#include "common.h"
#include "bsp.h"
#include "ps1types.h"
#include "ps1bsp.h"
#include "lighting.h"
#include "texture.h"
#include "tesselate.h"

static char path[_MAX_PATH];

template<class TData> size_t writeMapData(const std::vector<TData>& data, ps1bsp_dentry_t& dentry, FILE* f)
{
	dentry.offset = (unsigned int)ftell(f);
	dentry.size = sizeof(TData) * data.size();
	return fwrite(data.data(), sizeof(TData), data.size(), f);
}

static float computeFaceArea(const world_t* world, const face_t* face)
{
	const plane_t* plane = &world->planes[face->plane_id];

	// Construct a tangent and bitangent for the plane
	Vec3 tangent, bitangent;
	plane->getTangents(tangent, bitangent);

	// Project all face vertices onto the face's plane
	BoundBox bounds;
	for (int edgeListIdx = 0; edgeListIdx < face->ledge_num; ++edgeListIdx)
	{
		int edgeIdx = world->edgeList[face->ledge_id + edgeListIdx];
		int vertIndex = edgeIdx > 0 ?
			world->edges[edgeIdx].vertex0 :
			world->edges[-edgeIdx].vertex1;

		const vertex_t* vertex = &world->vertices[vertIndex];
		Vec3 vec = vertex->toVec();

		double x = tangent.dotProduct(vec);
		double y = bitangent.dotProduct(vec);
		bounds.includePoint(Vec3(x, y, 0.0));
	}

	Vec3 extents = bounds.max - bounds.min;
	return extents.x * extents.y;
}

typedef std::unordered_map<const face_t*, std::vector<Tesselator::Polygon>> FacePolygons;

int process_faces(const world_t* world, const std::vector<ps1bsp_texture_t>& textures)
{
	// Write some data to a file
	FILE* fbsp;
	fopen_s(&fbsp, "test.ps1bsp", "wb");
	if (!fbsp)
		return 0;

	ps1bsp_header_t outHeader = { 0 };	// Write an empty placeholder header first
	outHeader.version = 1;
	fwrite(&outHeader, sizeof(ps1bsp_header_t), 1, fbsp);

	Tesselator tesselator(world);
	
	// Convert faces defined by edges into faces defined by vertex indices
	std::vector<ps1bsp_face_t> outFaces;
	std::vector<ps1bsp_facevertex_t> outFaceVertices;
	FaceBounds faceBounds;
	for (int faceIdx = 0; faceIdx < world->numFaces; ++faceIdx)
	{
		const face_t* face = &world->faces[faceIdx];
		const texinfo_t* texinfo = &world->texInfos[face->texinfo_id];

		ps1bsp_face_t outFace = { 0 };
		outFace.planeId = face->plane_id;
		outFace.side = (unsigned char)face->side;
		outFace.firstFaceVertex = (unsigned short)outFaceVertices.size();
		outFace.textureId = (unsigned char)texinfo->texture_id;

		// Traverse the list of face edges to collect all of the face's vertices
		Vec3 vertexSum;
		BoundBox bounds;
		for (int edgeListIdx = 0; edgeListIdx < face->ledge_num; ++edgeListIdx)
		{
			int edgeIdx = world->edgeList[face->ledge_id + edgeListIdx];

			unsigned short vertIndex = edgeIdx > 0 ?
				world->edges[edgeIdx].vertex0 :
				world->edges[-edgeIdx].vertex1;

			const vertex_t* vertex = &world->vertices[vertIndex];
			Vec3 vertexPoint = vertex->toVec();

			// Calculate bounding box of this face
			if (edgeListIdx == 0)
				bounds.init(vertexPoint);
			else
				bounds.includePoint(vertexPoint);

			// Sum all vertices to calculate an average center point
			vertexSum = vertexSum + vertexPoint;

			// TODO: compute texture color * light at this vertex
			ps1bsp_facevertex_t faceVertex = { 0 };
			faceVertex.index = (unsigned short)tesselator.addVertex(vertexPoint);
			outFaceVertices.push_back(faceVertex);
		}

		faceBounds[face] = bounds;

