/*
 *
 *  Copyright (C) 2015-2024, Open Connections GmbH
 *  All rights reserved.  See COPYRIGHT file for details.
 *
 *  This software and supporting documentation are maintained by
 *
 *    OFFIS e.V.
 *    R&D Division Health
 *    Escherweg 2
 *    D-26121 Oldenburg, Germany
 *
 *
 *  Module: dcmiod
 *
 *  Author: Michael Onken
 *
 *  Purpose: Static helper functionality for dcmiod module
 *
 */

#ifndef IODUTIL_H
#define IODUTIL_H

#include "dcmtk/config/osconfig.h"
#include "dcmtk/dcmdata/dcdatset.h"
#include "dcmtk/dcmdata/dcelem.h"
#include "dcmtk/dcmdata/dcsequen.h"
#include "dcmtk/dcmiod/ioddef.h"
#include "dcmtk/dcmiod/iodrules.h"
#include "dcmtk/dcmiod/iodtypes.h"
#include "dcmtk/ofstd/ofdate.h"
#include "dcmtk/ofstd/ofstring.h"
#include "dcmtk/ofstd/oftime.h"
#include "dcmtk/ofstd/oftraits.h" // for OFremove_pointer

/** Class with helper functions used within the dcmiod module (and beyond)
 */
class DCMTK_DCMIOD_EXPORT DcmIODUtil
{

public:
    /** Get element from dataset and check it for correct value multiplicity
     *  and type.
     *  @param  dataset DICOM dataset from which the element should be retrieved.
     *          (Would be 'const' if the methods from 'dcmdata' would also
     *          (be 'const'.)
     *  @param  delem  DICOM element used to store the value (always creates
     *          a copy of the dataset element's value)
     *  @param  vm Value multiplicity (according to the data dictionary) to be
     *          checked for. (See DcmElement::checkVM() for a list of valid
     *          values.) Interpreted as cardinality (number of items) for
     *          sequence attributes.
     *  @param  type Value type (valid value: "1", "1C", "2", something else
     *          which is not checked)
     *  @param  moduleName Optional module name to be printed (NULL: no module
     *          printed at all)
     *  @return EC_Normal if element could be retrieved and value is correct,
     *          an error code otherwise
     */
    static OFCondition getAndCheckElementFromDataset(
        DcmItem& dataset, DcmElement& delem, const OFString& vm, const OFString& type, const char* moduleName = NULL);

    /** Get element from dataset and check it for correct value multiplicity and
     *  type.
     *  @param  dataset DICOM dataset from which the element should be retrieved.
     *          (Would be 'const' if the methods from 'dcmdata' would also
     *          be 'const')
     *  @param  tagKey Tag key of the element to get
     *  @param  delem DICOM element that is set to a copy of the dataset's
     *          orinal element
     *  @param  vm Value multiplicity (according to the data dictionary) to be
     *          checked for. (See DcmElement::checkVM() for a list of valid
     *          values.) Interpreted as cardinality (number of items) for
     *          sequence attributes.
     *  @param  type Value type (valid value: "1", "1C", "2", something else
     *          which is not checked)
     *  @param  moduleName Optional module name to be printed (NULL: no module
     *          printed at all)
     *  @return EC_Normal if element could be retrieved and value is correct, an
     *          error code otherwise
     */
    static OFCondition getAndCheckElementFromDataset(DcmItem& dataset,
                                                     const DcmTagKey& tagKey,
                                                     DcmElement*& delem,
                                                     const OFString& vm,
                                                     const OFString& type,
                                                     const char* moduleName = NULL);

    /** Get element from dataset and check it for correct value multiplicity
     *  and type.
     *  @param  dataset DICOM dataset from which the element should be retrieved.
     *          (Would be 'const' if the methods from 'dcmdata' would also
     *          be 'const'.)
     *  @param  delem DICOM element used to store the value (always creates
     *          a copy of the value from the original element)
     *  @param  rule  Rule describing parameters to be checked on element
     *  @return EC_Normal if element could be retrieved and value is correct, an
     *          error code otherwise
     */
    static OFCondition getAndCheckElementFromDataset(DcmItem& dataset, DcmElement& delem, const IODRule* rule);

    /** Get element from dataset and check it for correct value multiplicity
     *  and type.
     *  @param  dataset DICOM dataset from which the element should be retrieved.
     *          (Would be 'const' if the methods from 'dcmdata' would also
     *          be 'const')
     *  @param  delem DICOM element that is set to a copy of the dataset's
     *          orinal element
     *  @param  rule  Rule describing parameters to be checked on element.
     *  @return EC_Normal if element could be retrieved and value is correct, an
     *          error code otherwise
     */
    static OFCondition getAndCheckElementFromDataset(DcmItem& dataset, DcmElement*& delem, const IODRule* rule);

    /** Get current date in DICOM 'DA' format (YYYYMMDD)
     *  @param  dateString String used to store the current date.
     *          (empty string if current date could not be retrieved)
     *  @return Resulting character string
     */
    static const OFString& currentDate(OFString& dateString);

