#include "ch423.h"
#include "esphome/core/log.h"
#include "esphome/core/progmem.h"

namespace esphome::ch423 {

static constexpr uint8_t CH423_REG_SYS = 0x24;    // Set system parameters (0x48 >> 1)
static constexpr uint8_t CH423_SYS_IO_OE = 0x01;  // IO output enable
static constexpr uint8_t CH423_SYS_OD_EN = 0x04;  // Open drain enable for OC pins
static constexpr uint8_t CH423_REG_IO = 0x30;     // Write/read IO7-IO0 (0x60 >> 1)
static constexpr uint8_t CH423_REG_IO_RD = 0x26;  // Read IO7-IO0 (0x4D >> 1, rounded down)
static constexpr uint8_t CH423_REG_OCL = 0x22;    // Write OC7-OC0 (0x44 >> 1)
static constexpr uint8_t CH423_REG_OCH = 0x23;    // Write OC15-OC8 (0x46 >> 1)

static const char *const TAG = "ch423";

void CH423Component::setup() {
  // set outputs before mode
  this->write_outputs_();
  // Set system parameters and check for errors
  bool success = this->write_reg_(CH423_REG_SYS, this->sys_params_);
  // Only read inputs if pins are configured for input (IO_OE not set)
  if (success && !(this->sys_params_ & CH423_SYS_IO_OE)) {
    success = this->read_inputs_();
  }
  if (!success) {
    ESP_LOGE(TAG, "CH423 not detected");
    this->mark_failed();
    return;
  }

  ESP_LOGCONFIG(TAG, "Initialization complete. Warning: %d, Error: %d", this->status_has_warning(),
                this->status_has_error());
}

void CH423Component::loop() {
  // Clear all the previously read flags.
  this->pin_read_flags_ = 0x00;
}

void CH423Component::dump_config() {
  ESP_LOGCONFIG(TAG, "CH423:");
  if (this->is_failed()) {
    ESP_LOGE(TAG, ESP_LOG_MSG_COMM_FAIL);
  }
}

void CH423Component::pin_mode(uint8_t pin, gpio::Flags flags) {
  if (pin < 8) {
    if (flags & gpio::FLAG_OUTPUT) {
      this->sys_params_ |= CH423_SYS_IO_OE;
    }
  } else if (pin >= 8 && pin < 24) {
    if (flags & gpio::FLAG_OPEN_DRAIN) {
      this->sys_params_ |= CH423_SYS_OD_EN;
    }
  }
}

bool CH423Component::digital_read(uint8_t pin) {
  if (this->pin_read_flags_ == 0 || this->pin_read_flags_ & (1 << pin)) {
    // Read values on first access or in case it's being read again in the same loop
    this->read_inputs_();
  }

  this->pin_read_flags_ |= (1 << pin);
  return (this->input_bits_ & (1 << pin)) != 0;
}

void CH423Component::digital_write(uint8_t pin, bool value) {
  if (value) {
    this->output_bits_ |= (1 << pin);
  } else {
    this->output_bits_ &= ~(1 << pin);
  }
  this->write_outputs_();
}

bool CH423Component::read_inputs_() {
  if (this->is_failed()) {
    return false;
  }
  // reading inputs requires IO_OE to be 0
  if (this->sys_params_ & CH423_SYS_IO_OE) {
    return false;
  }
  uint8_t result = this->read_reg_(CH423_REG_IO_RD);
  this->input_bits_ = result;
  this->status_clear_warning();
  return true;
}

// Write a register. Can't use the standard write_byte() method because there is no single pre-configured i2c address.
bool CH423Component::write_reg_(uint8_t reg, uint8_t value) {
  auto err = this->bus_->write_readv(reg, &value, 1, nullptr, 0);
  if (err != i2c::ERROR_OK) {
    char buf[64];
    ESPHOME_snprintf_P(buf, sizeof(buf), ESPHOME_PSTR("write failed for register 0x%X, error %d"), reg, err);
    this->status_set_warning(buf);
    return false;
  }
  this->status_clear_warning();
  return true;
}

uint8_t CH423Component::read_reg_(uint8_t reg) {
  uint8_t value;
  auto err = this->bus_->write_readv(reg, nullptr, 0, &value, 1);
  if (err != i2c::ERROR_OK) {
    char buf[64];
    ESPHOME_snprintf_P(buf, sizeof(buf), ESPHOME_PSTR("read failed for register 0x%X, error %d"), reg, err);
    this->status_set_warning(buf);
    return 0;
  }
  this->status_clear_warning();
  return value;
}

bool CH423Component::write_outputs_() {
  bool success = true;
  // Write IO7-IO0
  success &= this->write_reg_(CH423_REG_IO, static_cast<uint8_t>(this->output_bits_));
  // Write OC7-OC0
  success &= this->write_reg_(CH423_REG_OCL, static_cast<uint8_t>(this->output_bits_ >> 8));
  // Write OC15-OC8
  success &= this->write_reg_(CH423_REG_OCH, static_cast<uint8_t>(this->output_bits_ >> 16));
  return success;
}

float CH423Component::get_setup_priority() const { return setup_priority::IO; }

void CH423GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this->pin_, flags); }
bool CH423GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) ^ this->inverted_; }

void CH423GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value ^ this->inverted_); }
size_t CH423GPIOPin::dump_summary(char *buffer, size_t len) const {
  return snprintf(buffer, len, "EXIO%u via CH423", this->pin_);
}
void CH423GPIOPin::set_flags(gpio::Flags flags) {
  flags_ = flags;
  this->parent_->pin_mode(this->pin_, flags);
}

}  // namespace esphome::ch423