/*
 * Fanalyze - Analyze similarities between multiple files
 * Programmed and designed by Matti 'ccr' Hamalainen
 * (C) Copyright 2018 Tecnic Software productions (TNSP)
 *
 * Please read file 'COPYING' for information on license and distribution.
 */
#include "dmtool.h"
#include "dmlib.h"
#include "dmargs.h"
#include "dmfile.h"

#define SET_MAX_FILES    (8)


/* Typedefs
 */
typedef struct
{
    char *filename;
    Uint8 *data;
    size_t size; // offset, crop_start, crop_end, doCrop?
} DMSourceFile;


/* Global variables
 */
int           nsrcFiles = 0;              // Number of source files
DMSourceFile  srcFiles[SET_MAX_FILES];    // Source file names


/* Arguments
 */
static const DMOptArg optList[] =
{
    {  0, '?', "help",        "Show this help", OPT_NONE },
    {  1, 'v', "verbose",     "Be more verbose", OPT_NONE },
};

static const int optListN = sizeof(optList) / sizeof(optList[0]);


void argShowHelp()
{
    dmPrintBanner(stdout, dmProgName, "[options] <input file #1> <input file #2> [...]");
    dmArgsPrintHelp(stdout, optList, optListN, 0);
}


BOOL argHandleOpt(const int optN, char *optArg, char *currArg)
{
    (void) optArg;

    switch (optN)
    {
    case 0:
        argShowHelp();
        exit(0);
        break;

    case 1:
        dmVerbosity++;
        break;

    default:
        dmErrorMsg("Unknown argument '%s'.\n", currArg);
        return FALSE;
    }

    return TRUE;
}


BOOL argHandleNonOpt(char *currArg)
{
    if (nsrcFiles < SET_MAX_FILES)
    {
        DMSourceFile *file = &srcFiles[nsrcFiles++];
        file->filename = currArg;
        return TRUE;
    }
    else
    {
        dmErrorMsg("Maximum number of input files exceeded (%d).\n",
            SET_MAX_FILES);
        return FALSE;
    }
}


#define SET_MAX_ELEMS 256
typedef struct
{
    Uint8 counts[SET_MAX_ELEMS];
    Uint8 variants, data;
} DMCompElem;


int main(int argc, char *argv[])
{
    DMCompElem *compBuf = NULL;
    size_t compBufSize = 0;
    int res;

    dmInitProg("fanalyze", "File format analyzer", "0.1", NULL, NULL);
    dmVerbosity = 1;

    // Parse arguments
    if (!dmArgsProcess(argc, argv, optList, optListN,
        argHandleOpt, argHandleNonOpt, OPTH_BAILOUT))
        exit(1);

    if (nsrcFiles < 1)
    {
        dmErrorMsg("Nothing to do. (try --help)\n");
        goto out;
    }

    // Read input files
    for (int nfile = 0; nfile < nsrcFiles; nfile++)
    {
        DMSourceFile *file = &srcFiles[nfile];
        if ((res = dmReadDataFile(NULL, file->filename, &file->data, &file->size)) != DMERR_OK)
        {
            dmErrorMsg("Could not read '%s': %s\n",
                file->filename, dmErrorStr(res));
            goto out;
        }

        dmPrint(2, "Input #%d: '%s', %" DM_PRIu_SIZE_T " bytes.\n",
            nfile + 1, file->filename, file->size);

        if (!compBufSize || file->size < compBufSize)
            compBufSize = file->size;
    }

    // Allocate comparision buffer
    // XXX: integer overflow?
    dmPrint(2, "Allocating %d element (%d bytes) comparision buffer.\n",
        compBufSize, compBufSize * sizeof(DMCompElem));

    if ((compBuf = dmCalloc(compBufSize, sizeof(DMCompElem))) == NULL)
    {
        dmErrorMsg("Out of memory. Could not allocate comparision buffer!\n");
        goto out;
    }

    // Begin analyzing ..
    dmPrint(2, "Analyzing ..\n");
    for (int nfile = 0; nfile < nsrcFiles; nfile++)
    {
        DMSourceFile *file = &srcFiles[nfile];
        for (size_t offs = 0; offs < compBufSize; offs++)
        {
            Uint8 data = offs < file->size ? file->data[offs] : 0;
            compBuf[offs].counts[data]++;
        }
    }

    for (size_t offs = 0; offs < compBufSize; offs++)
    {
        DMCompElem *el = &compBuf[offs];
        for (int n = 0; n < SET_MAX_ELEMS; n++)
        {
            if (el->counts[n] > 0)
            {
                el->variants++;
                el->data = n;
            }
        }
    }

    // Display results
    for (size_t offs = 0, n = 0; offs < compBufSize; offs++)
    {
        DMCompElem *el = &compBuf[offs];
        BOOL var = el->variants > 1;

        if (n == 0)
            printf("%08" DM_PRIx_SIZE_T " | ", offs);

        if (var)
            printf("[%2d] ", el->variants);
        else
            printf(" %02x  ", el->data);

        if (++n >= 16)
        {
            printf("\n");
            n = 0;
        }
    }

    printf("\n");

out:
    for (int nfile = 0; nfile < nsrcFiles; nfile++)
    {
        DMSourceFile *file = &srcFiles[nfile];
        dmFree(file->data);
    }

    return 0;
}