    /** Get current time in DICOM 'TM' format (HHMMSS)
     *  The optional UTC notation (e.g.\ +0100) is currently not supported.
     *  @param  timeString String used to store the current time
     *                     (empty string if current time could not be retrieved)
     *  @return Resulting character string, empty if time could not be retrieved
     */
    static const OFString& currentTime(OFString& timeString);

    /** Copy given element to the dataset
     *  The element is only added if 'result' is EC_Normal. A copy of the given
     *  element is created, i.e.\ the caller is responsible for deleting the
     *  original element handed to this function (if desired).
     *  @param  result Reference to status variable (checked before adding and
     *          updated afterwards!)
     *  @param  dataset Reference to DICOM dataset to which the element should
     *          be added
     *  @param  delem Reference to DICOM element which should be added; a
     *          copy is created so caller is responsible for deleting delem (if
     *          desired).
     *  @param  vm Value multiplicity (according to the data dictionary) to be
     *          checked for. (See DcmElement::checkVM() for a list of valid
     *          values.). Interpreted as cardinality (number of items) for
     *          sequence attributes.
     *  @param  type  Value type (valid value: "1", "2" or something else which
     *          is not checked)
     *  @param  moduleName Optional module name to be printed (NULL: no module
     *          printed at all)
     *  @return Current value of 'result', EC_Normal if successful,
     *          an error code otherwise
     */
    static OFCondition copyElementToDataset(OFCondition& result,
                                            DcmItem& dataset,
                                            const DcmElement& delem,
                                            const OFString& vm,
                                            const OFString& type,
                                            const char* moduleName = NULL);

    /** Copy given element to the dataset. The element is only added if 'result'
     *  is EC_Normal.
     *  @param  result reference to status variable (checked before adding and
     *          updated afterwards!)
     *  @param  dataset reference to DICOM dataset to which the element
     *          should be added
     *  @param  delem reference to DICOM element which should be added; the value
     *          is copied from the original dataset's element
     *  @param  rule  Rule describing parameters to be checked on element.
     *  @return Current value of 'result', EC_Normal if successful, an error code
     *          otherwise
     */
    static OFCondition
    copyElementToDataset(OFCondition& result, DcmItem& dataset, const DcmElement& delem, const IODRule* rule);

    /** Add given element to the dataset
     *  The element is only added if 'result' is EC_Normal and the 'delem'
     *  pointer is not NULL.
     *  @param  result Reference to status variable (checked before adding and
     *          updated afterwards!)
     *  @param  dataset Reference to DICOM dataset to which the element should
     *          be added
     *  @param  delem Pointer to DICOM element which should be added. The element
     *          is always consumed by this function, i.e.\ insertion was successful
     *          and therefore ownership is transferred to the dataset, or the
     *          element is deleted from memory if it could not be inserted.
     *  @param  rule  Rule describing parameters to be checked on element.
     *  @param  checkValue If OFTrue, the value of the element is checked for
     *          violations against VR, VM, charset and value length. If OFTrue,
     *          an error is printed and an error is returned. Otherwise, a warning
     *          is printed and EC_Normal is returned.
     *  @return Current value of 'result', EC_Normal if successful, an error code otherwise
     */
    static OFCondition
    addElementToDataset(OFCondition& result, DcmItem& dataset, DcmElement* delem, const IODRule* rule, const OFBool checkValue = OFTrue);

    /** Check element value for correct value multiplicity and type.
     *  @param  delem Pointer to DICOM element to be checked (might be NULL)
     *  @param  tagKey DICOM tag of the DICOM element the parameter 'delem' points to
     *  @param  vm Value multiplicity (according to the data dictionary) to be checked for.
     *          (See DcmElement::checkVM() for a list of valid values.)
     *          Interpreted as cardinality (number of items) for sequence attributes.
     *  @param  type Value type (valid value: "1", "1C", "2", something else)
     *  @param  searchCond Optional flag indicating the status of a previous 'search' function call
     *  @param  moduleName Optional module name to be printed (default: "IOD" if NULL)
     *  @param  logLevel The log level to log errors to
     *  @return EC_Normal if element value is correct, error otherwise
     */
    static OFCondition checkElementValue(const DcmElement* delem,
                                         const DcmTagKey& tagKey,
                                         const OFString& vm,
                                         const OFString& type,
                                         const OFCondition& searchCond             = EC_Normal,
                                         const char* moduleName                    = NULL,
                                         const dcmtk::log4cplus::LogLevel logLevel = dcmtk::log4cplus::WARN_LOG_LEVEL);

    /** Check element value for correct value multiplicity and type.
     *  @param  delem DICOM element to be checked
     *  @param  vm Value multiplicity (according to the data dictionary) to be checked for.
     *          (See DcmElement::checkVM() for a list of valid values.)
     *          Interpreted as cardinality (number of items) for sequence attributes.
     *  @param  type Value type (valid value: "1", "1C", "2", something else)
     *  @param  searchCond Optional flag indicating the status of a previous 'search' function call
     *  @param  moduleName Optional module name to be printed (default: "IOD" if NULL)
     *  @param  logLevel The log level to log errors to
     *  @return EC_Normal if element value is correct, error otherwise
     */
    static OFCondition checkElementValue(const DcmElement& delem,
                                         const OFString& vm,
                                         const OFString& type,
                                         const OFCondition& searchCond             = EC_Normal,
                                         const char* moduleName                    = NULL,
                                         const dcmtk::log4cplus::LogLevel logLevel = dcmtk::log4cplus::WARN_LOG_LEVEL);

