/* Copyright 2023 Dual Tachyon
 * https://github.com/DualTachyon
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *     Unless required by applicable law or agreed to in writing, software
 *     distributed under the License is distributed on an "AS IS" BASIS,
 *     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *     See the License for the specific language governing permissions and
 *     limitations under the License.
 */

#include <stdint.h>
#include <stdio.h>     // NULL

#include "bsp/dp32g030/gpio.h"
#include "bsp/dp32g030/spi.h"
#include "driver/gpio.h"
#include "driver/spi.h"
#include "driver/st7565.h"
#include "driver/system.h"
#include "misc.h"

uint8_t g_status_line[128];
uint8_t g_frame_buffer[7][128];

#ifdef ENABLE_CONTRAST
	uint8_t contrast = 31;  // 0 ~ 63
#endif

static void ST7565_WriteByte(uint8_t Value);

static inline void ST7565_LowLevelWrite(uint8_t Value)
{
        /* Wait for space in the fifo */
        while ((SPI0->FIFOST & SPI_FIFOST_TFF_MASK) != SPI_FIFOST_TFF_BITS_NOT_FULL) {}
        SPI0->WDR = Value;
}

void ST7565_DrawLine(const unsigned int Column, const unsigned int Line, const unsigned int Size, const uint8_t *pBitmap)
{
	unsigned int i;

	SPI_ToggleMasterMode(&SPI0->CR, false);

	ST7565_SelectColumnAndLine(Column + 4U, Line);

	GPIO_SetBit(&GPIOB->DATA, GPIOB_PIN_ST7565_A0);

	if (pBitmap != NULL)
	{
		for (i = 0; i < Size; i++)
		{
                    ST7565_LowLevelWrite(pBitmap[i]);
		}
	}
	else
	{
		for (i = 0; i < Size; i++)
		{
                    ST7565_LowLevelWrite(0);
		}
	}

	SPI_WaitForUndocumentedTxFifoStatusBit();

	SPI_ToggleMasterMode(&SPI0->CR, true);
}

void ST7565_BlitFullScreen(void)
{
	unsigned int Line;

	// reset some of the displays settings to try and overcome the
	// radios hardware problem - RF corrupting the display
	ST7565_Init(false);

	SPI_ToggleMasterMode(&SPI0->CR, false);

	ST7565_WriteByte(0x40);

	for (Line = 0; Line < ARRAY_SIZE(g_frame_buffer); Line++)
	{
		unsigned int Column;
		ST7565_SelectColumnAndLine(4, Line + 1);
		GPIO_SetBit(&GPIOB->DATA, GPIOB_PIN_ST7565_A0);
		for (Column = 0; Column < ARRAY_SIZE(g_frame_buffer[0]); Column++)
		{
                    ST7565_LowLevelWrite(g_frame_buffer[Line][Column]);
		}
		SPI_WaitForUndocumentedTxFifoStatusBit();
	}

	#if 0
		// whats the delay for, it holds things up :(
		SYSTEM_DelayMs(20);
	#else
//		SYSTEM_DelayMs(1);
	#endif

	SPI_ToggleMasterMode(&SPI0->CR, true);
}

void ST7565_BlitStatusLine(void)
{	// the top small text line on the display

	unsigned int i;

	SPI_ToggleMasterMode(&SPI0->CR, false);

	ST7565_WriteByte(0x40);    // start line ?

	ST7565_SelectColumnAndLine(4, 0);

	GPIO_SetBit(&GPIOB->DATA, GPIOB_PIN_ST7565_A0);

	for (i = 0; i < ARRAY_SIZE(g_status_line); i++)
	{
                ST7565_LowLevelWrite(g_status_line[i]);
	}

	SPI_WaitForUndocumentedTxFifoStatusBit();

	SPI_ToggleMasterMode(&SPI0->CR, true);
}

void ST7565_FillScreen(const uint8_t Value)
{
	unsigned int i;

	// reset some of the displays settings to try and overcome the
	// radios hardware problem - RF corrupting the display
	ST7565_Init(false);

