#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "cpu.h"

/* function: char *string_format(char* string)
 * input: pointer to a null-terminated string (must not be NULL)
 * return: pointer to a newly allocated string containing all space-separated words,
 * 	joined by single spaces; leading/trailing/multiple spaces are ignored.
 * on-error: returns NULL if memory allocation fails
 * misc: the returned pointer must be freed by the caller using free()
 * limits: processes at most 10 words, each up to 49 characters (last '\0')
 */
char *string_format(char* string) {
    // Wörterbuch array [Wort][Zeichenkette]
    char woerter[10][50] = { 0 };
    int wort_index = 0;
    int char_index = 0;

    while (*string != '\0') {
	// add '\0' stringterminator to end of word
	if (*string == ' ' && char_index > 0) {
	    // safty check for array length
	    if (wort_index > 9 || char_index > 49) {
		break;
	    }

	    // next slot is char
	    // add '\0' to end string
	    woerter[wort_index][char_index] = '\0';
	    wort_index++;
	    char_index = 0;
	    string++;
	    continue;
	} 
	// skip extra spaces
	else if (*string == ' ' && char_index == 0) {
	    string++;
	    continue;
	}

	// safty check for array length
	if (char_index >= 49) {
	    break;
	}

	woerter[wort_index][char_index] = *string;
	char_index++;
	string++;
    }

    // terminate last word with '\0'
    if (char_index > 0 && wort_index < 10 && char_index < 49) {
	woerter[wort_index][char_index] = '\0';
	wort_index++;
    }

    /* 
     * return
     */
    char *ptr = NULL;

    // get length of woerter array
    if (wort_index == 0) {
	ptr = NULL;
    } else {
    	int sum = 0;

	for (int i = 0; i < wort_index; i++) {
	    sum += strlen(woerter[i]);
	}
	sum += wort_index - 1; // for spaces
	sum += 1; // for Nulltermination
    

	ptr = (char *)malloc(sum);

	// check for NULL pointer
	if (ptr == NULL) {
	    return NULL;
	}

	//strcpy
	char *ende = ptr;

	for (int i = 0; i < wort_index; i++) {
	    ende = stpcpy(ende, woerter[i]);

	    if (i != wort_index - 1) {
		*(ende++) = ' ';
	    }
	}
    }

    return ptr;
}


int cpu(void) {
    FILE* file = fopen("/proc/cpuinfo", "r");

    //check file existence
    if (!file) {
	perror("/proc/cpuinfo not found");
	return 1;
    }

    char line[256];
    char *model_name = NULL;
    
    //read per line
    while (fgets(line, sizeof(line), file)) {
	char* p = strstr(line, "model name");

	if (p != NULL) {
	    model_name = strchr(p, ':') + 1; //skip :
	    break;
	}
    }

    if (model_name != NULL) {
	char *string = string_format(model_name);

	if (string == NULL) {
	    printf("CPU: Error string not found.\n");
	    free(string);
	    model_name = NULL;
	} else {
	    printf("CPU: %s\n", string);
	    free(string);
	    model_name = NULL;
	}

    } else {
	printf("CPU: Error model_name not found.\n");
    }

    fclose(file);
    return 0;
}