    /** Get string value from element
     *  @param  delem DICOM element from which the string value should be retrieved
     *  @param  stringValue Reference to variable in which the result should be stored.
     *          (This parameter is automatically cleared if an error occurs.)
     *  @param  pos Index of the value to get (0..vm-1), -1 for all components
     *  @return EC_Normal if successful, an error code otherwise
     */
    static OFCondition getStringValueFromElement(const DcmElement& delem, OFString& stringValue, const signed long pos);

    /** Get string value from item
     *  @param  key The tag key of the attribute whose value should be retrieved
     *  @param  item The item to search the attribute in
     *  @param  result Reference to variable in which the result should be stored.
     *          (This parameter is automatically cleared if an error occurs.)
     *  @param  pos Index of the value to get (0..vm-1), -1 for all components
     *  @return EC_Normal if successful, an error code otherwise
     */
    static OFCondition
    getStringValueFromItem(const DcmTagKey& key, DcmItem& item, OFString& result, const signed long& pos);

    /** Get Float64 value from item
     *  @param  key The tag key of the attribute whose value should be retrieved
     *  @param  item The item to search the attribute in
     *  @param  result Reference to variable in which the result should be stored.
     *  @param  pos Index of the value to get (0..vm-1)
     *  @return EC_Normal if successful, an error code otherwise
     */
    static OFCondition
    getFloat64ValueFromItem(const DcmTagKey& key, DcmItem& item, Float64& result, const unsigned long& pos);

    /** Get Float64 values from item
     *  @param  key The tag key of the attribute whose value should be retrieved
     *  @param  item The item to search the attribute in
     *  @param  result Reference to variable in which the result should be stored.
     *  @return EC_Normal if successful, an error code otherwise
     */
    static OFCondition getFloat64ValuesFromItem(const DcmTagKey& key, DcmItem& item, OFVector<Float64>& result);

    /** Get Float64 value from element
     *  @param  delem The element whose value should be retrieved
     *  @param  result Reference to variable in which the result should be stored.
     *  @param  pos Index of the value to get (0..vm-1)
     *  @return EC_Normal if successful, an error code otherwise
     */
    static OFCondition getFloat64ValueFromElement(const DcmElement& delem, Float64& result, const unsigned long pos);

    /** Get Float64 values from element
     *  @param  delem The element to get the value from
     *  @param  result Reference to variable in which the result should be stored.
     *  @return EC_Normal if successful, an error code otherwise
     */
    static OFCondition getFloat64ValuesFromElement(const DcmElement& delem, OFVector<Float64>& result);

    /** Set a DcmElement's content from Float64 vector
     *  @param  delem DICOM element to be filled
     *  @param  values Vector use as a source for the values
     *  @param  vm Value multiplicity (according to the data dictionary) to be
     *           checked for. (See DcmElement::checkVM() for a list of
     *           valid values.)
     *  @param  check If OFTrue, then it is checked whether number of values
     *          conforms to the value provided by the vm parameter.
     *  @return Dtatus, EC_Normal if successful, an error code otherwise
     */
    static OFCondition setFloat64ValuesOnElement(DcmElement& delem,
                                                 const OFVector<Float64>& values,
                                                 const OFString& vm,
                                                 const OFBool check);

    /** Get Float32 value from element
     *  @param  delem The element whose value should be retrieved
     *  @param  result Reference to variable in which the result should be stored.
     *  @param  pos Index of the value to get (0..vm-1)
     *  @return EC_Normal if successful, an error code otherwise
     */
    static OFCondition getFloat32ValueFromElement(const DcmElement& delem, Float32& result, const unsigned long pos);

    /** Set a DcmElement's content from Float32 vector
     *  @param  delem DICOM element to be filled
     *  @param  values Vector use as a source for the values
     *  @param  vm Value multiplicity (according to the data dictionary) to be
     *           checked for. (See DcmElement::checkVM() for a list of
     *           valid values.)
     *  @param  check If OFTrue, then it is checked whether number of values
     *          conforms to the value provided by the vm parameter.
     *  @return Dtatus, EC_Normal if successful, an error code otherwise
     */
    static OFCondition setFloat32ValuesOnElement(DcmElement& delem,
                                                 const OFVector<Float32>& values,
                                                 const OFString& vm,
                                                 const OFBool check);

    /** Set a DcmElement's content from Uint16 vector
     *  @param  delem DICOM element to be filled
     *  @param  values Vector use as a source for the values
     *  @param  vm Value multiplicity (according to the data dictionary) to be
     *           checked for. (See DcmElement::checkVM() for a list of
     *           valid values.)
     *  @param  check If OFTrue, then it is checked whether number of values
     *          conforms to the value provided by the vm parameter.
     *  @return Dtatus, EC_Normal if successful, an error code otherwise
     */
    static OFCondition
    setUint16ValuesOnElement(DcmElement& delem, const OFVector<Uint16>& values, const OFString& vm, const OFBool check);

