#include <stdio.h>
#include <stdlib.h>

//Outputfuction, very simple
void output(int len, int * text)
{
    int i;
    for (i = 0; i < len; i++)
        printf("%c",(char)text[i]);
}

//------------------------------------------------------------------------------
//Reads a character from stdin (as an integer), returns a pointer to the start
// of the text and length of the text as an integer in case of sucess.
int importCharacter(int ** alloc_me)
{
        int * text;
        // counter (return value)
        int text_length = 0;

        // init vars
        int blocksize = 10, memsize = 10;
        *alloc_me = malloc(memsize*sizeof(int));
        if (alloc_me == NULL)
        {
                return -2;
        }
        text = *alloc_me;

        int newChar;
        while ((newChar = getchar()) != EOF)
        {
            if (text_length == memsize)
            {
                memsize += blocksize;
                int * tmp;
                tmp = realloc(*alloc_me, memsize*sizeof(int));
                if (tmp == NULL)
                {
                    return -2;
                }
                *alloc_me = tmp;
            }
            if (newChar > 127)
            {
                return -3;
            }

            text[text_length] = newChar;
            text_length++;
        }
        //Nachdem alle Zeichen gelesen sind (getchar() = EOF) kommt die L?nge des
        //eingelesenen Textes zur?ck.
        return text_length;
}

int ReplaceCharacters (int ** alloc_me_changed, int * text
                       , int text_length, int * changed)

{
    // init vars
    int * text_changed      = NULL;
    int text_length_changed = 0;
//    int * my_text           = NULL;
//  int text_length         = importCharacter(&my_text);
// da liest du den ganzen text noch einmal -> von main übergeben
//    int changed             = 0;    als adresse übergeben
    int blocksize           = 10, memsize = 10;
    int MaxReplaceStrLength = 5;
    *alloc_me_changed = malloc((memsize)*sizeof(int));
    if (alloc_me_changed == NULL)
    {
        return -2;
    }

    text_changed = *alloc_me_changed;
    int newChar;
    int counter = 0;
    // Counter from first character in text to text_length
    while (counter < text_length)
    {
        newChar = text[counter];
        if (text_length_changed >= (memsize - MaxReplaceStrLength))
        {
            memsize += blocksize;
            int * tmp;
            tmp = realloc(*alloc_me_changed, memsize*sizeof(int));
            if (tmp == NULL)
            {
                return -2;
            }
            *alloc_me_changed = tmp;

        }
        switch (newChar)
        {
        case 38 :   // &
            text_changed[text_length_changed++] = '&';
            text_changed[text_length_changed++] = 'a';
            text_changed[text_length_changed++] = 'm';
            (*changed)++;
            break;
        case 60 : // <
            text_changed[text_length_changed++] = '&';
            text_changed[text_length_changed++] = 'l';
            text_changed[text_length_changed++] = 't';
            (*changed)++;
            break;
        case 62 : // >
            text_changed[text_length_changed++] = '&';
            text_changed[text_length_changed++] = 'g';
            text_changed[text_length_changed++] = 't';
            (*changed)++;
            break;
        case 64  :  // @
            text_changed[text_length_changed++] = ' ';
            text_changed[text_length_changed++] = '[';
            text_changed[text_length_changed++] = 'a';
            text_changed[text_length_changed++] = 't';
            text_changed[text_length_changed++] = ']';
            text_changed[text_length_changed++] = ' ';
            (*changed)++;
            break;

        default : text_changed[text_length_changed++] = newChar;
            break;
        }
        counter++;
        // text_length_changed++;
    }
    //Nachdem alle Zeichen gelesen sind (counter=text_length) kommt die L?nge des
    //eingelesenen Textes zur?ck.
    return text_length_changed;
}
int main()
{

    int * my_text      = NULL;
    int * text_changed = NULL;
    // read text
    int len1 = importCharacter(&my_text);
    if (len1 <= 0)
    {
        switch (len1)
        {
            case 0:
                printf ("No input text.\n");
                len1 = -1;
                break;

            case -2:
                printf ("Out of Memory.\n" );
                break;

            case -3:
                printf ("Invalid Input Character.\n" );
                break;

            default:
                printf ("Unknown error.\n");
                break;
        }
        free (my_text);
        return len1;
    }

    // write original text
    output (len1, my_text);
    printf("\n----------\n");

    // replace special characters by strings

    int NChanged = 0;
    int len2 = ReplaceCharacters(&text_changed, my_text, len1, &NChanged);
    if (len2 <= 0)
    {
        switch (len2)
        {
            case 0:
                printf ("No input text.\n");
                len2 = -1;
                break;

            case -2:
                printf ("Out of Memory.\n" );
                break;

            case -3:
                printf ("Invalid Input Character.\n" );
                break;

            default:
                printf ("Unknown error.\n");
                break;
        }
        free (my_text);
        free (text_changed);
        return len2;
    }
    // write text with replacements
    output (len2, text_changed);
    printf("\n----------\n");
     // write statistics
    printf("original string: %d chars\n", len1);
    printf("modified string: %d chars\n", len2);
    printf("modified chars : %d\n", NChanged);
    free (my_text);
    free (text_changed);
    return 0;

}