		// For visualizing and debugging lightmaps
		//if (face->ledge_num >= 10)
		//	export_lightmap(world, face, bounds, faceIdx);

		outFace.numFaceVertices = (unsigned char)(outFaceVertices.size() - outFace.firstFaceVertex);
		outFace.center = (vertexSum / face->ledge_num).convertWorldPosition();
		float area = computeFaceArea(world, face);	// TODO: divide by number of polygons
		outFace.center.pad = (short)(sqrt(area));
		outFaces.push_back(outFace);
	}

	std::vector<ps1bsp_polyvertex_t> outPolyVertices;
	std::vector<ps1bsp_polygon_t> outPolygons;

	// Iterate over all faces again; now that we know the bounds of each face, we can calculate lighting for all of them
	for (int faceIdx = 0; faceIdx < world->numFaces; ++faceIdx)
	{
		face_t* face = &world->faces[faceIdx];
		ps1bsp_face_t* outFace = &outFaces[faceIdx];
		const texinfo_t* texinfo = &world->texInfos[face->texinfo_id];
		const miptex_t* miptex = &world->miptexes[texinfo->texture_id];
		const ps1bsp_texture_t& ps1tex = textures[texinfo->texture_id];

		outFace->firstPolygon = (unsigned short)outPolygons.size();

		// Skip sky surfaces for now
		if (!strncmp(miptex->name, "sky", 3))
		{
			outFace->flags |= SURF_DRAWSKY;
			outFace->numPolygons = 0;
			continue;
		}

		// Invisible collision volumes don't have to be tessellated
		if (!strcmp(miptex->name, "clip") || !strcmp(miptex->name, "trigger"))
		{
			outFace->numPolygons = 0;
			continue;
		}

		// Draw water as fullbright transparent surfaces
		if (miptex->name[0] == '*')
		{
			outFace->flags |= SURF_DRAWTURB | SURF_DRAWWATER;
		}

		auto polygons = tesselator.tesselateFace(face);
		for (auto polyIter = polygons.begin(); polyIter != polygons.end(); ++polyIter)
		{
			ps1bsp_polygon_t outPoly = { 0 };
			outPoly.firstPolyVertex = (unsigned short)outPolyVertices.size();

			for (auto polyVertIter = polyIter->polyVertices.begin(); polyVertIter != polyIter->polyVertices.end(); ++polyVertIter)
			{
				size_t vertIndex = polyVertIter->vertexIndex;
				Vec3 normalizedUV = polyVertIter->normalizedUV;
		
				Vec3 vertex = tesselator.getVertices()[vertIndex];

				ps1bsp_polyvertex_t polyVert = { 0 };
				polyVert.index = (unsigned short)vertIndex;
				polyVert.u = (unsigned char)(normalizedUV.x * (ps1tex.w - 1)) + ps1tex.uoffs;
				polyVert.v = (unsigned char)(normalizedUV.y * (ps1tex.h - 1)) + ps1tex.voffs;

				int light = compute_faceVertex_light5(world, face, faceBounds, vertex);
				light = (int)((float)light * 1.5f);	// Compromise between overbright and non-overbright lighting. Looks good in practice.
				if (light > 255)
					light = 255;

				polyVert.light = (unsigned short)light;
				outPolyVertices.push_back(polyVert);
			}

			outPoly.numPolyVertices = (unsigned short)(outPolyVertices.size() - outPoly.firstPolyVertex);
			outPolygons.push_back(outPoly);

			outFace->totalQuads += (outPoly.numPolyVertices - 1) / 2;
		}

		// TODO: calculate average face lighting * color from texture data

		outFace->numPolygons = (unsigned char)(outPolygons.size() - outFace->firstPolygon);
	}

