//Copyright 2015 <>< Charles Lohr Under the MIT/x11 License, NewBSD License or
// ColorChord License.  You Choose.

#include "http.h"
#include "mystuff.h"
#include "esp8266_rom.h"

#define HTDEBUG( x... ) printf( x )

//#define ISKEEPALIVE "keep-alive"
#define ISKEEPALIVE "close"

struct HTTPConnection HTTPConnections[HTTP_CONNECTIONS];
struct HTTPConnection * curhttp;
uint8 * curdata;
uint16  curlen;
uint8   wsmask[4];
uint8   wsmaskplace;


ICACHE_FLASH_ATTR void InternalStartHTTP( );
ICACHE_FLASH_ATTR void HTTPHandleInternalCallback( );

ICACHE_FLASH_ATTR void HTTPClose( )
{
	//This is dead code, but it is a testament to Charles.
	//Do not do this here.  Wait for the ESP to tell us the
	//socket is successfully closed.
	//curhttp->state = HTTP_STATE_NONE;
	curhttp->state = HTTP_WAIT_CLOSE;
	espconn_disconnect( curhttp->socket ); 
}


void ICACHE_FLASH_ATTR HTTPGotData( )
{
	uint8 c;
	curhttp->timeout = 0;
	while( curlen-- )
	{
		c = HTTPPOP;
	//	sendhex2( h->state ); sendchr( ' ' );

		switch( curhttp->state )
		{
		case HTTP_STATE_WAIT_METHOD:
			if( c == ' ' )
			{
				curhttp->state = HTTP_STATE_WAIT_PATH;
				curhttp->state_deets = 0;
			}
			break;
		case HTTP_STATE_WAIT_PATH:
			curhttp->pathbuffer[curhttp->state_deets++] = c;
			if( curhttp->state_deets == MAX_PATHLEN )
			{
				curhttp->state_deets--;
			}
			
			if( c == ' ' )
			{
				//Tricky: If we're a websocket, we need the whole header.
				curhttp->pathbuffer[curhttp->state_deets-1] = 0;
				curhttp->state_deets = 0;

				if( strncmp( (const char*)curhttp->pathbuffer, "/d/ws", 5 ) == 0 )
				{
					curhttp->state = HTTP_STATE_DATA_WEBSOCKET;
					curhttp->state_deets = 0;
				}
				else
				{
					curhttp->state = HTTP_STATE_WAIT_PROTO; 
				}
			}
			break;
		case HTTP_STATE_WAIT_PROTO:
			if( c == '\n' )
			{
				curhttp->state = HTTP_STATE_WAIT_FLAG;
			}
			break;
		case HTTP_STATE_WAIT_FLAG:
			if( c == '\n' )
			{
				curhttp->state = HTTP_STATE_DATA_XFER;
				InternalStartHTTP( );
			}
			else if( c != '\r' )
			{
				curhttp->state = HTTP_STATE_WAIT_INFLAG;
			}
			break;
		case HTTP_STATE_WAIT_INFLAG:
			if( c == '\n' )
			{
				curhttp->state = HTTP_STATE_WAIT_FLAG;
				curhttp->state_deets = 0;
			}
			break;
		case HTTP_STATE_DATA_XFER:
			//Ignore any further data?
			curlen = 0;
			break;
		case HTTP_STATE_DATA_WEBSOCKET:
			WebSocketGotData( c );
			break;
		case HTTP_WAIT_CLOSE:
			if( curhttp->keep_alive )
			{
				curhttp->state = HTTP_STATE_WAIT_METHOD;
			}
			else
			{
				HTTPClose( );
			}
			break;
		default:
			break;
		};
	}

