#include <glib.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

gchar *plain_text(const char *text)
{
    const char *s;
    GString *plain=g_string_new(NULL);
    while(*text)
    {
	if (*text=='<')
	{
	    s=strchr(text+1,'>');
	    if (s)
	    {
		text=s+1;
		continue;
	    }
	}
	else if (g_str_has_prefix(text,"[**"))
	{
	    s=strchr(text+3,']');
	    if (s)
	    {
		text=s+1;
		continue;
	    }
	}
	else if (g_str_has_prefix(text,"\n/#\n"))
	    text+=3;
	else if (g_str_has_prefix(text,"\n/*\n"))
	    text+=3;
	else if (g_str_has_prefix(text,"\n#/\n"))
	    text+=3;
	else if (g_str_has_prefix(text,"\n*/\n"))
	    text+=3;
	g_string_append_c(plain,*text++);
    }
    return g_string_free(plain,FALSE);
}

main(int argc,char **argv)
{
    gchar *contents,*s;
    gchar **paras;
    gsize len;
    int i,j,cnt_s,cnt_d;
    GString *str;
    GString *open;
    GError *err=NULL;
    if (!g_file_get_contents(argc>1?argv[1]:"/dev/stdin",&contents,&len,&err))
    {
	fprintf(stderr,"%s: %s\n",argc>1?argv[1]:"stdin",err->message);
	exit(1);
    }
    open=g_string_new(NULL);
    paras=g_strsplit(contents,"\n\n",0);
    g_free(contents);
    for(i=0;paras[i];i++)
    {
	str=g_string_new(NULL);
	s=plain_text(paras[i]);
	if (g_str_has_prefix(s,open->str))
	{
	    /*
	     * Paragraph 1 elided closing quotation marks; paragraph
	     * 2 starts with opening quotation marks.
	     */
	    g_string_truncate(open,0);
	}
	else if (s[0]!='\'' && s[0]!='"')
	    /*
	     * Quotation marks span multiple paragraphs.
	     * Ideally we would check that the opening quotation
	     * mark is at the start of a paragraph and the
	     * closing quotation mark is at the end of paragraph.
	     */
	    ;
	else if (open->len)
	    g_warning("Quotation marks at start of paragraph don't "
	      "match open ones (%s):\n%s",open->str,paras[i]);
	g_free(s);
	for(j=0;paras[i][j];j++)
	{
	    if (paras[i][j]=='\'')
	    {
		if (open->len>0 && open->str[open->len-1]=='\'')
		{
		    g_string_truncate(open,open->len-1);
		    g_string_append_unichar(str,0x2019);
		}
		else
		{
		    g_string_append_c(open,'\'');
		    g_string_append_unichar(str,0x2018);
		}
	    }
	    else if (paras[i][j]=='"')
	    {
		if (open->len>0 && open->str[open->len-1]=='"')
		{
		    g_string_truncate(open,open->len-1);
		    g_string_append_unichar(str,0x201D);
		}
		else
		{
		    g_string_append_c(open,'"');
		    g_string_append_unichar(str,0x201C);
		}
	    }
	    else
		g_string_append_c(str,paras[i][j]);
	}
	g_free(paras[i]);
	paras[i]=g_string_free(str,FALSE);
    }
    if (open->len)
	g_warning("Unclosed quotation marks: %s",open->str);
    g_string_free(open,TRUE);
    contents=g_strjoinv("\n\n",paras);
    g_strfreev(paras);
    printf("%s",contents);
    g_free(contents);
    exit(0);
}