#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include <mpi.h>



////////////////////////////////////////////////////////////////////////////////
// Program main
////////////////////////////////////////////////////////////////////////////////

char *textData;
int textLength;

char *patternData[8];
int patternLength;
int patternCount;

clock_t c0, c1;
time_t t0, t1;

void outOfMemory()
{
    fprintf (stderr, "Out of memory\n");
    exit (0);
}

void readFromFile (FILE *f, char **data, int *length)
{
    int ch;
    int allocatedLength;
    char *result;
    int resultLength = 0;

    allocatedLength = 0;
    result = NULL;



    ch = fgetc (f);
    while (ch >= 0)
    {
        resultLength++;
        if (resultLength > allocatedLength)
        {
            allocatedLength += 10000;
            result = (char *) realloc (result, sizeof(char)*allocatedLength);
            if (result == NULL)
                outOfMemory();
        }
        result[resultLength-1] = ch;
        ch = fgetc(f);
    }
    *data = result;
    *length = resultLength;
}

int readData (i)
{
    FILE *f;
    char fileName[1000];
#ifdef DOS
        sprintf (fileName, "inputs\\text.txt");
#else
    sprintf (fileName, "inputs/text.txt");
#endif
    f = fopen (fileName, "r");
    if (f == NULL)
        return 0;
    readFromFile (f, &textData, &textLength);
    fclose (f);

        printf("Read pattern number %d \n", i);
        #ifdef DOS
                sprintf(fileName, "inputs\\pattern%d.txt", i);
        #else
                sprintf(fileName, "inputs/pattern%d.txt", i);
        #endif

        f = fopen(fileName, "r");
        if (f == NULL)
            return 0;
        readFromFile(f, &patternData[i], &patternLength);
        fclose(f);


    return 1;

}



int hostMatch(long *comparisons, int index)
{
    int i,j,k, lastI;
    char *pattern = patternData[index];
    i=0;
    j=0;
    k=0;
    lastI = textLength-patternLength;
        *comparisons=0;

    while (i<=lastI && j<patternLength)
    {
                (*comparisons)++;
        if (textData[k] == pattern[j])
        {
            k++;
            j++;
        }
        else
        {
            i++;
            k=i;
            j=0;
        }
    }
    if (j == patternLength)
        return i;
    else
        return -1;
}
void processData(int i)
{
    unsigned int result;
    long comparisons;

    printf("Text length = %d\n", textLength);
    printf("Pattern %d length = %d\n", i, patternLength);

    result = hostMatch(&comparisons, i);
    if (result == -1)
        printf("Pattern %d not found\n", i);
    else
        printf("Pattern %d found at position %d\n", i, result);
    printf("# comparisons = %ld\n", comparisons);

}

int main(int argc, char **argv)
{
    MPI_Init(NULL, NULL);
    int world_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
    int world_size;
    MPI_Comm_size(MPI_COMM_WORLD, &world_size);

    const int PATTERN_COUNT = 8;

    int patternsComplete = 0;
    int indavidualCount = PATTERN_COUNT / world_size;
    int i = world_rank + 1;
    while (patternsComplete < indavidualCount)
    {
        readData(i);
        processData(i);
        i = i + world_size;
        patternsComplete++;
    }

    MPI_Finalize();


}