/*
  * Copyright (c) 2012 Stefano Sabatini
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #include "config.h"
 #if HAVE_UNISTD_H

 #include <unistd.h>             /* getopt */

 #endif
 

 #include "libavutil/eval.h"

 #include "libavutil/mem.h"

 #if !HAVE_GETOPT
 #include "compat/getopt.c"
 #endif
 

 /**
  * @file
  * simple arithmetic expression evaluator
  */
 
 static void usage(void)
 {
     printf("Simple expression evalutor, please *don't* turn me to a feature-complete language interpreter\n");
     printf("usage: ffeval [OPTIONS]\n");
     printf("\n"
            "Options:\n"
            "-e                echo each input line on output\n"
            "-h                print this help\n"
            "-i INFILE         set INFILE as input file, stdin if omitted\n"
            "-o OUTFILE        set OUTFILE as output file, stdout if omitted\n"
            "-p PROMPT         set output prompt\n");
 }
 
 int main(int argc, char **argv)
 {

     int buf_size = 0;
     char *buf = NULL;

     const char *outfilename = NULL, *infilename = NULL;
     FILE *outfile = NULL, *infile = NULL;
     const char *prompt = "=> ";
     int count = 0, echo = 0;

     int c;

 #define GROW_ARRAY()                                                    \
     do {                                                                \
         if (!av_dynarray2_add((void **)&buf, &buf_size, 1, NULL)) {     \
             av_log(NULL, AV_LOG_ERROR,                                  \
                    "Memory allocation problem occurred\n");             \
             return 1;                                                   \
         }                                                               \
     } while (0)

     GROW_ARRAY();

     while ((c = getopt(argc, argv, "ehi:o:p:")) != -1) {
         switch (c) {
         case 'e':
             echo = 1;
             break;
         case 'h':
             usage();
             return 0;
         case 'i':
             infilename = optarg;
             break;
         case 'o':
             outfilename = optarg;
             break;
         case 'p':
             prompt = optarg;
             break;
         case '?':
             return 1;
         }
     }
 

     if (!infilename || !strcmp(infilename, "-")) {
         infilename = "stdin";
         infile = stdin;
     } else {
         infile = fopen(infilename, "r");
     }

     if (!infile) {
         fprintf(stderr, "Impossible to open input file '%s': %s\n", infilename, strerror(errno));
         return 1;
     }
 

     if (!outfilename || !strcmp(outfilename, "-")) {
         outfilename = "stdout";
         outfile = stdout;
     } else {
         outfile = fopen(outfilename, "w");
     }

     if (!outfile) {
         fprintf(stderr, "Impossible to open output file '%s': %s\n", outfilename, strerror(errno));
         return 1;
     }
 
     while ((c = fgetc(infile)) != EOF) {
         if (c == '\n') {
             double d;
 
             buf[count] = 0;
             if (buf[0] != '#') {

                 int ret = av_expr_parse_and_eval(&d, buf,
                                                  NULL, NULL,
                                                  NULL, NULL, NULL, NULL, NULL, 0, NULL);

                 if (echo)
                     fprintf(outfile, "%s ", buf);

                 if (ret >= 0) fprintf(outfile, "%s%f\n", prompt, d);

                 else          fprintf(outfile, "%s%f (%s)\n", prompt, d, av_err2str(ret));

             }
             count = 0;
         } else {

             if (count >= buf_size-1)
                 GROW_ARRAY();

             buf[count++] = c;
         }
     }
 
     av_free(buf);
     return 0;
 }