRECTION_OUTPUT) {
    return absl::FailedPreconditionError(
        "GPIO line in OUTPUT direction cannot be read");
  }

  int value = gpiod_line_get_value(gpio_line_.get());
  if (value < 0) {
    return absl::InternalError("Failed to get GPIO line value");
  }
  if (value == 1) {
    return true;
  }
  if (value == 0) {
    return false;
  }

  // This should not happen.
  return absl::InternalError("Invalid GPIO line value");
}

absl::Status Gpio::SetValue(bool value) {
  if (config_.gpio_direction() != GPIO_DIRECTION_OUTPUT) {
    return absl::FailedPreconditionError(
        "GPIO line is not in OUTPUT direction");
  }

  int write_value = value ? 1 : 0;
  if (gpiod_line_set_value(gpio_line_.get(), write_value) < 0) {
    return absl::InternalError("Failed to set GPIO line value");
  }
  return absl::OkStatus();
}

std::string Gpio::GetGpioName() const {
  if (config_.identifier_case() == GpioConfig::kGpioIdentifier) {
    return absl::StrCat(config_.gpio_identifier().chip_id(), ":",
                        config_.gpio_identifier().gpio_num());
  }
  if (config_.identifier_case() == GpioConfig::kLineName) {
    return config_.line_name();
  }
  // This should not happen.
  return "Unknown GPIO name";
}

absl::StatusOr<std::unique_ptr<Gpio>> Gpio::Create(const GpioConfig& config) {
  gpiod_line* line = nullptr;

  // If chip_id and gpio_num are provided, we can use the (chip_id, gpio_num) to
  // get the GPIO line. Otherwise, we use the line_name to get the GPIO line.
  if (config.identifier_case() == GpioConfig::kGpioIdentifier) {
    line = gpiod_line_get(config.gpio_identifier().chip_id().c_str(),
                          config.gpio_identifier().gpio_num());
  } else if (config.identifier_case() == GpioConfig::kLineName) {
    line = gpiod_line_find(config.line_name().c_str());
  } else {
    return absl::InvalidArgumentError(absl::StrCat(
        "Unsupported GPIO identifier: ", config.identifier_case()));
  }

  if (line == nullptr) {
    return absl::InternalError(
        absl::StrCat("Failed to find GPIO line: ", config.line_name()));
  }

  gpiod_line_request_config request_config{
      .consumer = "tlbmc-gpio",
      .flags = 0,
  };

  ECCLESIA_ASSIGN_OR_RETURN(auto request_type,
                            internal::ParseGpioRequestType(config));
  request_config.request_type = request_type;

  if (gpiod_line_request(line, &request_config, /*flags=*/0) < 0) {
    return absl::InternalError("Failed to request GPIO line");
  }

  int fd = -1;
  if (config.request_type_case() == GpioConfig::kGpioEventConfig) {
    fd = gpiod_line_event_get_fd(line);
    if (fd < 0) {
      return absl::InternalError("Failed to get GPIO line event fd");
    }
  }

  return absl::WrapUnique(new Gpio(config, GpioLineUniquePtr(line), fd));
}

}  // namespace milotic_tlbmc