    /** Get Uint16 values from DcmElement
     *  @param  delem  DICOM element to read from
     *  @param  values Vector used as destination for the values
     *  @return Status EC_Normal if successful, an error code otherwise
     */
    static OFCondition getUint16ValuesFromElement(DcmElement& delem, OFVector<Uint16>& values);

    /** Returns single item from given sequence. Returns error number of items
     *  is 0 or more than 1.
     *  @param  seq Sequence to read from.
     *  @param  item The resulting item, NULL in case of error
     *  @param  checkKey If given it is checked whether the given seq parameter
     *          matches the tag key provided in the checkKey parameter. If
     *          not, an error is returned.
     *  @return Status EC_Normal if successful, an error code otherwise
     */
    static OFCondition
    getAndCheckSingleItem(DcmSequenceOfItems& seq, DcmItem*& item, const DcmTagKey& checkKey = DCM_UndefinedTagKey);

    /** Copies Uint8 values from given element to destination container
     *  (must support push_back() method).
     *  @param elem the element to read from. If NULL, an error is returned.
     *  @param destination the container to store the Uint8 values to
     *  @return EC_Normal if successful, an error code otherwise
     */
    template <class Container>
    static OFCondition copyFromUint8Array(DcmElement* elem, Container& destination)
    {
        if (elem == NULL)
            return EC_IllegalParameter;

        size_t numValues = elem->getNumberOfValues();
        OFCondition result;
        for (size_t count = 0; (count < numValues) && result.good(); count++)
        {
            Uint8 value;
            result = elem->getUint8(value, OFstatic_cast(unsigned long, count));
            if (result.good())
            {
                destination.push_back(value);
            }
        }
        if (result.bad())
        {
            destination.clear();
        }
        return result;
    }

    /** Check whether SOP class UID matches the expected value
     *  @param  item Item to read from. NULL value causes error return value.
     *  @param  desiredSOPClass The value that is expected
     *  @param  valueFound The value actually found (empty if no value could
     *          be retrieved)
     *  @return EC_Normal if value could be found and equals expected value,
     *          EC_TagNotFound if SOP Class UID is not found in dataset,
     *          EC_InvalidValue if SOP class differs from expected value.
     */
    static OFCondition checkSOPClass(DcmItem* item, const OFString& desiredSOPClass, OFString& valueFound);

    /** Check whether given tag is a sequence tag
     *  @param  key the tag key to be checked
     *  @param  privateCreator The private creator to check for if tag is private
     *  @return OFTrue if given tag is a sequence tag, OFFalse otherwise
     */
    static OFBool isSequenceTag(const DcmTagKey& key, const OFString& privateCreator = "");

    /** Reads items from DICOM sequence into container by creating a dedicated
     *  container item for each DICOM item. The container must support
     *  push_back(T) function and the container's element type T must support
     *  the read(DcmItem*) function.
     *  @param  source The source sequence to read items from
     *  @param  seqKey The sequence's tag key that is expected
     *  @param  destination The destination container to read into
     *  @param  cardinality Expected number of items.
     *          See DcmElement::checkVM() for a list of valid values.
     *  @param  type The sequence type as noted in part 3 of the DICOM standard,
     *          i.e.\ "1,1C,2,2C or 3".
     *  @param  module Name of the module/macro this sequence is contained in. Used
     *          for error messages and can also be left empty.
     *  @return EC_Normal if successful, an error code otherwise
     */
    template <class Container>
    static OFCondition readSubSequence(DcmSequenceOfItems* source,
                                       const DcmTagKey& seqKey,
                                       Container& destination,
                                       const OFString& cardinality,
                                       const OFString& type,
                                       const OFString& module)
    {
        OFCondition result;
        OFCondition exists = EC_Normal;
        if (!source)
            exists = EC_TagNotFound;

        /* Check sequence and report errors as warnings, read anyway */
        checkElementValue(source, seqKey, cardinality, type, exists, module.c_str());
        if (source)
        {
            DcmItem* item = OFstatic_cast(DcmItem*, source->nextInContainer(NULL));
            size_t count  = 0;
            while (item != NULL)
            {
                if (item != NULL)
                {
                    // define the element type
                    typedef typename OFremove_pointer<typename Container::value_type>::type Element;
                    Element* newElem = new Element();
                    // read into container item (clears old data first)
                    if (newElem != NULL)
                    {
                        result = (newElem)->read(*item, OFFalse /* no need to delete anything */);
                        if (result.good())
                        {
                            destination.push_back(newElem);
                        }
                        else
                        {
                            delete newElem;
                            DCMIOD_WARN("Could not read item #" << count << " from "
                                                                << DcmTag(source->getTag()).getTagName()
                                                                << " (skipping item): " << result.text());
                        }
                    }
                    else
                    {
                        DCMIOD_ERROR("Could not store data from item #" << count << " from "
                                                                        << DcmTag(source->getTag()).getTagName()
                                                                        << " (skipping item): Memory exhausted?");
                    }
                }
                else
                {
                    DCMIOD_WARN("Could not get item #" << count << " from " << DcmTag(source->getTag()).getTagName()
                                                       << " (malformed data or internal error), skipping item");
                }
                item = OFstatic_cast(DcmItem*, source->nextInContainer(item));
                count++;
            }
        }
        else
        {
            result = EC_IllegalParameter;
        }
        return result;
    }

