//
//  main.cpp
//  assembly
//
//  Created by Ethan Laur on 3/11/14.
//  Copyright (c) 2014 Ethan Laur. All rights reserved.
//

#include <iostream>
#include <queue>
#include <sys/stat.h>
#include <unistd.h>
#include "Symtab.h"

#define DBGOUT(a); if (MDEBUG) { a; }
#define MDEBUG 0x01
#define MAX_LINE_LENGTH 1024

Symtab *symtab;
typedef std::queue<char *> lineQueue;

lineQueue * readlines(char *buf)
{
    lineQueue *ret = new lineQueue;
    char *str = strdup((const char *)buf);
    char *tok = strtok(str, "\n");
    do
    {
        ret->push(tok);
    }  while ((tok = strtok(NULL, "\n")) != NULL);
    return ret;
}

char *getlinefromqueue(lineQueue * in)
{
    if (in->size() <= 0) return NULL;
    char *str = (char *)malloc(MAX_LINE_LENGTH);
    strcpy(str, in->front());
    in->pop();
    return str;
}

void build_symtab(char *buf)
{
    lineQueue *lq = readlines(buf);
    char *line, tmp[30], sym_name[28], sym_name_tmp[28];
    int curr_location = 0, i;
    char *repl = NULL, rbuf[30];
    while ((line = getlinefromqueue(lq)) != NULL)
    {
        if (sscanf(line, "%s", tmp) > 0)
        {
            if (tmp[0] == ':')
            {
                for (i = 1; i < 28 && tmp[i] != ':'; i++); //i now points to the next colon
                strncpy(sym_name_tmp, tmp + 1, i - 1); //grab the symbol
                sprintf(rbuf, "%s", sym_name_tmp);
                DBGOUT(printf("[DEBUG build_symtab] Inserting symbol %s to location 0x%04x\n",
                            sym_name, curr_location););
                sprintf(sym_name, "$%s", sym_name_tmp);
                symtab->insertNode(sym_name, curr_location);
                //while ((repl = strstr(buf, rbuf)) != NULL)
                //{
                //  repl[0] = ';';
                //}
            }
            else if (tmp[0] == ';') {} //ignore comments
            else //we have an instruction
            {
                curr_location += 4;
            }
        }
        free(line);
    }
    delete lq;
    if (line != NULL)
        free(line);
}

char * insert_symtab(char *buf)
{
    char *ret = (char *)malloc(strlen(buf) + 512);
    char *tmp = NULL;
    char *repl = NULL;
    char obuf[32]; //for converting int to hex
    Symtab_struct *cursym;
    lineQueue *lq = readlines(buf);
    int i;
    strcpy(ret, "");
    while (!lq->empty())
    {
        tmp = getlinefromqueue(lq);
        for (i = 0; (cursym = symtab->findNodeByNumber(i)) != NULL; i++)
        {
            sprintf(obuf, "0x%04x", cursym->sym_location);
            //printf("-->looking for %s\n", cursym->sym_name);
            if ((repl = strstr(tmp, "$start")) != NULL)
            {
                printf("---->Found %s\n", cursym->sym_name);
                strncpy (repl, obuf, strlen(cursym->sym_name));
            }
        }
        strcat(ret, tmp);
        strcat(ret, "\n");
    }
    return ret;
}

char *process_includes(char *buf)
{
    char *ret = NULL;
    char *tmplstr = (char *)malloc(MAX_LINE_LENGTH);
    char *tmpstr = (char *)malloc(30);
    char *finpstr = (char *)malloc(MAX_LINE_LENGTH);
    char *includepos = NULL;
    FILE *f = NULL;
    FILE *o = NULL;
    struct stat st;
    lineQueue *lq = readlines(buf);
    lineQueue *tmplq = new lineQueue; //for reading files
    ssize_t retsize;
    int read_ret, num_inc = 0;
    while (!lq->empty())
    {
        strcpy(tmplstr, lq->front());
        lq->pop();
        if ((includepos = strstr(tmplstr, "%include")) != NULL)
        {
            sscanf(tmplstr, "%%include '%s'", tmpstr);
            tmpstr[strlen(tmpstr) - 1] = 0; //trim the '
            if ((f = fopen(tmpstr, "r")) == NULL)
            {
                printf("[WARN process_includes] Cannot find file included %s\n", tmpstr);
            }
            else
            {
                read_ret = 0;
                while (read_ret != EOF)
                {
                    int sp;
                    for (sp = 0; sp < MAX_LINE_LENGTH - 1 && (read_ret = fscanf(f, "%c", &finpstr[sp])) != EOF;sp++);
                    finpstr[sp] = 0;
                    tmplq->push(finpstr);
                }
                if ((o = fopen("/tmp/as.tmp", "a")) == NULL)
                {
                    if ((o = fopen("/tmp/as.tmp", "w")) == NULL)
                    {
                        printf("[ERR process_includes] Cannot write temporary files\n");
                        exit(1);
                    }
                }
                while (!tmplq->empty())
                {
                    fprintf(o, "%s", tmplq->front());
                    tmplq->pop();
                }
                fflush(o);
                fclose(o);
                ++num_inc;
            }
        }
    }
    if (stat("/tmp/as.tmp", &st) == 0)
        retsize = strlen(buf) + st.st_size + 256;
    else
        retsize = strlen(buf) + 256;
    ret = (char *)malloc(retsize);
    memset(ret, 0, retsize);
    strcpy(ret, buf);
    if (num_inc > 0)
    {
        if ((o = fopen("/tmp/as.tmp", "r")) == NULL)
        {
            printf("[ERR process_includes] Cannot read temproary files\n");
            exit(1);
        }
        fread(ret + strlen(buf), st.st_size, 1, o);
        fclose(o);
    }
    unlink("/tmp/as.tmp");
    while ((includepos = strstr(ret, "%include")) != NULL)
    {
        includepos[0] = ';';
    }
    //delete tmplq;
    //delete lq;
    return ret;
}

int main(int argc, const char * argv[])
{
    symtab = new Symtab();
    FILE *f = fopen(argv[1], "rb");
    char buf[1024] = {0};
    int sp = 0;
    for (sp = 0; fscanf(f, "%c", &buf[sp]) != EOF; sp++);
    char *buf2 = process_includes(buf);
    build_symtab(buf2);
    char *buf3 = insert_symtab(buf2);
    printf("%s\n", buf3);
}

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