}


static void DoHTTP( uint8_t timed )
{
	switch( curhttp->state )
	{
	case HTTP_STATE_NONE: //do nothing if no state.
		break;
	case HTTP_STATE_DATA_XFER:
		if( TCPCanSend( curhttp->socket, 1024 ) ) //TCPDoneSend
		{
			if( curhttp->is_dynamic )
			{
				HTTPCustomCallback( );
			}
			else
			{
				HTTPHandleInternalCallback( );
			}
		}
		break;
	case HTTP_WAIT_CLOSE:
		if( TCPDoneSend( curhttp->socket ) )
		{
			if( curhttp->keep_alive )
			{
				curhttp->state = HTTP_STATE_WAIT_METHOD;
			}
			else
			{
				HTTPClose( );
			}
		}
		break;
	case HTTP_STATE_DATA_WEBSOCKET:
		if( TCPCanSend( curhttp->socket, 1024 ) ) //TCPDoneSend
		{
			WebSocketTickInternal();
		}
		break;
	default:
		if( timed )
		{
			if( curhttp->timeout++ > HTTP_SERVER_TIMEOUT )
			{
				HTTPClose( );
			}
		}
	}
}

void HTTPTick( uint8_t timed )
{
	uint8_t i;
	for( i = 0; i < HTTP_CONNECTIONS; i++ )
	{
		if( curhttp ) { printf( "Unexpected Race Condition\n" );}
		curhttp = &HTTPConnections[i];
		DoHTTP( timed );
		curhttp = 0;
	}
}

void ICACHE_FLASH_ATTR HTTPHandleInternalCallback( )
{
	uint16_t i, bytestoread;

	if( curhttp->isdone )
	{
		HTTPClose( );
		return;
	}
	if( curhttp->is404 )
	{
		START_PACK
		PushString("HTTP/1.1 404 Not Found\r\nConnection: close\r\n\r\nFile not found.");
		EndTCPWrite( curhttp->socket );
		curhttp->isdone = 1;
		return;
	}
	if( curhttp->isfirst )
	{
		char stto[10];
		uint8_t slen = os_strlen( curhttp->pathbuffer );
		const char * k;

		START_PACK;
		//TODO: Content Length?  MIME-Type?
		PushString("HTTP/1.1 200 Ok\r\n");

		if( curhttp->bytesleft < 0xfffffffe )
		{
			PushString("Connection: "ISKEEPALIVE"\r\nContent-Length: ");
			Uint32To10Str( stto, curhttp->bytesleft );
			PushBlob( stto, os_strlen( stto ) );
			curhttp->keep_alive = 1;
		}
		else
		{
			PushString("Connection: close\r\n");
			curhttp->keep_alive = 0;
		}

		PushString( "\r\nContent-Type: " );
		//Content-Type?
		while( slen && ( curhttp->pathbuffer[--slen] != '.' ) );
		k = &curhttp->pathbuffer[slen+1];
		if( strcmp( k, "mp3" ) == 0 )
		{
			PushString( "audio/mpeg3" );
		}
		else if( strcmp( k, "gz" ) == 0 )
		{
			PushString( "text/plain\r\nContent-Encoding: gzip\r\nCache-Control: public, max-age=3600" );			
		}
		else if( curhttp->bytesleft == 0xfffffffe )
		{
			PushString( "text/plain" );
		}
		else
		{
			PushString( "text/html" );
		}

		PushString( "\r\n\r\n" );
		EndTCPWrite( curhttp->socket );
		curhttp->isfirst = 0;

		return;
	}

	START_PACK

	for( i = 0; i < 4 && curhttp->bytesleft; i++ )
	{
		int bpt = curhttp->bytesleft;
		if( bpt > MFS_SECTOR ) bpt = MFS_SECTOR;
		curhttp->bytesleft = MFSReadSector( generic_ptr, &curhttp->data.filedescriptor );
		generic_ptr += bpt;
	}

	EndTCPWrite( curhttp->socket );

	if( !curhttp->bytesleft )
		curhttp->isdone = 1;
}

void ICACHE_FLASH_ATTR InternalStartHTTP( )
{
	int32_t clusterno;
	int8_t i;
	const char * path = &curhttp->pathbuffer[0];

	if( curhttp->pathbuffer[0] == '/' )
		path++;

	if( path[0] == 'd' && path[1] == '/' )
	{
		curhttp->is_dynamic = 1;
		curhttp->isfirst = 1;
		curhttp->isdone = 0;
		curhttp->is404 = 0;
		HTTPCustomStart();
		return;
	}

	if( !path[0] )
	{
		path = "index.html";
	}

	i = MFSOpenFile( path, &curhttp->data.filedescriptor );
	curhttp->bytessofar = 0;

	if( i < 0 )
	{
		HTDEBUG( "404(%s)\n", path );
		curhttp->is404 = 1;
		curhttp->isfirst = 1;
		curhttp->isdone = 0;
		curhttp->is_dynamic = 0;
	}
	else
	{
		curhttp->isfirst = 1;
		curhttp->isdone = 0;
		curhttp->is404 = 0;
		curhttp->is_dynamic = 0;
		curhttp->bytesleft = curhttp->data.filedescriptor.filelen;
	}