    /** Reads DICOM sequence into container by creating a dedicated container element
     *  for each DICOM item. The container must support push_back(T) function
     *  and the container's element type T must support the read(DcmItem*) function.
     *  @param  source The source DICOM item read the sequence from
     *  @param  seqKey The tag key of the sequence to be read
     *  @param  destination The destination container to read into
     *  @param  cardinality Expected number of items.
     *          See DcmElement::checkVM() for a list of valid values.
     *  @param  type The sequence type as noted in part 3 of the DICOM standard,
     *          i.e.\ "1,1C,2,2C or 3".
     *  @param  module Name of the module/macro this sequence is contained in. Used
     *          for error messages and can also be left empty.
     *  @return status EC_Normal if successful, an error code otherwise
     */
    template <class Container>
    static OFCondition readSubSequence(DcmItem& source,
                                       const DcmTagKey& seqKey,
                                       Container& destination,
                                       const OFString& cardinality,
                                       const OFString& type,
                                       const OFString& module)
    {
        OFCondition result;
        DcmSequenceOfItems* seq = NULL;

        /* Get sequence and read it */
        source.findAndGetSequence(seqKey, seq);
        result = readSubSequence(seq, seqKey, destination, cardinality, type, module);
        return result;
    }

    /** Reads DICOM sequence into container by creating a dedicated container
     *  element for each DICOM item. The container must support the
     *  push_back(T) function and the container's element type T must support
     *  the read(DcmItem*) function.
     *  @param  source The source DICOM item read the sequence from
     *  @param  seqKey The tag key of the sequence to be read
     *  @param  destination The destination container to read into
     *  @param  rule The rule for reading this sequence. If NULL, an error is returned.
     *  @return EC_Normal if successful, an error code otherwise
     */
    template <class Container>
    static OFCondition readSubSequence(DcmItem& source, const DcmTagKey& seqKey, Container& destination, IODRule* rule)
    {
        if (rule == NULL)
        {
            DCMIOD_ERROR("Cannot read sequence " << seqKey << " (no rule supplied)");
            return IOD_EC_NoSuchRule;
        }
        return readSubSequence<Container>(
            source, seqKey, destination, rule->getVM(), rule->getType(), rule->getModule());
    }

    /** Reads single DICOM item from a specific sequence into a destination class.
     *  The container must support the read(DcmItem) function. If a single item
     *  (i.e.\ the first item of the specified sequence) cannot be read, an error
     *  is returned.
     *  @param  source The source DICOM item read the sequence from
     *  @param  seqKey The tag key of the sequence to be read
     *  @param  destination The destination container to read into
     *  @param  type The sequence type as noted in part 3 of the DICOM standard,
     *          i.e.\ "1,1C,2,2C or 3".
     *  @param  module Name of the module/macro this sequence is contained in.
     *          Used for error messages and can also be left empty.
     *  @return EC_Normal if successful, an error code otherwise
     */
    template <class Container>
    static OFCondition readSingleItem(
        DcmItem& source, const DcmTagKey& seqKey, Container& destination, const OFString& type, const OFString& module)
    {
        OFCondition result;
        /* Check sequence, reports cardinality and type errors as warnings */
        checkSubSequence(result, source, seqKey, "1", type, module, dcmtk::log4cplus::WARN_LOG_LEVEL);

        /* Try to read sequence into internal data (ignore errors as much as possible) */
        DcmItem* item = NULL;
        result        = source.findAndGetSequenceItem(seqKey, item, 0);
        if (item != NULL)
        {
            // read into Container (clears old data first)
            result = destination.read(*item, OFTrue /* clear old data */);
        }
        return result;
    }

    /** Reads single DICOM item from a specific sequence into a destination class.
     *  The container must support the read(DcmItem) function. If a single item
     *  (i.e.\ the first item of the specified sequence) cannot be read, an error
     *  is returned.
     *  @param  source The source DICOM item read the sequence from
     *  @param  seqKey The tag key of the sequence to be read
     *  @param  destination The destination container to read into
     *  @param  rule The rule (for the sequence) used for reading.
     *  @return EC_Normal if successful, an error code otherwise.  If the rule
     *          equlas NULL, then nothing is read at all and an error is returned
     *          (IOD_EC_NoSuchRule), but no error is reported to the logger.
     */
    template <class Container>
    static OFCondition
    readSingleItem(DcmItem& source, const DcmTagKey& seqKey, Container& destination, IODRule* rule = NULL)
    {
        if (rule == NULL)
        {
            DCMIOD_DEBUG("Will not read sequence " << seqKey << ": No rule supplied");
            return IOD_EC_NoSuchRule;
        }

        return readSingleItem(source, seqKey, destination, rule->getType(), rule->getModule());
    }

