/** \file kill.c
	The killring.

	Works like the killring in emacs and readline. The killring is cut
	and paste with a memory of previous cuts. It supports integration
	with the X clipboard.
*/

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <termios.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <algorithm>

#include "fallback.h"
#include "util.h"

#include "wutil.h"
#include "kill.h"
#include "proc.h"
#include "sanity.h"
#include "common.h"
#include "env.h"
#include "exec.h"
#include "path.h"

/**
   Maximum entries in killring
*/
#define KILL_MAX 8192

 /** Last kill string */
//static ll_node_t *kill_last=0;

/** Current kill string */
//static ll_node_t *kill_current=0;

/** Kill ring */
typedef std::list<wcstring> kill_list_t;
static kill_list_t kill_list;

/**
   Contents of the X clipboard, at last time we checked it
*/
static wchar_t *cut_buffer=0;

/**
   Test if the xsel command is installed.  Since this is called often,
   cache the result.
*/
static int has_xsel()
{
	static int res=-1;
	if (res < 0) {
		res = !! path_get_path(L"xsel", NULL);
    }
    
	return res;
}

void kill_add( const wcstring &str )
{
    ASSERT_IS_MAIN_THREAD();
    if (str.empty())
        return;
        
	wcstring cmd;
    wchar_t *escaped_str = NULL;
	kill_list.push_front(str);

	/*
	   Check to see if user has set the FISH_CLIPBOARD_CMD variable,
	   and, if so, use it instead of checking the display, etc.

	   I couldn't think of a safe way to allow overide of the echo
	   command too, so, the command used must accept the input via stdin.
	*/

	const env_var_t clipboard_wstr = env_get_string(L"FISH_CLIPBOARD_CMD");
	if( !clipboard_wstr.missing() )
	{
		escaped_str = escape( str.c_str(), 1 );
        cmd.assign(L"echo -n ");
        cmd.append(escaped_str);
        cmd.append(clipboard_wstr);
	}
	else
	{
	/* This is for sending the kill to the X copy-and-paste buffer */
		if( !has_xsel() ) {
			return;
		}

	const env_var_t disp_wstr = env_get_string( L"DISPLAY" );
	if( !disp_wstr.missing() )
	{
			escaped_str = escape( str.c_str(), 1 );
            cmd.assign(L"echo ");
            cmd.append(escaped_str);
            cmd.append(L"|xsel -b" );
		}
	}

	if (! cmd.empty())
	{
		if( exec_subshell(cmd) == -1 )
		{
			/* 
			   Do nothing on failiure
			*/
		}
		
		free( cut_buffer );
	
		cut_buffer = escaped_str;
	}
}

/**
   Remove first match for specified string from circular list
*/
static void kill_remove( const wcstring &s )
{
    ASSERT_IS_MAIN_THREAD();
    kill_list_t::iterator iter = std::find(kill_list.begin(), kill_list.end(), s);
    if (iter != kill_list.end())
        kill_list.erase(iter);
}
		
		

void kill_replace( const wcstring &old, const wcstring &newv )
{
	kill_remove( old );
	kill_add( newv );	
}

const wchar_t *kill_yank_rotate()
{
    ASSERT_IS_MAIN_THREAD();
    // Move the first element to the end
    if (kill_list.empty()) {
        return NULL;
    } else {
        kill_list.splice(kill_list.end(), kill_list, kill_list.begin());
        return kill_list.front().c_str();
    }
}

/**
   Check the X clipboard. If it has been changed, add the new
   clipboard contents to the fish killring.
*/
static void kill_check_x_buffer()
{		
	if( !has_xsel() )
		return;
	
	const env_var_t disp = env_get_string(L"DISPLAY");
	if( ! disp.missing())
	{
		size_t i;
		wcstring cmd = L"xsel -t 500 -b";
		wcstring new_cut_buffer=L"";
        wcstring_list_t list;
		if( exec_subshell( cmd, list ) != -1 )
		{
					
			for( i=0; i<list.size(); i++ )
			{
				wcstring next_line = escape_string( list.at(i), 0 );
                if (i > 0) new_cut_buffer += L"\\n";
                new_cut_buffer += next_line;
			}
		
			if( new_cut_buffer.size() > 0 )
			{
				/*  
					The buffer is inserted with backslash escapes,
					since we don't really like tabs, newlines,
					etc. anyway.
				*/
				
                if (cut_buffer == NULL || cut_buffer != new_cut_buffer)
                {
                    free(cut_buffer);
                    cut_buffer = wcsdup(new_cut_buffer.c_str());
                    kill_list.push_front( new_cut_buffer );
                }
			}
		}
	}
}


const wchar_t *kill_yank()
{
	kill_check_x_buffer();
    if (kill_list.empty()) {
        return L"";
    } else {
        return kill_list.front().c_str();
    }
}

void kill_sanity_check()
{
}

void kill_init()
{
}

void kill_destroy()
{
	if( cut_buffer )
		free( cut_buffer );
}