#include <iostream>
//
// Created by michael on 23/08/17.
//

//----------------------
// Includes
//----------------------

#include "MantidNexusGeometry/NexusGeometryParser.h"

#include <string>
#include <vector>

namespace Mantid {
namespace NexusGeometry {

using namespace H5;

//Eigen typedefs
typedef Eigen::Matrix<double, 3, Eigen::Dynamic> Pixels;

//Anonymous namespace for H5 constants
namespace {
    const H5G_obj_t GROUP_TYPE = static_cast<H5G_obj_t> (0);
    const H5std_string NX_CLASS = "NX_class";
    const H5std_string NX_ENTRY = "NXentry";
    const H5std_string NX_INSTRUMENT = "NXinstrument";
    const H5std_string NX_DETECTOR = "NXdetector";
    const H5std_string DETECTOR_IDS = "detector_number";
    const H5std_string X_PIXEL_OFFSET = "x_pixel_offset";
    const H5std_string Y_PIXEL_OFFSET = "y_pixel_offset";
    const H5std_string Z_PIXEL_OFFSET = "z_pixel_offset";
    const H5std_string DEPENDS_ON = "depends_on";
    const H5std_string NO_DEPENDENCY = ".";
    const H5std_string PIXEL_SHAPE = "pixel_shape";
    //Transformation types
    const H5std_string TRANSFORMATION_TYPE = "transformation_type";
    const H5std_string TRANSLATION = "translation";
    const H5std_string ROTATION =  "rotation";
    const H5std_string VECTOR = "vector";
    const H5std_string UNITS = "units";
    //Radians and degrees
    const H5std_string DEGREES = "degrees";
    const static double PI = 3.1415926535;
    const static double DEGREES_IN_SEMICIRCLE = 180;
    //Nexus shape types
    const H5std_string NX_CYLINDER = "NXcylindrical_geometry";
}

/// Constructor opens the nexus file
NexusGeometryParser::NexusGeometryParser(
    H5std_string &fileName, iAbstractBuilder_sptr iAbsBuilder_sptr ) {
    
    // Disable automatic printing, so Load algorithm can deal with errors
    // appropriately
    Exception::dontPrint();
    try {
        H5File file(fileName, H5F_ACC_RDONLY);
        this->nexusFile = file;
        this->rootGroup = this->nexusFile.openGroup("/");
    } catch (FileIException e) {
        this->exitStatus = OPENING_FILE_ERROR;
    } catch (GroupIException e) {
        this->exitStatus = OPENING_ROOT_GROUP_ERROR;
    }
    //Initialize the instrumentAbstractBuilder
    this->iBuilder_sptr = iAbsBuilder_sptr;
}

/// OFF NEXUS GEOMETRY PARSER
ParsingErrors NexusGeometryParser::ParseNexusGeometry()
{
    // Determine if nexusFile was successfully opened
    switch (this->exitStatus){
        case NO_ERROR: break;
        default:
            return this->exitStatus;
    }
    
    // Get path to all detector groups
    try{
    std::vector<Group> detectorGroups = this->openDetectorGroups();
    for(std::vector<Group>::iterator iter = detectorGroups.begin(); iter < detectorGroups.end(); ++iter)
    {
        //Get the pixel offsets
        Pixels pixelOffsets = this->getPixelOffsets(*iter);
        //Get the transformations
        Eigen::Transform<double, 3, 2> transforms = this->getTransformations(*iter);
        //Calculate pixel positions
        Pixels detectorPixels = transforms * pixelOffsets;
        //Get the pixel detIds
        std::vector<int> detectorIds = this->getDetectorIds(*iter);
        // Force call of shape
        this->parseNexusShape(*iter);

        for(size_t i = 0; i < detectorIds.size(); ++i)
        {
            int index = static_cast<int>(i);
            std::string name = std::to_string(index);
            Eigen::Vector3d detPos = detectorPixels.col(index);
            this->iBuilder_sptr->addDetector(name, detectorIds[index], detPos, this->shape);
        }
    }
    //Sort the detectors
    this->iBuilder_sptr->sortDetectors();