	// Convert vertex data
	const auto& inVertices = tesselator.getVertices();
	std::vector<ps1bsp_vertex_t> outVertices;
	for (auto vertIter = inVertices.begin(); vertIter != inVertices.end(); ++vertIter)
	{
		const Vec3& inVertex = *vertIter;
	
		ps1bsp_vertex_t outVertex = { 0 };
		// Ensure we don't overflow 16-bit short values. Most Quake maps will stay within these bounds so it *should* be fine (for now).
		if (inVertex.x > -8192 && inVertex.x < 8192 && inVertex.y > -8192 && inVertex.y < 8192 && inVertex.z > -8192 && inVertex.z < 8192)
		{
			outVertex.x = (short)(inVertex.x * 4);
			outVertex.y = (short)(inVertex.y * 4);
			outVertex.z = (short)(inVertex.z * 4);
		}
		else
		{
			printf("Error: vertices found outside of acceptable range: (%f, %f, %f)\n", inVertex.x, inVertex.y, inVertex.z);
			fclose(fbsp);
			return 0;
		}

		outVertices.push_back(outVertex);
	}

	// Convert planes
	std::vector<ps1bsp_plane_t> outPlanes;
	for (int planeIdx = 0; planeIdx < world->numPlanes; ++planeIdx)
	{
		plane_t* plane = &world->planes[planeIdx];

		ps1bsp_plane_t outPlane = { 0 };
		outPlane.normal = plane->normal.convertNormal();
		outPlane.dist = (short)(plane->dist * 4);
		outPlane.type = (short)plane->type;

		outPlanes.push_back(outPlane);
	}

	// Convert nodes
	std::vector<ps1bsp_node_t> outNodes;
	for (int nodeIdx = 0; nodeIdx < world->numNodes; ++nodeIdx)
	{
		node_t* node = &world->nodes[nodeIdx];

		ps1bsp_node_t outNode = { 0 };
		outNode.planeId = node->plane_id;
		outNode.children[0] = node->front;
		outNode.children[1] = node->back;

		outNode.boundingSphere = node->box.toBoundingSphere();

		outNodes.push_back(outNode);
	}

	// Convert leaves
	std::vector<ps1bsp_leaf_t> outLeaves;
	for (int leafIdx = 0; leafIdx < world->numLeaves; ++leafIdx)
	{
		dleaf_t* leaf = &world->leaves[leafIdx];

		ps1bsp_leaf_t outLeaf = { 0 };
		outLeaf.type = (short)leaf->type;
		outLeaf.vislist = leaf->vislist;
		outLeaf.firstLeafFace = leaf->lface_id;
		outLeaf.numLeafFaces = leaf->lface_num;

		outLeaf.mins = leaf->bound.getMins().convertWorldPosition();
		outLeaf.maxs = leaf->bound.getMaxs().convertWorldPosition();

		outLeaves.push_back(outLeaf);
	}

	std::vector<unsigned short> outLeafFaces(world->faceList, world->faceList + world->faceListLength);
	std::vector<unsigned char> outVisData(world->visList, world->visList + world->visListLength);

	// Write collected data to file and update header info
	writeMapData(textures, outHeader.textures, fbsp);
	writeMapData(outVertices, outHeader.vertices, fbsp);
	writeMapData(outPolygons, outHeader.polygons, fbsp);
	writeMapData(outPolyVertices, outHeader.polyVertices, fbsp);
	writeMapData(outFaces, outHeader.faces, fbsp);
	writeMapData(outFaceVertices, outHeader.faceVertices, fbsp);
	writeMapData(outPlanes, outHeader.planes, fbsp);
	writeMapData(outNodes, outHeader.nodes, fbsp);
	writeMapData(outLeaves, outHeader.leaves, fbsp);
	writeMapData(outLeafFaces, outHeader.leafFaces, fbsp);
	writeMapData(outVisData, outHeader.visData, fbsp);

