#ifndef __SSD1306_H__
#define __SSD1306_H__

#include "stm32c0xx_hal.h"
#include <stdbool.h>

#define SSD1306_I2C_ADDR         0x3C << 1  // 左移 1 給 HAL 用
#define SSD1306_WIDTH            128
#define SSD1306_HEIGHT           64

bool ssd1306_Init(I2C_HandleTypeDef *hi2c);
void ssd1306_Fill(uint8_t color);
void ssd1306_UpdateScreen(I2C_HandleTypeDef *hi2c);
void ssd1306_SetCursor(uint8_t x, uint8_t y);
void ssd1306_WriteChar(char ch);
void ssd1306_WriteString(const char* str);

#endif
I2C_HandleTypeDef hi2c1; 

void MX_I2C1_GPIO_Init(void)
{
  __HAL_RCC_GPIOB_CLK_ENABLE();  // 開啟 GPIOB 時脈

  GPIO_InitTypeDef GPIO_InitStruct = {0};

  GPIO_InitStruct.Pin = GPIO_PIN_8 | GPIO_PIN_9; // PB8=SCL, PB9=SDA
  GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;        // Alternate Function, Open Drain
  GPIO_InitStruct.Pull = GPIO_PULLUP;            // I2C 通常需上拉
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF6_I2C1;     // AF6 對應到 I2C1 on PB8/PB9 (查對應資料手冊)

  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
}

void MX_I2C1_Init(void)
{
  hi2c1.Instance = I2C1;
  hi2c1.Init.Timing = 0x2000090E;  // 針對 48MHz SYSCLK 和 100kHz I2C
  hi2c1.Init.OwnAddress1 = 0;
  hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
  hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  hi2c1.Init.OwnAddress2 = 0;
  hi2c1.Init.OwnAddress2Masks = I2C_OA2_NOMASK;
  hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;

  if (HAL_I2C_Init(&hi2c1) != HAL_OK)
  {
    // 處理初始化錯誤
  }

  /** Configure Analogue filter */
  HAL_I2CEx_ConfigAnalogFilter(&hi2c1, I2C_ANALOGFILTER_ENABLE);

  /** Configure Digital filter */
  HAL_I2CEx_ConfigDigitalFilter(&hi2c1, 0);
}

void scan_i2c_devices(void)
{
  for (uint8_t addr = 1; addr < 128; addr++)
  {
    if (HAL_I2C_IsDeviceReady(&hi2c1, (addr << 1), 3, 10) == HAL_OK)
    {
      printf("I2C Device Found at 0x%02X\n", addr);
    }
    else
    {
      printf(".");
    }
  }
  printf("\nScan done.\n");
}


void SystemClock_Config(void)
{
  // 目前先不做設定，後面會補
}


#include "ssd1306.h"

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_I2C1_GPIO_Init();
  MX_I2C1_Init();

  printf("Start scanning...\n");
  scan_i2c_devices();

  printf("Init OLED...\n");
  ssd1306_Init(&hi2c1);

  ssd1306_Fill(1);
  ssd1306_UpdateScreen(&hi2c1);

  printf("Draw text...\n");
  ssd1306_Fill(0);
  ssd1306_SetCursor(2, 0);
  ssd1306_WriteString("Hello");
  ssd1306_UpdateScreen(&hi2c1);

  while (1) {}
}