/*
  * 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/log.h"
 #include "libavutil/bprint.h"
 
 #if !HAVE_GETOPT
 #include "compat/getopt.c"
 #endif
 
 /**
  * @file
  * escaping utility
  */
 
 static void usage(void)
 {
     printf("Escape an input string, adopting the av_get_token() escaping logic\n");
     printf("usage: ffescape [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"
            "-l LEVEL          set the number of escaping levels, 1 if omitted\n"
            "-m ESCAPE_MODE    select escape mode between 'full', 'lazy', 'quote', default is 'lazy'\n"
            "-o OUTFILE        set OUTFILE as output file, stdout if omitted\n"
            "-p PROMPT         set output prompt, is '=> ' by default\n"
            "-s SPECIAL_CHARS  set the list of special characters\n");
 }
 
 #define WHITESPACES " \n\t"
 
 enum EscapeMode {
     ESCAPE_MODE_FULL,
     ESCAPE_MODE_LAZY,
     ESCAPE_MODE_QUOTE,
 };
 
 static int escape(char **dst, const char *src, const char *special_chars,
                   enum EscapeMode mode)
 {
     AVBPrint dstbuf;
 
     av_bprint_init(&dstbuf, 1, AV_BPRINT_SIZE_UNLIMITED);
 
     switch (mode) {
     case ESCAPE_MODE_FULL:
     case ESCAPE_MODE_LAZY:
         /* \-escape characters */
 
         if (mode == ESCAPE_MODE_LAZY && strchr(WHITESPACES, *src))
             av_bprintf(&dstbuf, "\\%c", *src++);
 
         for (; *src; src++) {
             if ((special_chars && strchr(special_chars, *src)) ||
                 strchr("'\\", *src) ||
                 (mode == ESCAPE_MODE_FULL && strchr(WHITESPACES, *src)))
                 av_bprintf(&dstbuf, "\\%c", *src);
             else
                 av_bprint_chars(&dstbuf, *src, 1);
         }
 
         if (mode == ESCAPE_MODE_LAZY && strchr(WHITESPACES, dstbuf.str[dstbuf.len-1])) {
             char c = dstbuf.str[dstbuf.len-1];
             dstbuf.str[dstbuf.len-1] = '\\';
             av_bprint_chars(&dstbuf, c, 1);
         }
         break;
 
     case ESCAPE_MODE_QUOTE:
         /* enclose between '' the string */
         av_bprint_chars(&dstbuf, '\'', 1);
         for (; *src; src++) {
             if (*src == '\'')
                 av_bprintf(&dstbuf, "'\\''");
             else
                 av_bprint_chars(&dstbuf, *src, 1);
         }
         av_bprint_chars(&dstbuf, '\'', 1);
         break;
 
     default:
         /* unknown escape mode */
         return AVERROR(EINVAL);
     }
 
     if (!av_bprint_is_complete(&dstbuf)) {
         av_bprint_finalize(&dstbuf, NULL);
         return AVERROR(ENOMEM);
     } else {
         av_bprint_finalize(&dstbuf, dst);
         return 0;
     }
 }
 
 int main(int argc, char **argv)
 {
     AVBPrint src;
     char *src_buf, *dst_buf;
     const char *outfilename = NULL, *infilename = NULL;
     FILE *outfile = NULL, *infile = NULL;
     const char *prompt = "=> ";
     enum EscapeMode escape_mode = ESCAPE_MODE_LAZY;
     int level = 1;
     int echo = 0;
     char *special_chars = NULL;
     int c;
 
     while ((c = getopt(argc, argv, "ehi:l:o:m:p:s:")) != -1) {
         switch (c) {
         case 'e':
             echo = 1;
             break;
         case 'h':
             usage();
             return 0;
         case 'i':
             infilename = optarg;
             break;
         case 'l':
         {
             char *tail;
             long int li = strtol(optarg, &tail, 10);
             if (*tail || li > INT_MAX || li < 0) {
                 av_log(NULL, AV_LOG_ERROR,
                         "Invalid value '%s' for option -l, argument must be a non negative integer\n",
                         optarg);
                 return 1;
             }
             level = li;
             break;
         }
         case 'm':
             if      (!strcmp(optarg, "full"))  escape_mode = ESCAPE_MODE_FULL;
             else if (!strcmp(optarg, "lazy"))  escape_mode = ESCAPE_MODE_LAZY;
             else if (!strcmp(optarg, "quote")) escape_mode = ESCAPE_MODE_QUOTE;
             else {
                 av_log(NULL, AV_LOG_ERROR,
                        "Invalid value '%s' for option -m, "
                        "valid arguments are 'full', 'lazy', 'quote'\n", optarg);
                 return 1;
             }
             break;
         case 'o':
             outfilename = optarg;
             break;
         case 'p':
             prompt = optarg;
             break;
         case 's':
             special_chars = optarg;
             break;
         case '?':
             return 1;
         }
     }
 
     if (!infilename || !strcmp(infilename, "-")) {
         infilename = "stdin";
         infile = stdin;
     } else {
         infile = fopen(infilename, "r");
     }
     if (!infile) {
         av_log(NULL, AV_LOG_ERROR, "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) {
         av_log(NULL, AV_LOG_ERROR, "Impossible to open output file '%s': %s\n", outfilename, strerror(errno));
         return 1;
     }
 
     /* grab the input and store it in src */
     av_bprint_init(&src, 1, AV_BPRINT_SIZE_UNLIMITED);
     while ((c = fgetc(infile)) != EOF)
         av_bprint_chars(&src, c, 1);
     av_bprint_chars(&src, 0, 1);
 
     if (!av_bprint_is_complete(&src)) {
         av_log(NULL, AV_LOG_ERROR, "Could not allocate a buffer for the source string\n");
         av_bprint_finalize(&src, NULL);
         return 1;
     }
     av_bprint_finalize(&src, &src_buf);
 
     if (echo)
         fprintf(outfile, "%s", src_buf);
 
     /* escape */
     dst_buf = src_buf;
     while (level--) {
         if (escape(&dst_buf, src_buf, special_chars, escape_mode) < 0) {
             av_log(NULL, AV_LOG_ERROR, "Could not escape string\n");
             return 1;
         }
         av_free(src_buf);
         src_buf = dst_buf;
     }
 
     fprintf(outfile, "%s%s", prompt, dst_buf);
     av_free(dst_buf);
     return 0;
 }