	// Write final header
	fseek(fbsp, 0, SEEK_SET);
	fwrite(&outHeader, sizeof(ps1bsp_header_t), 1, fbsp);
	fclose(fbsp);

	printf("PS1BSP: wrote %d vertices, %d faces, %d polygons, %d planes, %d nodes, %d leaves, %d leaf faces\n", 
		outVertices.size(), outFaces.size(), outPolygons.size(),
		outPlanes.size(), outNodes.size(), outLeaves.size(), outLeafFaces.size());

	return 1;
}

int process_bsp(const world_t *world)
{
	// Test exporting texture data
	std::vector<ps1bsp_texture_t> textures;
	if (!process_textures(world, textures))
	{
		return 0;
	}

	// Inspect faces/edges data
	if (!process_faces(world, textures))
	{
		return 0;
	}

	return 1;
}

int load_bsp(const char* bspname, world_t* world)
{
	FILE* f;
	dheader_t* header = &world->header;

	world->name = bspname;

	sprintf_s(path, _MAX_PATH, "%s.bsp", bspname);
	fopen_s(&f, path, "rb");
	if (f == NULL)
		return 0;

	fread(header, sizeof(dheader_t), 1, f);
	printf("Header model version: %d\n", header->version);

	// Load entities
	fseek(f, header->entities.offset, SEEK_SET);
	world->entitiesLength = header->entities.size + 1;
	world->entities = (char*)malloc(world->entitiesLength * sizeof(char));
	if (world->entities == NULL)
		return 0;

	memset(world->entities, 0, world->entitiesLength * sizeof(char));
	fread(world->entities, sizeof(char), world->entitiesLength, f);

	// Load textures
	mipheader_t* mipheader = &world->mipheader;
	fseek(f, header->miptex.offset, SEEK_SET);
	fread(&mipheader->numtex, sizeof(long), 1, f);
	mipheader->offset = (long*)malloc(mipheader->numtex * sizeof(long));
	if (mipheader->offset == NULL)
		return 0;

	fread(mipheader->offset, sizeof(long), mipheader->numtex, f);

	world->miptexes = (miptex_t*)malloc(mipheader->numtex * sizeof(miptex_t));
	if (world->miptexes == NULL)
		return 0;

	const int numMipLevels = 4;
	world->textures = (unsigned char**)malloc(mipheader->numtex * numMipLevels * sizeof(unsigned char*));
	if (world->textures == NULL)
		return 0;

	memset(world->textures, 0, mipheader->numtex * numMipLevels * sizeof(unsigned char*));

	for (int texNum = 0; texNum < mipheader->numtex; ++texNum)
	{
		miptex_t* miptex = &world->miptexes[texNum];

		unsigned long miptexOffset = header->miptex.offset + mipheader->offset[texNum];
		fseek(f, miptexOffset, SEEK_SET);
		fread(miptex, sizeof(miptex_t), 1, f);

		for (int mipLevel = 0; mipLevel < numMipLevels; ++mipLevel)
		{
			unsigned long mipOffset = *(&miptex->offset1 + mipLevel);
			fseek(f, miptexOffset + mipOffset, SEEK_SET);

			size_t numBytes = (miptex->width * miptex->height) >> mipLevel;
			unsigned char* texBytes = (unsigned char*)malloc(sizeof(unsigned char) * numBytes);
			if (texBytes == NULL)
				return 0;

			fread(texBytes, sizeof(unsigned char), numBytes, f);
			world->textures[texNum * numMipLevels + mipLevel] = texBytes;
		}
	}

	// Load planes
	world->numPlanes = header->planes.size / sizeof(plane_t);
	world->planes = (plane_t*)malloc(header->planes.size);
	if (world->planes == NULL)
		return 0;

	fseek(f, header->planes.offset, SEEK_SET);
	fread(world->planes, sizeof(plane_t), world->numPlanes, f);
	
	// Load vertices
	world->numVertices = header->vertices.size / sizeof(vertex_t);
	world->vertices = (vertex_t*)malloc(header->vertices.size);
	if (world->vertices == NULL)
		return 0;

	fseek(f, header->vertices.offset, SEEK_SET);
	fread(world->vertices, sizeof(vertex_t), world->numVertices, f);