}








LOCAL void ICACHE_FLASH_ATTR
http_disconnetcb(void *arg) {
    struct espconn *pespconn = (struct espconn *) arg;
	((struct HTTPConnection * )pespconn->reverse)->state = 0;
}

LOCAL void http_recvcb(void *arg, char *pusrdata, unsigned short length)
{
    struct espconn *pespconn = (struct espconn *) arg;

	//Though it might be possible for this to interrupt the other
	//tick task, I don't know if this is actually a probelem.
	//I'm adding this back-up-the-register just in case.
	if( curhttp ) { printf( "Unexpected Race Condition\n" );}

	curhttp = (struct HTTPConnection * )pespconn->reverse;
	curdata = (uint8*)pusrdata;
	curlen = length;
	HTTPGotData();
	curhttp = 0 ;

}

void ICACHE_FLASH_ATTR
httpserver_connectcb(void *arg)
{
	int i;
    struct espconn *pespconn = (struct espconn *)arg;

	for( i = 0; i < HTTP_CONNECTIONS; i++ )
	{
		if( HTTPConnections[i].state == 0 )
		{
			pespconn->reverse = &HTTPConnections[i];
			HTTPConnections[i].socket = pespconn;
			HTTPConnections[i].state = HTTP_STATE_WAIT_METHOD;
			break;
		}
	}
	if( i == HTTP_CONNECTIONS )
	{
		espconn_disconnect( pespconn );
		return;
	}

//	espconn_set_opt(pespconn, ESPCONN_NODELAY);
//	espconn_set_opt(pespconn, ESPCONN_COPY);

    espconn_regist_recvcb( pespconn, http_recvcb );
    espconn_regist_disconcb( pespconn, http_disconnetcb );

}


int ICACHE_FLASH_ATTR URLDecode( char * decodeinto, int maxlen, const char * buf )
{
	int i = 0;

	for( ; buf && *buf; buf++ )
	{
		char c = *buf;
		if( c == '+' )
		{
			decodeinto[i++] = ' ';
		}
		else if( c == '?' || c == '&' )
		{
			break;
		}
		else if( c == '%' )
		{
			if( *(buf+1) && *(buf+2) )
			{
				decodeinto[i++] = hex2byte( buf+1 );
				buf += 2;
			}
		}
		else
		{
			decodeinto[i++] = c;
		}
		if( i >= maxlen -1 )  break;
		
	}
	decodeinto[i] = 0;
	return i;
}



void ICACHE_FLASH_ATTR WebSocketGotData( uint8_t c )
{
	switch( curhttp->state_deets )
	{
	case 0:
	{
		int i = 0;
		char inkey[120];
		unsigned char hash[SHA1_HASH_LEN];
		SHA1_CTX c;
		int inkeylen = 0;

		curhttp->is_dynamic = 1;
		while( curlen > 20 )
		{
			curdata++; curlen--;
			if( strncmp( curdata, "Sec-WebSocket-Key: ", 19 ) == 0 )
			{
				break;
			}
		}

		if( curlen <= 21 )
		{
			HTDEBUG( "No websocket key found.\n" );
			curhttp->state = HTTP_WAIT_CLOSE;
			return;
		}

		curdata+= 19;
		curlen -= 19;


