#include "pca9554.h"
#include "esphome/core/log.h"

namespace esphome::pca9554 {

// for 16 bit expanders, these addresses will be doubled.
const uint8_t INPUT_REG = 0;
const uint8_t OUTPUT_REG = 1;
const uint8_t INVERT_REG = 2;
const uint8_t CONFIG_REG = 3;

static const char *const TAG = "pca9554";

void PCA9554Component::setup() {
  this->reg_width_ = (this->pin_count_ + 7) / 8;
  // Test to see if device exists
  if (!this->read_inputs_()) {
    ESP_LOGE(TAG, "PCA95xx not detected at 0x%02X", this->address_);
    this->mark_failed();
    return;
  }

  // No polarity inversion
  this->write_register_(INVERT_REG, 0);
  // All inputs at initialization
  this->config_mask_ = 0;
  // Invert mask as the part sees a 1 as an input
  this->write_register_(CONFIG_REG, ~this->config_mask_);
  // All outputs low
  this->output_mask_ = 0;
  this->write_register_(OUTPUT_REG, this->output_mask_);
  // Read the inputs
  this->read_inputs_();
  ESP_LOGD(TAG, "Initialization complete. Warning: %d, Error: %d", this->status_has_warning(),
           this->status_has_error());

  if (this->interrupt_pin_ != nullptr) {
    this->interrupt_pin_->setup();
    this->interrupt_pin_->attach_interrupt(&PCA9554Component::gpio_intr, this, gpio::INTERRUPT_FALLING_EDGE);
    // Don't invalidate cache on read — only invalidate when interrupt fires
    this->set_invalidate_on_read_(false);
  }
  // Disable loop until an input pin is configured via pin_mode()
  // For interrupt-driven mode, loop is re-enabled by the ISR
  // For polling mode, loop is re-enabled when pin_mode() registers an input pin
  this->disable_loop();
}
void IRAM_ATTR PCA9554Component::gpio_intr(PCA9554Component *arg) { arg->enable_loop_soon_any_context(); }
void PCA9554Component::loop() {
  // Invalidate the cache so the next digital_read() triggers a fresh I2C read
  this->reset_pin_cache_();
  // Only disable the loop once INT has actually gone HIGH. Input transitions that straddle the
  // I2C read leave INT asserted without re-firing a falling edge, which would strand us with
  // stale state forever; keep looping until the line is released so we self-heal.
  if (this->interrupt_pin_ != nullptr && this->interrupt_pin_->digital_read()) {
    this->disable_loop();
  }
}

void PCA9554Component::dump_config() {
  ESP_LOGCONFIG(TAG,
                "PCA9554:\n"
                "  I/O Pins: %d",
                this->pin_count_);
  LOG_PIN("  Interrupt Pin: ", this->interrupt_pin_);
  LOG_I2C_DEVICE(this)
  if (this->is_failed()) {
    ESP_LOGE(TAG, ESP_LOG_MSG_COMM_FAIL);
  }
}

bool PCA9554Component::digital_read_hw(uint8_t pin) {
  // Read all pins from hardware into input_mask_
  return this->read_inputs_();  // Return true if I2C read succeeded, false on error
}

bool PCA9554Component::digital_read_cache(uint8_t pin) {
  // Return the cached pin state from input_mask_
  return this->input_mask_ & (1 << pin);
}

void PCA9554Component::digital_write_hw(uint8_t pin, bool value) {
  if (value) {
    this->output_mask_ |= (1 << pin);
  } else {
    this->output_mask_ &= ~(1 << pin);
  }
  this->write_register_(OUTPUT_REG, this->output_mask_);
}

void PCA9554Component::pin_mode(uint8_t pin, gpio::Flags flags) {
  if (flags == gpio::FLAG_INPUT) {
    // Clear mode mask bit
    this->config_mask_ &= ~(1 << pin);
    // Enable polling loop for input pins (not needed for interrupt-driven mode
    // where the ISR handles re-enabling loop)
    if (this->interrupt_pin_ == nullptr) {
      this->enable_loop();
    }
  } else if (flags == gpio::FLAG_OUTPUT) {
    // Set mode mask bit
    this->config_mask_ |= 1 << pin;
  }
  this->write_register_(CONFIG_REG, ~this->config_mask_);
}

bool PCA9554Component::read_inputs_() {
  uint8_t inputs[2];

  if (this->is_failed()) {
    ESP_LOGD(TAG, "Device marked failed");
    return false;
  }

  this->last_error_ = this->read_register(INPUT_REG * this->reg_width_, inputs, this->reg_width_);
  if (this->last_error_ != i2c::ERROR_OK) {
    this->status_set_warning();
    ESP_LOGE(TAG, "read_register_(): I2C I/O error: %d", (int) this->last_error_);
    return false;
  }
  this->status_clear_warning();
  this->input_mask_ = inputs[0];
  if (this->reg_width_ == 2) {
    this->input_mask_ |= inputs[1] << 8;
  }
  return true;
}

bool PCA9554Component::write_register_(uint8_t reg, uint16_t value) {
  uint8_t outputs[2];
  outputs[0] = (uint8_t) value;
  outputs[1] = (uint8_t) (value >> 8);
  this->last_error_ = this->write_register(reg * this->reg_width_, outputs, this->reg_width_);
  if (this->last_error_ != i2c::ERROR_OK) {
    this->status_set_warning();
    ESP_LOGE(TAG, "write_register_(): I2C I/O error: %d", (int) this->last_error_);
    return false;
  }

  this->status_clear_warning();
  return true;
}

float PCA9554Component::get_setup_priority() const { return setup_priority::IO; }

void PCA9554GPIOPin::setup() { pin_mode(flags_); }
void PCA9554GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this->pin_, flags); }
bool PCA9554GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
void PCA9554GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
size_t PCA9554GPIOPin::dump_summary(char *buffer, size_t len) const {
  return buf_append_printf(buffer, len, 0, "%u via PCA9554", this->pin_);
}

}  // namespace esphome::pca9554