	// Load edges
	world->numEdges = header->edges.size / sizeof(edge_t);
	world->edges = (edge_t*)malloc(header->edges.size);
	if (world->edges == NULL)
		return 0;

	fseek(f, header->edges.offset, SEEK_SET);
	fread(world->edges, sizeof(edge_t), world->numEdges, f);

	world->edgeListLength = header->ledges.size / sizeof(int);
	world->edgeList = (int*)malloc(header->ledges.size);
	if (world->edgeList == NULL)
		return 0;

	fseek(f, header->ledges.offset, SEEK_SET);
	fread(world->edgeList, sizeof(int), world->edgeListLength, f);

	// Load texture info
	world->numTexInfos = header->texinfo.size / sizeof(texinfo_t);
	world->texInfos = (texinfo_t*)malloc(header->texinfo.size);
	if (world->texInfos == NULL)
		return 0;

	fseek(f, header->texinfo.offset, SEEK_SET);
	fread(world->texInfos, sizeof(texinfo_t), world->numTexInfos, f);

	// Load faces
	world->numFaces = header->faces.size / sizeof(face_t);
	world->faces = (face_t*)malloc(header->faces.size);
	if (world->faces == NULL)
		return 0;

	fseek(f, header->faces.offset, SEEK_SET);
	fread(world->faces, sizeof(face_t), world->numFaces, f);

	world->faceListLength = header->lface.size / sizeof(unsigned short);
	world->faceList = (unsigned short*)malloc(header->lface.size);
	if (world->faceList == NULL)
		return 0;

	// Load visibility list
	fseek(f, header->lface.offset, SEEK_SET);
	fread(world->faceList, sizeof(unsigned short), world->faceListLength, f);

	world->visListLength = header->visilist.size / sizeof(unsigned char);
	world->visList = (unsigned char*)malloc(header->visilist.size);
	if (world->visList == NULL)
		return 0;

	fseek(f, header->visilist.offset, SEEK_SET);
	fread(world->visList, sizeof(unsigned char), world->visListLength, f);

	// Load nodes
	world->numNodes = header->nodes.size / sizeof(node_t);
	world->nodes = (node_t*)malloc(header->nodes.size);
	if (world->nodes == NULL)
		return 0;

	fseek(f, header->nodes.offset, SEEK_SET);
	fread(world->nodes, sizeof(node_t), world->numNodes, f);

	// Load leaves
	world->numLeaves = header->leaves.size / sizeof(dleaf_t);
	world->leaves = (dleaf_t*)malloc(header->leaves.size);
	if (world->leaves == NULL)
		return 0;

	fseek(f, header->leaves.offset, SEEK_SET);
	fread(world->leaves, sizeof(dleaf_t), world->numLeaves, f);

	// Load lightmaps
	world->lightmapLength = header->lightmaps.size / sizeof(unsigned char);
	world->lightmap = (unsigned char*)malloc(header->lightmaps.size);
	if (world->lightmap == NULL)
		return 0;

	fseek(f, header->lightmaps.offset, SEEK_SET);
	fread(world->lightmap, sizeof(unsigned char), world->lightmapLength, f);

	fclose(f);
	return 1;
}

void free_bsp(world_t* world)
{
	free(world->lightmap);
	free(world->leaves);
	free(world->nodes);
	free(world->visList);

	free(world->texInfos);
	free(world->faces);
	free(world->faceList);
	free(world->edges);
	free(world->edgeList);
	free(world->vertices);
	free(world->planes);

	for (int i = 0; i < world->mipheader.numtex; ++i)
	{
		free(world->textures[i]);
	}

	free(world->textures);
	free(world->miptexes);
	free(world->mipheader.offset);

	free(world->entities);
}

int main(int argc, char** argv)
{
	world_t world = { 0 };
	if (!load_bsp(argv[1], &world))
		return 1;

	int result = process_bsp(&world);

	free_bsp(&world);
	return !result;
}