#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include "control.h"
#include "io.h"
#include "bsp_driver_sd.h"
#include "profiling.h"

// The top 4 address bits determine which device is used. (16 pages, 256 devices)
// 0xFF means that the device does not exist
// WATCH OUT THE DEVICE ADDRESS NEED TO BE REVERSED (MSB IS ON THE RIGHT)
uint8_t memory_map_0[16] = {0b00010000, 0b10001000, 0b01001000, 0b11001000, 0b00101000, 0b10101000, 0b01101000, 0b11101000, 0b00011000, 0b10011000, 0b01011000, 0b11011000, 0b00111000, 0b10111000, 0b01111000, 0b11111000};
uint8_t memory_map_1[16] = {0b00001000, 0b10001000, 0b01001000, 0b11001000, 0b00101000, 0b10101000, 0b01101000, 0b11101000, 0b00011000, 0b10011000, 0b01011000, 0b11011000, 0b00111000, 0b10111000, 0b01111000, 0b11111000};

Control control;

extern UART_HandleTypeDef huart2;
extern uint8_t ack[1];
extern uint8_t nack[1];

// @todo For some reason increasing SD_PAGES does not work
#define SD_PAGES 1
#define CPM_PAGE_SIZE 128

#define SD_PAGE_SIZE 512
#define CPM_PAGES (SD_PAGE_SIZE/CPM_PAGE_SIZE*SD_PAGES)

uint8_t get_device(uint16_t address) {
	uint8_t page = address >> 12;
	if (control.memory_config == 0) {
		return memory_map_0[page];
	} else if (control.memory_config == 1) {
		return memory_map_1[page];
	}

	return 0xFF;
}

uint32_t calculate_lba() {
	uint32_t temp = (control.storage.lba_1) + (control.storage.lba_2 << 8) + (control.storage.lba_3 << 16);
	if (temp/CPM_PAGES != control.storage.lba/CPM_PAGES) {
		control.storage.dirty |= 1;
	}

	/* printf("LBA [1]: %li\n\r", control.storage.lba_1); */
	/* printf("LBA [2]: %li\n\r", control.storage.lba_2); */
	/* printf("LBA [3]: %li\n\r", control.storage.lba_3); */
	/* printf("LBA: %li\n\r", control.storage.lba); */

	return temp;
}

void control_program_eeprom(uint8_t* data, uint16_t length) {
	// Take control of the bus
	send_busrq(1);
	while (!has_busak()) {
		control_cycle();
	}

	enable_address_out(1);

	select_device(memory_map_0[0]);

	for (uint16_t i = 0; i < length; ++i) {
		write_address(i);
		write_data(data[i]);

		enable_data_out(1);
		send_memrq(1);
		send_wr(1);

		send_wr(0);
		enable_data_out(0);
		send_rd(1);

		for (;;) {
			uint8_t d = read_data();
			if (d == data[i]) {
				break;
			}
		}

		send_rd(0);
		send_memrq(0);

		uint8_t progress[] = {(i+1) & 0xFF, (i+1) >> 8};
		HAL_UART_Transmit(&huart2, progress, sizeof(progress), HAL_MAX_DELAY);
	}

	enable_address_out(0);

	// Release the bus again
	send_busrq(0);

	// Restart the z80
	control_reset();

	HAL_UART_Transmit(&huart2, ack, sizeof(ack), HAL_MAX_DELAY);
}

void handle_memrq() {
	uint16_t address = read_address();
	uint8_t device = get_device(address);
	select_device(device);
}

void handle_io_read() {
	uint8_t address = read_address() & 0xFF;

	switch (address) {
		// @todo This should be detected on startup
		// Stand in for graphics hardware
		/* case 0x03: */
		/* 	write_data(0x01); */
		/* 	break; */

		/* Stand in for the keyboard hardware */
		/* case 0x1E: */
		/* 	write_data(char_c); */
		/* 	char_r = 0; */
		/* 	break; */

