#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include <sys/types.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];

#define CPM_RECORD_SIZE 128
#define CPM_RECODS_PER_BLOCK 128
#define CPM_BLOCK_SIZE CPM_RECORD_SIZE*CPM_RECODS_PER_BLOCK

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;
}

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; */

		// Read byte from disk
		case 0x08:
			if (control.storage.ready && control.storage.command == 0x20) {
				if (control.storage.counter < control.storage.size) {
					write_data(control.storage.buffer[control.storage.counter]);
					control.storage.counter++;
				} else {
					write_data(0x00);
				}

				if (control.storage.counter >= control.storage.size) {
					control.storage.ready = 0;
					control.storage.command = 0;
				}
			} else {
				write_data(0x00);
			}
			break;

		// Check if disk is ready
		case 0x0f:
			if (control.storage.command == 0x20 && !control.storage.ready) {
				switch (control.storage.type) {
					case TYPE_NONE: 
						control.storage.size = 0;
						control.storage.ready = 1;
						break;

					case TYPE_FILE: {
						FRESULT fr = f_lseek(control.storage.file, control.storage.offset * CPM_RECORD_SIZE);
						if (fr) {
							printf("File error: %i\n\r", fr);
						} else {
							control.storage.ready = 1;
						}

						fr = f_read(control.storage.file, control.storage.buffer, CPM_RECORD_SIZE, &control.storage.size);
						if (fr) {
							printf("File error: %i\n\r", fr);
						} else {
							control.storage.ready = 1;
						}

						break;
					}

					case TYPE_DIR: {
						for (int i = 0; i < 128; i += 32) {
							control.storage.buffer[i] = 0xe5;
						}

						for (int i = 0; i < 4; ++i) {
							if (4*control.storage.offset + i >= control.storage.A.entry_count) {
								break;
							}

							control.storage.buffer[32*i + 0] = 0x00;
							for (int j = 0; j < 8; ++j) {
								control.storage.buffer[32*i + 1 + j] = control.storage.A.entries[4*control.storage.offset + i].name[j];
							}

							for (int j = 0; j < 3; ++j) {
								control.storage.buffer[32*i + 9 + j] = control.storage.A.entries[4*control.storage.offset + i].ext[j];
							}

							uint16_t extents = 0x00;
							uint16_t records = control.storage.A.entries[4*control.storage.offset + i].size;

							while (records >= 0x80) {
								extents++;
								records -= 0x80;
							}

							control.storage.buffer[32*i + 12] = extents & 0xFF; // Extent low
							control.storage.buffer[32*i + 13] = 0x00; // Reserved 0x00
							control.storage.buffer[32*i + 14] = (extents >> 8) & 0xFF; // Extent high
							control.storage.buffer[32*i + 15] = records;

							for (int j = 0; j < 16; ++j) {
								control.storage.buffer[32*i + 16 + j] = 0x00;
							}

							for (int j = 0; j < (extents+1); ++j) {
								control.storage.buffer[32*i + 16 + j*2] = control.storage.A.entries[4*control.storage.offset + i].start + j;
								control.storage.buffer[32*i + 17 + j*2] = 0x00;
							}
						}

						control.storage.size = 128;
						control.storage.ready = 1;

						break;
					}

				}
			}

			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;

		// Write byte to disk
		case 0x08:
			break;

		case 0x0b: {
			uint32_t temp = control.storage.lba & 0xFFFF00;
			control.storage.lba = temp + value;
			break;
		}

		case 0x0c: {
			uint32_t temp = control.storage.lba & 0xFF00FF;
			control.storage.lba = temp + (value << 8);
			break;
		}

		case 0x0d: {
			uint32_t temp = control.storage.lba & 0x00FFFF;
			control.storage.lba = temp + (value << 16);
			break;
		}

		// Receive disk command
		case 0x0f: {
			control.storage.ready = 0;
			control.storage.counter = 0;
			control.storage.command = value;
			FRESULT fr = 0;

			if (control.storage.type == TYPE_FILE) {
				fr = f_close(control.storage.file);
				if (fr) {
					printf("File error: %i\n\r", fr);
				}
			}