    //Parse source and sample and add to instrument
    this->parseAndAddSource();
    this->parseAndAddSample();

    } catch (...) {
        this->exitStatus = UNKNOWN_ERROR;
    }

    return this->exitStatus;
}

/// Open subgroups of parent group
std::vector<Group> NexusGeometryParser::openSubGroups(Group &parentGroup, H5std_string CLASS_TYPE){
    std::vector<Group> subGroups;
    
    //Iterate over children, and determine if a group
    for (hsize_t i = 0; i < parentGroup.getNumObjs(); ++i){
        if(parentGroup.getObjTypeByIdx(i) == GROUP_TYPE){
            H5std_string childPath = parentGroup.getObjnameByIdx(i);
            //Open the sub group
            Group childGroup = parentGroup.openGroup(childPath);
            //Iterate through attributes to find NX_class
            for(int i = 0; i < childGroup.getNumAttrs(); ++i){
                //Test attribute at current index for NX_class
                Attribute attribute = childGroup.openAttribute(i);
                if(attribute.getName() == NX_CLASS){
                    //Get attribute data type
                    DataType dataType = attribute.getDataType();
                    //Get the NX_class type
                    H5std_string classType;
                    attribute.read(dataType, classType);
                    //If group of correct type, append to subGroup vector
                    if(classType == CLASS_TYPE){
                        subGroups.push_back(childGroup);
                    }
                }
            }
        }
    }
    return subGroups;
}


// Open all detector groups into a vector
std::vector<Group> NexusGeometryParser::openDetectorGroups ()
{
    std::vector<Group> rawDataGroupPaths = this->openSubGroups (this->rootGroup, NX_ENTRY);

    //Open all instrument groups within rawDataGroups
    std::vector<Group> instrumentGroupPaths;
    for (std::vector<Group>::iterator iter = rawDataGroupPaths.begin (); iter < rawDataGroupPaths.end (); iter++)
    {
        std::vector<Group> instrumentGroups = this->openSubGroups (*iter, NX_INSTRUMENT);
        instrumentGroupPaths.insert (instrumentGroupPaths.end (), instrumentGroups.begin (), instrumentGroups.end ());
    }
    //Open all detector groups within instrumentGroups
    std::vector<Group> detectorGroupPaths;
    for(std::vector<Group>::iterator iter = instrumentGroupPaths.begin(); iter < instrumentGroupPaths.end (); iter++)
    {
        //Open sub detector groups
        std::vector<Group> detectorGroups = this->openSubGroups (*iter, NX_DETECTOR);
        //Append to detectorGroups vector
        detectorGroupPaths.insert (detectorGroupPaths.end (), detectorGroups.begin (), detectorGroups.end ());
    }
    //Return the detector groups
    return detectorGroupPaths;
}

//Function to return the detector ids in the same order as the opffsets
std::vector<int> NexusGeometryParser::getDetectorIds ( Group &detectorGroup)
{
    H5std_string detectorName = detectorGroup.getObjName();
    std::vector<int> detIds;

    for (unsigned int i = 0; i < detectorGroup.getNumObjs (); ++i)
    {
        H5std_string objName = detectorGroup.getObjnameByIdx (i);
        H5std_string objPath = detectorName + "/" + objName;
        if(objName == DETECTOR_IDS)
        {
            detIds = this->get1DDataset<int> (objPath);
        }
    }
    return detIds;
}

//Function to return the (x,y,z) offsets of pixels in the chosen detectorGroup
Pixels NexusGeometryParser::getPixelOffsets (Group &detectorGroup)
{
    H5std_string detectorName = detectorGroup.getObjName();

    //Initialise matrix
    Pixels offsetData;
    std::vector<double> xValues, yValues, zValues;
    for (unsigned int i = 0; i < detectorGroup.getNumObjs (); i++)
    {
        H5std_string objName = detectorGroup.getObjnameByIdx (i);
        H5std_string objPath = detectorName + "/" + objName;
        if(objName == X_PIXEL_OFFSET)
        {
            xValues = this->get1DDataset<double>(objPath);
        }
        if(objName == Y_PIXEL_OFFSET)
        {
            yValues = this->get1DDataset<double>(objPath);
        }
        if(objName == Z_PIXEL_OFFSET)
        {  
            zValues = this->get1DDataset<double> (objPath);
        }
    }