    /** Write given container into a DICOM sequence that is created within the
     *  given item. The sequence is created from scratch, i.e.\ any old sequence
     *  (and its items) will be overwritten.
     *  @param  result If writing is successful, result will contain EC_Normal.
     *          Otherwise an error code is set.
     *  @param  seqKey The tag key of the sequence to be write
     *  @param  source The source container to read from. Must support the
     *          write(DcmItem*) function.
     *  @param  destination The DICOM destination item to write the sequence to
     *  @param  cardinality  Expected number of items (i.e.\ expected number of
     *          elements in source container). See DcmElement::checkVM() for a
     *          list of valid values.
     *  @param  type The sequence type as noted in part 3 of the DICOM standard,
     *          i.e.\ "1,1C,2,2C or 3".
     *  @param  module Name of the module/macro this sequence is contained in. Used
     *                 for error messages and can also be left empty.
     */
    template <class Container>
    static void writeSubSequence(OFCondition& result,
                                 const DcmTagKey& seqKey,
                                 Container& source,
                                 DcmItem& destination,
                                 const OFString& cardinality,
                                 const OFString& type,
                                 const OFString& module)
    {
        if (result.good())
        {
            // Delete old data
            destination.findAndDeleteElement(seqKey);

            // If we have meaningful data, write it
            OFBool haveData = source.size() > 0;
            if (haveData)
            {
                destination.insertEmptyElement(seqKey);
                Uint32 count                    = 0;
                typename Container::iterator it = source.begin();
                while (it != source.end() && result.good())
                {
                    if ((*it) != NULL)
                    {
                        DcmItem* localItem = NULL;
                        // If item is NULL result.bad() is always true.
                        result = destination.findOrCreateSequenceItem(seqKey, localItem, -2 /* append new */);
                        if (result.good())
                        {
                            result = (*it)->write(*localItem);
                            if (result.bad())
                            {
                                destination.findAndDeleteSequenceItem(seqKey, -1 /* last */);
                                DCMIOD_ERROR("Could not write item #" << count << " in " << DcmTag(seqKey).getTagName()
                                                                      << ": " << result.text());
                            }
                        }
                        else
                        {
                            DCMIOD_ERROR("Could not insert item data #" << count << " of "
                                                                        << DcmTag(seqKey).getTagName()
                                                                        << " (internal error), ignoring");
                        }
                    }
                    else
                    {
                        DCMIOD_ERROR("Found uninitialized container item (NULL value) for sequence "
                                     << DcmTag(seqKey).getTagName() << " (internal error, skipping)");
                    }
                    count++;
                    it++;
                }
            }
            // If we do not have data, create empty sequence if type 2
            else if (type == "2")
            {
                destination.insertEmptyElement(seqKey);
            }

            // Check result
            checkSubSequence(result, destination, seqKey, cardinality, type, module, dcmtk::log4cplus::ERROR_LOG_LEVEL);

            // Clean up if we did not have success */
            if (result.bad())
            {
                destination.findAndDeleteElement(seqKey);
            }
        }
    }

    /** Write given container into a DICOM sequence that is created within the given item.
     *  The container. The sequence is created from scratch, i.e.\ any old sequence
     *  (and its items) will be overwritten.
     *  @param  result If writing is successful, result will contain EC_Normal. Otherwise
     *          an error code is set.
     *  @param  seqKey The tag key of the sequence to be write
     *  @param  source The source container to read from. Must support the write(DcmItem*)
     *          function.
     *  @param  destination The DICOM destination item to write the sequence to
     *  @param  rule Rule describing the requirements for this sequence. If NULL
     *          an error is returned (IOD_EC_NoSuchRule), but no error error is reported
     *          to the logger.
     */
    template <class Container>
    static void writeSubSequence(
        OFCondition& result, const DcmTagKey& seqKey, Container& source, DcmItem& destination, IODRule* rule)
    {
        if (result.good())
        {
            if (rule == NULL)
            {
                DCMIOD_DEBUG("Will not write sequence " << seqKey << ": No rule supplied");
                result = IOD_EC_NoSuchRule;
            }
            else
            {
                writeSubSequence<Container>(
                    result, rule->getTagKey(), source, destination, rule->getVM(), rule->getType(), rule->getModule());
            }
        }
    }

    /** Writes given container into a DICOM item of a specific sequence. The
     *  sequence is created from scratch so that any old information will be lost.
     *  @param  result If writing is successful, result will contain EC_Normal.
     *          Otherwise an error code is set.
     *  @param  seqKey The tag key of the sequence to be written
     *  @param  source The source container to read from. Must support the write(DcmItem*)
     *          function.
     *  @param  destination The DICOM item that should hold the sequence
     *          (with a single item) in the end.
     *  @param  type The sequence type as noted in part 3 of the DICOM standard,
     *          i.e.\ "1,1C,2,2C or 3".
     *  @param  module Name of the module/macro this sequence is contained in.
     *          Used for error messages and can also be left empty.
     */
    template <class Container>
    static void writeSingleItem(OFCondition& result,
                                const DcmTagKey& seqKey,
                                Container& source,
                                DcmItem& destination,
                                const OFString& type,
                                const OFString& module)
    {
        if (result.good())
        {
            // Delete old data
            destination.findAndDeleteElement(seqKey);