#define WS_KEY_LEN 36
#define WS_KEY "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
#define WS_RETKEY_SIZEM1 32

		while( curlen > 1 )
		{
			uint8_t lc = *(curdata++);
			inkey[i] = lc;
			curlen--;
			if( lc == '\r' )
			{
				inkey[i] = 0;
				break;
			}
			i++;
			if( i >= sizeof( inkey ) - WS_KEY_LEN - 5 )
			{
				HTDEBUG( "Websocket key too big.\n" );
				curhttp->state = HTTP_WAIT_CLOSE;
				return;
			}
		}
		if( curlen <= 1 )
		{
			HTDEBUG( "Invalid websocket key found.\n" );
			curhttp->state = HTTP_WAIT_CLOSE;
			return;
		}

		if( i + WS_KEY_LEN + 1 >= sizeof( inkey ) )
		{
			HTDEBUG( "WSKEY Too Big.\n" );
			curhttp->state = HTTP_WAIT_CLOSE;
			return;
		}

		ets_memcpy( &inkey[i], WS_KEY, WS_KEY_LEN + 1 );
		i += WS_KEY_LEN;
		SHA1_Init( &c );
		SHA1_Update( &c, inkey, i );
		SHA1_Final( hash, &c );

#if	(WS_RETKEY_SIZE > MAX_PATHLEN - 10 )
#error MAX_PATHLEN too short.
#endif

		my_base64_encode( hash, SHA1_HASH_LEN, curhttp->pathbuffer + (MAX_PATHLEN-WS_RETKEY_SIZEM1)  );

		curhttp->bytessofar = 0;
		curhttp->bytesleft = 0;

		NewWebSocket();

		//Respond...
		curhttp->state_deets = 1;
		break;
	}
	case 1:
		if( c == '\n' ) curhttp->state_deets = 2;
		break;
	case 2:
		if( c == '\r' ) curhttp->state_deets = 3;
		else curhttp->state_deets = 1;
		break;
	case 3:
		if( c == '\n' ) curhttp->state_deets = 4;
		else curhttp->state_deets = 1;
		break;
	case 5: //Established connection.
	{
		if( curlen < 5 ) //Can't interpret packet.
			break;

		uint8_t fin = c & 1;
		uint8_t opcode = c << 4;
		uint32_t payloadlen = *(curdata++);
		curlen--;
		if( !(payloadlen & 0x80) )
		{
			HTDEBUG( "Unmasked packet.\n" );
			curhttp->state = HTTP_WAIT_CLOSE;
			break;
		}

		if( payloadlen == 127 )
		{
			//Very long payload.
			//Not supported.
			HTDEBUG( "Unsupported payload packet.\n" );
			curhttp->state = HTTP_WAIT_CLOSE;
			break;
		}
		else if( payloadlen == 126 )
		{
			payloadlen = (curdata[0] << 8) | curdata[1];
			curdata += 2;
			curlen -= 2;
		}
		else
		{
			payloadlen &= 0x7f;
		}

		wsmask[0] = curdata[0];
		wsmask[1] = curdata[1];
		wsmask[2] = curdata[2];
		wsmask[3] = curdata[3];
		curdata += 4;
		curlen -= 4;
		wsmaskplace = 0;

		WebSocketData( payloadlen );
		curlen -= payloadlen;
		curdata += payloadlen;
		
		break;
	}
	default:
		break;
	}
}

void ICACHE_FLASH_ATTR WebSocketTickInternal()
{
	switch( curhttp->state_deets )
	{
	case 4: //Has key full HTTP header, etc. wants response.
		START_PACK;
		PushString( "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: " );
		PushString( curhttp->pathbuffer + (MAX_PATHLEN-WS_RETKEY_SIZEM1) );
		PushString( "\r\n\r\n" );
		EndTCPWrite( curhttp->socket );
		curhttp->state_deets = 5;
		curhttp->keep_alive = 0;
		break;
	case 5:
		WebSocketTick();
		break;
	}
}

void ICACHE_FLASH_ATTR WebSocketSend( uint8_t * data, int size )
{
	START_PACK;
	PushByte( 0x81 );
	if( size > 126 )
	{
		PushByte( 0x00 | 126 );
		PushByte( size>>8 );
		PushByte( size&0xff );
	}
	else
	{
		PushByte( 0x00 | size );
	}
	PushBlob( data, size );
	EndTCPWrite( curhttp->socket );
}

uint8_t WSPOPMASK()
{
	uint8_t mask = wsmask[wsmaskplace];
	wsmaskplace = (wsmaskplace+1)&3;
	return (*curdata++)^(mask);
}