package net.osmand.binary;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Stack;

import net.osmand.data.index.IndexConstants;

import com.google.protobuf.CodedOutputStream;
import com.google.protobuf.WireFormat;
import com.google.protobuf.WireFormat.JavaType;

public class BinaryIndexWriter {

	private final OutputStream out;
	private CodedOutputStream codedOutStream;
	
	private static class Bounds {
		public Bounds(int leftX, int rightX, int topY, int bottomY) {
			super();
			this.bottomY = bottomY;
			this.leftX = leftX;
			this.rightX = rightX;
			this.topY = topY;
		}
		int leftX = 0;
		int rightX = 0;
		int topY = 0;
		int bottomY = 0;
		
		
	}
	private Stack<Bounds> stackBounds = new Stack<Bounds>();
	
	// internal constants to track state of index writing
	private Stack<Integer> state = new Stack<Integer>();
	private final static int OSMAND_STRUCTURE_INIT = 1;
	private final static int MAP_INDEX_INIT = 2;
	private final static int MAP_ROOT_LEVEL_INIT = 3;
	private final static int MAP_TREE = 4;
	private final static int MAP_DATA = 5;

	public BinaryIndexWriter(OutputStream out) throws IOException{
		this.out = out;
		codedOutStream = CodedOutputStream.newInstance(out);
		codedOutStream.writeInt32(OsmandOdb.OsmAndStructure.VERSION_FIELD_NUMBER, IndexConstants.BINARY_MAP_VERSION);
		state.push(OSMAND_STRUCTURE_INIT);
	}
//		message MapTree {
//		   required sint32 left = 1; // delta encoded
//		   required sint32 right = 2; // delta encoded
//		   required sint32 top = 3; // delta encoded
//		   required sint32 bottom = 4; // delta encoded
//		   
//		   optional StringTable stringTable = 5;
//		   optional uint64 baseId = 6;
//		   
//		   repeated MapTree subtrees = 7;
//		   repeated MapData leafs = 8;
//		   
//		}
//	/// Simple messages
//	message MapData {
//		  required bytes coordinates = 1; // array of delta x,y uin32 could be read by codedinputstream
//		  repeated sint32 types = 2;
//		  
//		  required sint64 id = 3; // delta encoded
//		  optional uint32 stringId = 4;
//		  
//		  repeated sint64 restrictions = 5; // delta encoded 3 bytes for type and other for id 
//		}

	public void startWriteMapIndex() throws IOException{
		assert state.peek() == OSMAND_STRUCTURE_INIT;
		state.push(MAP_INDEX_INIT);
		codedOutStream.writeTag(OsmandOdb.OsmAndStructure.MAPINDEX_FIELD_NUMBER, WireFormat.FieldType.MESSAGE.getWireType());
		// TODO write size of map index 
		codedOutStream.writeFixed32NoTag(0);
		
	}
	
	public void endWriteMapIndex() throws IOException{
		Integer st = state.pop();
		assert st == MAP_INDEX_INIT;
		codedOutStream.writeRawVarint32(0);
	}
		
	public void startWriteMapLevelIndex(int maxZoom, int minZoom, int leftX, int rightX, int topY, int bottomY) throws IOException{
		assert state.peek() == MAP_INDEX_INIT;
		state.push(MAP_ROOT_LEVEL_INIT);
		
		codedOutStream.writeTag(OsmandOdb.OsmAndMapIndex.LEVELS_FIELD_NUMBER, WireFormat.FieldType.MESSAGE.getWireType());
		// TODO write size of level map index 
		codedOutStream.writeFixed32NoTag(0);
		
		codedOutStream.writeInt32(OsmandOdb.MapRootLevel.MAXZOOM_FIELD_NUMBER, maxZoom);
		codedOutStream.writeInt32(OsmandOdb.MapRootLevel.MINZOOM_FIELD_NUMBER, minZoom);
		codedOutStream.writeInt32(OsmandOdb.MapRootLevel.LEFT_FIELD_NUMBER, leftX);
		codedOutStream.writeInt32(OsmandOdb.MapRootLevel.RIGHT_FIELD_NUMBER, rightX);
		codedOutStream.writeInt32(OsmandOdb.MapRootLevel.TOP_FIELD_NUMBER, topY);
		codedOutStream.writeInt32(OsmandOdb.MapRootLevel.BOTTOM_FIELD_NUMBER, bottomY);
		
		stackBounds.push(new Bounds(leftX, rightX, topY, bottomY));
	}
	
	public void endWriteMapLevelIndex() throws IOException{
		assert state.peek() == MAP_ROOT_LEVEL_INIT;
		state.pop();
		
		stackBounds.pop();
		codedOutStream.writeRawVarint32(0);
	}
	
	public void startMapTreeElement(int leftX, int rightX, int topY, int bottomY) throws IOException{
		assert state.peek() == MAP_ROOT_LEVEL_INIT || state.peek() == MAP_TREE;
		if(state.peek() == MAP_ROOT_LEVEL_INIT){
			codedOutStream.writeTag(OsmandOdb.MapRootLevel.ROOT_FIELD_NUMBER, WireFormat.FieldType.MESSAGE.getWireType());
		} else {
			codedOutStream.writeTag(OsmandOdb.MapTree.SUBTREES_FIELD_NUMBER, WireFormat.FieldType.MESSAGE.getWireType());
		}
		// TODO write size of level map index 
		codedOutStream.writeFixed32NoTag(0);
		state.push(MAP_TREE);
		
		
		Bounds bounds = stackBounds.peek();
		codedOutStream.writeSInt32(OsmandOdb.MapTree.LEFT_FIELD_NUMBER, leftX - bounds.leftX);
		codedOutStream.writeSInt32(OsmandOdb.MapTree.RIGHT_FIELD_NUMBER, rightX - bounds.rightX);
		codedOutStream.writeSInt32(OsmandOdb.MapTree.TOP_FIELD_NUMBER, topY - bounds.topY);
		codedOutStream.writeSInt32(OsmandOdb.MapTree.BOTTOM_FIELD_NUMBER, bottomY - bounds.bottomY);
		stackBounds.push(new Bounds(leftX, rightX, topY, bottomY));
		
	}
	
	public void endWriteMapTreeElement() throws IOException{
		assert state.peek() == MAP_TREE;
		state.pop();
		
		stackBounds.pop();
	}
	
	public void writeMapData(long id) throws IOException{
		assert state.peek() == MAP_TREE;
		// TODO
		codedOutStream.writeInt64NoTag(id);
	}
	
	
	
	public void close() throws IOException{
		assert state.peek() == OSMAND_STRUCTURE_INIT;
		codedOutStream.flush();
		out.close();
	}
}