module dinc.mime.Encodings;

/**
 * code to convert encodings...
 * 
 * 
 * based on my code in Part - I need to change Source to be a Buffered Input Stream!/.
 * 
 */
import std.stream;

 
	char[] quotedPrintable(char[] in_str) 
	{
		auto o_ms = new MemoryStream();
		auto i_ms = new MemoryStream(in_str);
		quotedPrintable(i_ms, o_ms);
		
		return o_ms.toString();
		
	}
	
	void quotedPrintable(InputStream source, OutputStream output, uint len=0) 
	{
		char c = '\0';
		char c1 = '\0';
		char c2 = '\0';
		int c1p = 0;
		int c2p = 0;
		int i = -1;
		while (!source.eof() && (!len || i < len)) {
			i++;
			c = source.getc();
			if (char.init == c) {
				return;
			}
			if (c == '_') {
				output.write(' ');
				continue;
			}
			if (c != '=') {
				output.write(c);
				continue;
			}
			c1 = source.getc();
			if (char.init == c1) {
				output.write(c);
				return;
			}
			c2 = source.getc();
			
			if (char.init == c2) {
				output.write(c);
				output.write(c1);
				return;
			}
			c1p = std.string.find(std.string.hexdigits, c1);
			c2p = std.string.find(std.string.hexdigits, c2);
			
			// got an encoded str..
			if ((c1p > -1) && (c2p > -1)) {
				std.stdio.writefln("CONV %s => %x", ""~ c1 ~ c2,  (c1p << 4) + c2p);
				output.write(cast(char)((c1p << 4) + c2p));
				i+=2;
				continue;						 
			}
			// unget the two chars..
			source.ungetc(c2);
			source.ungetc(c1);
			
			int eaten = 0;
			
			while (true) {
				c1 = source.getc();
				if (char.init == c1) {
					return;
				}
				i++;
				eaten++;
				if (len && (i >= len)) { // end of readable area!
					return;
				}
				if ((c1 == 32) || (c1 == 9)) { // space or tab...
					continue;
				}
				break;
			}
			// we have now eaten the white space... after =
			if (c1 == 10) {
				// got a \n after = -> just ignore it...
				continue; 
			}
			if (c1 != 13) {
				// not a \r => write the =, then output =...
				output.write('=');
				for(int ii =0; ii < eaten; ii++) { // convert them all to spaces?!?!?
					output.write(' ');
				}
				// not a line break... - we have eaten the = and the spaces after it!!!
				// should be push them onto the sttream???
				
				continue;
			}
			c1 = source.getc();
			// eat the next char...
			if (char.init == c1) {
				return; //eof
			}
			
			if (c1 != 10) {
				source.ungetc(c1);
				continue;
			}
			i++;
			
			 
		}

	}	
	char[] base64(char[] in_str) 
	{
		auto o_ms = new MemoryStream();
		auto i_ms = new MemoryStream(in_str);
		base64(i_ms, o_ms);
		
		return o_ms.toString();
		
	}
	void base64(InputStream source, OutputStream output, uint len=0)  // must be wrapped in try/catch!
	{
		int i=0;
		// cant tell the lenght!!!
		//if(estr.length % 4)
		//	throw new Base64Exception("Invalid encoded base64 string");
		uint arrayIndex(char ch) {
			if(ch >= 'A' && ch <= 'Z')
				return ch - 'A';
			if(ch >= 'a' && ch <= 'z')
				return 'Z' - 'A' + 1 + ch - 'a';
			if(ch >= '0' && ch <= '9')
				return 'Z' - 'A' + 1 + 'z' - 'a' + 1 + ch - '0';
			if(ch == '+')
				return 'Z' - 'A' + 1 + 'z' - 'a' + 1 + '9' - '0' + 1;
			if(ch == '/')
				return 'Z' - 'A' + 1 + 'z' - 'a' + 1 + '9' - '0' + 1 + 1;
			throw new Exception("invalid encoding");
		}
		
		
		bool sgetChar(out char c)
		{
			if (len && i > len) { // end of what we are suppsed to read..
				return false;
			}
			c = source.getc();
			if (char.init == c) {
				return false;
			}
			if ((c == 32) || (c == 10) || (c == 13)) {
				return sgetChar(c);
			}
			i++;
			return true;
		}
		
	 
		///uint estrmax = estr.length / 4;
		uint x;
		 
		char  ch;
		char sp1;
		char sp2;
		
		while(true) {
			if (!sgetChar(sp1)) {
				return; // end!!!
			}
			if (!sgetChar(sp2)) {
				return; // end!!!
			}
			
			x = arrayIndex(sp1) << 18 | arrayIndex(sp2) << 12;
			 
			if (!sgetChar(ch)) {
				return; // end!!!
			}
			 
			if(ch == '=')
			{
				if (!sgetChar(ch)) {
					return; // end!!!
				}
				
				if(ch!= '=') {
					return; // invalid but we allow it..
				}
				output.write(cast(char) (x >> 16));
				 
				return;
			}
			x |= arrayIndex(ch) << 6;
			if (!sgetChar(ch)) {
				return; // end!!!
			}
			 
			if(ch == '=')
			{
				output.write(cast(char) (x >> 16));
				output.write(cast(char) ((x >> 8) & 0xFF));
				return;
			}
			x |= arrayIndex(ch);
			output.write(cast(char) (x >> 16));
			output.write(cast(char) ((x >> 8) & 0xFF));
			output.write(cast(char) (x & 0xFF));
		}
	}