#include <iostream>
#include <streambuf>
#include <vector>
#include <algorithm>
#include <string>
#include <cstring>

using namespace std;

#include "fetch.h"

class libfetch_buffer : public streambuf
{
	public:
		explicit libfetch_buffer( fetchIO *io, size_t bufSize = 256, size_t putBack = 1 );
 
	private:
		int_type underflow( );
	
	private:
		fetchIO *m_io;
		const size_t m_putBack;
		vector<char> m_buf;
};

libfetch_buffer::libfetch_buffer( fetchIO *io, size_t bufSize, size_t putBack )
	: m_io( io ), m_putBack( max( putBack, size_t( 1 ) ) ),
	  m_buf( max( bufSize, putBack ) + putBack )
{
	char *end = &m_buf.front( ) + m_buf.size( );
	setg( end, end, end );
}

streambuf::int_type libfetch_buffer::underflow( )
{
	// check if buffer is exhausted, if not, return current character
	if( gptr( ) < egptr( ) ) 
		return traits_type::to_int_type( *gptr( ) );
	
	char *base = &m_buf.front( );
	char *start = base;
	
	// move put back away
	if( eback( ) == base ) {
		memmove( base, egptr( ) - m_putBack, m_putBack );
		start += m_putBack;
	}
	
	// read from source
	ssize_t n = fetchIO_read( m_io, start, m_buf.size( ) - ( start - base ) );
	if( n == 0 ) {
		return traits_type::eof( );
	} else if( n < 0 ) {
		// TODO handle error
	}
	
	// set pointers
	setg( base, start, start + n );
	
	return traits_type::to_int_type( *gptr( ) );
}

class libfetch_istream : public istream
{
	public:
		libfetch_istream( const char *url );
		~libfetch_istream( );
	
		string lastErrMsg( ) const;
		
	private:
		fetchIO *m_io;
		libfetch_buffer *m_buf;
};

libfetch_istream::libfetch_istream( const char *url )
	: m_io( 0 ), m_buf( 0 )
{
	m_io = fetchGetURL( url, "" );
	if( m_io == NULL ) {
		setstate( badbit );
		return;
	}
	m_buf = new libfetch_buffer( m_io );
	rdbuf( m_buf );
}

libfetch_istream::~libfetch_istream( )
{
	if( m_buf ) delete m_buf;
	if( m_io ) fetchIO_close( m_io );
}

string libfetch_istream::lastErrMsg( ) const
{
	return fetchLastErrString;
}

int main( int argc, char *argv[] )
{
	char *urlstring;
		
	if( argc != 2 ) {
		cerr << "Usage: test2 <url>" << endl;
		return 1;
	}

	urlstring = argv[1];
	
	fetchTimeout = 2;
		
	libfetch_istream is( urlstring );
	string s;
	
	if( !is.good( ) ) {
		cerr << "ERROR in libfetch input stream: " << is.lastErrMsg( ) << endl;
		return 1;
	}
	
	while( is.good( ) && !is.eof( ) ) {
		getline( is, s );
		cout << s << endl;
	}
		
	return 0;
}