		/* Stand in for the keyboard hardware */
		/* case 0x1F: */
		/* 	#<{(| write_data(0x01 * char_r); |)}># */
		/* 	write_data(0x00); */
		/* 	break; */

		case 0x08:
			if (control.storage.ready && control.storage.action == 0x20) {
				write_data(control.storage.buffer[control.storage.counter + (control.storage.lba % CPM_PAGES)*CPM_PAGE_SIZE]);
				control.storage.counter++;

				if (control.storage.counter >= CPM_PAGE_SIZE) {
					control.storage.ready = 0;
					control.storage.action = 0;
				}
			} else {
				write_data(0x00);
			}

			break;

		case 0x0f:
			// Check if we need to read and in that case to the read
			if (control.storage.action && !control.storage.ready) {
				if (!control.storage.dirty || BSP_SD_ReadBlocks((uint32_t*)control.storage.buffer, control.storage.lba/CPM_PAGES, SD_PAGES, SD_DATATIMEOUT) == MSD_OK) {
					// Indicate that we are ready to read/write
					control.storage.ready = 1;
					control.storage.dirty = 0;
				} else {
					// If we failed to read we will try again next time
					/* printf("READ FAIL!\n\r"); */
				}
			}

			write_data(0x08*control.storage.ready);
			break;

		default: {
			/* uint8_t value = read_data(); */
			/* #<{(| if (value == 0) { |)}># */
			/* 	printf("IO Read: %.2X @ %.2X\n\r", value, address); */
			/* #<{(| } |)}># */
			return;
		}
	}

	enable_data_out(1);
}

void handle_io_write() {
	uint8_t address = read_address() & 0xFF;
	uint8_t value = read_data();

	switch (address) {
		case 0x00:
			control.memory_config = 0;
			break;

		case 0x01:
			control.memory_config = 1;
			break;

		case 0x02:
			printf("%c", value);
			break;

		case 0x08:
			if (control.storage.ready && control.storage.action == 0x30) {
				control.storage.buffer[control.storage.counter + (control.storage.lba % CPM_PAGES)*CPM_PAGE_SIZE] = value;
				control.storage.counter++;

				if (control.storage.counter >= CPM_PAGE_SIZE) {
					// @todo We need to figure out some way to actually prevent write fails from occuring
					if (BSP_SD_WriteBlocks((uint32_t*)control.storage.buffer, control.storage.lba/CPM_PAGES, SD_PAGES, SD_DATATIMEOUT) != MSD_OK) {
						printf("WRITE FAIL!!\n\r");
					}
					control.storage.ready = 0;
					control.storage.action = 0;
				}
			}
			break;

		case 0x0b:
			control.storage.lba_1 = value;
			break;

		case 0x0c:
			control.storage.lba_2 = value;
			break;

		case 0x0d:
			control.storage.lba_3 = value;
			break;

		case 0x0f:
			if (value == 0x20 || value == 0x30) {
				control.storage.lba = calculate_lba();
				control.storage.action = value;
				control.storage.counter = 0;
			}
			break;

		default:
			printf("IO Write: %.2X @ %.2X\n\r", value, address);
			break;
	}
}

void handle_ioreq() {
		if (has_wr()) {
			handle_io_write();
		} else if (has_rd()) {
			handle_io_read();
		}
}

void control_cycle() {
	set_clock(1);

	// We need this not detect IO multiple times
	static uint8_t had_ioreq = 0;
	if (!has_ioreq()) {
		had_ioreq = 0;
	}

	// @todo We are forgetting to set this somewhere
	enable_data_out(0);

	if (has_memrq()) {
		handle_memrq();
	} else if (has_ioreq() && !has_m1()) {
		had_ioreq++;
		if (had_ioreq == 3) {
			handle_ioreq();
		}
	} else if (has_ioreq() && has_m1()) {
		printf("Interrupt ackknowledged\n\r");
	}

	set_clock(0);
}

// @todo Properly reset everything
void control_reset() {
	free(control.storage.buffer);
	Control temp = {0, {1, 0, 0, 0, 0, 0, 0, 0, NULL}};
	control = temp;
	control.storage.buffer = (uint8_t*)malloc(SD_PAGES*SD_PAGE_SIZE);

	set_reset(1);
	for (int i = 0; i <= 10; ++i) {
		set_clock(i % 2);
	}
	set_reset(0);
}