            /* If we have data, write it */
            OFCondition haveData = source.check(OFTrue /* Be quiet */);
            if (haveData.good())
            {
                DcmItem* localItem = NULL;
                // If item is NULL result.bad() is always true.
                result = destination.findOrCreateSequenceItem(seqKey, localItem, 0);
                if (result.good())
                {
                    result = source.write(*localItem);
                    // It can happen that check() returns OK but no elements have to be
                    // written at all (e.g.\ if it contains only type 3 attributes). In that
                    // case a sequence with a single empty item is written which must be removed
                    // afterwards.
                    if (result.good() && (localItem->card() == 0))
                    {
                        destination.findAndDeleteElement(seqKey);
                    }
                }
            }
            /* If we do not have data, insert empty for type 2 */
            else if (type == "2")
            {
                destination.insertEmptyElement(seqKey);
            }
            else if (type == "1C")
            {
                DCMIOD_TRACE("Skipping type 1C sequence " << seqKey << ": No data or incomplete data available");
            }
            else if (type == "3")
            {
                DCMIOD_TRACE("Skipping type 3 sequence " << seqKey << ": No data or incomplete data available");
            }
            /* Check outcome */
            checkSubSequence(result, destination, seqKey, "1", type, module, dcmtk::log4cplus::ERROR_LOG_LEVEL);
        }
    }

    /** Writes given container into a DICOM item of a specific sequence.
     *  The sequence is created from scratch so that any old information
     *  will be lost.
     *  @param  result If writing is successful, result will contain EC_Normal.
     *          Otherwise an error code is set.
     *  @param  seqKey The tag key of the sequence to be written
     *  @param  source The source container to read from. Must support the
     *          write(DcmItem*) function.
     *  @param  destination The DICOM item that should hold the sequence
     *          (with a single item) in the end.
     *  @param  rule The rule for writing the given sequence
     */
    template <class Container>
    static void writeSingleItem(
        OFCondition& result, const DcmTagKey& seqKey, Container& source, DcmItem& destination, IODRule* rule)
    {
        if (result.good())
        {
            if (rule == NULL)
            {
                DCMIOD_ERROR("Cannot write sequence " << seqKey << " (no rule supplied)");
                result = EC_CannotCheck;
            }
            else
            {
                writeSingleItem(result, seqKey, source, destination, rule->getType(), rule->getModule());
            }
        }
    }

    /** Check whether a given sequence exists in a given item and whether it conforms to
     *  to its requirement type
     *  @param  result If sequence is valid, result is set to EC_Normal, otherwise
     *          to an error.
     *  @param  surroundingItem The item that should contain the given sequence.
     *  @param  seqKey The sequence to look for
     *  @param  cardinality Expected number of items (i.e.\ expected number of
     *          elements in source container). See DcmElement::checkVM() for a
     *          list of valid values.
     *  @param  type The sequence type as noted in part 3 of the DICOM standard,
     *          i.e.\ "1,1C,2,2C or 3".
     *  @param  module Name of the module/macro this sequence is contained in.
     *          Used for error messages and can also be left empty.
     *  @param  logLevel The log level to write errors to
     */
    static void checkSubSequence(OFCondition& result,
                                 DcmItem& surroundingItem,
                                 const DcmTagKey& seqKey,
                                 const OFString& cardinality,
                                 const OFString& type,
                                 const OFString& module,
                                 const dcmtk::log4cplus::LogLevel logLevel);

    /** Deletes all elements from given container and calls "delete" on each
     *  of them to clear memory.
     *  @param container  The container that should be cleared. Must contain
     *         pointers to objects that are allocated on the heap.
     */
    template <class Container>
    static void freeContainer(Container& container)
    {
        typename Container::iterator it = container.begin();
        while (it != container.end())
        {
            delete *it;
            it++;
        }
        container.clear();
    }

    /** Clones and copies all elements from source to destination container by
     *  copy constructing all elements.
     *  If copying fails (because memory is exhausted), EC_MemoryExhausted is returned
     *  and the destination container is returned empty, i.e. all temporary copies
     *  of its elements are freed and removed from the container.
     *  @param  src  The container that should be copied. Must contain pointers
     *          to objects that are allocated on the heap, and that are
     *          copy-constructible
     *  @param  dst  The container to copy the cloned elements to.
     *  @return EC_Normal if successful, error otherwise
     */
    template <class Container>
    static OFCondition copyContainer(const Container& src, Container& dst)
    {
        typedef typename OFremove_pointer<typename Container::value_type>::type Element;
        typename Container::const_iterator it = src.begin();
        while (it != src.end())
        {
            if (*it != NULL)
            {
                Element* elem = new Element(**it);
                if (elem == NULL)
                {
                    freeContainer(dst);
                    return EC_MemoryExhausted;
                }
                dst.push_back(elem);
            }
            else
            {
                DCMIOD_ERROR("Could not copy element while copying container: Element in source is NULL, skipping");
            }
            it++;
        }
        return EC_Normal;
    }

