// TODO: add decimal point hex and octal support
// TODO: add limit to maximum imput allowed
#include <stdio.h> //printf(), fprintf()
#include <assert.h> //assert()
#include <stdlib.h> //exit()
#include <stdbool.h> //_Bool, false, true
#include "my_atoi.h"

#define ASCIIFIRST 48
#define ASCIILAST  57 
#define NULL '\0'

double my_atoi(char* str)
{
	int i = 0, start = 0, base = 10, floatIndex;
	double num2Convert = 0;
	_Bool boolHex = false, boolOctal = false, boolNegative = false, boolFloat = false, priorZero = false;
	
//017 -017 no decimals for hex or octal NULL, -NULL, .NULL, 0xNULL, 0XNULL, -.NULL, -0xNULL, -0XNULL, 0x., -0x., 0X., -0X., -0[8,9,a-f,A-F],  xX can only be in the second or third index 8-9, a-f, A-F, -, ., xX octal: - 0-7 decimal: - . 0-9 hex: 0-9 a-f A-F - xX

if (str[0] == '-') {
	boolNegative = 1;
	++start;
	++i;
}

do {
	switch (str[i]) {
		case '0':
			if (!priorZero) {
				priorZero = true;
				if (i == 0 || (i == 1 && boolNegative)) {
					if (str[i + 1] == NULL) {
						return 0;
					} else if (str[i + 1] == '.') {
						boolFloat = 1;
						floatIndex = i = 1;
						++i;
					} else {
						boolOctal = 1;
						++start;
					}
				}
			}
			break;
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
			break;
		case '8':
		case '9':
			if (boolOctal) {
				fprintf(stderr, "ERROR: %c is an invalid input for octal numbers\n", str[i]);
				exit(-1);
			}
			break;
		case 'a':
		case 'A':
		case 'b':
		case 'B':
		case 'c':
		case 'C':
		case 'd':
		case 'D':
		case 'e':
		case 'E':
		case 'f':
		case 'F':
			if (!boolHex) {
				fprintf(stderr, "ERROR: %c is an invalid input for octal and/or decimal numbers\n", str[i]);
				exit(-1);
			}
			break;
		case '.':
			if (boolFloat) {
				fprintf(stderr, "ERROR: String contains more than one '.'\n");
				exit(-1);
			} else if (boolHex || boolOctal) {
				fprintf(stderr, "ERROR: Currently not accepting hexidecimal or octal floating point numbers.\n");
				exit(-1);
			} else {
				boolFloat = 1;
				floatIndex = i;
			}
			break;
		case NULL:
			if (i == 0 || str[i - 1] == '-' || str[i - 1] == 'x' || str[i - 1] == 'X'){
				fprintf(stderr, "ERROR: Entered an empty number.\n");
				exit(-1);
			}
			break;
		case 'x':
		case 'X':
			if (i != 1 && i != 2 && str[i - 1] != 0) {
				fprintf(stderr, "ERROR: 'x or X' characters can only be included once and must be preceeded by a 0.\n");
				exit(-1);
			} 
			boolOctal = 0;
			boolHex = 1;
			++start;
			break;
		default:
			fprintf(stderr, "ERROR: Invalid character included.\n");
			exit(-1);
	}
	++i;
} while (str[i] != NULL); //when this is done I will be the number of characters including null termination


	if (boolHex) {
		for (int j = i - 1, multi = 1, base = 16; j > start - 1; multi *= base, --j) {
			switch (str[j]) {
				case '0':
				case '1':
				case '2':
				case '3':
				case '4':
				case '5':
				case '6':
				case '7':
				case '8':
				case '9':
					num2Convert += (multi * (str[j] - ASCIIFIRST));
					break;
				case 'a':
				case 'A':
					num2Convert += multi * 10;
					break;
				case 'b':
				case 'B':
					num2Convert += multi * 11;
					break;
				case 'c':
				case 'C':
					num2Convert += multi * 12;
					break;
				case 'd':
				case 'D':
					num2Convert += multi * 13;
					break;
				case 'e':
				case 'E':
					num2Convert += multi * 14;
					break;
				case 'f':
				case 'F':
					num2Convert += multi * 15;
					break;
				default:
					fprintf(stderr, "ERROR: out of bounds character for hexadecimal. Only use 0-9,Aa-Ff\n");
			}
		}
	} else if (boolOctal) {
		for (int j = i - 1, multi = 1, base = 8; j > start - 1; multi *= base, --j) {
			if (str[j] > ASCIILAST - 2) {
				fprintf(stderr, "ERROR: out of bounds range for octal number. Only use 0-7.\n");
			} else {
				num2Convert += multi * (str[j] - ASCIIFIRST);
			}
		}
	} else if (boolFloat) {
		fprintf(stderr, "NEED TO FIGURE OUT HOW TO CONVERT FLOATS STILL\n");
		//count distance from end -1 to floatIndex and take that number and divide it by the appropriate multiple of 10
		//then do the portion to the left of the decimal the exact same as usual
		{
		double multi = .1;
		for (int j = floatIndex + 1, base = 10;  j < i; multi /= base, ++j) {
				num2Convert += multi * (str[j] - ASCIIFIRST); 
		}
		}
		for (int j = floatIndex - 1, multi = 1, base = 10; j >= start; multi *= base, --j) {
				num2Convert += multi * (str[j] - ASCIIFIRST); 
		}
	} else {
		for (int j = i - 1, multi = 1, base = 10; j >= start; multi *= base, --j) {
				num2Convert += multi * (str[j] - ASCIIFIRST); 
		}
	}

	if (boolNegative) {
		num2Convert *= -1;
	}

	printf("boolHex: %d, boolOctal: %d, boolFloat: %d, boolNegative: %d, \n", boolHex, boolOctal, boolFloat, boolNegative);

	return num2Convert;

}