    // Determine size of dataset
    int rowLength = 0;
    bool xEmpty = xValues.empty();
    bool yEmpty = yValues.empty();
    bool zEmpty = zValues.empty();

    if(!xEmpty)
        rowLength = static_cast<int>(xValues.size ());
    else if(!yEmpty)
        rowLength = static_cast<int>(yValues.size());
    // Need at least 2 dimensions to define points
    else
        return offsetData;

    // Default x,y,z to zero if no data provided
    offsetData.resize (3,rowLength);
    offsetData.setZero(3, rowLength);

    if(!xEmpty)
    {
        for(int i = 0; i < rowLength; i++)
            offsetData(0,i) = xValues[i];
    }
    if(!yEmpty)
    {
        for(int i = 0; i < rowLength; i++)
            offsetData(1,i) = yValues[i];
    }
    if(!zEmpty)
    {
        for(int i = 0; i < rowLength; i++)
            offsetData(2,i) = zValues[i];
    }
    // Return the coordinate matrix
    return offsetData;
}

//Function to read in a dataset into a vector
template<typename valueType>
std::vector<valueType> NexusGeometryParser::get1DDataset(H5std_string &dataset)
{

    //Open data set
    DataSet data = this->nexusFile.openDataSet (dataset);

    //Get data type
    DataType dataType = data.getDataType ();

    //Get data size
    DataSpace dataSpace = data.getSpace ();

    //Create vector to hold data
    std::vector<valueType> values;
    values.resize (dataSpace.getSelectNpoints ());

    //Read data into vector
    data.read (values.data (), dataType, dataSpace);

    //Return the data vector
    return values;
}

H5std_string
NexusGeometryParser::get1DStringDataset(const H5std_string &dataset) {
    //Open data set
    DataSet data = this->nexusFile.openDataSet (dataset);
    //Get size
    DataSpace dataspace = data.getSpace ();
    //Initialize string
    H5std_string value;

    //Read into string
    data.read(value, data.getDataType (), dataspace);

    return value;
}

//Function to get the transformations from the nexus file, and create the Eigen transform object
Eigen::Transform<double, 3, Eigen::Affine> NexusGeometryParser::getTransformations(Group &detectorGroup)
{
    //Get path to depends_on file
    H5std_string detectorPath = detectorGroup.getObjName ();
    H5std_string depends_on = detectorPath + "/" + DEPENDS_ON;

    //Get absolute dependency path
    H5std_string dependency = this->get1DStringDataset(depends_on);

    //Initialise transformation holder as zero-degree rotation
    Eigen::Transform<double, 3, Eigen::Affine> transforms;
    Eigen::Vector3d axis(1.0,0.0,0.0);
    transforms = Eigen::AngleAxisd(0.0, axis);

    //Breaks when no more dependencies (dependency = ".")
    //Transformations must be applied in opposite order to direction of discovery
    while(dependency != NO_DEPENDENCY)
    {
        //Open the transformation data set
        DataSet transformation = this->nexusFile.openDataSet (dependency);
        
        //Get magnitude of current transformation
        double magnitude = this->get1DDataset<double>(dependency)[0];
        //Containers for transformation data
        Eigen::Vector3d transformVector(0.0,0.0,0.0);
        H5std_string transformType;
        H5std_string transformUnits;
        for(int i = 0; i < transformation.getNumAttrs (); i++)
        {
            //Open attribute at current index
            Attribute attribute = transformation.openAttribute (i);
            H5std_string attributeName = attribute.getName();
            //Get next dependency
            if(attributeName == DEPENDS_ON)
            {
                DataType dataType = attribute.getDataType ();
                attribute.read(dataType, dependency);
            }
            //Get transform type
            else if(attributeName == TRANSFORMATION_TYPE)
            {
                DataType dataType = attribute.getDataType ();
                attribute.read(dataType, transformType);
            }
            //Get unit vector for transformation
            else if(attributeName == VECTOR)
            {
                std::vector<double> unitVector;
                DataType dataType = attribute.getDataType ();

