# TODO: check
# *** Open Babel Error  in ParseFile
#    Could not find contribution data file.
# 3d creation??
CACTUS_URI="http://cactus.nci.nih.gov/chemical/structure/"
require 'openbabel'
require "base64"

module OpenTox

  class Compound

    field :inchi, type: String
    attr_readonly :inchi
    field :smiles, type: String
    field :inchikey, type: String
    field :names, type: Array
    field :cid, type: String
    field :chemblid, type: String
    field :image_id, type: BSON::ObjectId
    field :sdf_id, type: BSON::ObjectId
    #belongs_to :dataset
    #belongs_to :data_entry

    #def  == compound
      #self.inchi == compound.inchi
    #end

    # Create a compound from smiles string
    # @example
    #   compound = OpenTox::Compound.from_smiles("c1ccccc1")
    # @param [String] smiles Smiles string
    # @return [OpenTox::Compound] Compound
    def self.from_smiles smiles
      # do not store smiles because it might be noncanonical
      Compound.find_or_create_by :inchi => obconversion(smiles,"smi","inchi")
    end

    # Create a compound from inchi string
    # @param inchi [String] smiles InChI string
    # @return [OpenTox::Compound] Compound
    def self.from_inchi inchi
      Compound.find_or_create_by :inchi => inchi
    end

    # Create a compound from sdf string
    # @param sdf [String] smiles SDF string
    # @return [OpenTox::Compound] Compound
    def self.from_sdf sdf
      # do not store sdf because it might be 2D
      Compound.find_or_create_by :inchi => obconversion(sdf,"sdf","inchi")
    end

    # Create a compound from name. Relies on an external service for name lookups.
    # @example
    #   compound = OpenTox::Compound.from_name("Benzene")
    # @param name [String] can be also an InChI/InChiKey, CAS number, etc
    # @return [OpenTox::Compound] Compound
    def self.from_name name
      Compound.find_or_create_by :inchi => RestClientWrapper.get(File.join(CACTUS_URI,URI.escape(name),"stdinchi"))
    end

    # Get InChIKey
    # @return [String] InChI string
    def inchikey
      update(:inchikey => obconversion(inchi,"inchi","inchikey")) unless self["inchikey"]
      self["inchikey"]
    end

    # Get (canonical) smiles
    # @return [String] Smiles string
    def smiles
      update(:smiles => obconversion(inchi,"inchi","smi")) unless self["smiles"] # should give canonical smiles, "can" seems to give incorrect results
      self["smiles"]
    end

    # Get sdf
    # @return [String] SDF string
    def sdf
      if self.sdf_id.nil? 
        sdf = obconversion(inchi,"inchi","sdf")
        file = Mongo::Grid::File.new(sdf, :filename => "#{id}.sdf",:content_type => "chemical/x-mdl-sdfile")
        sdf_id = $gridfs.insert_one file
        update :sdf_id => sdf_id
      end
      $gridfs.find_one(_id: self.sdf_id).data
    end

    # Get png image
    # @example
    #   image = compound.png
    # @return [image/png] Image data
    def png
      if self.image_id.nil?
       png = obconversion(inchi,"inchi","_png2")
       file = Mongo::Grid::File.new(Base64.encode64(png), :filename => "#{id}.png", :content_type => "image/png")
       update(:image_id => $gridfs.insert_one(file))
      end
      Base64.decode64($gridfs.find_one(_id: self.image_id).data)

    end

    # Get all known compound names. Relies on an external service for name lookups.
    # @example
    #   names = compound.names
    # @return [String] Compound names
    def names
      update(:names => RestClientWrapper.get("#{CACTUS_URI}#{inchi}/names").split("\n")) unless self["names"] 
      self["names"]
    end

    # @return [String] PubChem Compound Identifier (CID), derieved via restcall to pubchem
    def cid
      pug_uri = "http://pubchem.ncbi.nlm.nih.gov/rest/pug/"
      update(:cid => RestClientWrapper.post(File.join(pug_uri, "compound", "inchi", "cids", "TXT"),{:inchi => inchi}).strip) unless self["cid"] 
      self["cid"]
    end

    # @return [String] ChEMBL database compound id, derieved via restcall to chembl
    def chemblid
      # https://www.ebi.ac.uk/chembldb/ws#individualCompoundByInChiKey
      uri = "http://www.ebi.ac.uk/chemblws/compounds/smiles/#{smiles}.json"
      update(:chemblid => JSON.parse(RestClientWrapper.get(uri))["compounds"].first["chemblId"]) unless self["chemblid"] 
      self["chemblid"]
    end

    private

    def self.obconversion(identifier,input_format,output_format,option=nil)
      obconversion = OpenBabel::OBConversion.new
      obconversion.set_options(option, OpenBabel::OBConversion::OUTOPTIONS) if option
      obmol = OpenBabel::OBMol.new
      obconversion.set_in_and_out_formats input_format, output_format
      obconversion.read_string obmol, identifier
      case output_format
      when /smi|can|inchi/
        obconversion.write_string(obmol).gsub(/\s/,'').chomp
      when /sdf/
        OpenBabel::OBOp.find_type("Gen3D").do(obmol) 
        sdf = obconversion.write_string(obmol)
        if sdf.match(/.nan/)
          $logger.warn "3D generation failed for compound #{identifier}, trying to calculate 2D structure"
          OpenBabel::OBOp.find_type("Gen2D").do(obmol) 
          sdf = obconversion.write_string(obmol)
          if sdf.match(/.nan/)
            $logger.warn "2D generation failed for compound #{identifier}"
            sdf = nil
          end
        end
        sdf
      else
        obconversion.write_string(obmol)
      end
    end

    def obconversion(identifier,input_format,output_format,option=nil)
      self.class.obconversion(identifier,input_format,output_format,option=nil)
    end
  end
end