			// @todo We need to make it easier to set this up
			if (control.storage.lba == 0) {
				// bootloader
				control.storage.offset = control.storage.lba - 0;
				fr = f_open(control.storage.file, "0:loader.bin", FA_READ);
				control.storage.type = TYPE_FILE;
			} else if (control.storage.lba >= 1 && control.storage.lba < 45) {
				// cpm
				control.storage.offset = control.storage.lba - 1;
				fr = f_open(control.storage.file, "0:cpm22.bin", FA_READ);
				control.storage.type = TYPE_FILE;
			} else if (control.storage.lba >= 45 && control.storage.lba < 51) {
				// bios
				control.storage.offset = control.storage.lba - 45;
				fr = f_open(control.storage.file, "0:bios.bin", FA_READ);
				control.storage.type = TYPE_FILE;
			} else if (control.storage.lba >= 256 && control.storage.lba < (256+32)) {
				// @todo Max out at end of disk A
				control.storage.offset = control.storage.lba - 256;
				control.storage.type = TYPE_DIR;
			} else if (control.storage.lba > (256+32)) {
				control.storage.type = TYPE_NONE;

				for (uint8_t i = 0; i < control.storage.A.entry_count; ++i) {
					if (control.storage.lba >= (control.storage.A.entries[i].start-1)*CPM_RECODS_PER_BLOCK+384 && control.storage.lba < ((control.storage.A.entries[i].start-1)*CPM_RECODS_PER_BLOCK+384 + control.storage.A.entries[i].size)) {
						control.storage.offset = control.storage.lba - (control.storage.A.entries[i].start-1)*CPM_RECODS_PER_BLOCK - 384;

						char buf[128];
						snprintf(buf, 128, "0:A/%s", control.storage.A.entries[i].filename);
						fr = f_open(control.storage.file, buf, FA_READ);

						control.storage.type = TYPE_FILE;
						break;
					}
				}
			} else {
				// Empty
				printf("Unknown %li\n\r", control.storage.lba);
				control.storage.type = TYPE_NONE;
			}

			if (fr) {
				printf("File error: %i\n\r", fr);
			}
			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);

	// @todo Pretty sure this is not actually correct,
	// since the pointer is always not NULL once we malloc,
	// even if we do not have a file open/disk mounted
	if (control.storage.file) {
		f_close(control.storage.file);
		free(control.storage.file);
	}
	if (control.storage.fs) {
		f_mount(0, "0:", 0);
		free(control.storage.fs);
	}

	Control temp = {0, {NULL, NULL, 0, 0, 0, 0, 0, NULL, 0, TYPE_NONE, {0}}};
	control = temp;

	control.storage.buffer = (uint8_t*)malloc(CPM_RECORD_SIZE);

	control.storage.fs = (FATFS*)malloc(sizeof(FATFS));
	control.storage.file = (FIL*)malloc(sizeof(FIL));
	FRESULT fr = f_mount(control.storage.fs, "0:", 0);
	if (fr) {
		printf("File error: %i\n\r", fr);
	}

	DIR dir;
	FILINFO fno;
	fr = f_opendir(&dir, "0:A");
	control.storage.A.end = 1;
	if (fr == FR_OK) {
		for (;;) {
			fr = f_readdir(&dir, &fno);
			if (fr != FR_OK || fno.fname[0] == 0) {
				break;
			}

			if (!(fno.fattrib & AM_DIR)) {
				uint8_t index = control.storage.A.entry_count;
				control.storage.A.entries[index].start = control.storage.A.end;

				// Calculate the number of records
				uint32_t size = (fno.fsize + CPM_RECORD_SIZE - 1) / CPM_RECORD_SIZE;

				// Increment the end by the number of blocks
				control.storage.A.end += (size + CPM_RECODS_PER_BLOCK) / CPM_RECODS_PER_BLOCK;

				// Store the size in the number of records
				control.storage.A.entries[index].size = size;

				control.storage.A.entries[index].filename = strdup(fno.fname);
				
				uint8_t name_len = 9;
				for (uint8_t i = 0; i < 8; ++i) {
					char c = ' ';

					if (name_len == 9 && fno.fname[i] != '.') {
						c = fno.fname[i];
					} else if (name_len == 9){
						name_len = i+1;
					}

					control.storage.A.entries[index].name[i] = c;
				}

				uint8_t done = 0;
				for (uint8_t i = 0; i < 3; ++i) {
					char c = ' ';
					
					if (!done && fno.fname[name_len+i] != 0) {
						c = fno.fname[name_len+i];
					} else {
						done = 1;
					}

					control.storage.A.entries[index].ext[i] = c;
				}

				control.storage.A.entry_count++;

			}
		}
	}

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