                //Get data size
                DataSpace dataSpace = attribute.getSpace ();

                //Resize vector to hold data
                unitVector.resize (dataSpace.getSelectNpoints ());

                //Read the data into Eigen vector
                attribute.read(dataType, unitVector.data());
                transformVector(0) = unitVector[0];
                transformVector(1) = unitVector[1];
                transformVector(2) = unitVector[2];
            }
            else if (attributeName == UNITS)
            {
                DataType dataType = attribute.getDataType ();
                attribute.read(dataType, transformUnits);
            }
        }
        //Transform_type = translation
        if(transformType == TRANSLATION)
        {
            //Translation = magnitude*unitVector
            transformVector *= magnitude;
            Eigen::Translation3d translation(transformVector);
            transforms *= translation;
        }
        else if(transformType == ROTATION)
        {
            double angle = magnitude;
            if (transformUnits == DEGREES){
                //Convert angle from degrees to radians
                angle *= PI/DEGREES_IN_SEMICIRCLE;
            }
            Eigen::AngleAxisd rotation(angle, transformVector);
            transforms *=rotation;
        }
    }
    return transforms;
}

///Choose what shape type to parse
void NexusGeometryParser::parseNexusShape(Group &detectorGroup)
{
    Group shapeGroup;
    try{
        shapeGroup = detectorGroup.openGroup(PIXEL_SHAPE);
    } catch(...){
        //Placeholder - no group pixel_shape
    }

    H5std_string shapeType;
    for (int i = 0; i < shapeGroup.getNumAttrs(); ++i)
    {
        Attribute attribute = shapeGroup.openAttribute(i);
        H5std_string attributeName = attribute.getName();
        if(attributeName == NX_CLASS)
        {
            attribute.read(attribute.getDataType(), shapeType);
        }
    }
    //Give shape group to correct shape parser
    if(shapeType == NX_CYLINDER)
    {
        this->parseNexusCylinder(shapeGroup);
    }
}

//Parse cylinder nexus geometry
void NexusGeometryParser::parseNexusCylinder(Group &shapeGroup){
    H5std_string pointsToVertices = shapeGroup.getObjName() + "/cylinder";
    std::vector<int> cPoints = this->get1DDataset<int>(pointsToVertices);
    
    H5std_string verticesData = shapeGroup.getObjName() + "/vertices";
    // 1D reads row first, then columns
    std::vector<double> vPoints = this->get1DDataset<double>(verticesData);
    Eigen::Map<Eigen::Matrix<double, 3, 3>> vertices(vPoints.data());
    //Read points into matrix, sorted by cPoints ordering
    Eigen::Matrix<double, 3, 3> vSorted;
    for(int i = 0; i < 3; ++i){
        vSorted.col(cPoints[i]) = vertices.col(i);
    }
    this->shape = this->sAbsCreator.createCylinder(vSorted);
}

//Parse source and add to instrument
void NexusGeometryParser::parseAndAddSource()
{
    H5std_string sourcePath = "raw_data_1/instrument/source";
    Group sourceGroup = this->rootGroup.openGroup(sourcePath);
    auto sourceName = this->get1DStringDataset("/name");
    auto defaultPos = Eigen::Vector3d(0.0,0.0,0.0);
    // TODO incomplete
}
//Parse sample and add to instrument
void NexusGeometryParser::parseAndAddSample()
{
    std::string sampleName = "sample";
    H5std_string samplePath = "raw_data_1/sample";
    Group sampleGroup = this->rootGroup.openGroup(samplePath);
    auto sampleTransforms = this->getTransformations(sampleGroup);
    auto samplePos = sampleTransforms*Eigen::Vector3d(0.0,0.0,0.0);

    this->iBuilder_sptr->addSample(sampleName, samplePos);
}
}
}