    /** Compares all elements in source and destination container by
     *  using their respective compare(const Container& rhs) method.
     *  If the number or elements in the Containers are different, the
     *  containers are not considered equal.
     *  @param src  The first container
     *  @param dst  The second container
     *  @return Zero if containers are equal, other number otherwise
     */
    template <class Container>
    static int compareContainer(const Container& src, const Container& dst)
    {
        size_t card = src.size();
        if (card != dst.size())
            return -1;
        typename Container::const_iterator it  = src.begin();
        typename Container::const_iterator it2 = dst.begin();
        while (it != src.end())
        {
            if ((*it)->compare(**it2) != 0)
                return 1;
            it++;
            it2++;
        }
        return 0;
    }

    template <typename ModuleType>
    static OFCondition setContentDateAndTimeNow(ModuleType& module)
    {
        OFDate date;
        date.setCurrentDate();
        OFString tempstr;
        date.getISOFormattedDate(tempstr, OFFalse /* no delimiters */);
        OFCondition result = module.setContentDate(tempstr);
        if (result.good())
        {
            OFTime time;
            time.setCurrentTime();
            time.getISOFormattedTime(tempstr, OFTrue /* include seconds */, OFFalse, OFFalse, OFFalse);
            result = module.setContentTime(tempstr);
        }
        return result;
    }

    /** Function that takes a string representation of a tag key and
     *  converts it to a tag key instance if possible
     *  @param  keyString String of the format "(gggg,eeee)"
     *  @return The tag key if it could be parsed, DCM_UndefinedTagKey is returned
     *          instead (0xffff,0xffff)
     */
    static const DcmTagKey parseTagKey(const OFString& keyString);

    /** Decompress given dataset if possible. Decompression codecs have to be
     *  registered beforehand.
     *  @param  dset The dataset to decompress
     *  @return EC_Normal if decompression works, error otherwise
     */
    static OFCondition decompress(DcmDataset& dset);

    /** Create new Unique Identifier (UID)
     *  @param  level 0: instance level, 1: Series level, >=2: Study level.
     *          Calling always with level=0 is not an error but will result
     *          in unique values, too.
     *  @return The UID created.
     */
    static OFString createUID(const Uint8 level = 0);

    /** Print warning if more than 2147483647 frames are present. This is the maximum
     *  number since the Number of Frames attribute has a VR of IS which allows
     *  a maximum of 2^31-1.
     *  The method returns the number of frames that can be used, i.e. either
     *  2147483647 if the maximum is exceeded, otherwise the actual number
     *  of frames.
     *  @param  numFramesPresent The number of frames actually present
     *  @param  warning The message to be printed if Number of Frames
     *          is larger than 2147483647.
     *  @return Number of frames that can be safely used.
     */
    static Uint32 limitMaxFrames(const size_t numFramesPresent, const OFString& warning);

    /** Extracts Frame structures from the given pixel data element. Only
     *  applicable for pixel data with Bits Allocated = 1. Within the pixel data element,
     *  all frames are packed next to each other, with the end of one frame and the
     *  beginning of the next frame packed bit by bit next to each other (right to left!).
     *  The resulting Frames are a bit-by-bit copy of their original counterpart.
     *  However, their first bit is aligned to the first bit/byte in the Frame,
     *  and the unused bits in the last byte (if any) are zeroed out.
     *  @param  pixData The pixel data to read from
     *  @param  numFrames The number of frames to read
     *  @param  bitsPerFrame The number of bits per frame (usually rows * columns)
     *  @param  results The resulting frames. Memory for the frames is allocated
     *          by the method, so the Vector can/should be empty before calling.
     *  @result Return EC_Normal on success, error otherwise
     */
    static OFCondition extractBinaryFrames(Uint8* pixData,
                                           const size_t numFrames,
                                           const size_t bitsPerFrame,
                                           OFVector<DcmIODTypes::Frame*>& results);

    /** Resets the given condition to EC_Normal if checkValue is true and
     *  prints a related message as a warning to the debug logger.
     *  @param  result The condition to check. Only EC_ValueRepresentationViolated, EC_MaximumLengthViolated,
     *          EC_InvalidCharacter and EC_ValueMultiplicityViolated are handled. Those codes
     *          are reset to EC_Normal if the checkValue is OFFalse.
     *  @param  checkValue If this value is false, the condition is reset to EC_Normal
     *  @param  elem Used if the condition is reset to EC_Normal to print a warning
     */
    static void resetConditionIfCheckDisabled(OFCondition& result, const OFBool checkValue, DcmElement& elem);

private:
    // We only have static functions so we do not need an instance of
    // this class so far.

    /** Undefined default constructor (only static functions)
     */
    DcmIODUtil();

    /** Undefined destructor
     */
    ~DcmIODUtil();
};

#endif // IODUTIL_H
