/**
 * Copyright (c) 2017-2018 Tara Keeling
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <driver/spi_master.h>
#include <driver/gpio.h>
#include <freertos/task.h>
#include "gds.h"
#include "gds_err.h"
#include "gds_private.h"
#include "gds_default_if.h"

static const int GDS_SPI_Command_Mode = 0;
static const int GDS_SPI_Data_Mode = 1;

static spi_host_device_t SPIHost;
static int DCPin;

static bool SPIDefaultWriteBytes( spi_device_handle_t SPIHandle, int WriteMode, const uint8_t* Data, size_t DataLength );
static bool SPIDefaultWriteCommand( struct GDS_Device* Device, uint8_t Command );
static bool SPIDefaultWriteData( struct GDS_Device* Device, const uint8_t* Data, size_t DataLength );

bool GDS_SPIInit( int SPI, int DC ) {
	SPIHost = SPI;
	DCPin = DC;
    return true;
}

bool GDS_SPIAttachDevice( struct GDS_Device* Device, int Width, int Height, int CSPin, int RSTPin, int BackLightPin, int Speed, int Mode ) {
    spi_device_interface_config_t SPIDeviceConfig = { };
    spi_device_handle_t SPIDevice;

    NullCheck( Device, return false );
	
	if (CSPin >= 0) {
		ESP_ERROR_CHECK_NONFATAL( gpio_set_direction( CSPin, GPIO_MODE_OUTPUT ), return false );
		ESP_ERROR_CHECK_NONFATAL( gpio_set_level( CSPin, 0 ), return false );
	}
	
    SPIDeviceConfig.clock_speed_hz = Speed > 0 ? Speed : SPI_MASTER_FREQ_8M;
    SPIDeviceConfig.spics_io_num = CSPin;
    SPIDeviceConfig.queue_size = 1;
    SPIDeviceConfig.mode = Mode;
	SPIDeviceConfig.flags = SPI_DEVICE_NO_DUMMY;
	if (Device->SPIParams) Device->SPIParams(SPIDeviceConfig.clock_speed_hz, &SPIDeviceConfig.mode, 
											 &SPIDeviceConfig.cs_ena_pretrans, &SPIDeviceConfig.cs_ena_posttrans);
	
    ESP_ERROR_CHECK_NONFATAL( spi_bus_add_device( SPIHost, &SPIDeviceConfig, &SPIDevice ), return false );
	
	Device->WriteCommand = SPIDefaultWriteCommand;
    Device->WriteData = SPIDefaultWriteData;
    Device->SPIHandle = SPIDevice;
    Device->RSTPin = RSTPin;
    Device->CSPin = CSPin;
	Device->Backlight.Pin = BackLightPin;	
	Device->IF = GDS_IF_SPI;
	Device->Width = Device->TextWidth = Width;
	Device->Height = Height;
	
	if ( RSTPin >= 0 ) {
        ESP_ERROR_CHECK_NONFATAL( gpio_set_direction( RSTPin, GPIO_MODE_OUTPUT ), return false );
        ESP_ERROR_CHECK_NONFATAL( gpio_set_level( RSTPin, 0 ), return false );
		GDS_Reset( Device );
    }
	
	return GDS_Init( Device );
}

static bool SPIDefaultWriteBytes( spi_device_handle_t SPIHandle, int WriteMode, const uint8_t* Data, size_t DataLength ) {
    spi_transaction_t SPITransaction = { };

    NullCheck( SPIHandle, return false );
    NullCheck( Data, return false );

    if ( DataLength > 0 ) {
		gpio_set_level( DCPin, WriteMode );

		SPITransaction.length = DataLength * 8;
		
		if (DataLength <= 4) {
			SPITransaction.flags = SPI_TRANS_USE_TXDATA;
			SPITransaction.tx_data[0] = *Data++; SPITransaction.tx_data[1] = *Data++;
			SPITransaction.tx_data[2] = *Data++; SPITransaction.tx_data[3] = *Data;
		} else {
			SPITransaction.tx_buffer = Data;
		}	
            
		// only do polling as we don't have contention on SPI (otherwise DMA for transfers > 16 bytes)		
		ESP_ERROR_CHECK_NONFATAL( spi_device_polling_transmit(SPIHandle, &SPITransaction), return false );
    }

    return true;
}

static bool SPIDefaultWriteCommand( struct GDS_Device* Device, uint8_t Command ) {
    static uint8_t CommandByte = 0;

    NullCheck( Device, return false );
    NullCheck( Device->SPIHandle, return false );

    CommandByte = Command;

    return SPIDefaultWriteBytes( Device->SPIHandle, GDS_SPI_Command_Mode, &CommandByte, 1 );
}

static bool SPIDefaultWriteData( struct GDS_Device* Device, const uint8_t* Data, size_t DataLength ) {
    NullCheck( Device, return false );
    NullCheck( Device->SPIHandle, return false );

    return SPIDefaultWriteBytes( Device->SPIHandle, GDS_SPI_Data_Mode, Data, DataLength );
}