	SPI_ToggleMasterMode(&SPI0->CR, false);

	for (i = 0; i < 8; i++)
	{
		unsigned int j;
		ST7565_SelectColumnAndLine(0, i);
		GPIO_SetBit(&GPIOB->DATA, GPIOB_PIN_ST7565_A0);
		for (j = 0; j < 132; j++)
		{
                        ST7565_LowLevelWrite(Value);
		}
		SPI_WaitForUndocumentedTxFifoStatusBit();
	}

	SPI_ToggleMasterMode(&SPI0->CR, true);
}

void ST7565_Init(const bool full)
{
	if (full)
	{
		SPI0_Init();
		ST7565_HardwareReset();
	}

	SPI_ToggleMasterMode(&SPI0->CR, false);

	if (full)
	{
		ST7565_WriteByte(0xE2);      // internal reset
		SYSTEM_DelayMs(120);
	}
	
	ST7565_WriteByte(0xA2);          // bias 9
//	ST7565_WriteByte(0xA3);          // bias 7

	ST7565_WriteByte(0xC0);          // COM normal
//	ST7565_WriteByte(0xC8);          // COM reverse

//	ST7565_WriteByte(0xA0);          // normal ADC .. mirrors the screen
	ST7565_WriteByte(0xA1);          // reverse ADC

	ST7565_WriteByte(0xA6);          // normal screen
//	ST7565_WriteByte(0xA7);          // inverse screen

	ST7565_WriteByte(0xA4);          // all points normal

	ST7565_WriteByte(0x24);          // ???

	ST7565_WriteByte(0x81);          //
	#ifdef ENABLE_CONTRAST
		ST7565_WriteByte(contrast);  // brightness 0 ~ 63
	#else
		ST7565_WriteByte(31);        // brightness 0 ~ 63
	#endif

	if (full)
	{
		ST7565_WriteByte(0x28 | 4u); // enable voltage converter VC=1 VR=0 VF=0
		SYSTEM_DelayMs(50);

		ST7565_WriteByte(0x28 | 6u); // enable voltage regulator VC=1 VR=1 VF=0
		SYSTEM_DelayMs(50);

		ST7565_WriteByte(0x28 | 7u); // enable voltage follower  VC=1 VR=1 VF=1
		SYSTEM_DelayMs(10);

		ST7565_WriteByte(0x20 | 6u); // set lcd operating voltage (regulator resistor, ref voltage resistor)
	}

	ST7565_WriteByte(0x40);          // start line ?
	ST7565_WriteByte(0xAF);          // display on ?

	SPI_WaitForUndocumentedTxFifoStatusBit();

	SPI_ToggleMasterMode(&SPI0->CR, true);

	if (full)
		ST7565_FillScreen(0x00);
}

void ST7565_HardwareReset(void)
{
	GPIO_SetBit(  &GPIOB->DATA, GPIOB_PIN_ST7565_RES);
	SYSTEM_DelayMs(1);
	GPIO_ClearBit(&GPIOB->DATA, GPIOB_PIN_ST7565_RES);
	SYSTEM_DelayMs(20);
	GPIO_SetBit(  &GPIOB->DATA, GPIOB_PIN_ST7565_RES);
	SYSTEM_DelayMs(120);
}

void ST7565_SelectColumnAndLine(const uint8_t Column, const uint8_t Line)
{
	GPIO_ClearBit(&GPIOB->DATA, GPIOB_PIN_ST7565_A0);
        ST7565_LowLevelWrite(Line + 176);
        ST7565_LowLevelWrite(((Column >> 4) & 0x0F) | 0x10);
        ST7565_LowLevelWrite((Column >> 0) & 0x0F);
	SPI_WaitForUndocumentedTxFifoStatusBit();
}

static void ST7565_WriteByte(uint8_t Value)
{
	GPIO_ClearBit(&GPIOB->DATA, GPIOB_PIN_ST7565_A0);
        ST7565_LowLevelWrite(Value);
}

#ifdef ENABLE_CONTRAST
	void ST7565_SetContrast(const uint8_t value)
	{
		contrast = (value > 45) ? 45 : (value < 26) ? 26 : value;
	}

	uint8_t ST7565_GetContrast(void)
	{
		return contrast;
	}
#endif